JP6503708B2 - Optical film and image display device - Google Patents

Description

  The present invention relates to an optical film that controls light emitted from a light source and emits the light to an observer, and an image display apparatus including the optical film.

  In an image display apparatus that emits an image to an observer, such as a liquid crystal display, rear projection, organic EL, FED, etc., the image source and the quality of image light from the image source are enhanced and emitted to the observer An optical film comprising a plurality of layers having various functions is provided.

  For example, Patent Document 1 is disclosed as such an optical film. The optical film described in Patent Document 1 includes an optical function sheet layer having a prism portion arranged along a sheet surface so as to transmit light and a light absorbing portion arranged so as to absorb light between the prism portions. Is equipped. Thus, the quality of the image light is enhanced by reflecting and absorbing the image light and the outside light.

  Furthermore, a rough surface forming layer is provided on the optical film described in Patent Document 1, and it is possible to make the image light less likely to be uneven even in an atmosphere of high temperature, high temperature and high humidity.

JP, 2010-107660, A

However, even when the optical film described in Patent Document 1 is used, when the image display apparatus is disposed in an environment requiring durability such as in-vehicle, the optical film may be warped. Therefore, measures were often taken to prevent warpage with a plurality of base material layers by further using an additional base material layer that has stiffness and can prevent deformation, but there are problems with the thickness and cost of the optical film It has happened.
Further, in an environment requiring thermal durability, such as in a car, etc., so-called optical adhesion may be a problem, and appearance problems due to the generation of interference fringes may also be generated.

  Therefore, in view of the above problems, it is an object of the present invention to provide an optical film in which problems due to warpage or optical adhesion hardly occur even in an environment of high temperature, high temperature and high humidity, such as in a vehicle. Also, an image source unit and an image display device provided with the optical film are provided.

  Hereinafter, the present invention will be described. In addition, in order to make an understanding of this invention easy, the referential mark of an accompanying drawing is added in parentheses, but thereby, this invention is not limited to the form of illustration.

The invention according to claim 1 is an optical film (20) having a plurality of layers, which is laminated on one surface of a substrate layer (28) and a substrate layer, and is capable of transmitting light. And a plurality of light transmitting portions (23) arranged along the layer surface of the layer, and an interface between the light transmitting portions disposed between adjacent light transmitting portions and having a refractive index lower than that of the light transmitting portions and absorbing light 15 μm or more and 25 μm or less laminated on the optical functional layer (22) having the light absorbing portion (24) which is made possible, and the surface of the optical functional layer opposite to the side on which the base material layer is laminated The surface roughening layer has a rough surface formed on the surface opposite to the optical functional layer, and the surface roughness of the rough surface is Ra of 0. An optical material having a cross-link density of 320 to 740, which is 1 μm to 0.2 μm and the material forming the rough surface forming layer is a resin To solve the problems by Irumu.

  In the invention according to claim 2, in the optical film (20) according to claim 1, the base material layer (28) is made of polycarbonate.

  The invention according to claim 3 comprises a surface light source device (11), a liquid crystal panel (12), and the optical film (20) according to claim 1 or 2, wherein the optical film is a surface light source device and a liquid crystal It is an image source unit disposed between the panel.

  The invention according to claim 4 is a video display device (1) comprising a housing (2) and the video source unit (5) according to claim 3, which is disposed inside the housing.

  According to the present invention, even when used in an environment where durability is required such as in a car, it is possible to make it difficult to cause problems in the warping and the optical adhesion of the optical film.

FIG. 1 is an external perspective view of an image display device 1; FIG. 5 is an exploded perspective view of the image source unit 5; FIG. 2 is a cross-sectional view of a video source unit 5; FIG. 5 is an enlarged view focusing on the rough surface forming layer 21 and the optical function layer 22;

  The present invention will be described below based on the embodiments shown in the drawings. However, the present invention is not limited to the embodiment. Here, many of the elements included in the present invention are actually very fine and thin layers, and for ease of understanding, in each drawing, a part thereof is shown by being deformed or enlarged. The elements are denoted by reference numerals, but some of the reference numerals to be repeated may be omitted for the sake of easy viewing.

FIG. 1 is a view for explaining one mode, and is a perspective view showing an image display apparatus 1 provided with an image source unit 5. In FIG. 1, the right side of the drawing is the observer side. Here, in the present embodiment, the video display device 1 is a car-mounted video display device, and for example, a car navigation device and the like are included therein. The video display device 1 includes a housing 2, and the video source unit 5 is incorporated inside the housing 2.
The housing 2 is a member which forms an outer shell of the video display device 1 and accommodates most of the members constituting the video display device inside thereof. The housing 2 has an opening, through which the so-called screen portion of the image source unit 5 is exposed for visual recognition. In addition, the video display device 1 is provided with various known components for functioning as a video display device.

  FIG. 2 is an exploded perspective view of the image source unit 5. Although FIG. 2 illustrates a part of the layers constituting the image source unit in isolation for the sake of easy understanding, in actuality, the layers are stacked directly and so on (see FIG. 3). FIG. 3 is a cross-sectional view in the thickness direction including the line (line in the vertical direction) indicated by III-III in FIG. Also, when the image source unit 5 is disposed in the image display device 1, the right side of the drawing of FIGS. 2 and 3 is the viewer side, and the left side of the drawing of FIGS. 2 and 3 is the light source side (surface light source device side) It becomes.

  The image source unit 5 is configured to include an image source 10 and a functional layer 30 disposed on the image output side (that is, the viewer side) of the image source 10.

  In the present embodiment, the liquid crystal panel 12 is included as the image source 10. Specifically, the image source 10 includes the surface light source device 11, the optical film 20, and the liquid crystal panel 12. That is, in the present embodiment, the optical film 20 is disposed between the surface light source device 11 and the liquid crystal panel 12.

Here, the surface light source device 11 and the liquid crystal panel 12 can have a known structure.
For example, in the case of the surface light source device 11, a reflective sheet, a light guide plate (a light source is disposed on the side surface), and diffusion from the light source side (left in FIG. 3) to the viewer (right in FIG. 3). Examples include a surface light source device in which a sheet, a lens sheet, and a reflective polarizing sheet are stacked in this order.
On the other hand, for the liquid crystal panel 12, a polarizing filter, a glass substrate, a liquid crystal layer, a glass substrate, and a polarizing filter are laminated in this order from the light source side (left in FIG. 3) to the viewer (right in FIG. 3). Liquid crystal panels can be mentioned.

  The optical film 20 is a film disposed on the light emission side of the surface light source device 11 between the surface light source device 11 and the liquid crystal panel 12 and is composed of a plurality of layers. In the present embodiment, the optical film 20 includes the rough surface forming layer 21, the optical functional layer 22, and the base material layer 28 from the side of the surface light source device 11. Each layer will be described below. Here, for the sake of convenience, the substrate layer 28, the optical function layer 22, and the roughened surface layer 21 will be described in this order.

The base material layer 28 is a layer which becomes a base material which forms the optical function layer 22 in one side. The base material layer 28 has translucency and supports the optical function layer 22 so as to prevent its deformation. From this point of view, specific examples of the material constituting the base material layer 28 include, for example, acrylic, styrene, polycarbonate, polyethylene terephthalate (PET), acrylonitrile, a transparent resin having triacetyl cellulose (TAC) as a main component, epoxy acrylate, A urethane acrylate reactive resin (ionizing radiation curable resin etc.) can be mentioned.
Among them, it is preferable to use TAC, methacrylic resin, and polycarbonate having small birefringence in consideration of the combination with the liquid crystal panel. Furthermore, it is desirable to use a polycarbonate having a high glass transition temperature in applications where high heat resistance is required, such as in a car. Specifically, the glass transition point of polycarbonate is 143 ° C., and in general, it is suitable for automotive applications where durability at 105 ° C. is required.

  The thickness of the base material layer 28 is not particularly limited, but is preferably 25 μm or more and 300 μm or less. If the thickness of the base material layer 28 is out of this range, there is a possibility that a problem may occur in processability. For example, when the substrate layer 28 is thinner than 25 μm, wrinkles tend to occur. Moreover, when the base material layer 28 becomes thicker than 300 micrometers, winding-up of the optical film 20 will become difficult.

  In the present embodiment, the optical function layer 22 changes the light direction to the front direction so that the image light emitted from the image source 10 is not reflected on the windshield of the car, and has a function of absorbing some light and external light. Have. In FIG. 4, the optical function layer 22 and the roughened layer 21 in FIG.

  The optical function layer 22 has a cross section shown in FIG. 3 and FIG. 4 and has a shape extending in the back / front direction of the paper surface with respect to the paper surface. In the present embodiment, in the posture in which the image display device 1 is installed in a car, the extending direction is the horizontal direction. This prevents the image light from being transferred to the windshield as described later.

  The optical function layer 22 has a substantially trapezoidal light transmitting portion 23 and a light absorbing portion 24 having a substantially trapezoidal cross section formed between two adjacent light transmitting portions 23 in the cross section shown in FIGS. 3 and 4. And. Therefore, in the present embodiment, in the posture in which the image display device 1 is installed in a car, the light transmitting portions 23 and the light absorbing portions 24 are alternately arranged in the vertical direction.

  The light transmitting portion 23 is a portion whose main function is to transmit light, and in the present embodiment, in the cross section shown in FIG. 3 and FIG. It has a substantially trapezoidal shape having a short upper bottom on the formation layer 21 side (surface light source device 11 side). The light transmitting portions 23 extend along the layer surface of the base layer 28 while maintaining the cross section, and are arranged at predetermined intervals in a direction different from the extending direction. And between the light transmission parts 23 which adjoin, the space | interval which has a substantially trapezoidal cross section is formed. Accordingly, the space has a long lower base on the upper bottom side of the light transmitting portion 23 and a trapezoidal cross section having a short upper base on the lower base side of the light transmitting portion 23, and the necessary material described later is filled here As a result, the light absorbing portion 24 is formed. In the present embodiment, the light transmission parts 23 adjacent to each other are connected at a long lower bottom side.

  The light transmitting portion 23 has a refractive index Nt. Such a light transmission part 23 can be formed by curing the transmission part composition. Details will be described later. The value of the refractive index Nt is not particularly limited, but as described later, the refractive index is 1.55 or more from the viewpoint of appropriately totally reflecting light at the interface with the light absorbing portion 24 in the slope of the trapezoidal cross section. Is preferred. However, since the material having an excessively high refractive index is often easily broken, the refractive index is preferably 1.61 or less. More preferably, it is 1.56 or less.

  The light absorbing portion 24 is disposed at the above-described interval formed between the adjacent light transmitting portions 23 and has a cross-sectional shape similar to that of the interval. Therefore, the short upper base faces the substrate layer 28 side (observer side), and the long lower base faces the rough surface forming layer 21 side (surface light source device 11 side). The light absorbing portion 24 has a refractive index Nr and is configured to be able to absorb light. Specifically, light absorbing particles are dispersed in a binder having a refractive index of Nr. It is preferable that the refractive index Nr be a refractive index lower than the refractive index Nt of the light transmitting portion 23. By making the refractive index of the light absorbing portion 24 smaller than the refractive index of the light transmitting portion 23, light incident on the light transmitting portion 23 under a predetermined condition can be totally reflected at the interface with the light absorbing portion 24. The value of the refractive index Nr is not particularly limited, but is preferably 1.50 or less from the viewpoint of appropriately performing the total reflection, and among them, 1.47 or more is preferable from the viewpoint of availability. More preferably, it is 1.49 or more.

  The difference in refractive index between the refractive index Nt of the light transmitting portion 23 and the refractive index Nr of the light absorbing portion 24 is not particularly limited, but is preferably 0.05 or more and 0.14 or less. By increasing the refractive index difference, more light can be totally reflected.

  The optical function layer 22 is not particularly limited. For example, the light transmitting portion 23 and the light absorbing portion 24 are formed as follows. That is, it is preferable that the pitch of the light transmission part 23 represented by Pk in FIG. 3 and the light absorption part 24 is 20 micrometers or more and 100 micrometers or less. In addition, the angle between the interface on the oblique side of the light absorbing portion 24 and the light transmitting portion 23 shown by θk in FIG. 4 and the normal to the layer surface of the optical function layer 22 is 1 ° or more and 10 ° or less preferable. And it is preferable that the thickness of the light absorption part 24 shown by Dk in FIG. 3 is 50 micrometers or more and 150 micrometers or less. Within these ranges, the balance between light transmission and light absorption is often appropriate.

  In this embodiment, an example is shown in which the interface between the light transmitting portion 23 and the light absorbing portion 24 is in a straight line in the cross section, but the present invention is not limited thereto. It is also good. In addition, the cross-sectional shapes of the plurality of light transmitting portions 23 and the light absorbing portions 24 may be the same, or may be different cross-sectional shapes with predetermined regularity.

  The rough surface forming layer 21 is stacked on the side of the optical function layer 22 opposite to the side on which the base layer 28 is disposed, and the rough surface 21 a is formed on the side not in contact with the optical function layer 22. Is the layer being The roughened layer 21 is configured to have the following features.

  The thickness of the roughened layer 21 (Mt in FIG. 4) is 15 μm or more and 25 μm or less. Here, the thickness of the rough surface forming layer 21 is the distance in the thickness direction between the tip of the rough surface 21a and the layer surface on the side where the rough surface 21a is not formed, as can be seen from Mt shown in FIG. If the thickness is smaller than 15 μm, it is difficult to obtain a dimensional allowance when forming a rough surface, which may cause a manufacturing problem. On the other hand, if the thickness is larger than 25 μm, the optical film 20 is easily warped.

  The surface roughness of the rough surface 21 a of the rough surface forming layer 21 is 0.1 μm or more and 0.2 μm or less as Ra (μm) (arithmetic average roughness according to JIS B 0601 (2001)). When the surface roughness is smaller than 0.1 μm, when the optical film 20 is brought into contact with another layer, the generation of interference fringes due to so-called optical adhesion becomes a problem. On the other hand, if the surface roughness is larger than 0.2 μm, the unevenness based on the roughness is likely to be visually recognized by human eyes, which may cause appearance defects such as scintillation (so-called screen flicker).

Further, in the rough surface forming layer 21, the material constituting the rough surface forming layer 21 is a resin, and the molecular weight between crosslinking (crosslinking density) of the resin is 320 or more and 740 or less. When the molecular weight between crosslinks is smaller than 320, the optical film 20 is easily warped. On the other hand, when the molecular weight between crosslinks is greater than 740, when the optical film 20 is brought into contact with another layer, the generation of interference fringes due to so-called optical adhesion becomes a problem.
Here, the molecular weight between crosslinks can be calculated from the value obtained by dividing the total molecular weight by the number of crosslinking points (total molecular weight / number of crosslinking points).
The overall molecular weight is the sum of the product of the number of moles and the molecular weight determined for each component of the material forming the roughened layer 21 and is the sum of the products determined for each component (((number of moles of each component X Molecular weight of each component)).
With the number of crosslinking points, the number of functional groups -1 is determined for each component of the material forming the rough surface forming layer 21, this is doubled, the product with the molecular weight is determined, and the sum of the products obtained for each component (Σ ((number of functional groups of each component−1) × 2) × molecular weight of each component).

  As a specific material for forming such a rough surface forming layer 21, for example, a urethane acrylate resin containing dipentaerythritol pentaacrylate having five functional groups as a monomer can be mentioned.

  By forming such a roughened layer 21, in the optical film having the optical functional layer and the base material layer, the problem of interference fringes due to warping and optical adhesion even in a high temperature, high temperature, high humidity environment such as vehicle Can be solved. For example, it is possible to simplify the layer configuration without having to sandwich the optical functional layer between two base layers, etc. by using an additional base layer. That is, the base material layer can also be only one layer.

Such an optical film 20 is produced, for example, as follows.
First, the light transmitting portion 23 is formed on one surface of the base layer 28. This inserts the base material sheet used as the base material layer 28 between the die roll which has on the surface the shape which can transfer the shape of the light transmission part 23, and the nip roll arrange | positioned so as to oppose this. And a mold roll and a nip roll are rotated, supplying the composition which comprises a light transmissive part between a base material sheet and a mold roll. Thus, the composition constituting the light transmission part is filled in the groove (shape obtained by inverting the shape of the light transmission part) corresponding to the light transmission part formed on the surface of the mold roll, and the composition is the surface of the mold roll It follows the shape.

  Here, as a composition which comprises a light transmissive part, ionizing-radiation-hardening-type resin, such as an epoxy acrylate type, a urethane acrylate type, a polyether acrylate type, polyester acrylate type, a polythiol type, can be mentioned, for example.

  Light for curing by a light irradiation device is applied from the substrate sheet side to the composition which is sandwiched between the mold roll and the substrate sheet and which constitutes the light transmitting portion filled therein. Thereby, the composition can be cured and its shape can be fixed. Then, the base layer 28 and the formed light transmitting portion 23 are released from the mold roll by the mold release roll.

  Next, the light absorbing portion 24 is formed. In order to form the light absorbing portion 24, first, the space between the light transmitting portions 23 formed as described above is filled with the composition constituting the light absorbing portion. After that, the excess composition is scraped off with a doctor blade or the like. Then, the remaining composition is cured by being irradiated with light for curing the composition from the light transmitting part 23 side to form the light absorbing part 24.

  The material used as the light absorbing portion is not particularly limited, and for example, it is colored in a photocurable resin such as urethane (meth) acrylate, polyester (meth) acrylate, epoxy (meth) acrylate, and butadiene (meth) acrylate. There may be mentioned compositions in which the light absorbing particles are dispersed.

Further, instead of dispersing the light absorbing particles, the entire light absorbing portion can be colored with a pigment or a dye.
In the case of using light absorbing particles, light absorbing colored particles such as carbon black are preferably used, but the present invention is not limited thereto, and may be selected according to the characteristics of light from the surface light source device and image light to be emitted. Colored particles that selectively absorb specific wavelengths may be used. Specific examples thereof include organic fine particles colored with carbon black, graphite, metal salts such as black iron oxide, dyes, pigments and the like, colored glass beads, and the like. In particular, colored organic fine particles are preferably used from the viewpoints of cost, quality and availability. The average particle diameter of the colored particles is preferably 1.0 μm or more and 20 μm or less.

  Furthermore, the composition which comprises the roughening layer 21 is apply | coated to the surface on the opposite side to the side by which the base material layer 28 is arrange | positioned among the optical function layers 22. FIG. Then, the composition is cured by an appropriate method in a state in which the applied material is sandwiched between the roll mold forming the rough surface 21 a and the optical function layer 22. Thereby, the material sandwiched is hardened and the roughened layer 21 is formed.

  The functional layer 30 can be a known layer having various functions disposed closer to the viewer than the liquid crystal panel. Examples thereof include an antireflective layer, an antiglare layer, and a hard coat layer.

  The video source unit 5 having the above configuration can be manufactured, for example, as follows. That is, the manufactured optical film 20 is disposed on the light emission side of the surface light source device 11 so that the rough surface 21 a faces the surface light source device 11, and the liquid crystal panel 12 and the functional layer 30 on the observer side of the optical film 20. Stack up. At this time, the optical film 20 is configured such that the rough surface forming layer 21 is configured as described above, so that warpage is less likely to occur, and the combination with the surface light source device 11 is also easily performed. In addition, when the optical film 20 is stacked on the surface light source device 11, optical contact is prevented by the rough surface 21a, and the generation of interference fringes is also suppressed. As described above, even when high heat resistance and humidity resistance are required by the optical film 20 as in-vehicle use, both the warp and the optical adhesion become good with a thin layer configuration. There is no need to stack a plurality of base layers having stiffness in order to prevent warpage, the layer configuration can be simplified, and the image display apparatus can be thinned.

  The image source unit 5 configured as described above is housed in the housing 2 and arranged so that the functional layer 30 side is the observer side, whereby the image display device 1 can be obtained. At that time, an electric circuit, a power supply circuit and the like for operating the image source unit 5 are also provided as needed.

  Such an image display device is disposed in a car and operates, for example, as follows. It demonstrates, showing an example of an optical path. However, the example of the optical path is a conceptual one for the purpose of explanation, and does not strictly represent reflection, refraction, and the like.

  When the image display apparatus 1 is operated, projection light is emitted from the surface light source device 11 as shown in FIG. The light L10 emitted from the surface light source device 11 passes through the optical film 20 without reaching the interface between the light transmitting portion 23 and the light absorbing portion 24. The liquid crystal panel 12 obtains image information and transmits it, and the functional layer 30 also transmits it. Then, when reaching the observer side, the observer can observe the image light.

  The light L11 emitted from the surface light source device 11 reaches the interface between the light transmitting portion 23 and the light absorbing portion 24 and is totally reflected in relation to the refractive index difference between the two and the incident angle to the interface. , And transmits through the functional layer 30 to the observer side. At this time, since the interface between the light transmitting portion 23 and the light absorbing portion 24 is inclined as described above with respect to the normal to the light exit surface of the optical film 20, the direction of the light L11 is changed downward. . This prevents reflection on the windshield. Further, since the light L11 is directed in the front direction, it also contributes to the improvement of the front luminance of the image light.

  In this example, the above-described optical film was laminated on a light source, and warpage and optical adhesion were examined. Moreover, the optical film of the aspect which is not contained in the optical film demonstrated above as a comparative example was also produced, and evaluated similarly.

Example 1
The optical film of Example 1 (100 mm in the vertical direction × 200 mm in the horizontal direction) has the following specifications. The direction in which the light transmitting portion and the light absorbing portion extend is the horizontal direction.
Base material layer: polycarbonate resin (Keiwa Co., Ltd.), thickness 130 μm
-Light transmitting part: UV curable urethane acrylate resin (Sanyo Chemical Industries, Ltd., CR03)
-Light absorbing part: UV-curable urethane acrylate resin containing 20% by mass of black beads having an average particle size of 4 μm (DNP Fine Chemical Co., Ltd., EL 132)
Shape of light absorbing portion: long lower base in trapezoidal cross section 9.4 μm, short upper base 4.0 μm, height (Dk in FIG. 3) 102.0 μm, pitch between adjacent light absorbing portions (FIG. 3) Pk) is 39.0 μm
· Distance from upper bottom of light absorbing portion to surface of base layer (Lk in FIG. 3): 25 μm
Rough surface forming layer: UV curable urethane acrylate resin (Sanyo Chemical Industries, Ltd., BCP 34), thickness 15 μm, rough surface roughness Ra = 0.2 μm, average molecular weight between crosslinks (crosslink density) = 561

Here, the rough surface roughness of the roughened layer is a value measured at a surface magnification of 500 using a laser microscope (VK-8700, manufactured by Keyence Corporation). Moreover, the average inter-crosslinking molecular weight of the roughened layer was determined by the following equation.
Average molecular weight between crosslinks = total molecular weight / number of crosslink points (total molecular weight: mole number of compounding component of each component × molecular weight of each component, number of crosslink points = Σ <[(functional group of each component−1) × 2] X Molecular weight of each component>)

  For Examples 2 to 5 and Comparative Examples 1 to 4, the thickness of the roughened layer, the rough roughness of the roughened layer, and the molecular weight between crosslinks of the material constituting the roughened layer were changed. Specific values are shown in Table 1. The change in molecular weight between crosslinks was performed by changing the component ratio of the material forming the roughened layer.

Warpage and sticking (optical adhesion) of the optical films of the examples and comparative examples shown above were evaluated. Specific methods and evaluation criteria are as follows.
After warping the optical film in an air atmosphere at 105 ° C. and humidity 0% for 1000 hours, it is left on a flat surface for 24 hours at normal temperature and normal humidity, and the four ends of the optical film are JIS Class 1 gauge It did by measuring. As a result, that whose curvature was 5 mm or less was made into "(circle)", and what whose curvature exceeded 5 mm was made into "x".
For sticking, the optical film of each example is laminated on a reflective polarizing sheet (3M Japan Co., Ltd.) and fixed with a frame of plastic, stainless steel, etc., at an atmosphere of air at 105 ° C. and 0% humidity for 1000 hours. After exposing and cooling to normal temperature and normal humidity, it was performed by illuminating from the back with a backlight and observing visually. The backlight of this example is composed of a reflective sheet, a light guide plate (a light source is disposed on the side surface), a diffusion sheet, a lens sheet, and a reflective polarizing sheet. As a result, the thing in which the sticking pattern was not visually recognized was made into "(circle)" and the thing in which the sticking pattern was visually recognized was made into "x".
The results of the evaluation are also shown in Table 1.

  As can be seen from Table 1, by satisfying the above conditions, both warpage and sticking can be made favorable.

DESCRIPTION OF SYMBOLS 1 Image display apparatus 5 Image source unit 10 Image source 11 Area light source device 12 Liquid crystal panel 20 Optical film 21 Rough surface formation layer 21a Rough surface 22 Optical function layer 28 Base material layer

Claims (4)

An optical film having a plurality of layers,
A substrate layer,
A plurality of light transmitting portions laminated on one surface of the base material layer and arranged along the layer surface of the base material layer so as to transmit light, and the light transmitting portions disposed between the adjacent light transmitting portions parts and a lower refractive index than the light transmitting portion to form a surface, and the optical functional layer having a light-absorbing portion which is capable of absorbing light,
And a roughened layer having a thickness of 15 μm or more and 25 μm or less laminated on the surface of the optical functional layer opposite to the side on which the base material layer is laminated,
The roughened layer has a rough surface formed on the surface opposite to the optical functional layer, and the surface roughness of the rough surface is 0.1 μm or more and 0.2 μm or less in Ra.
An optical film, wherein the material forming the roughened layer is a resin having a crosslinking density of 320 or more and 740 or less.   The optical film according to claim 1, wherein the base material layer is made of polycarbonate.   An image source unit comprising a surface light source device, a liquid crystal panel, and the optical film according to claim 1 or 2, wherein the optical film is disposed between the surface light source device and the liquid crystal panel. And
The video source unit according to claim 3 disposed inside the housing.

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