JP2009075219A - Optical element, backlight unit using the same, and display device - Google Patents

Abstract

An optical element, a backlight unit, characterized in that an optical element having a simplified structure with fewer manufacturing steps is formed by utilizing the difference in surface wettability from the viewpoint of configuration and manufacturing. A display device and a method for manufacturing an optical element are provided.
An optical element has a base layer. A first structure 3 having a light collecting function is provided on one surface of the base material layer 4. A second structure is provided on the other surface of the base material layer 4. The second structure is configured by patterning a transmissive portion 1 that transmits light and a reflective portion 2 that reflects light. The reflection part 2 is formed by applying and curing a liquid substance having no wettability to the surface of the transmission part 1 on the other surface of the base material layer 4 where the transmission part 1 is not located. Has been.
[Selection] Figure 1

Description

  The present invention relates to a display element, a backlight unit using the same, and a display device.

  Liquid crystal display devices using a liquid crystal panel are widely used not only for image display means of mobile phones, personal digital assistants, and personal computer displays, but also for televisions as home appliances. Furthermore, in order to make more use of the advantages of the liquid crystal display device, it has spread to general households as an image display device for information appliances for large screens, which has been difficult with conventional cathode ray tube (CRT) televisions. Developments not only for increasing the size but also for increasing the brightness and reducing the thickness and weight have been proceeding at a very high speed.

  In such a liquid crystal display device, a light source is often built in the device, and in order to obtain the brightness necessary for displaying an image, a backlight unit including the light source is provided on the back side of the liquid crystal panel. It is arranged. The light source employed in this backlight unit is roughly classified into a light guide lamp such as a cold cathode fluorescent lamp (CCFT) which is subjected to multiple reflection within a flat light guide plate made of acrylic resin having excellent light transmittance. There are "light plate light guide method" (so-called edge light method) and "direct type" that does not use a light guide plate. Especially, the direct type is used for display devices such as large liquid crystal displays that are difficult to use the light guide plate. ing.

  As the direct liquid crystal display device, the device shown in FIG. 6 is generally used. In this, a liquid crystal unit 40 composed of a liquid crystal panel 43 sandwiched between polarizing plates 41 and 42 is provided on the upper side, and light emitted from a light source 30 comprising a cold cathode tube is diffused on the lower surface side thereof. The light is diffused by an optical sheet such as a film 50 and condensed on the display area of the liquid crystal panel 43. Furthermore, in order to efficiently use the light from the light source 30 accommodated in the lamp house 31 as illumination light, a light reflection plate 32 is disposed on the back surface of the light source 30.

The light reflection plate 32 having a high reflectance is obtained by printing a material obtained by mixing a titanium oxide (TiO ₂ ) powder, which is a white pigment, in a solution such as a transparent adhesive in a predetermined pattern, for example, a dot pattern, and then drying it. It is formed, and is a device for increasing the brightness with the role of guiding light to the exit surface side.

  However, in the display device illustrated in FIG. 6, since the control of the viewing angle is left only to the diffusibility of the diffusion film 50, the control is difficult, the central portion in the front direction of the display is bright, and conversely the periphery There was a problem of getting darker as I went to the club. This causes a reduction in the light utilization efficiency, resulting in a decrease in luminance when the liquid crystal screen is viewed from the side.

  As one method for solving this problem, a brightness enhancement film (BEF), which is a registered trademark of 3M USA, is widely used. As shown in FIG. 7, BEF is a film in which unit prisms 61 having a triangular cross section are periodically arranged in one direction on a transparent substrate 60. The prism 61 is compared with the wavelength of light. It is getting bigger. BEF collects light from “off-axis” and redirects it “on-axis” or “recycle” toward the viewer. ) ”Function. When using the display (when observing), the BEF increases the on-axis brightness by reducing the off-axis brightness. Here, “on-axis” is a direction that coincides with the visual direction of the viewer, and is generally the normal direction to the display screen (direction F shown in FIG. 7).

  When the repetitive array structure of the prisms is arranged in only one direction, the direction can be changed or recycled only in the parallel direction. In order to control the luminance of the display light in the horizontal and vertical directions, the prism groups are arranged in parallel. It is used in a structure in which two sheets are stacked and combined so that the directions are substantially orthogonal to each other.

By adopting this BEF, a display designer can achieve a desired on-axis brightness while reducing power consumption. Patent Documents 1 to 3 can be cited as examples of patent documents in which a luminance control member having a repetitive array structure of prisms represented by BEF is adopted for a display.
In the optical sheet using the BEF as a luminance control member as described above, the light from the light source is emitted from the film at a finally controlled angle by refraction, thereby increasing the intensity of light toward the viewer side. It becomes possible to control.

  In the optical sheet using the BEF as a brightness control member as described above, the light L from the light source 30 is finally emitted at a controlled angle φ by the refraction action X as shown in FIG. The light intensity in the visual direction F of the viewer can be increased. On the other hand, however, the light component Y due to the reflection / refraction action is also emitted in the lateral direction without traveling in the visual direction V of the viewer.

  Therefore, the light intensity distribution emitted from the optical sheet using the BEF has the highest light intensity when the angle with respect to the visual direction F of the viewer is 0 ° as shown by the dotted line B in FIG. As shown as a small light intensity peak around ± 90 ° shown on the axis, there is a problem that the light (side lobe) Y emitted from the lateral direction is increased.

  Therefore, the luminance distribution is desirably a smooth luminance distribution having no light intensity peak around ± 90 °. Further, when only the on-axis luminance is excessively improved, the peak width of the luminance distribution curve is remarkably narrowed, and the viewing area is extremely limited. In order to increase the peak width appropriately, it is necessary to newly use a light diffusing film which is a separate member from the prism sheet, which causes an increase in the number of members.

  As described above, it is difficult to say that the conventional optical sheets and devices sufficiently satisfy the demands for high brightness, low power consumption, etc., and are low in price, high brightness, high display quality, and low consumption. Development of a backlight unit and a display device capable of realizing a power liquid crystal display device has been awaited.

As a method for solving these problems, there is an optical sheet having a light reflecting portion and a light transmitting portion on the back side of a structure having a light collecting function. This is an optical sheet corresponding to a structure having a light condensing function, in which a light transmitting layer is provided on the back surface side of a lens convex portion, which is a portion for condensing light, and a light reflecting layer is provided on a lens concave portion. When used as a light path control member of a unit, the light entering the light transmission layer is emitted to the outside with respect to the light from the illumination light source that enters through the diffusion plate, and other light is emitted from the light reflection layer to the light source side. It plays a role to return to. The light returned by the light reflection layer is reflected again by the light reflection plate 32 on the light source side, and is emitted to the outside again through the light transparent layer as an illumination light source. In this way, it is possible to suppress the unusable light Y emitted in the lateral direction, which has been a problem due to the light reflection layer, and to efficiently reuse the light from the illumination light source without waste. Patent documents showing this optical sheet include those exemplified in Patent Document 4.
Japanese Patent Publication No. 1-378001 JP-A-6-102506 Japanese National Patent Publication No. 10-506500 Japanese Patent Application No. 2007-500652

  In the optical sheet exemplified in Patent Document 4, a light intensity distribution as shown by a solid line A in FIG. 9 is obtained. However, in order to form a light reflecting layer, on the back surface of the structure having a light collecting function. An adhesive layer for transferring the light reflecting layer is required. In addition, when transferring the light reflecting layer, a step of once producing the light reflecting layer on a release film or the like is required, and a simplified structure with fewer manufacturing steps is desired from the viewpoint of configuration and manufacturing. .

  The present invention has been made in view of the above-described circumstances, and uses a difference in surface wettability in a step of forming a light transmission and light reflection structure on the back surface of a structure having a light collecting function. It is said. By using this water / oil repellent pattern, it is possible to omit the adhesive layer necessary for transferring the light reflecting layer, leading to a reduction in the number of manufacturing steps. Further, by omitting the adhesive layer, it is possible to provide an optical element having improved light transmittance as compared with the current optical sheet.

In order to solve the above problems, the present invention uses a structure having a light collecting function formed on one side, forms a pattern with different surface wettability on the back surface, and utilizes this difference in surface wettability. The present invention provides an optical element having a structure that transmits and reflects light, and improves the light transmittance by omitting an adhesive layer that has been required so far, and greatly simplifies the manufacturing process. It has the feature that becomes possible.
That is, the invention according to claim 1 is provided on the other surface of the base material layer, the first structure having a light collecting function provided on one surface of the base material layer, and the other surface of the base material layer. The second structure is configured by patterning a transmissive part that transmits light and a reflective part that reflects light, and the reflective part includes the transmissive part. A liquid substance that does not have wettability with respect to the surface of the substrate is formed by being applied and cured on the other surface of the base material layer where the transmission portion is not located. It is an optical element.

  According to a second aspect of the present invention, in the optical element according to the first aspect, the transmissive portion is made of a photocurable resin and is formed in a portion where light is collected by the first structure, The reflection part is provided in places other than the part where the light is collected. An example of the first structure is a striped cylindrical lens.

According to a third aspect of the present invention, in the optical element according to the first or second aspect, the transmissive portion and the reflective portion are formed in a stripe shape.
When the first structure is a microlens, for example, the transmission part and the reflection part can have a sea-island structure.
According to a fourth aspect of the present invention, in the optical element according to any one of the first to third aspects, the transmitting portion is formed of a material having water and oil repellency.

  According to a fifth aspect of the present invention, in the optical element according to any one of the first to fourth aspects, the reflecting portion is formed of any one of a resin and a pigment, a metal powder, or a combination thereof. Features.

  According to a sixth aspect of the present invention, in the optical element according to any one of the first to fourth aspects, the reflecting portion is made of a resin containing a white pigment ratio of 50% or more.

The optical element manufacturing method of the present invention irradiates light from a surface having a light collecting function to form a pattern having different surface wettability on the opposite surface of the structure having the light collecting function, and this surface wettability is different. An optical element is obtained by forming a structure that transmits and reflects light using a pattern.
That is, according to claim 7 of the present invention, a base material layer provided with a first structure having a light collecting function is provided on one surface, and the entire area of the other surface of the base material layer is light transmissive. Applying a photocurable resin, irradiating light from the first structure side to cure the photocurable resin located in a portion where the light is collected by the first structure and uncured The light curable resin is removed to form a transmission part that transmits light by the cured photocurable resin, and the surface of the transmission part is formed on the other surface of the base material layer where the transmission part is not located. A reflective part that reflects light is formed by applying and curing a liquid substance that does not have wettability to the optical element.

  According to an eighth aspect of the present invention, in the optical element according to any one of the first to sixth aspects, a light diffusing structure having a function of diffusing light in parallel with the base material layer is integrated with the reflecting portion. It is an optical path control member characterized by being formed.

  According to a ninth aspect of the present invention, in the optical path control member according to the eighth aspect, the light diffusion structure is integrated with the reflecting portion via an adhesive layer or an adhesive layer. It is a member.

  According to a tenth aspect of the present invention, in the optical element according to any one of the first to sixth aspects, in the thickness direction of the base material layer, the reflection portion protrudes from the transmission portion, and the reflection A light diffusion structure having a function of diffusing light in parallel with the base material layer is integrated in the part, and a gap is interposed between the transmission part and the light diffusion structure. It is an optical path control member.

An eleventh aspect of the present invention is a backlight unit comprising a light source and the optical path control member according to any one of the eighth to tenth aspects.
According to a twelfth aspect of the present invention, there is provided a display device comprising: an image display element that defines a display image according to transmission / shading in pixel units; and the backlight unit according to the eleventh aspect.

  According to the present invention, it is possible to provide an optical element with improved light transmittance as compared with conventional optical sheets, and it is possible to reduce the number of manufacturing steps.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 to FIG. 5 are examples of schematic cross-sectional views showing the configuration of the optical element and the optical path control member according to the present embodiment and their usage, and the scale or ratio of each part does not match the actual.
(First embodiment)

1 and 2 show an outline of an embodiment according to the present invention. As shown in FIGS. 1 and 2, the optical element 10 of this embodiment is provided with a structure 3 having a light collecting function on one surface in the thickness direction of the base material layer 4, and the thickness of the base material layer 4. On the other surface in the vertical direction, a water / oil repellent material layer 1 that transmits light and a layer 2 that reflects light toward the light source are provided.
In the present embodiment, the water / oil repellent material layer 1 corresponds to the “transmission part” in the claims, and the water / oil repellent material layer 1 is formed of a material having water / oil repellency. Yes.
The layer 2 that reflects light toward the light source corresponds to the “reflecting portion” in the claims, and the structure 3 corresponds to the “first structure” in the claims. The water / oil repellent material layer 1 and the layer 2 that reflects light toward the light source constitute a “second structure” in the claims.

  The structure 3 having a condensing function is a shape having a function of condensing and emitting light from a light source to the outside through the water / oil repellent material layer 1 and the base material layer 4, and has a stripe shape as shown in FIG. Examples thereof include those having regular shapes represented by cylindrical lenses, or those having different lens diameters and arrangements represented by microlenses as shown in FIG. In addition, this condensing shape is not limited to a semi-cylindrical shape.

  The structure 3 having a light collecting function is made of a processable material that transmits light, and uses an extrusion molding method, an injection method using a polyethylene terephthalate resin, a polycarbonate resin, a polymethyl methacrylate resin, a cycloolefin polymer resin, or the like. It can be formed by a molding method or a hot press molding method. It is also possible to mold using UV or radiation curable resin. Note that a plurality of resins containing a material that can be cured by UV or radiation may be mixed and used.

  Further, the surface shape on the side on which the water / oil repellent layer 1 is formed is not limited to a flat shape as shown in FIGS. 1 and 2, and a predetermined unevenness or a certain shape may be formed. good. In this case, the water / oil repellent material layer 1 may be formed only in the concave portion, and a structure 2 for reflecting light may be provided on the convex portion. Alternatively, the water / oil repellent layer may be formed in advance on the convex portion, When the light reflecting layer is formed, a layer that transmits light and a layer that reflects light can be manufactured by preventing the light reflecting layer from being formed on the convex portion.

  The base material layer 4 bears a base material for producing the structure 3 having a light condensing function, and forms the structure 3 having the light condensing function on the base material layer 4 in production by the above-described method. Examples of the material used for the base material layer 3 include highly transparent resins such as acrylic resins, polyethylene terephthalate resins, and polycarbonate resins. The base material layer 4 may be made of the same material as that of the structure 3 having a light collecting function, and the structure 3 and the base material layer having the function are manufactured and processed simultaneously on both sides at the time of forming the structure 3 having the function. You can also get 4 at once.

  The thickness of the base material layer 4 depends on the focal length of the structure 3 having a light collecting function. In order to form a good pattern when the light incident from the structure 3 having a light collecting function during the manufacturing process passes through the water and oil repellent material layer 1 and the base material layer 4 and is collected, The total thickness of the oil repellent material layer 1 and the base material layer 4 needs to be within the distance to the focal point F of the structure 3 having a light collecting function. The thickness of the base material layer 4 is preferably 10 to 200 microns.

  Examples of the material used for the water- and oil-repellent material layer 1 of the present invention include a photocurable fluorine-based resin having high transparency and strong water-repellent properties, or a fluorine-containing functional material. . In addition, since a material capable of forming a layer with good film quality is desirable, these fluorine-based materials are contained or added to a photocurable resin capable of forming a thin film with high transparency and uniformity. A material may be used.

  Since the water / oil repellent material layer 1 of the present invention requires high transparency in order to transmit light, the thickness of the water / oil repellent material layer 1 is 10 microns or less, more preferably 2 microns or less. Desirably, the transmittance is desirably 90% or more.

  Further, when the water / oil repellent material layer 1 is formed, a thin film is desirable in order to increase the light transmittance. Therefore, the viscosity of the material in the coating process is desirably low enough to easily form the thin film. Further, it is preferably 100 mPa · s or less.

  The present invention is characterized in that a structure for reflecting light is formed by utilizing the difference in wettability of the surface. By applying a resin having characteristics not compatible with the water / oil repellent material including the light reflecting material to the water / oil repellent material layer 1 having the pattern formed thereon, that is, on the surface of the water / oil repellent material layer 1. By applying a liquid substance that does not have wettability, it is possible to form the resin layer 2 (reflecting portion) that reflects light to a portion other than the water / oil repellent material layer 1. The resin used here is desirably a material that is strongly incompatible with the water / oil repellent material layer 1 used, and is preferably a transparent material that does not interfere with light reflection. Of course, the liquid substance constituting the resin layer 2 (reflecting portion) has wettability with respect to the other surface in the thickness direction of the base material layer 4.

  The transparent resin constituting the light reflecting layer 2 is a thermoplastic resin such as polyester resin, acrylic resin, polycarbonate resin, polystyrene resin, cycloolefin resin, or polyester acrylate, urethane acrylate. , A material obtained by imparting hydrophilicity having at least one hydroxyl group or amide group having hydrophilicity to a transparent resin such as a photocurable resin composed of an epoxy acrylate oligomer or an acrylate resin, and further vinyl pyrrolidone, etc. The hydrophilic resin is an example. It is also possible to use the transparent resin containing or added a material or a dispersant for improving hydrophilicity. It is a material that is not compatible with the fluorine-based material described above, and is not formed on the fluorine-based material by application, but can be formed on a pattern without the fluorine-based material. Resins imparted with properties are preferred.

  The thickness of the layer 2 that reflects light is preferably 5 microns to 20 microns thicker than the water / oil repellent material layer 1. This is a height necessary for reflecting light from the light source, and a stable gap 7 is formed by utilizing the difference in height between the water / oil repellent material layer 1 and the light reflecting layer 2. Because of the height required.

  Examples of the material of the layer 2 that reflects light toward the light source include white pigments and metal powders that reflect light. Examples thereof include titanium oxide, barium sulfate, magnesium carbonate, zinc oxide, magnesium oxide, clay, aluminum hydroxide, zinc sulfide, silica and silicone. These white pigments and metal powders may be used alone or in combination.

  The light absorption in the layer 2 that reflects light is desirably 1% or less. If it exceeds 1%, the integrated light amount emitted from the optical element 10 is reduced, and the luminance is lowered. Therefore, the reflectance of the layer 2 that reflects light requires 70% or more, and more preferably 80% or more. The ratio of the white pigment or metal powder to be mixed is desirably 60% or more, and these may be used alone or in combination of two or more.

When forming the layer 2 for reflecting light, the viscosity of the mixed material is 10 to 3000 mP. s is desirable, and in particular, 100 to 1000 mP · s is more preferable.
(Second Embodiment)

  FIG. 3 shows an outline of a method for manufacturing an optical element of the present invention. As shown in FIG. 3A, first, the water / oil repellent material layer 1 is formed over the entire area of the other surface of the base material layer 4 having the structure 3. Next, as shown in FIG. 3B, the parallel light H is irradiated from the structure 3 side having the light collecting function, and the light depending on the structure 3 having the light collecting function reaches the water / oil repellent material layer 1. Then, only the part where the light reaches is cured.

  As a method for forming the water / oil repellent material layer 1, various coating apparatuses such as a roll coater, a spin coater, and a die coater, a printing method, or a coating method using a dispenser or a spray may be used.

  As a method of forming the pattern of the water / oil repellent material layer 1, parallel light having an arbitrary absorption wavelength indicated by the water / oil repellent material is selected, and light having an optimum exposure amount is irradiated from the structure 3 having a condensing function. By doing so, only the predetermined water / oil repellent material layer 1 can be cured. Next, as shown in FIG. 3C, a predetermined pattern of the water- and oil-repellent material layer 1 can be formed by removing the uncured portion that has not received light by a process such as solvent development. .

  Next, as shown in FIG. 3D, a material mixed with a white pigment and a photosensitive resin is applied onto the pattern of the formed water / oil repellent material layer 1, that is, the water / oil repellent material layer 1. Is applied to the other surface of the base material layer 4 where no water and oil repellent material layer 1 is provided, and a layer 2 for reflecting light toward the light source is formed at a location where the water / oil repellent material layer 1 is not present. Is cured to produce the optical element 10 of the present invention.

(Third embodiment)
An outline of the optical path control member 20 according to the present invention is shown in FIG. The optical element 10 shown in FIG. 1 can be obtained by being bonded to and integrated with the diffusion plate 6 via an adhesive or adhesive layer 5. Here, the adhesive or adhesive layer 5 has a structure in which only the light reflecting layer 2 is attached, and a gap 7 is formed between the water / oil repellent material layer 1 and the adhesive layer 5. Such a gap 7 is made of a gas such as air or nitrogen, for example.
In the present embodiment, the diffusion plate 6 corresponds to a “light diffusion structure” in the claims.

  When the optical element 10 of the present invention and the diffusion plate 6 are bonded together, the entire surface may be used or at least partial bonding may be used. In addition, as a method of bonding, an apparatus such as a roll laminator or a press machine can be used. Further, in the bonding step, the roll portion that touches the optical element 10, the adhesive or adhesive layer 5, or the diffusion plate 6 may be made of rubber or metal, and may be bonded in combination of the upper and lower parts separately. .

  In addition, the material used for the adhesive or adhesive layer 5 is preferably a material having excellent transparency in order to transmit light, and examples thereof include acrylic, urethane, rubber, and silicone adhesives or adhesives. . In either case, since it is used in a high-temperature backlight, it is desirable that the storage elastic modulus G ′ is 1.0E + 04 Pa or more at 100 ° C. If the value is lower than this, there is a possibility that the diffusion plate 6 and the optical element 10 will be peeled off or displaced during use. In order to secure the void 7, transparent fine particles such as beads may be mixed in the adhesive or adhesive layer 5. The pressure-sensitive adhesive or adhesive layer 5 may have a multilayer structure including a transparent resin layer or may be used as a single layer.

(Fourth embodiment)
The optical element of the present invention produced by the above description is a backlight unit of a liquid crystal display device, an organic or inorganic electroluminescent display device, a viewing angle control film of a display such as a plasma display, a contrast enhancement film, and a solar cell. It can be applied to light control films and projection screens. Here, FIG. 5 shows a form of a liquid crystal display device using the optical path control member 20 according to the present invention.

  The liquid crystal display device shown in FIG. 5 has a lamp house 31 including a light source 30 and a light reflecting plate 32 that reflects light from the light source as a backlight part, and is adhered to the diffuser 6 via an adhesive or adhesive layer 5 thereon. It is shown that the optical path control member 20 composed of the combined optical elements 10 and the liquid crystal unit 40 sandwiched between the deflecting plates 41 and 42 and the liquid crystal panel 43 disposed thereon are shown.

  Hereinafter, the present invention will be described more specifically as examples, but the present invention is not limited thereto. In this example, a specific example of the optical path control member 20 of the third embodiment will be described.

  First, an ultraviolet curable resin (refractive index: 1.51) containing urethane acrylate as a main component is applied onto a biaxially stretchable easy-adhesion PET film (thickness: 125 μm) for use as the base material layer 4 to collect light. Using the cylinder mold cut into the shape of the structure 3 having a function, the structure 3 and the substrate 4 having a light collecting function with a lens pitch of 140 microns were produced. Next, a thin film having a thickness of 2 microns made of a solvent-free fluorine-based UV curable resin (viscosity: 40 mP · s) is formed on the back side of the substrate 4 using a wire bar, and this has a light collecting function. The structure 3 was irradiated with parallel UV light having an optimum exposure amount (55 mJ / cm 2), and only the predetermined fluorine-based UV curable resin layer was cured on the back surface. Thereafter, the fluorine-based UV curable resin layer at the uncured portion is removed using a methyl ethyl ketone solvent to form a water-repellent layer pattern 1 having a width of 98 μm as the fluorine-based UV curable resin layer width following the shape of the condenser lens. did.

  Also, as a method for removing the fluorine-based UV curable resin layer at the uncured site, in addition to the above solvent development method, uncured resin removal operation with warm air is performed, and it is confirmed that the same effect as solvent development is obtained did. This is because the contact angle value for water on the substrate surface before forming the fluorine-based UV curable resin layer and the contact angle value for the substrate surface after removing the uncured resin are measured and compared. Judgment from what was obtained.

  Next, 1% of a dispersant was added to N-vinyl-2-pyrrolidone containing 60% by weight of titanium oxide, and then the titanium oxide was uniformly mixed using a dispersing device to obtain a viscosity of 960 mP · s, reflectance. A material constituting the layer 2 reflecting 81.3% light was obtained.

  Finally, on the formed water-repellent layer pattern 1, a material obtained by adding 1% of a dispersant to N-vinyl-2-pyrrolidone containing 60% by weight of titanium oxide is applied using an applicator, and the water-repellent layer pattern A layer 2 that reflects light containing titanium oxide having a thickness of 11 microns was formed on the base material layer 4 having no 1. Finally, the formed resin layer containing titanium oxide is irradiated with UV light to cure the resin, thereby forming a stripe pattern of a water-repellent layer pattern 1 for transmitting light and a layer 2 for reflecting light to form an optical element. 10 was obtained.

  The optical element 10 obtained above was bonded to the polystyrene diffuser plate 6 through the adhesive layer 5 to produce an optical path control member 20. This is because a roll coater is used on the diffusion plate 6 to apply an adhesive whose main component is an acrylic resin, and the optical element 10 produced thereon is bonded together with a roll laminator apparatus, and then 1 in an oven at 80 ° C. It was obtained by curing the adhesive for hours. As a result of optical measurement of this optical path control member, it was confirmed that the luminance was improved by 4% as compared with the conventional optical path control member (Patent Document 4). It was also confirmed that other light distribution characteristics were equivalent.

  Further, after the optical path control member 20 thus prepared was stored for 24 hours in an environment of a temperature of 80 ° C. and a temperature of 60 ° C./humidity of 95%, the appearance was evaluated, and as a result, abnormalities such as peeling, peeling and floating were observed. It was confirmed that it was equivalent to a conventional optical sheet.

The present invention is characterized in that a difference in surface wettability is utilized in a step of forming a light transmission and light reflection structure on the back surface of a structure having a light collecting function. By utilizing this difference in surface wettability, it is possible to omit the adhesive layer necessary for transferring the light reflecting layer, leading to a reduction in the number of manufacturing steps. Further, by omitting the adhesive layer, it is possible to provide an optical element having improved light transmittance as compared with the current optical sheet.
As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, Structural design change etc. of the range which does not deviate from the summary of this invention are included.

It is explanatory drawing of the optical element of 1st Embodiment of this invention. It is explanatory drawing of the optical element of 2nd Embodiment of this invention. It is explanatory drawing of the manufacturing process of the optical element of 1st Embodiment of this invention. It is explanatory drawing of the optical path control member of 1st Embodiment of this invention. It is explanatory drawing of the liquid crystal display device of 1st Embodiment of this invention. It is explanatory drawing of the structural example of the optical sheet for liquid crystal displays by a prior art. It is explanatory drawing of the liquid crystal display device of a direct type system by a prior art. It is explanatory drawing of BEF by a prior art. It is explanatory drawing of the light intensity distribution radiate | emitted from BEF by a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Water / oil repellent material layer 2 Layer which reflects light to the light source side 3 Structure which has a condensing function 4 Base material layer 5 Adhesive layer 6 Diffusion plate 7 Space | gap 10 Optical element 20 Optical path control member 30 Light source 31 Lamp house 32 Light reflection Plate 40 Liquid crystal unit 41 Deflector plate 42 Deflector plate 43 Liquid crystal panel 50 Diffusion film 60 Base material 61 Unit prism having a triangular cross section F Focus H Parallel light
L Light from light source V Normal direction to display screen X Refracted light Y Light emitted in the lateral direction by reflection / refractive action

Claims (12)

A base material layer;
A first structure having a light collecting function provided on one surface of the base material layer;
A second structure provided on the other surface of the base material layer,
The second structure is configured by patterning a transmission part that transmits light and a reflection part that reflects light,
The reflection part is formed by applying and curing a liquid substance that does not have wettability to the surface of the transmission part on the other surface of the base material layer where the transmission part is not located. Being
An optical element. The optical element according to claim 1,
The transmission part is made of a photocurable resin and is formed in a part where light is collected by the first structure,
The reflection part is provided at a place other than the part where the light is collected,
An optical element. The optical element according to claim 1 or 2,
The transmission part and the reflection part are formed in a stripe shape,
An optical element. The optical element according to any one of claims 1 to 3,
The transmission part is made of a material having water and oil repellency,
An optical element. The optical element according to any one of claims 1 to 4,
The reflection part is formed from any of resin and pigment or metal powder,
An optical element. The optical element according to any one of claims 1 to 4,
The reflection part is made of a resin containing a white pigment ratio of 50% or more.
An optical element. A base material layer provided with a first structure having a light collecting function on one surface is provided,
A photocurable resin having light permeability is applied to the entire area of the other surface of the base material layer,
Irradiating light from the first structure side to cure the photocurable resin located at a portion where light is collected by the first structure, and removing the uncured photocurable resin Forming a transmission part for transmitting light by the cured photocurable resin;
A reflective part that reflects light by applying and curing a liquid substance that does not have wettability to the surface of the transmissive part on the other surface of the base material layer where the transmissive part is not located. Form,
A method for manufacturing an optical element. The optical element according to any one of claims 1 to 6,
A light diffusing structure having a function of diffusing light in parallel with the base material layer is integrated with the reflecting portion.
An optical path control member. In the optical path control member according to claim 8,
The light diffusing structure is integrated with the reflective portion via an adhesive layer or an adhesive layer.
An optical path control member. The optical element according to any one of claims 1 to 6,
In the thickness direction of the base material layer, the reflection part protrudes from the transmission part,
A light diffusing structure having a function of diffusing light in parallel with the base material layer is integrated with the reflecting portion,
A gap is interposed between the transmission part and the light diffusion structure,
An optical path control member.   A backlight unit comprising a light source and the optical path control member according to any one of claims 8 to 10. An image display element that defines a display image according to transmission / shading in pixel units;
A display device comprising the backlight unit according to claim 11.

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