JP6563231B2 - Master production method, optical body production method, optical member production method, and display device production method - Google Patents

Description

  The present invention relates to a master manufacturing method, an optical body, an optical member, and a display device.

  In general, in a display device such as a television and an optical element such as a camera lens, an antireflection treatment is performed on a light incident surface in order to reduce surface reflection and increase transmitted light. As such an antireflection treatment, for example, an optical body in which a micro uneven structure (for example, a moth-eye structure) having an average period of unevenness is equal to or less than a visible light wavelength is laminated on a light incident surface. Proposed.

  On the surface having such a micro concavo-convex structure, since the refractive index changes gently with respect to the incident light, a sudden change in the refractive index that causes reflection does not occur. Therefore, by forming such a micro uneven structure on the surface of the light incident surface, reflection of incident light can be prevented over a wide wavelength band.

  As a method for forming a micro concavo-convex structure in which the average period of concavo-convex is on the order of nanometers, for example, Patent Document 1 below discloses a method of performing dry etching using nanometer-sized island-shaped fine particles as a protective mask. ing. Patent Documents 2 and 3 listed below disclose forming a plurality of recesses less than a micrometer in an aluminum film by using an anodic oxidation method of the aluminum film. Further, Patent Document 4 below discloses that a micro uneven structure having an average period of unevenness of a predetermined wavelength or less is formed using electron beam lithography.

  Patent Documents 5 to 7 listed below disclose structures in which micro uneven structures regularly arranged with a period of a predetermined wavelength or less are formed on a substrate having a surface roughness larger than a predetermined wavelength. Has been. In the structures disclosed in Patent Documents 5 to 7, the incidence angle dependency of the antireflection characteristics can be reduced by regularly forming the micro uneven structure on such a rough surface.

  Further, Patent Document 8 below discloses a nanoimprint method using a roll-shaped mold as a method for manufacturing an optical body having the micro uneven structure as described above in a large area. Specifically, in Patent Document 8, an optical body having a micro-concave structure transferred by rotating and pressing it onto a resin film or the like using a roll mold having a micro-concave structure formed on the outer peripheral surface as a master mold Can be manufactured in a large area. Patent Document 8 discloses photoreactive or thermal reaction lithography using laser light as a method for forming a micro uneven structure on the outer peripheral surface of such a roll-shaped mold.

JP2012-1000A Japanese Patent No. 4916597 JP 2009-288337 A JP 2009-128541 A Japanese Patent No. 4794351 Japanese Patent No. 5105771 Japanese Patent No. 5201913 JP 2014-43068 A

  However, in an optical body having a periodic micro concavo-convex structure as disclosed in Patent Documents 5 to 7, when high-intensity external light is irradiated, diffracted light due to the periodicity of the micro concavo-convex structure is not generated. There was a problem that it occurred.

  Further, in order to manufacture an optical body having a micro uneven structure in a large area, as disclosed in Patent Document 8, when forming the micro uneven structure on a roll-shaped mold by lithography with laser light, random It was difficult to form a micro uneven structure. This is because in lithography using laser light, the roll-shaped mold is moved in the axial direction while being rotated, and exposure is performed every round, so that periodicity occurs due to the locus of exposure.

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a master manufacturing method capable of manufacturing an optical body with suppressed diffracted light in a large area, and manufacturing using the master. Another object is to provide an optical member, an optical member including the optical member, and a display device including the optical member.

  In order to solve the above problems, according to one aspect of the present invention, a laser modulated by a control signal having no periodicity within a predetermined range is provided on the outer peripheral surface of a master body including a cylindrical or columnar base material. By irradiating, a step of randomly forming a micro uneven structure having an average period of unevenness in a visible light wavelength or less in the circumferential direction and the axial direction of the master body, and forming an etching resist layer on the outer peripheral surface of the master body A step of forming a macro uneven structure having an average period of unevenness larger than a visible light wavelength with respect to the etching resist layer, and etching the etching resist layer and the master body to obtain an outer periphery of the base material. There is provided a method for manufacturing a master including a step of superimposing the micro uneven structure and the macro uneven structure on a surface.

  The laser irradiation distance with respect to the circumferential direction of the master body corresponding to 1 bit of the control signal may be 0.2 μm or less.

  The interval between the laser irradiation positions with respect to the axial direction of the master body may be not less than 75 nm and not more than 350 nm.

  The etching resist layer may include an inorganic resist layer formed on the outer peripheral surface of the master body and an organic resist layer formed on the inorganic resist layer.

  Etching to the inorganic resist layer using the organic resist layer as a mask and etching to the master body using the inorganic resist layer as a mask may be performed by dry etching using different gases.

  The dry etching may be vertical anisotropic etching using a gas containing at least fluorine atoms and containing at least two of carbon atoms, fluorine atoms, oxygen atoms and hydrogen atoms.

  The organic resist layer may be formed by atomizing and spraying an organic resist diluted with a solvent.

  The master body is composed of the base material and a base material resist layer formed on the outer peripheral surface of the base material, and the micro uneven structure is formed on the base material resist layer, and the inorganic resist A layer may be formed on the base resist layer so as to embed the micro uneven structure, and the base resist layer may be etched simultaneously with the inorganic resist layer.

  The etching rate of the base resist layer may be different from the etching rate of the inorganic resist layer.

  The master body may be formed of the base material, and the micro uneven structure may be formed on the base material.

  Moreover, in order to solve the said subject, according to another viewpoint of this invention, the said micro unevenness | corrugation formed in the outer peripheral surface of the said original disk with respect to the resin base material using the original disk manufactured by said manufacturing method. An optical body in which the structure and the macro uneven structure are transferred is provided.

  The haze value of the optical body may be 20% or more.

  Moreover, in order to solve the said subject, according to another viewpoint of this invention, the optical member which laminated | stacked said optical body on the substrate surface is provided.

  Moreover, in order to solve the said subject, according to another viewpoint of this invention, the display apparatus which laminated | stacked said optical body on the display surface is provided.

  In order to solve the above problems, according to another aspect of the present invention, a macro uneven structure formed on the surface of a resin base material and having an average period of unevenness larger than a visible light wavelength is superimposed on the macro uneven structure. An optical body having a randomly formed micro uneven structure having an average period of unevenness of not more than a visible light wavelength, a haze value of 20% or more, and a display panel in which the optical body is laminated on a display surface; Are provided.

  According to the present invention, it is possible to randomly form a micro concavo-convex structure on a master using lithography using laser light.

  As described above, according to the present invention, it is possible to provide a master that can manufacture an optical body with suppressed diffracted light in a large area.

It is the perspective view which showed typically the original disk manufactured by the manufacturing method which concerns on one Embodiment of this invention. It is sectional drawing which shows typically the cross-sectional shape at the time of cut | disconnecting the original recording concerning the embodiment in the thickness direction. It is explanatory drawing explaining the exposure apparatus which performs exposure by the laser beam with respect to the original disk which concerns on the same embodiment. It is explanatory drawing explaining the control signal used for the modulation | alteration of a laser beam in exposure apparatus. It is a schematic diagram which shows the latent image pattern of the resist layer which concerns on a comparative example. It is a schematic diagram which shows an example of the latent image pattern of the resist layer which concerns on the same embodiment. It is a schematic diagram which shows the other example of the latent image pattern of the resist layer which concerns on the same embodiment. It is sectional drawing explaining 1 process of the manufacturing method of the original disk which concerns on the same embodiment. It is sectional drawing explaining 1 process of the manufacturing method of the original disk which concerns on the same embodiment. It is sectional drawing explaining 1 process of the manufacturing method of the original disk which concerns on the same embodiment. It is sectional drawing explaining 1 process of the manufacturing method of the original disk which concerns on the same embodiment. It is sectional drawing explaining 1 process of the manufacturing method of the original disk which concerns on the same embodiment. It is sectional drawing explaining 1 process of the manufacturing method of the original disk which concerns on the same embodiment. It is sectional drawing explaining 1 process of the manufacturing method of the original disk which concerns on the same embodiment. It is explanatory drawing explaining the transfer apparatus which manufactures an optical body using the original recording concerning the embodiment. It is explanatory drawing which showed the course of incident light at the time of laminating | stacking an optical body with lower scattering efficiency than the optical body which concerns on the embodiment on an internal reflector. It is explanatory drawing which showed the course of the incident light at the time of laminating | stacking the optical body which concerns on the embodiment on an internal reflector. It is an observation image by SEM of the evaluation sample which concerns on Test Examples 1-4. 3 is an SEM image obtained by observing the surface of the optical body according to Example 1 at a magnification of 50000 times. It is a graph which shows the result of the regular reflection spectroscopy measurement of the optical body which concerns on Example 1 and Comparative Example 1. FIG. 6 is a graph showing the results of spectroscopic measurement of diffracted light of optical bodies according to Examples 1 and 2 and Comparative Example 1. FIG. It is explanatory drawing explaining the method to evaluate anti-glare property in the display apparatus or display board which bonded the optical body on the display surface. It is the reflection image image of the light of the fluorescent lamp in the display board which stuck the optical body. It is the reflected image image of the light of the fluorescent lamp in the display apparatus which stuck the optical body.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, the duplicate description is abbreviate | omitted by attaching | subjecting the same code | symbol.

<1. About Master>
[1.1. Master structure]
First, with reference to FIG. 1 and FIG. 2, the master disc manufactured by the manufacturing method which concerns on one Embodiment of this invention is demonstrated. FIG. 1 is a perspective view schematically showing a master disc manufactured by the manufacturing method according to the present embodiment. FIG. 2 is a cross-sectional view schematically showing a cross-sectional shape when the master according to this embodiment is cut in the thickness direction.

  As shown in FIG. 1, the master 1 according to this embodiment includes a base material 10 in which a macro uneven structure 11 and a micro uneven structure 13 are formed on an outer peripheral surface so as to overlap each other.

The base material 10 is, for example, a cylindrical member. However, the shape of the substrate 10 may be a hollow cylindrical shape having a cavity inside as shown in FIG. 1, or may be a solid columnar shape having no cavity inside. Further, the material of the substrate 10 is not particularly limited, it is possible to use quartz glass, such as fused quartz glass or synthetic quartz glass (SiO _2). Although the magnitude | size of the base material 10 is not specifically limited, For example, the length of an axial direction may be 100 mm or more, an outer diameter may be 50 mm or more and 300 mm or less, and thickness is 2 mm or more. It may be 50 mm or less.

  The macro concavo-convex structure 11 is a concavo-convex structure in which the average period of the concavo-convex is larger than the visible light wavelength. The micro concavo-convex structure 13 is a concavo-convex structure in which the average period of the concavo-convex is less than or equal to the visible light wavelength, and is superimposed on the macro concavo-convex structure 11. Further, the two-dimensional arrangement of the unevenness of the micro uneven structure 13 is randomly formed in the axial direction and the circumferential direction of the substrate 10 (that is, not having periodicity). The specific structure of the macro uneven structure 11 and the micro uneven structure 13 will be described later with reference to FIG.

  Here, the master 1 is a roll-to-roll type nanoimprint master. By pressing the outer peripheral surface of the master 1 against the resin base material or the like, the macro uneven structure 11 and the micro uneven structure 13 formed on the outer peripheral surface are transferred to the resin base material or the like. As a result, the master 1 can produce a transfer product onto which the macro uneven structure 11 and the micro uneven structure 13 are transferred with a high production efficiency and a large area. In addition, the transcription | transfer material by which the macro uneven | corrugated structure 11 and the micro uneven | corrugated structure 13 were transcribe | transferred by the original recording 1 concerning this embodiment can be used as optical bodies, such as an antireflection film, for example.

  Next, with reference to FIG. 2, the macro uneven structure 11 and the micro uneven structure 13 formed on the outer peripheral surface of the master 1 will be described in more detail.

  As shown in FIG. 2, the macro concavo-convex structure 11 includes a trough 113 that is concave in the thickness direction of the base material 10 and a peak 111 that is convex in the thickness direction of the base material 10. The average period of unevenness of the macro uneven structure 11 is larger than the visible light wavelength (for example, more than 830 nm), and preferably 1 μm or more and 100 μm or less. Here, the period of unevenness in the macro uneven structure 11 represents a distance P1 between the valleys 113 and 113 adjacent to each other or between the peaks 111 and 111, as shown in FIG. More specifically, the macro uneven structure 11 may be an antiglare (anti-glare) structure having an average period of unevenness of 1 μm to 100 μm.

  The micro concavo-convex structure 13 is a concavo-convex structure formed so as to overlap the macro concavo-convex structure 11, and is a convex portion positioned between the concave portion 133 that is concave in the thickness direction of the substrate 10 and the adjacent concave portions 133 and 133. 131.

  Here, the unevenness of the micro uneven structure 13 is randomly formed. Specifically, the period and amplitude of the unevenness of the micro uneven structure 13 are randomly formed. However, the unevenness period of the micro uneven structure 13 is, on average, not more than a visible light wavelength (for example, not more than 830 nm), and preferably not less than 100 nm and not more than 350 nm. Moreover, the amplitude of the unevenness of the micro uneven structure 13 is formed, for example, in the range of greater than 0 nm and less than or equal to 600 nm.

  In addition, as shown in FIG. 1, the period of the unevenness in the micro uneven structure 13 is a distance P2 between the apexes of the adjacent protrusions 131 and 131 or between the centers of the bottom surfaces of the adjacent recesses 133 and 133. Represent. Further, the amplitude of the unevenness of the micro uneven structure 13 represents a difference in height between the apex of the convex part 131 and the bottom point of the concave part 133.

  In such an optical body to which the concavo-convex structure of the master 1 is transferred, the concavo-convex period of the micro concavo-convex structure 13 is random, and therefore, due to the periodicity of the micro concavo-convex structure 13 when irradiated with strong external light. The generated diffracted light can be suppressed. In addition, the optical body manufactured by the master 1 has the micro uneven structure 13 having unevenness of various periods, and thus can have uniform antireflection characteristics for a wide range of wavelengths. Furthermore, since the optical body manufactured by the master 1 includes the micro uneven structure 13 having unevenness of various amplitudes, the antireflection characteristic is improved more than the micro uneven structure 13 including unevenness of a single amplitude. be able to.

  In particular, the optical body manufactured by the master 1 described above includes light in a wide range of wavelength bands, and is effective for preventing reflection of sunlight having high intensity. Therefore, the optical body manufactured by the master 1 can be suitably used as an antireflection film for a display panel such as an in-vehicle display device and a meter panel used outdoors.

  Moreover, the optical body manufactured by the master 1 can have both high anti-glare characteristics due to the macro uneven structure 11 and high anti-reflective characteristics due to the randomly formed micro uneven structure 13. Therefore, the optical body manufactured by the master 1 can be suitably used as a stray light prevention film in a camera barrel or spectrometer in which internal reflection light and scattered light are required to be suppressed as much as possible.

[1.2. Master exposure method]
Next, an exposure method for forming a latent image corresponding to a random micro concavo-convex structure on the master according to the present embodiment described above will be described with reference to FIGS.

  In the master 1 according to this embodiment, the latent image corresponding to the micro uneven structure 13 is formed by lithography using laser light. Below, with reference to FIG. 3, the exposure apparatus 200 which performs the exposure by the laser beam with respect to the original disk which concerns on this embodiment is demonstrated first. FIG. 3 is an explanatory diagram for explaining an exposure apparatus that performs exposure with a laser beam on the master according to the present embodiment.

  As shown in FIG. 3, the exposure apparatus 200 includes a laser light source 201, a first mirror 203, a photodiode (PD) 205, a condensing lens 207, and an electro-optic deflector (Electro Optical Deflector: EOD). 209, a collimator lens 211, a control mechanism 230, a second mirror 213, a moving optical table 220, a spindle motor 225, and a turntable 227. The base material 10 of the master 1 is placed on the turntable 227 with a resist layer formed on the outer peripheral surface.

  The laser light source 201 is a light source that oscillates a laser beam 20 for exposing a resist layer formed on the outer peripheral surface of the base material 10. For example, a semiconductor that emits a laser beam having a wavelength in the blue light band of 400 nm to 500 nm. It is a laser. The laser light 20 emitted from the laser light source 201 travels straight as a parallel beam and is reflected by the first mirror 203. The laser light 20 reflected by the first mirror 203 is focused on the electro-optic deflection element 209 by the condensing lens 207 and then converted into a parallel beam again by the collimator lens 211. The parallel laser beam 20 is reflected by the second mirror 213 and guided horizontally onto the moving optical table 220.

  The first mirror 203 is composed of a polarization beam splitter, and has a function of reflecting one of the polarization components and transmitting the other of the polarization components. The polarization component transmitted through the first mirror 203 is photoelectrically converted by the photodiode 205, and the photoelectrically received light signal is input to the laser light source 201. Thereby, the laser light source 201 can modulate the laser light 20 based on feedback by the received light reception signal.

  The electro-optic deflection element 209 is an element that can control the irradiation position of the laser light 20. The exposure apparatus 200 can change the irradiation position of the laser light 20 guided onto the moving optical table 220 by the electro-optic deflection element 209.

  The moving optical table 220 includes a beam expander (BEX) 221 and an objective lens 223. The laser beam 20 guided to the moving optical table 220 is shaped into a desired beam shape by the beam expander 221 and then irradiated to the resist layer formed on the outer peripheral surface of the base material 10 through the objective lens 223. Is done.

  Here, the substrate 10 is rotated by the turntable 227 and the resist layer is irradiated with the laser beam 20 while moving the laser beam 20 in the axial direction of the substrate 10, thereby spiraling the substrate 10. Exposure is performed. The laser beam 20 is moved by moving the moving optical table 220 in the arrow R direction.

  In addition, the exposure apparatus 200 includes a control mechanism 230 for controlling the irradiation position with the laser light 20. The control mechanism 230 includes a formatter 231 and a driver 233, and controls the irradiation of the laser light 20. Further, the driver 233 controls the output of the laser light source 201 based on the control signal generated by the formatter 231.

  In the exposure apparatus 200 according to the present embodiment, the control signal of the laser light 20 generated by the formatter 231, the number of rotations of the turntable 227, the feed pitch of the moving optical table 220, and the like can be controlled. The latent image to be formed can be randomly formed in the axial direction and the circumferential direction of the substrate 10.

  Subsequently, a control method of the exposure apparatus 200 for making the latent image corresponding to the micro concavo-convex structure 13 random in the axial direction and the circumferential direction will be described with reference to FIGS. FIG. 4 is an explanatory diagram for explaining a control signal used for laser light modulation in the exposure apparatus 200. FIG. 5A is a schematic diagram showing a two-dimensional pattern of the latent image of the resist layer according to the comparative example. FIGS. 5B and 5C are examples of the two-dimensional pattern of the latent image of the resist layer according to the present embodiment. It is a schematic diagram shown. In FIGS. 5A to 5C, the black portions correspond to the latent images formed by exposure.

  In the master production method according to the present embodiment, the control signal generated by the formatter 231 is not the periodic control signal A illustrated in FIG. 4 but the control signal having no periodicity in the predetermined range illustrated in FIG. B is used.

  Here, when the master disk is exposed by controlling the laser beam 20 using a control signal A that is a rectangular wave having a fixed period as shown in FIG. 4, for example, a latent image pattern as shown in FIG. 5A is formed. . Specifically, FIG. 5A shows a latent image pattern in which rectangular-shaped latent images are periodically formed in the axial direction (track direction) and the circumferential direction (dot direction) of the substrate 10.

  On the other hand, when the master disk is exposed by controlling the laser beam 20 using the control signal B having no periodicity within a predetermined range as shown in FIG. 4, for example, a latent image pattern as shown in FIG. 5B is formed. be able to. Specifically, FIG. 5B shows a latent image pattern in which latent images are formed at random lengths and intervals in the axial direction (track direction) and the circumferential direction (dot direction) of the substrate 10.

  The control signal B may be random within a predetermined range (if it does not have periodicity), and all the signals need not be random. That is, the control signal B may be a signal in which a random signal within a predetermined range is repeated at a constant period. As such a signal, for example, a pseudo random signal (PRBS) can be exemplified.

  Here, the predetermined range represents, for example, the random length of the pseudo random signal. In addition, although the randomness is ensured within the set random length, the pseudo-random signal repeats the set random length in the macro range. Therefore, when the random length set by the pseudo-random signal is excessively short, periodicity with a random long period is seen in the formed latent image, and diffracted light is generated in the optical body to which the micro uneven structure 13 is transferred. Sometimes. Therefore, the random length of the pseudo random signal is preferably sufficiently long, and a preferable length is 2 to the 23rd power or more.

  Further, when the master disk is exposed by controlling the laser beam 20 using the control signal B having no periodicity in such a predetermined range, the depth of the latent image formed can be made random. This is because, when the irradiation time of the laser beam 20 is sufficiently long, a latent image is formed up to the lower layer of the resist layer, but when the irradiation time of the laser beam 20 is short, the time integral value of the laser beam 20 becomes small. This is because a latent image is not formed up to the lower layer of the resist layer, and a shallow latent image is formed. When the latent image is shallow, the amplitude of the unevenness of the micro uneven structure 13 can be reduced by etching when the micro uneven structure 13 is formed on the substrate 10. Therefore, according to such a control signal B, the amplitude of the unevenness of the micro uneven structure 13 formed on the substrate 10 can be made random.

  Further, the exposure apparatus 200 controls the number of rotations of the turntable 227, the feed pitch of the moving optical table 220, and the like, whereby the interval of the irradiation position of the laser beam 20 with respect to the axial direction of the substrate 10 (ie, the track pitch). Is preferably 75 nm or more and 350 nm or less.

  When the interval between the irradiation positions of the laser beam 20 with respect to the axial direction of the base material 10 becomes excessively large, periodicity is caused in the axial direction of the base material 10 due to the spiral exposure trajectory by the laser light 20. there is a possibility. In such a case, since the density of the unevenness of the micro uneven structure 13 formed on the master 1 is reduced, the antireflection characteristics of the optical body manufactured using the master 1 may be reduced.

  Therefore, the exposure apparatus 200 is manufactured by improving the density of the unevenness of the micro uneven structure 13 formed on the master 1 by narrowing the interval between the irradiation positions of the laser light 20 with respect to the axial direction of the substrate 10 to 350 nm or less. It is preferable to improve the optical characteristics of the optical body. The exposure apparatus 200 preferably forms the micro uneven structure 13 as a continuous structure between the adjacent tracks by overlapping the latent images formed by the irradiation of the laser light 20 between the adjacent tracks. In such a case, the exposure apparatus 200 can remove the periodicity due to the exposure trajectory from the latent image pattern.

  However, when the interval between the irradiation positions of the laser beam 20 with respect to the axial direction of the base material 10 is excessively narrowed, the latent images for each track are connected, and a latent image having a size larger than the visible light wavelength is formed. There is a possibility that the period of the unevenness of the uneven structure 13 is larger than the visible light wavelength. Therefore, the interval between the irradiation positions of the laser beam 20 with respect to the axial direction of the base material 10 is preferably 75 nm or more.

  Further, the exposure apparatus 200 controls the frequency of the control signal B, the number of rotations of the turntable 227, and the like, thereby irradiating the laser beam with respect to the circumferential direction of the substrate 10 corresponding to one bit of the control signal (that is, The 1-bit exposure length) is preferably 0.2 μm or less.

  When the laser beam 20 is controlled using a control signal having no periodicity within a predetermined range, the interval between the latent images in the circumferential direction of the substrate 10 may be increased depending on the control signal. In such a case, since the density of the unevenness of the micro uneven structure 13 formed on the master 1 is lowered, the antireflection characteristic of the optical body manufactured using the master 1 may be lowered. Depending on the control signal, a latent image larger than the visible light wavelength may be formed in the circumferential direction of the substrate 10. In such a case, the period of the unevenness of the micro uneven structure 13 formed on the master 1 becomes larger than the visible light wavelength, and the antireflection characteristic may be deteriorated.

  Therefore, the exposure apparatus 200 controls the irradiation distance of the laser light 20 with respect to the circumferential direction of the base material 10 corresponding to one bit of the control signal to 0.2 μm or less so that the interval between the latent images becomes large or the base material 10 It is preferable not to form a long latent image in the circumferential direction. In such a case, the exposure apparatus 200 can form a latent image on the master 1 corresponding to the micro uneven structure 13 that can further improve the antireflection characteristics of the optical body.

  Note that the lower limit of the irradiation distance of the laser beam 20 in the circumferential direction of the base material 10 corresponding to one bit of the control signal is not particularly limited. However, in consideration of the resolution of the resist formed on the outer peripheral surface of the base material 10, the ability of the formatter 231 to generate a control signal, etc., the irradiation distance of the laser light 20 with respect to the circumferential direction of the base material 10 is, for example, It may be 40 nm or more.

  Further, when the control signal for controlling the laser beam 20 includes a signal for which the continuous irradiation distance of the laser beam 20 exceeds the threshold value, the exposure apparatus 200 controls the formatter 231 to control the signal exceeding the threshold value. Is preferably not output. In such a case, since the exposure apparatus 200 can control the exposure so as not to form a latent image larger than the visible light wavelength, it corresponds to the micro concavo-convex structure 13 that reduces the antireflection characteristic of the optical body. It is possible to prevent the latent image from being formed on the master.

  When the master 1 is exposed using the control signal B having no periodicity within the predetermined range as described above, and preferable exposure conditions, for example, a latent image pattern as shown in FIG. 5C can be formed. . Specifically, in FIG. 5C, a latent image that is partially connected in the axial direction (track direction) of the substrate 10 and finely divided in the circumferential direction (dot direction) of the substrate 10 is formed. The latent image pattern is shown.

  According to the exposure method described above, the exposure apparatus 200 corresponds to the micro concavo-convex structure 13 with respect to the resist layer formed on the outer peripheral surface of the base material 10, and the axial direction and the peripheral direction of the base material 10. A random latent image can be formed.

[1.3. Master production method]
Next, with reference to FIGS. 6-12, the manufacturing method of the original disk which concerns on this embodiment is demonstrated. 6-12 is sectional drawing explaining each process of the manufacturing method of the original disk which concerns on this embodiment. In addition, each following process can be implemented using a well-known general apparatus. Moreover, since it is possible to apply general manufacturing conditions about the specific conditions in each process, detailed description, such as a numerical value, is abbreviate | omitted.

  First, as shown in FIG. 6, for example, a base material resist layer 15 is formed on a base material 10 such as washed quartz glass. The shape of the base material 10 may be, for example, a cylindrical shape or a columnar shape.

  As the base resist layer 15, either an organic resist or an inorganic resist can be used. As the organic resist, for example, a novolac resist or a chemically amplified resist can be used. As the inorganic resist, for example, a metal oxide containing one or more transition metals such as tungsten (W) and molybdenum (Mo) can be used. However, the base resist layer 15 is preferably formed of a heat-reactive resist containing a metal oxide in order to perform heat-reactive lithography.

  When an organic resist is used for the base resist layer 15, the base resist layer 15 can be formed by using spin coating, slit coating, dip coating, spray coating, screen printing, or the like. Moreover, when using an inorganic type resist for the base material resist layer 15, the base material resist layer 15 can be formed into a film by using a sputtering method. In addition, as a film thickness of the base-material resist layer 15, 20 nm or more and 100 nm or less can be used, for example.

  Next, as shown in FIG. 7, the base resist layer 15 is exposed by the exposure apparatus 200, and a latent image 15 </ b> A corresponding to the micro uneven structure 13 is formed on the base resist layer 15. Here, the exposure apparatus 200 exposes the base resist layer 15 by the exposure method described above, and forms a random latent image 15A in the axial direction and the circumferential direction of the base 10.

  When patterning the base resist layer 15 by thermal reaction lithography, the exposure apparatus 200 irradiates the base resist layer 15 with the modulated laser beam 20. Thereby, a part of the base resist layer 15 irradiated with the laser beam 20 can be denatured by a thermal reaction, so that a latent image 15A corresponding to the micro uneven structure 13 can be formed on the base resist layer 15. it can.

  Subsequently, as shown in FIG. 8, a developing solution is dropped onto the base resist layer 15 on which the latent image 15A is formed, and the base resist layer 15 is developed. Thereby, the micro uneven structure 13 is formed in the base resist layer 15. In FIG. 8, the base resist layer 15 is a positive resist, and the latent image 15A portion exposed by the laser beam 20 is removed by development processing. It is not limited. For example, the base resist layer 15 may be a negative resist. In such a case, since the unexposed portion is removed by the development process, a pattern in which the portion of the latent image 15 </ b> A exposed with the laser beam 20 remains is formed on the base material resist layer 15.

Next, as shown in FIG. 9, an inorganic resist layer 17 is formed on the base resist layer 15 so as to embed the micro uneven structure 13. The inorganic resist layer 17 uses, for example, SiO ₂ , Si, DLC (Diamond Like Carbon), transition metals such as W and Mo, metal oxides including one or more transition metals such as W and Mo, and the like. Thus, the film can be formed by sputtering or the like. In addition, as a film thickness of the inorganic resist layer 17, 100 nm or more and 1500 nm or less can be used, for example.

In the method for manufacturing the master 1 according to the present embodiment, the base resist layer 15 on which the micro uneven structure 13 is formed is etched simultaneously with the inorganic resist layer 17 formed on the base resist layer 15 in a process described later. Is done. Therefore, the material of the inorganic resist layer 17 is preferably selected so that the etching rate is different from that of the base resist layer 15. For example, when the base resist layer 15 is a metal oxide such as tungsten oxide, the inorganic resist layer 17 is preferably SiO ₂ , Si, DLC, or the like.

  On the other hand, when the etching rate of the inorganic resist layer 17 is the same as the etching rate of the base resist layer 15, the inorganic resist layer 17 and the base resist layer 15 are uniformly etched. The micro uneven structure 13 disappears. Therefore, in order to form the micro uneven structure 13 on the substrate 10, it is preferable that the etching rate of the inorganic resist layer 17 is different from the etching rate of the substrate resist layer 15.

  Subsequently, as shown in FIG. 10, an organic resist layer 19 having a macro uneven structure 11 having an average period of unevenness larger than the visible light wavelength on the surface is formed on the inorganic resist layer 17. Any organic resin can be used as the organic resin for forming the organic resist layer 19. For example, organic resins such as novolac resins and acrylic resins can be used.

  Here, the organic resist layer 19 is preferably formed by atomizing and spraying an organic resin dissolved in a diluent. According to this method, since the organic resist layer 19 having the macro concavo-convex structure 11 formed on the surface can be formed in a thinner film, variations in etching in the subsequent etching process can be suppressed.

  Specifically, the organic resin is diluted with a diluent containing a solvent that volatilizes during spraying, and the diluted organic resin is sprayed onto the inorganic resist layer 17 with a spray coater or the like to form the organic resist layer 19. be able to. In addition, as a solvent which volatilizes during spraying, a solvent having a low boiling point such as acetone, isopropyl alcohol, dimethyl ether, and methyl acetate can be used. Moreover, as a dilution ratio of the organic resin, a diluent of 10 to 30 (that is, a dilution ratio of 10 times to 30 times) can be used with respect to the organic resin 1 in terms of mass ratio.

  Further, after the organic resist layer 19 is formed on the inorganic resist layer 17 by a coating method such as a spin coat method, the macro uneven structure 11 is formed by transfer by imprinting of a rough surface film or sandblasting. Also good. In addition, when forming the organic resist layer 19 by application | coating methods, such as a spin coat method, as a film thickness of the organic resist layer 19, 50 nm or more and 2000 nm or less can be used, for example.

  Subsequently, as shown in FIG. 11, the inorganic resist layer 17 is etched using the organic resist layer 19 on which the macro uneven structure 11 is formed as a mask. Thereby, the macro uneven structure 11 is formed in the inorganic resist layer 17. In the etching of the inorganic resist layer 17 in this step, dry etching having vertical anisotropy is preferably used. For example, reactive ion etching (RIE) is preferably used. On the other hand, it is not preferable to use isotropic etching such as wet etching because the shape of the macro uneven structure 11 formed in the inorganic resist layer 17 may be greatly changed.

Etching of the inorganic resist layer 17 using the organic resist layer 19 as a mask uses an etching gas containing at least fluorine atoms and at least two or more of carbon atoms, fluorine atoms, oxygen atoms and hydrogen atoms. Is preferred. Specifically, a fluorocarbon gas such as CHF ₃ , CH ₂ F ₂ , CF ₄ , C ₂ F ₈ , and C ₃ F ₈ can be used as an etching gas. It is also possible to add additive gases such as O ₂ gas, H ₂ gas, and Ar gas to the etching gas.

Here, the height of the unevenness of the macro uneven structure 11 formed in the inorganic resist layer 17 can be controlled by the type and ratio of the etching gas. For example, by increasing the proportion of O ₂ gas added to the etching gas, the height of the unevenness of the macro uneven structure 11 formed in the inorganic resist layer 17 can be reduced. This is because the etching rate of the organic resist layer 19 increases when the proportion of O ₂ gas in the etching gas increases.

In this step, after the inorganic resist layer 17 is etched, an O ₂ ashing process or a wiping process using an organic solvent may be performed for the purpose of removing the remaining organic resist layer 19.

  Next, as shown in FIG. 12, the base material 10 is etched using the inorganic resist layer 17 in which the macro uneven structure 11 is formed and the base resist layer 15 in which the micro uneven structure 13 is formed as a mask. Thereby, the macro uneven structure 11 and the micro uneven structure 13 are superimposed on the substrate 10. For the etching of the base material 10 in this step, it is preferable to use dry etching having vertical anisotropy as in the etching to the inorganic resist layer 17, for example, reactive ion etching (RIE) is used. Is preferred. On the other hand, when isotropic etching such as wet etching is used, there is a high possibility that the micro concavo-convex structure 13 is not formed on the substrate 10, which is not preferable.

In addition, the etching of the substrate 10 using the inorganic resist layer 17 and the substrate resist layer 15 as a mask includes at least a fluorine atom and an etching including at least two or more of carbon atoms, fluorine atoms, oxygen atoms, and hydrogen atoms. A gas is preferably used. Specifically, a fluorocarbon gas such as CHF ₃ , CH ₂ F ₂ , CF ₄ , C ₂ F ₈ , and C ₃ F ₈ can be used as an etching gas. It is also possible to add additive gases such as O ₂ gas, H ₂ gas, and Ar gas to the etching gas.

  Note that an etching gas for etching the base material 10 using the inorganic resist layer 17 and the base material resist layer 15 as a mask is different from an etching gas for etching the inorganic resist layer 17 using the organic resist layer 19 as a mask. It is preferable to use seeds. This includes a step of etching an inorganic substance (inorganic resist layer 17) using an organic substance (organic resist layer 19) as a mask, and quartz glass or the like (base material 10) mainly using inorganic substances (inorganic resist layer 17 and base resist layer 15) as a mask. This is because the etching conditions necessary for obtaining an appropriate etching rate ratio are often different from those in the step of etching.

  Here, the inorganic resist layer 17 on which the macro uneven structure 11 is formed is etched simultaneously with the base resist layer 15, and the macro uneven structure 11 formed on the inorganic resist layer 17 is formed on the base 10. Further, the micro uneven structure 13 formed on the base resist layer 15 is formed on the base material 10 so as to overlap with the macro uneven structure 11 in the following manner.

  Specifically, when the etching rate of the inorganic resist layer 17 is slower than the etching rate of the base material resist layer 15, the base material resist layer 15 is etched first. 10 is exposed first. Therefore, etching of the substrate 10 proceeds using the inorganic resist layer 17 formed in the recesses of the micro concavo-convex structure 13 as a mask. Therefore, the micro concavo-convex structure 13 in which the micro concavo-convex structure 13 formed in the base resist layer 15 and the micro concavo-convex structure are reversed is formed on the macro concavo-convex structure 11.

  Further, when the etching rate of the inorganic resist layer 17 is faster than the etching rate of the base material resist layer 15, the etching of the inorganic resist layer 17 proceeds first, so that the base material 10 in contact with the inorganic resist layer 17 is exposed first. To do. Therefore, etching of the substrate 10 proceeds using the substrate resist layer 15 on which the micro uneven structure 13 is formed as a mask. Therefore, the micro concavo-convex structure 13 having the same concavo-convex position as the micro concavo-convex structure 13 formed in the base resist layer 15 is superimposed on the macro concavo-convex structure 11.

  In this step, the substrate 10 on which the macro uneven structure 11 and the micro uneven structure 13 are superimposed are further subjected to a cleaning process for removing the remaining inorganic resist layer 17 and substrate resist layer 15. It may be done.

  The master 1 according to this embodiment is manufactured through the above steps. According to the method for manufacturing a master according to the present embodiment, the macro uneven structure 11 having an average period of unevenness larger than the visible light wavelength, the average period of unevenness being equal to or less than the visible light wavelength, and the axial direction and the circumference of the substrate 10 The master 1 in which the random micro uneven structure 13 is formed so as to overlap in the direction can be manufactured.

The inorganic resist layer 17 may be formed of a single layer or may be formed of a plurality of layers. When the inorganic resist layer 17 is formed of a plurality of layers, the inorganic resist layer 17 is formed by laminating resists having different properties such as DLC and SiO ₂ , DLC and metal oxide, metal oxide and Si, for example. It is preferable. Thereby, the selection range of the etching conditions with respect to the base material 10 can be expanded.

  In the above, a method is shown in which the inorganic resist layer 17 is formed so as to embed the base resist layer 15 on which the micro uneven structure 13 is formed, and the inorganic resist layer 17 and the base resist layer 15 are simultaneously etched. However, the present invention is not limited to such examples. For example, the substrate 10 is first etched using the substrate resist layer 15 on which the micro uneven structure 13 is formed as a mask, and then the inorganic resist layer 17 is formed on the substrate 10 on which the micro uneven structure 13 is formed. May be. In such a case, the inorganic resist layer 17 is formed of, for example, a plurality of layers of a DLC layer formed on the substrate 10 and a metal oxide (for example, tungsten oxide) layer formed on the DLC layer. May be.

  However, when the micro concavo-convex structure 13 is formed by etching the base 10 first, the height of the concavo-convex of the micro concavo-convex structure 13 formed on the base 10 is equal to the micro concavo-convex structure formed on the base resist layer 15. It becomes larger than the height of 13 unevenness. Therefore, the aspect ratio of the micro concavo-convex structure 13 formed on the substrate 10 is not preferable because the coverage of the inorganic resist layer 17 is reduced and etching variations with respect to the inorganic resist layer 17 are likely to occur.

  On the other hand, when the inorganic resist layer 17 is formed on the base resist layer 15 on which the micro uneven structure 13 is formed, the height of the unevenness of the micro uneven structure 13 formed on the base resist layer 15 is reduced. The aspect ratio is also reduced. Therefore, it is preferable because the variation in etching with respect to the inorganic resist layer 17 hardly occurs when the coverage of the inorganic resist layer 17 is improved.

<2. Optical bodies manufactured using the master disc>
[2.1. Manufacturing method of optical body]
Next, an optical body manufactured using the master 1 according to this embodiment will be described. The optical body manufactured using the master 1 according to this embodiment can be used as, for example, an antireflection film, a stray light prevention film, or the like. Specifically, the optical body transfers the macro concavo-convex structure 11 and the micro concavo-convex structure 13 formed on the outer peripheral surface of the master 1 according to the present embodiment to a resin substrate or the like using a roll-to-roll nanoimprint method. Can be manufactured.

  Below, with reference to FIG. 13, the transfer apparatus which can manufacture an optical body continuously using the original disk 1 which concerns on this embodiment is demonstrated. FIG. 13 is an explanatory diagram for explaining a transfer device that manufactures an optical body using a master according to the present embodiment.

  As shown in FIG. 13, the transfer device 300 includes a base material supply roll 301, a take-up roll 302, guide rolls 303 and 304, a nip roll 305, a peeling roll 306, a coating device 307, and a light source 309. Prepare. Further, the transfer apparatus 300 is provided with the master 1 having an uneven structure formed on the outer peripheral surface. That is, the transfer apparatus 300 shown in FIG. 13 is a roll-to-roll nanoimprint transfer apparatus.

  The substrate supply roll 301 is a roll in which the sheet-shaped resin substrate 3 is wound in a roll shape, and the take-up roll 302 is an optical body 4 in which the resin layer 310 to which the uneven structure of the master 1 is transferred is laminated. It is a roll to wind. The guide rolls 303 and 304 are rolls that transport the resin base material 3 or the optical body 4. The nip roll 305 is a roll for pressing the resin base material 3 on which the resin layer 310 is laminated against the master 1, and the peeling roll 306 is the optical body 4 on which the resin layer 310 on which the uneven structure of the master 1 is transferred is mastered. 1 is a roll that peels from 1.

  The coating device 307 includes coating means such as a coater, and applies the photocurable resin composition to the resin base material 3 to form the resin layer 310. The coating device 307 may be, for example, a gravure coater, a wire bar coater, or a die coater. The light source 309 is a light source that emits light having a wavelength capable of curing the photocurable resin composition, and may be, for example, an ultraviolet lamp.

  In addition, a photocurable resin composition is resin hardened | cured when the light of a predetermined wavelength is irradiated. Specifically, the photocurable resin composition may be an ultraviolet curable resin such as an acrylic resin acrylate or an epoxy acrylate. Moreover, the photocurable resin composition may contain an initiator, a filler, a functional additive, a solvent, an inorganic material, a pigment, an antistatic agent, a sensitizing dye, or the like, if necessary.

  In the transfer device 300, first, the resin base material 3 is continuously sent out from the base material supply roll 301 through the guide roll 303. The photocurable resin composition is applied to the sent resin base material 3 by the coating device 307, and the resin layer 310 is laminated on the resin base material 3. In addition, the resin base material 3 on which the resin layer 310 is laminated is pressed against the master 1 by the nip roll 305. As a result, the uneven structure formed on the outer peripheral surface of the master 1 is transferred to the resin layer 310. The resin layer 310 to which the concavo-convex structure is transferred is cured by irradiating light from the light source 309, and the optical body 4 on which the cured resin layer 310 is laminated is separated from the master 1 by the separation roll 306, and then guided. It is sent out to the take-up roll 302 via the roll 304 and taken up.

  According to such a transfer apparatus 300, it is possible to continuously manufacture an optical body on which the macro uneven structure 11 and the micro uneven structure 13 formed on the outer peripheral surface of the master 1 according to this embodiment are transferred in a large area. it can.

[2.2. Application example of optical body]
Then, with reference to FIG. 14A-FIG. 14B, the application example of the optical body manufactured with the original disk which concerns on this embodiment is demonstrated.

  The optical body 4 according to the present embodiment can be suitably used as an antireflection film laminated on a display surface such as a display device or a display plate, for example. In addition, it is preferable that the haze value of the optical body 4 is 20% or more, and it is more preferable that it is 40% or more. Hereinafter, the reason why the optical body 4 according to this embodiment is suitable as an antireflection film will be described.

  1stly, the optical body 4 has a high antireflection characteristic by providing the periodic micro uneven | corrugated structure whose average period of an unevenness | corrugation is below visible light wavelength. Therefore, since the optical body 4 can suppress the reflection of the incident light to the display surface, it is possible to improve the visibility of characters and images displayed on the display device, the display plate, and the like.

  Secondly, the optical body 4 has a high anti-glare property by providing on the surface a macro uneven structure having an average period of unevenness larger than the visible light wavelength. Therefore, since the optical body 4 can suppress reflection of external light or the like on a display surface such as a display device or a display plate, the visibility of displayed characters and images can be improved.

  Thirdly, the optical body 4 preferably has a haze value (that is, scattering efficiency) of 20% or more. Since the optical body 4 has high scattering efficiency, the internal reflection light generated at the interface between the display device and the display plate and the optical body 4 and the internal reflection light from the display device and the display plate can be suppressed. The haze value of the optical body 4 is more preferably 40% or more. The upper limit value of the haze value of the optical body 4 is not particularly defined and may be 100%.

  Furthermore, with reference to FIG. 14A and FIG. 14B, the mechanism in which the optical body 4 which concerns on this embodiment suppresses internal reflection is demonstrated. FIG. 14A is an explanatory diagram showing the course of incident light when an optical body 4A having a lower scattering efficiency than the optical body 4 according to the present embodiment is laminated on the internal reflector 5. FIG. 14B is an explanatory diagram showing the course of incident light when the optical body 4 according to this embodiment is laminated on the internal reflector 5. The internal reflector 5 is, for example, a display device or a display plate.

  As shown in FIG. 14A, in the internal reflector 5 in which the optical body 4A is laminated, the scattering efficiency on the surface of the optical body 4A is low. Therefore, when strong incident light 6A is incident, a part of the incident light 6A is internal. It reaches the reflector 5. Here, since reflection occurs at the interface of the members having different refractive indexes, a part of the incident light 6A is reflected by the interface 51 between the optical body 4A and the internal reflector 5, and regular reflection light 6B is generated. . Therefore, in the internal reflector 5 in which the optical body 4A having a lower scattering efficiency than the optical body 4 according to the present embodiment is laminated, internal reflection cannot be sufficiently suppressed, and thus reflection of external light cannot be sufficiently suppressed. .

  On the other hand, as shown in FIG. 13B, in the internal reflector 5 in which the optical body 4 according to the present embodiment is laminated, the scattering efficiency on the surface of the optical body 4 is high. Almost all of the light 6A can be scattered at the surface. Thereby, in the optical body 4, the incident light 6 </ b> A reaching the internal reflector 5 can be greatly reduced, so that the specularly reflected light 6 </ b> B reflected at the interface 51 between the optical body 4 </ b> A and the internal reflector 5 is almost all. Does not occur. Therefore, the internal reflector 5 in which the optical bodies 4 according to the present embodiment are laminated can sufficiently suppress the reflection of external light.

  Note that such an effect of suppressing internal reflection by the optical body 4 is more effectively exhibited in a liquid crystal display device in which a large number of members having different refractive indexes are stacked. Further, such an optical body 4 can be used more effectively in an in-vehicle display device or a display panel in which strong external light is incident and there is a strong demand for suppressing reflection of external light on the display surface. .

  The master according to the present embodiment and the optical body manufactured by the master have been described in detail above.

<3. Example>
Hereinafter, the master according to the present embodiment will be described more specifically with reference to examples and comparative examples. In addition, the Example shown below is one example of conditions for showing the feasibility and effects of the master and the manufacturing method thereof according to the present embodiment, and the master and the manufacturing method according to the invention are the following examples. It is not limited.

[3.1. Evaluation of exposure method]
First, exposure with a laser beam was performed while changing the exposure conditions, and it was confirmed that a random micro uneven structure can be formed by the exposure method according to the present embodiment.

(Test Example 1)
First, a base resist layer is formed by sputtering on a peripheral surface of a base material (axial length: 480 mm × outside diameter: 132 mm) made of cylindrical quartz glass, using a material containing tungsten oxide by a sputtering method. did. Next, thermal reaction lithography using a laser beam was performed by the exposure apparatus shown in FIG. 3, and a latent image corresponding to a random micro uneven structure was formed on the base resist layer. Subsequently, the exposed substrate was developed with NMD3 (tetramethylammonium hydroxide 2.38 mass% aqueous solution) (manufactured by Tokyo Ohka Kogyo Co., Ltd.) to form a micro uneven structure on the substrate resist layer.

  As a laser light source of the exposure apparatus, a laser diode that emits laser light having a wavelength in the blue light band of 400 nm to 500 nm was used. Further, as the laser light control signal, a pseudo-random signal having a bit number of 50 M per second and a random length generated by a PRBS signal generator of 2 23 is used. Further, the exposure was performed with the rotational speed of the cylindrical base material set to 900 rpm and the axial feed rate of the base material set to 1.5 μm / second. At this time, in the exposure pattern, the irradiation distance of the laser beam corresponding to one bit of the control signal was 0.12 μm, and the track pitch of the exposure pattern was 100 nm.

(Test Example 2)
The exposure was performed under the same conditions as in Test Example 1 except that the number of revolutions of the cylindrical base material was 300 rpm and the axial feed rate of the base material was 0.5 μm / second. At this time, in the exposure pattern, the irradiation distance of the laser beam corresponding to one bit of the control signal was 0.041 μm, and the track pitch of the exposure pattern was 100 nm.

(Test Example 3)
The exposure was performed under the same conditions as in Test Example 1 except that the axial feed rate of the substrate was 2.76 μm / second. At this time, in the exposure pattern, the irradiation distance of the laser beam corresponding to one bit of the control signal was 0.12 μm, and the track pitch of the exposure pattern was 184 nm.

(Test Example 4)
The exposure was performed under the same conditions as in Test Example 1 except that the axial feed rate of the substrate was 1.125 μm / sec. At this time, in the exposure pattern, the irradiation distance of the laser beam corresponding to one bit of the control signal was 0.12 μm, and the track pitch of the exposure pattern was 75 nm.

(Evaluation result of micro uneven structure)
The evaluation samples according to Test Examples 1 to 4 manufactured above were observed at 20000 times with a scanning electron microscope (SEM), and it was confirmed that a random micro uneven structure was formed. An image representing the observation result is shown in FIG. FIG. 15 is an SEM observation image of the evaluation sample according to Test Examples 1 to 4.

  Referring to the observation images of Test Examples 1 and 2 in FIG. 15, it can be seen that a random micro uneven structure is formed when the irradiation distance of the laser beam corresponding to one bit of the control signal is 0.2 μm or less. . Further, referring to the observation images of Test Examples 1, 3, and 4 in FIG. 15, when the track pitch (interval of the laser irradiation position with respect to the axial direction of the base material) is 75 nm or more and 350 nm or less, a random micro uneven structure is formed. It can be seen that it is formed.

  However, referring to the observation image of Test Example 4, the connection of latent images between adjacent tracks increases, so that the uneven structure with an uneven period longer than the visible light wavelength increases. This shows that the track pitch is preferably 75 nm or more. In addition, since the spot diameter of the laser light is approximately 300 nm, there is a possibility that connection of latent images between adjacent tracks may not occur when the track pitch exceeds 350 nm. Therefore, it can be seen that the track pitch is preferably 350 nm or less.

  Therefore, according to the exposure method concerning this embodiment, it turns out that the micro uneven structure whose uneven | corrugated average period is below visible light wavelength can be formed on a base-material resist layer at random.

[3.2. Evaluation of the master]
Subsequently, the master according to the present embodiment was manufactured by the following steps, and an optical body was manufactured using the manufactured master.

Example 1
First, a base resist layer is formed by sputtering on a peripheral surface of a base material (axial length: 480 mm × outside diameter: 132 mm) made of cylindrical quartz glass, using a material containing tungsten oxide by a sputtering method. did. Next, thermal reaction lithography using a laser beam was performed by the exposure apparatus 200 shown in FIG. 3, and a latent image corresponding to a random micro uneven structure was formed on the base resist layer.

  As a laser light source of the exposure apparatus, a laser diode that emits laser light having a wavelength in the blue light band of 400 nm to 500 nm was used. Further, as the laser light control signal, a pseudo-random signal having a bit number of 50 M per second and a random length generated by a PRBS signal generator of 2 23 is used. Further, the exposure was performed with the rotational speed of the cylindrical base material set to 900 rpm and the axial feed rate of the base material set to 1.5 μm / second. At this time, in the exposure pattern, the irradiation distance of the laser beam corresponding to 1 bit of the control signal was 0.12 μm, and the track pitch of the exposure pattern was 100 nm.

  Subsequently, the exposed portion of the substrate resist is dissolved by developing the substrate with NMD3 (tetramethylammonium hydroxide 2.38 mass% aqueous solution) (manufactured by Tokyo Ohka Kogyo Co., Ltd.), and the substrate resist layer A random micro uneven structure was formed.

Next, an inorganic resist layer made of SiO ₂ was formed to a thickness of 1000 nm on the base material resist layer on which a random micro uneven structure was formed. Note that the inorganic resist layer was formed by oxygen-added sputtering using a Si target.

  Subsequently, using a solution obtained by diluting a novolac resin P4210 (manufactured by AZ Co., Ltd.) 20 times by mass with a diluent consisting only of acetone, the P4210 is atomized on the inorganic resist layer by spray coating. Sprayed. As a result, an organic resist layer having a macro uneven structure was formed on the inorganic resist layer.

Next, using the organic resist layer as a mask, the inorganic resist layer was etched using CHF ₃ gas (30 sccm) and CF ₄ gas (30 sccm) at a gas pressure of 0.5 Pa and an input power of 200 W for 20 minutes. Subsequently, using the inorganic resist layer and the base material resist layer as a mask, the base material was etched for 120 minutes at a gas pressure of 0.5 Pa and an input power of 200 W using CHF ₃ gas (30 sccm).

  Through the above steps, a master was produced in which the micro uneven structure formed on the base resist layer and the macro uneven structure formed on the organic resist layer were superimposed.

Moreover, the optical body was manufactured using the master disc manufactured above. Specifically, with the transfer device 300 shown in FIG. 13, the micro uneven structure and the macro uneven structure formed on the outer peripheral surface of the master were transferred to an ultraviolet curable resin, and the optical body according to Example 1 was manufactured. . A polyethylene terephthalate film was used as the resin substrate of the optical body. The ultraviolet curable resin was cured by irradiating with 1000 mJ / cm ² of ultraviolet light for 1 minute with a metal halide lamp.

(Example 2)
A master according to Example 2 in the same manner as in Example 1 except that the axial feed rate of the base material during exposure is 2.76 μm / sec and the irradiation interval of laser light in the axial direction of the base material is 184 nm. Manufactured. In addition, an optical body was manufactured in the same manner as in Example 1 by using the master according to Example 2.

(Comparative Example 1)
In the exposure pattern, a periodic array of hexagonal lattices in which circular dots are arranged in rows (tracks) at a pitch of about 230 nm along the circumferential direction of the substrate, and the interval between adjacent tracks is about 150 nm. A master according to Comparative Example 1 was manufactured in the same manner as in Example 1 except that it was used. In addition, an optical body was manufactured in the same manner as in Example 1 using the master according to Comparative Example 1.

(Evaluation results)
The concavo-convex structure formed on the master was evaluated by evaluating the optical body to which the concavo-convex structure formed on the master was transferred.

  First, the concavo-convex structure formed on the optical body according to Example 1 was observed using SEM. The result is shown in FIG. FIG. 16 is an SEM image obtained by observing the surface of the optical body according to Example 1 at a magnification of 50000 times. The image A is an SEM image observed without tilting the optical body, and the image B is an SEM image observed with the optical body tilted 45 degrees.

  Referring to image A in FIG. 16, it can be seen that a micro uneven structure having a size equal to or smaller than the visible light wavelength is randomly formed on the surface of the optical body according to Example 1. In addition, referring to the image B in FIG. 16 observed with the optical body tilted, it can be seen that the micro uneven structure formed on the surface of the optical body according to Example 1 is also random in amplitude (height). .

  Next, regular reflection spectroscopy measurement was performed on the optical bodies according to Example 1 and Comparative Example 1, and the antireflection characteristics of the optical bodies were evaluated. Specifically, after directly irradiating the sample with light from the light source, the reflected light from the sample is collected by a spherical mirror, and the collected reflected light is guided to an integrating sphere and homogenized by multiple reflection. Specular reflection spectroscopy was measured.

  FIG. 17 shows the results of specular reflection spectrometry for the optical bodies according to Example 1 and Comparative Example 1. A spectrophotometer V550 (manufactured by JASCO Corporation) and an absolute reflectance measuring instrument ARV474S (manufactured by JASCO Corporation) were used for each reflectance measurement. FIG. 17 is a graph showing the results of specular reflection spectrometry of the optical bodies according to Example 1 and Comparative Example 1.

  As shown in FIG. 17, in the optical body according to Example 1, since the micro uneven structure having irregularities in the period and amplitude of the unevenness is formed, the specular reflection is greater than that in the optical body according to Comparative Example 1 in a wide wavelength band. It can be seen that the reflectance of the spectrum is low. Therefore, it can be seen that the optical body according to Example 1 has improved antireflection characteristics compared to the optical body according to Comparative Example 1.

Next, the color tone of regular reflection light of the optical bodies according to Example 1 and Comparative Example 1 was measured, and luminous reflectance (Y) and reflection chromaticity (a ^* , b ^* ) were calculated. Here, the luminous reflectance of regular reflected light (also referred to as spectral regular luminous reflectance) is the Y value of (Y, x, y) when the color of regular reflected light is expressed in the Yxy color system. And represents the brightness of the color of the specularly reflected light. The reflection chromaticity (a ^* , b ^* ) represents the color tone of the regular reflection light.

That is, the lower the luminous reflectance (Y), the lower the brightness of the regular reflection light, indicating that the regular reflection is suppressed. Further, the closer the reflection chromaticity (a ^* , b ^* ) is to 0, the more the reflected light is not colored and the reflected light does not selectively reflect light of a specific wavelength.

  The measurement results of the color tone of the regular reflection light of the optical bodies according to Example 1 and Comparative Example 1 are shown in Table 1 below. A haze meter HM-150 (manufactured by Murakami Color Research Laboratory Co., Ltd.) was used for measuring the color tone of the regular reflection light.

  Referring to the results in Table 1, the optical body according to Example 1 has a lower luminous reflectance (Y) and a lower brightness of the color of the specularly reflected light than the optical body according to Comparative Example 1. I understand that. That is, it can be seen that the optical body according to Example 1 can suppress regular reflection with respect to the optical body according to Comparative Example 1.

Further, the optical body according to Example 1 has a reflection chromaticity (a ^* , b ^* ) close to 0 as compared with the optical body according to Comparative Example 1, and suppresses regular reflection uniformly in a wide wavelength band. You can see that

  Furthermore, the presence or absence of diffracted light was evaluated for the optical bodies according to Examples 1 and 2 and Comparative Example 1. Specifically, the presence or absence of diffracted light was evaluated when each optical body was irradiated with light at an incident angle of 75 degrees. For the measurement, a spectrophotometer V570 (manufactured by JASCO Corporation) was used, and the detector angle was set to a direction rotated 5 degrees from the incident direction of light toward the direction perpendicular to the surface of the optical body.

  The results of spectroscopic measurement of diffracted light with respect to the optical bodies according to Examples 1 and 2 and Comparative Example 1 are shown in FIG. FIG. 18 is a graph showing the results of spectroscopic measurement of diffracted light of the optical bodies according to Examples 1 and 2 and Comparative Example 1.

  As shown in FIG. 18, the optical body according to Comparative Example 1 has a significantly increased reflectance near the wavelength of 350 nm, and it can be seen that diffracted light is generated. On the other hand, in the optical bodies according to Examples 1 and 2, the phenomenon that the reflectance is remarkably increased at a specific wavelength is not seen, and it can be seen that the diffracted light is suppressed.

  From the above results, the optical body manufactured using the master according to the present embodiment has a good microscopic structure with an average period of irregularities that is equal to or less than the visible light wavelength, and thus has good antireflection characteristics. It can be seen that diffracted light can be suppressed.

[3.3. Evaluation of application examples of optical bodies]
Then, with reference to FIGS. 19-21, the evaluation result at the time of applying the optical body which concerns on this embodiment as an antireflection film is demonstrated. Specifically, it was evaluated whether or not the reflection of external light on the display surface can be prevented when the optical body according to the present embodiment is attached to a display device or a display plate.

  First, an optical body was manufactured under the following conditions and bonded to a display device or a display plate to obtain Examples and Comparative Examples.

  Note that iPodTouch (registered trademark) was used as the display device. As the display board, a 2.0 mm thick polycarbonate (PC) board with a polyethylene terephthalate (PET) film printed in black through an optical adhesive sheet (PDS1 manufactured by PANAC) was used.

(Example 3)
Tungsten oxide was used for the inorganic resist layer, and after the organic resist layer was formed by spraying, the inorganic resist layer was etched for 10 minutes at a gas pressure of 0.5 Pa and an input power of 200 W using CF ₄ gas (30 sccm). In the same manner as in Example 1, a master was manufactured and an optical body was further manufactured. The manufactured optical body was attached to a display device or a display plate via an optical adhesive sheet (PDS1 manufactured by PANAC).

Example 4
After forming the organic resist layer by spraying, the inorganic resist layer was etched for 20 minutes using CHF ₃ gas (15 sccm) and CF ₄ gas (15 sccm) at a gas pressure of 0.5 Pa and an input power of 200 W. A master was produced in the same manner as in Example 1 except that the formation of the organic resist layer and the etching of the inorganic resist layer were taken as one cycle, and the cycle was repeated seven times, and an optical body was further produced. The manufactured optical body was attached to a display device or a display plate via an optical adhesive sheet (PDS1 manufactured by PANAC).

(Example 5)
A master was manufactured in the same manner as in Example 4 except that the number of repetitions of the cycle comprising the formation of the organic resist layer and the etching of the inorganic resist layer was 3, and an optical body was further manufactured. The manufactured optical body was attached to a display device or a display plate via an optical adhesive sheet (PDS1 manufactured by PANAC).

(Example 6)
The optical body according to Example 5 was attached to a display device or a display plate using a high haze pressure-sensitive adhesive (prototype) having a haze value of 45%.

(Comparative Example 2)
A polyethylene terephthalate film was used as a base material, and an AG (Antiglare) layer having a haze value of 18% was laminated on one side of the base material by wet coating. On the AG layer, SiO _x (film thickness 3 nm), Nb ₂ O ₅ (film thickness 20 nm), SiO ₂ (film thickness 35 nm), Nb ₂ O ₅ (film thickness 35 nm), and SiO ₂ (film thickness 100 nm) in this order. An antireflection layer was formed by forming a multilayer thin film by sputtering. The optical body was manufactured by the above process. The manufactured optical body was attached to a display device or a display plate via an optical adhesive sheet (PDS1 manufactured by PANAC).

(Comparative Example 3)
A cellulose triacetate (TAC) film was used as a substrate, and an AG hard coat layer having a haze value of 9% was laminated on one side of the substrate by wet coating. Next, a resin layer having a refractive index lower than that of the AG hard coat layer and containing a filler was laminated on the AG hard coat layer by wet coating to form an antireflection layer. The optical body was manufactured by the above process. The manufactured optical body was attached to a display device or a display plate via an optical adhesive sheet (PDS1 manufactured by PANAC).

(Comparative Example 4)
In Comparative Example 1, the base material resist layer was used as a mask after the development processing of the base material resist layer, the base material was etched using CHF ₃ gas, and a master having a micro uneven structure formed on the outer peripheral surface of the base material was manufactured. . In addition, an optical body was manufactured in the same manner as in Example 1 using a master on which only such a micro uneven structure was formed. The manufactured optical body was attached to a display device or a display plate via an optical adhesive sheet (PDS1 manufactured by PANAC).

(Comparative Example 5)
A commercially available anti-glare film for display in which an antiglare layer having a haze value of about 23% and a hard coat layer were laminated on a polyethylene terephthalate film was purchased. The purchased anti-glare film was affixed to a display device or a display board through an optical adhesive sheet (PDS1 manufactured by PANAC).

(Evaluation method)
First, various optical characteristics of the optical bodies according to Examples 3 to 6 and Comparative Examples 2 to 5 were evaluated.

Various optical properties of the optical body alone include luminous reflectance (Y), reflection chromaticity (a ^* , b ^* ), glossiness (20 °, 60 °, 75 °), total light transmittance, and haze value. Was measured. For these characteristic evaluations, a haze meter HM-150 (manufactured by Murakami Color Research Laboratory Co., Ltd.) was used.

  Table 2 shows the evaluation results of the above optical body alone.

  Referring to the results in Table 2, the optical bodies according to Examples 3 to 6 have lower luminous reflectance (Y) and lower glossiness than the optical bodies according to Comparative Examples 2 to 5, and thus reflect. It can be seen that the prevention characteristics are high. Moreover, the optical body which concerns on Examples 3-6 has the total light transmittance equivalent to Comparative Examples 2-5, and it turns out that a high antireflection characteristic and high transparency are compatible.

  Next, in Examples 3 to 6 and Comparative Examples 2 to 5, it was evaluated whether or not the reflection of external light was suppressed on the display device or the display surface of the display plate to which the optical body was attached. Specifically, the luminous reflectance (Y) and anti-glare property of the display panel or display device in which the optical body was attached to the display surface were evaluated.

  The luminous reflectance (Y) was measured using a haze meter HM-150 (Murakami Color Research Laboratory Co., Ltd.).

  The antiglare property was evaluated by the method shown in FIG. FIG. 19 is an explanatory diagram illustrating a method for evaluating the antiglare property of a display panel or a display device in which an optical body is attached to a display surface.

  As shown in FIG. 19, the anti-glare property is that the light of the fluorescent lamp 410 is projected on the evaluation sample 400 through the slit 420 having a 5 mm width opening, and the degree of blur of the reflected image of the fluorescent lamp 410 is visually determined. It was evaluated with. Further, the degree of blur of the reflected image of the fluorescent lamp 410 was captured by the imaging device 430, and the captured image was acquired.

The following criteria were used for determining the degree of blur: 5 is better and 1 is bad.
5: The outline of the light from the fluorescent lamp cannot be discriminated at all.
4: The outline of the light of the fluorescent lamp can be distinguished slightly.
3: Although the light from the fluorescent lamp is blurred, the outline can be almost discriminated.
2: The light from the fluorescent lamp is hardly blurred and the contour can be distinguished.
1: The light of the fluorescent lamp is not blurred at all, and the contour can be clearly distinguished.

  Table 3 shows the evaluation results of the display board or display device in which the optical body is attached to the display surface. Moreover, the reflected image image of a fluorescent lamp is shown in FIG. 20 and FIG. FIG. 20 is a reflection image image of the fluorescent lamp light on the display plate with the optical body attached, and FIG. 21 is a reflection image image of the fluorescent lamp light on the display device with the optical body attached. In FIGS. 20 and 21, as a reference, a reflected image of light from a fluorescent lamp in a display panel or a display device without an optical body is also shown.

  Referring to the results in Table 3, the optical bodies according to Examples 3 to 6 have low luminous reflectance even when the optical bodies according to Comparative Examples 2 to 5 are attached to the display board or the display device. It can be seen that reflection is suppressed.

  20 and 21, in the optical bodies according to Examples 3 to 6, the reflection of the light from the fluorescent lamp is significantly suppressed as compared with the optical bodies according to Comparative Examples 2 to 5. I understand.

  Specifically, since the optical body according to Comparative Example 4 has only a micro uneven structure, the antireflection property is high, but the haze value is low and the antiglare property is low. Therefore, for example, when strong light is incident, reflection on the surface of the optical body can be suppressed, but internally reflected light is generated at the interface between the display panel or display device and the optical body, so that the light of the fluorescent lamp is reflected. It will be crowded.

  In addition, the optical body according to Comparative Example 5 has a high haze value and high antiglare properties, and thus the contour of the light of the fluorescent lamp cannot be determined. However, since the optical body according to Comparative Example 5 does not have an antireflection layer and has low antireflection characteristics, the light from the fluorescent lamp is scattered and the entire surface is visually recognized as being whitish.

  Moreover, since the optical bodies according to Comparative Examples 2 and 3 have higher antiglare properties than Comparative Example 4 and are formed with an antireflection layer, the reflection of the light from the fluorescent lamp can be slightly discriminated from the outline. Is suppressed. However, even though the reflection on the surface of the optical body can be suppressed, the internal reflection light at the interface between the display panel or the display device and the optical body cannot be suppressed. It has occurred.

  On the other hand, since Examples 3 to 6 have high antireflection characteristics and high antiglare characteristics, the reflection of light from a fluorescent lamp is significantly suppressed as compared with Comparative Examples 2 to 5. Particularly, in Examples 3 and 4 in which the haze value on the surface of the optical body is 40% or more, the reflection of light from the fluorescent lamp is suppressed to the extent that it cannot be visually recognized. This is presumably because incident light is significantly scattered on the surface of the optical body, so that internally reflected light having visible light intensity is not generated.

  In addition, although Example 6 which provided the haze (scattering) effect with the adhesive agent on the back surface of the light incident surface of the optical body has a higher haze value in the entire optical body than the optical body according to Example 4, Reflection of light by reflected light was not suppressed as compared with Example 4. This indicates that in order to suppress reflection of light due to internally reflected light, in particular, the scattering property of the light incident surface of the optical body (that is, the haze value of the light incident surface) is important. It is thought that there is.

  From the above results, the optical body manufactured by the master according to the present embodiment can be suitably used as an antireflection film, and is reflected in outside light, particularly in an outdoor environment irradiated with strong outside light. It can be seen that it can be significantly suppressed.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Master 10 Base material 11 Macro uneven structure 13 Micro uneven structure 15 Base resist layer 17 Inorganic resist layer 19 Organic resist layer 111 Mountain part 113 Valley part 131 Convex part 133 Concave part

Claims (14)

By irradiating the outer peripheral surface of the master body including the cylindrical or columnar base material with a laser modulated by a control signal having no periodicity within a predetermined range, the average period of the irregularities is a microscopic wavelength that is less than or equal to the visible light wavelength. Forming a concavo-convex structure randomly in the circumferential direction and the axial direction of the master body, and
Forming an etching resist layer on the outer peripheral surface of the master body; and
For the etching resist layer, forming a macro uneven structure having an average period of unevenness larger than the visible light wavelength;
Etching the etching resist layer and the master body to form the micro uneven structure and the macro uneven structure on the outer peripheral surface of the base material,
A method of manufacturing a master including   2. The master production method according to claim 1, wherein an irradiation distance of the laser with respect to a circumferential direction of the master body corresponding to one bit of the control signal is 0.2 μm or less.   3. The master production method according to claim 1, wherein an interval between the laser irradiation positions with respect to the axial direction of the master body is 75 nm or more and 350 nm or less.   The said etching resist layer contains the inorganic resist layer formed on the outer peripheral surface of the said original disk main body, and the organic resist layer formed on the said inorganic resist layer as described in any one of Claims 1-3. Manufacturing method of the master.   5. The etching of the inorganic resist layer using the organic resist layer as a mask and the etching of the master body using the inorganic resist layer as a mask are performed by dry etching using different gases. Manufacturing method of the master.   The master etching according to claim 5, wherein the dry etching is vertical anisotropic etching using a gas containing at least fluorine atoms and containing at least two of carbon atoms, fluorine atoms, oxygen atoms and hydrogen atoms. Production method.   The said organic resist layer is a manufacturing method of the original recording as described in any one of Claims 4-6 formed by atomizing and spraying the organic resist diluted with the solvent. The master body is composed of the base material and a base material resist layer formed on the outer peripheral surface of the base material,
The micro uneven structure is formed on the base resist layer,
The inorganic resist layer is formed on the base resist layer so as to embed the micro uneven structure,
The method for producing a master according to any one of claims 4 to 7, wherein the base resist layer is etched simultaneously with the inorganic resist layer.   The method for manufacturing a master according to claim 8, wherein an etching rate of the base resist layer is different from an etching rate of the inorganic resist layer. The master body is composed of the base material,
The said micro uneven structure is a manufacturing method of the original recording as described in any one of Claims 4-7 formed in the said base material. Using the master manufactured by the manufacturing method according to any one of claims 1 to 10, the micro uneven structure and the macro uneven structure formed on the outer peripheral surface of the master are transferred to a resin base material. The manufacturing method of an optical body. The manufacturing method of the optical body of Claim 11 whose haze value is 20% or more. The optical body manufactured by the manufacturing method according to claim 11 or 12 was laminated on the surface of the substrate, a manufacturing method of an optical member. The optical body manufactured by the manufacturing method according to claim 11 or 12 was laminated on the display surface, a method of manufacturing a display device.