Abstract: An optical recording medium has a five-layer structure including five recording layers, namely an L0 layer, an L1 layer, an L2 layer, an L3 layer, and an L4 layer in this order from a side farthest away from a laser light incident surface. The materials of the respective recording layers are selected so that the rate of change in transmittance Tb/Ta as taken from the laser light incident surface satisfies 0.93<Tb/Ta<1.07 when recording on the L0 layer among the recording layers, where: Ta is transmittance of laser light to reach the L0 layer when the L0 layer is irradiated with the laser light of optimum recording power after recording marks are formed on all the recording layers closer to the laser light incident surface (being the L1 to L4 layers); and Tb is transmittance of laser light to reach the L0 layer when the L0 layer is irradiated with the laser light of optimum recording power with no recording mark formed on any of the recording layers closer to the laser light incident surface.

Abstract: A multilayer recording medium has a three-layered structure for an increased capacity, including an L0 layer, an L1 layer, and an L2 layer in order from the side farthest away from the incident surface of laser light. The recording layers are made of respective recording film materials selected so that the recording films of the recording layers have respective recording-reaction temperatures T0, T1, and T2, where T0?T1?T2 and T0<T2. This makes the recording sensitivities of the respective recording layers substantially the same and, by extension, the optimal recording powers of the laser light for the respective recording layers substantially the same so that the recording power of the laser light necessary for recording information on the L0 layer in particular is prevented from becoming excessively high.

Abstract: An optical information medium includes a light-transmitting supporting substrate, an information recording layer on one surface of the supporting substrate, a protective layer on the information recording layer, and a light-transmitting hard coat layer on an other surface of the supporting substrate. The medium is configured to have a recording/reproducing beam incident into the information recording layer through the hard coat later and the supporting substrate.

Abstract: An object is to stick an artificial fingerprint liquid on a test sample in a constant condition. An artificial fingerprint stamping apparatus 1 operates such that as an arm 10 lowers, the self weight of a stamp unit 3 causes an artificial fingerprint transfer member 9 at the lower end of a stamp pin 6 attached to the arm 10 via a ball bush 11 to be pressed against an artificial fingerprint liquid transfer disk D1 for a predefined period of time, and thus an artificial fingerprint liquid is transferred onto the lower end surface of the artificial fingerprint transfer member 9. Then, after the artificial fingerprint transfer member 9 is positioned above a test disc D1, the arm 10 is lowered so that the self weight of the stamp unit 3 causes the artificial fingerprint transfer member 9 to be pressed against the test disc D1 for a predefined period of time.

Abstract: A hardcoat agent composition comprising a fluorine-containing polyether compound (A) having a perfluoropolyether unit, urethane bond and active energy ray reactive group and a curable compound (B) having equal to or more than 2 active energy ray polymerizing groups in the molecule. An optical information medium having a film substance composed of single or multiple layers containing at least the recording layer 4 or the reflecting layer on the supporting substrate 20, the optical information medium wherein at least either the surface of the supporting substrate 20 or that of the above-mentioned film substance is formed by the hardcoat layer 8 containing a curable substance of the above-mentioned hardcoat agent composition.

Abstract: A multilayer optical recording medium enabled to retain an ideal signal regenerating property in spite of accidental adhesion of finger mark or alien substance is provided. The multilayer optical recording medium 1 is provided with a plurality of information-recording layers 20, 22, 24, and 26 capable of reading information with a reading light irradiated through a light incidence surface 38A on one side and is so adapted that the light incidence side information-recording layer 26 approximating most closely to the light incidence surface 38A may be set at a small recording capacity as compared with the recording capacities of at least one of the other information-recording layers.

Abstract: A simple method for evaluating an optical information medium by judging quantitatively and reproducibly the surface quality of the optical information medium by the use of an artificial fingerprint liquid as an evaluation dispersion liquid, is provided. An optical information medium having a remarkably excellent anti-staining property of the surface which is on the incident side of recording/reproducing beam is provided. A method for evaluating an optical information medium, comprising: adhering an artificial fingerprint liquid containing a fine-particle-form substance and a dispersion medium capable of dispersing the fine-particle-form substance onto the surface of the optical information medium which is on the incident side of a recording/reproducing beam; observing the state of the artificial fingerprint liquid droplets adhered to the surface; and judging the quality of the medium surface.

Abstract: The invention provides an optical recording disk, with which the worsening of jitter can be prevented effectively even when fingerprints become adhered onto a laser light incidence surface. An optical recording disk 10 comprises a substrate 2, a recording layer 5, formed on the substrate, a light transmitting layer 7, formed on the recording layer, and a hard coat layer 8, formed on the light transmitting layer, and is characterized in that, when an operation of adhering an artificial fingerprint solution onto the optical recording disk's light incidence surface, onto which laser light is made incident, is performed and then an operation of wiping off the artificial fingerprint solution that has been adhered onto the light incidence surface is repeated five times, jitter becomes no more than 1.15 times that prior to the adhesion of the artificial fingerprint solution.

Abstract: A method for transferring an artificial fingerprint liquid to a surface of an optical information medium includes preparing a pseudo-fingerprint transferring stamp which is a plug made of silicone rubber, applying an artificial fingerprint liquid containing a fine-particle-form substance and a dispersion medium capable of dispersing the fine-particle-form substance onto a polycarbonate substrate by spin coating to prepare a master plate for artificial fingerprint liquid transfer, pressing said one end face of the transferring stamp with a load of 4.9 N for 10 seconds against the surface of the master plate, and then, pressing said one end face of the transferring stamp onto which the artificial fingerprint liquid is transferred against a surface of an optical information medium.

Abstract: The present invention provides a hard coat agent composition that is useful for forming a hard coat layer with excellent anti-staining properties and lubricity, as well as superior scratch resistance and abrasion resistance, on the surfaces of various articles. The present invention also provides an optical information medium using the above hard coat agent composition. A hard coat agent composition comprising a fluorine-containing block copolymer (A1), a fluorine-containing polyether compound (A2) comprising an active energy ray-reactive group, and an active energy ray-curable compound (B). An optical information medium comprising a film element composed of one or more layers including at least a recording layer (4) or a reflective layer, on a supporting substrate (20), wherein at least one of the supporting substrate (20)-side surface and the film element-side surface is formed of a hard coat layer (8) comprising a cured product of the hard coat agent composition.

Abstract: A method for evaluating an optical information medium by judging quantitatively and reproducibly the surface quality of the optical information medium by the use of a novel artificial fingerprint liquid as an evaluation dispersion liquid including: adhering, under predetermined conditions, the evaluation dispersion liquid; measuring a recording/reproducing characteristic (e.g. error rate) of the medium with the evaluation dispersion liquid droplets adhered to the medium surface; and judging the optical information medium as an acceptable medium when the measured recording and/or reproducing characteristic is equal to, or better than, a predetermined value.

Abstract: The present invention provides a hard coat agent composition that is useful for forming a hard coat layer with excellent anti-staining properties and lubricity, as well as superior scratch resistance and abrasion resistance, on the surfaces of various articles. The present invention also provides an optical information medium using the above hard coat agent composition. A hard coat agent composition comprising a fluorine-containing polyether compound (A) comprising an active energy ray-reactive group, and a curable compound (B) comprising two, or three or more active energy ray-polymerizable groups within each molecule. An optical information medium comprising a film element composed of one or more layers including at least a recording layer (4) or a reflective layer, on a supporting substrate (20), wherein at least one of the supporting substrate (20)-side surface and the film element-side surface is formed of a hard coat layer (8) comprising a cured product of the hard coat agent composition.

Abstract: The present invention provides an optical information medium in which the recording and/or reproducing beam incident side surface displays excellent anti-staining properties and lubricity, as well as superior scratch resistance and abrasion resistance. An optical information medium comprising a film element composed of one or more layers including at least a recording layer (4) or a reflective layer, on a supporting substrate (20), wherein at least one of the supporting substrate (20)-side surface and the film element-side surface is formed of a hard coat layer (8) comprising a cured product of the hard coat agent composition comprising a fluorine-containing block copolymer (A) and an active energy ray-curable compound (B).

Abstract: The present invention provides an antireflection film for transfer that can be transferred to the surface of plates or other less-flexible articles to form an antireflection layer with a uniform thickness that not only provides a high antireflection effect on a light in the visible light range but also offers a high solvent resistance. The present invention also provides an antireflection-treated article.

Abstract: A simple method for evaluating an optical information medium by judging quantitatively and reproducibly the surface quality of the optical information medium by the use of an artificial fingerprint liquid as an evaluation dispersion liquid, is provided. An optical information medium having a remarkably excellent anti-staining property of the surface which is on the incident side of recording/reproducing beam is provided. A method for evaluating an optical information medium, comprising: adhering an artificial fingerprint liquid containing a fine-particle-form substance and a dispersion medium capable of dispersing the fine-particle-form substance onto the surface of the optical information medium which is on the incident side of a recording/reproducing beam; observing the state of the artificial fingerprint liquid droplets adhered to the surface; and judging the quality of the medium surface.

Abstract: A simple method for evaluating an optical information medium by judging quantitatively and reproducibly the surface quality of the optical information medium by the use of an artificial fingerprint liquid as an evaluation dispersion liquid, is provided. An optical information medium having a remarkably excellent anti-staining property of the surface which is on the incident side of recording/reproducing beam is provided. A method for evaluating an optical information medium, comprising: adhering an artificial fingerprint liquid containing a fine-particle-form substance and a dispersion medium capable of dispersing the fine-particle-form substance onto the surface of the optical information medium which is on the incident side of a recording/reproducing beam; observing the state of the artificial fingerprint liquid droplets adhered to the surface; and judging the quality of the medium surface.

Abstract: The present invention provides a simple method for evaluating an optical information medium by judging quantitatively and reproducibly the surface quality of the optical information medium by the use of a novel artificial fingerprint liquid as an evaluation dispersion liquid. A method for evaluating an optical information medium, comprising the steps of: adhering, under predetermined conditions, an evaluation dispersion liquid containing a fine-particle-form substance and a dispersion medium capable of dispersing the fine-particle-form substance onto the surface of the optical information medium which is on the incident side of a recording/reproducing beam; measuring an area ratio of the medium surface occupied with the evaluation dispersion liquid droplets adhered per unit area of the medium surface; and judging the optical information medium as an acceptable medium when the measured area ratio is 6% or less.

Abstract: The present invention provides a hard coat agent composition that is useful for forming a hard coat layer with excellent anti-staining properties and lubricity, as well as superior scratch resistance and abrasion resistance, on the surfaces of various articles. The present invention also provides an optical information medium using the above hard coat agent composition. A hard coat agent composition comprising a fluorine-containing block copolymer (A1), a fluorine-containing polyether compound (A2) comprising an active energy ray-reactive group, and an active energy ray-curable compound (B). An optical information medium comprising a film element composed of one or more layers including at least a recording layer (4) or a reflective layer, on a supporting substrate (20), wherein at least one of the supporting substrate (20)-side surface and the film element-side surface is formed of a hard coat layer (8) comprising a cured product of the hard coat agent composition.

Abstract: A method of testing an information recording medium includes a step of attaching an artificial fingerprint to an incident surface of an information recording medium, a step of reproducing a signal recorded in an attached region to which the artificial fingerprint has been attached, and a step of judging whether the information recording medium is defective or non-defective based on a signal quality of the reproduced signal. An information recording medium testing apparatus includes a fingerprint attaching unit that attaches an artificial fingerprint onto an incident surface of an information recording medium, a signal reproducing unit that reproduces a signal recorded in an attached region to which the artificial fingerprint has been attached, and a judging unit that judges whether the information recording medium is defective or non-defective based on a signal quality of the reproduced signal.

Abstract: The present invention provides an optical information medium in which the recording and/or reproducing beam incident side surface displays excellent anti-staining properties and lubricity, as well as superior scratch resistance and abrasion resistance. An optical information medium comprising a film element composed of one or more layers including at least a recording layer (4) or a reflective layer, on a supporting substrate (20), wherein at least one of the supporting substrate (20)-side surface and the film element-side surface is formed of a hard coat layer (8) comprising a cured product of the hard coat agent composition comprising a fluorine-containing block copolymer (A) and an active energy ray-curable compound (B).