Abstract: A blue-light-emitting element includes a polyimide containing a repeating unit represented by formula (1): (wherein X represents a divalent alicyclic hydrocarbon group having 6 to 24 carbon atoms). Since the polyimide has a high glass transition temperature and toughness and exhibits a stable luminous efficiency; the blue-light-emitting element is suitable for an organic EL display.

Abstract: A lens apparatus which has a small size but allows a higher magnification and an image-pickup apparatus including the lens apparatus are disclosed. The lens apparatus provides a variable magnification by moving a first lens and a second lens placed closer to an image plane than the first lens in the direction of an optical axis. The lens apparatus includes a first driving member which is rotated around the optical axis to move the first lens in the optical axis direction, a second driving member which moves the second lens by itself in the optical axis direction, and a driving mechanism which at least drives the rotation of the first driving member. The second driving member is moved in the optical axis direction relative to the first driving member by the rotation of the first driving member.

Abstract: A winding device includes a winding member that rotates to wind a flexible member therearound, a first rotating member that is rotatable, a second rotating member that is rotatable coaxially with the winding member and has a smaller resistance to rotation in a predetermined direction than that to rotation in a direction opposite the predetermined direction, and an engaging member. When the first rotating member is subjected to a first torque, the engaging member brings the winding member, the first rotating member, and the second rotating member into engagement with one another, so that the winding member becomes rotatable together with the first rotating member in the predetermined direction. When the first rotating member is subjected to a second torque in a direction opposite that of the first torque, the engaging member releases the engagement, so that the winding member becomes rotatable in the direction opposite the predetermined direction.

Abstract: A lens barrier driving device that prevents an increase in the number of parts constituting a lens barrier driving mechanism and avoids light leakage from a penetrating portion. A lens barrier is disposed on an object side of a lens and is openable and closable. A transmission member transmits power to a barrier driving member. The barrier driving member opens and closes the lens barrier. A cam member is able to engage with the transmission member. A first member holds the cam member. A second member is provided with a penetrating portion. The penetrating portion is disposed between the lens barrier and the first member. A rib portion of the transmission member penetrates the penetrating portion. A light shielding portion of the transmission member shields a incident light through the penetrating portion.

Abstract: A work having a portion to be ground, such as a tapered surface, is ground by a grinder driven by a driving device. During grinding operation, coolant is supplied to a grinding surface of the grinder and the portion to be ground. After the grinding operation is completed, the coolant is continued to be supplied for removing sludge on the grinder while the grinder is leaving the work and returning to its original position. The coolant may be pressurized to a higher level when it is supplied for removing the sludge than when it is supplied during the grinding operation. The number of works that have been already ground may be counted, and the coolant for removing the sludge may be supplied only when the number of works exceeds a predetermined number. Alternatively, the sludge is removed by brushing when the number of works does not reach the predetermined number.

Abstract: A head-mounted device for mounting on the head of a user includes a first pressing member for pressing a first portion of the head from a first direction; a second pressing member for pressing a second portion of the head from a second direction that is different from the first direction; a string member that concatenates the first pressing member and the second pressing member; a structure that guides the string member so that the first and the second pressing members move in the first and the second directions, respectively, according to changes in the length of the string member; and an adjusting unit that adjusts the length of the string member.

Abstract: A head-mounted device to be worn on a user's head includes a first pressing member to press, for example, an occipital region, a second pressing member to press, for example, a parietal region, and first and second linear members connected to the first and second pressing members respectively. The first and second linear members are guided so that a change in lengths of the first and second linear members causes the first and second pressing members to move in the first and second directions respectively. An adjustment unit to adjust the lengths of the first and second linear members includes first and second wind-up units connected to a rotational operation member and to wind up the first and second linear members respectively.

Abstract: A work having a portion to be ground, such as a tapered surface, is ground by a grinder driven by a driving device. During grinding operation, coolant is supplied to a grinding surface of the grinder and the portion to be ground. After the grinding operation is completed, the coolant is continued to be supplied for removing sludge on the grinder while the grinder is leaving the work and returning to its original position. The coolant may be pressurized to a higher level when it is supplied for removing the sludge than when it is supplied during the grinding operation. The number of works that have been already ground may be counted, and the coolant for removing the sludge may be supplied only when the number of works exceeds a predetermined number. Alternatively, the sludge is removed by brushing when the number of works does not reach the predetermined number.

Abstract: A lens apparatus which has a small size but allows a higher magnification and an image-pickup apparatus including the lens apparatus are disclosed. The lens apparatus provides a variable magnification by moving a first lens and a second lens placed closer to an image plane than the first lens in the direction of an optical axis. The lens apparatus includes a first driving member which is rotated around the optical axis to move the first lens in the optical axis direction, a second driving member which moves the second lens by itself in the optical axis direction, and a driving mechanism which at least drives the rotation of the first driving member. The second driving member is moved in the optical axis direction relative to the first driving member by the rotation of the first driving member.

Abstract: A lens barrier driving device that enable to suppress an increase in the number of parts constituting a lens barrier driving mechanism and avoid light leakage from a penetrating portion, ghosts, and the like which may degrade the optical performance. A lens barrier driving device drives a lens barrier. The lens barrier is disposed on an object side of a lens and is openable and closable. A transmission member transmits power to a barrier driving member. The barrier driving member opens and closes the lens barrier. A cam member is able to engage with the transmission member. A first member holds the cam member. A second member is provided with a penetrating portion. The penetrating portion is disposed between the lens barrier and the first member. A rib portion of the transmission member penetrates the penetrating portion. A light shielding portion of the transmission member shields a incident light through the penetrating portion.

Abstract: There is provided an optical device which comprises a fixed barrel, a movable cam ring, and collars and abutments. The movable cam ring is shifted relative to the fixed barrel to move an optical unit, the movable cam ring being fitted to the fixed barrel. Collars and abutments can be engaged with each other when the movable cam ring is in a predetermined positional relationship with respect to the fixed barrel. The collars and abutments preventing the movable cam ring from being disengaged from the fixed barrel and displaced in a direction along an optical axis relative to the fixed barrel.

Abstract: A lens barrel and an optical device that can be reduced in size while maintaining high optical performance. A lens barrel has a cam ring (3) that is disposed for rotation about an optical axis. A linked member (37) can advance and recede in a direction of the optical axis with rotation of the cam ring about the optical axis. First and second cam grooves (3d, 3e) is formed in the cam ring for guiding advancement and receding of the linked member in the direction of the optical axis. First and second cam-followers (8a, 8b) are provided in the linked member and are engageable with the first cam groove and the second cam groove, respectively. The second cam-follower is disengageable from its corresponding second cam groove. A depth of the second cam groove in a position where the second cam-follower is introduced into the second cam groove is deeper that of the second cam groove at a different position.

Abstract: A lens barrel and an optical device that can be reduced in size while maintaining high optical performance. A lens barrel has a cam ring (3) that is disposed for rotation about an optical axis. A linked member (37) can advance and recede in a direction of the optical axis with rotation of the cam ring about the optical axis. First and second cam grooves (3d, 3e) is formed in the cam ring for guiding advancement and receding of the linked member in the direction of the optical axis. First and second cam-followers (8a, 8b) are provided in the linked member and are engageable with the first cam groove and the second cam groove, respectively. The second cam-follower is disengageable from its corresponding second cam groove. A depth of the second cam groove in a position where the second cam-follower is introduced into the second cam groove is deeper that of the second cam groove at a different position.

Abstract: There is provided an optical device which comprises a fixed barrel, a movable cam ring, and collars and abutments. The movable cam ring is shifted relative to the fixed barrel to move an optical unit, the movable cam ring being fitted to the fixed barrel. Collars and abutments can be engaged with each other when the movable cam ring is in a predetermined positional relationship with respect to the fixed barrel. The collars and abutments preventing the movable cam ring from being disengaged from the fixed barrel and displaced in a direction along an optical axis relative to the fixed barrel.

Abstract: A camera which causes a lens unit to move accurately through a cam member is disclosed. The camera comprises a lens unit with movable lenses making up a view finder optical system, a cam member having a cam which engages with the lens unit for driving the lens unit in conjunction with the operation of the image-taking optical system, a first bias member which biases the cam member in one of moving directions of the cam member, and a second bias member which biases the lens unit so as to contact the cam surface.

Abstract: There is provided an optical device which comprises a fixed barrel, a movable cam ring, and collars and abutments. The movable cam ring is shifted relative to the fixed barrel to move an optical unit, the movable cam ring being fitted to the fixed barrel. Collars and abutments can be engaged with each other when the movable cam ring is in a predetermined positional relationship with respect to the fixed barrel. The collars and abutments preventing the movable cam ring from being disengaged from the fixed barrel and displaced in a direction along an optical axis relative to the fixed barrel.

Abstract: A method for preparing bromofluorenes includes a step of dispersing a compound selected from the group consisting of fluorene, fluorenone, and derivatives of fluorene and fluorenone in water to prepare a disperse system. Bromination is initiated by adding bromine Br2 into the disperse system. Thus, bromofluorenes can be efficiently and economically prepared without using any environmentally harmful organic solvent requiring a high cost to dispose of.

Abstract: A camera which causes a lens unit to move accurately through a cam member is disclosed. The camera comprises a lens unit with movable lenses making up a view finder optical system, a cam member having a cam which engages with the lens unit for driving the lens unit in conjunction with the operation of the image-taking optical system, a first bias member which biases the cam member in one of moving directions of the cam member, and a second bias member which biases the lens unit so as to contact the cam surface.

Abstract: There is provided an optical device which comprises a fixed barrel, a movable cam ring, and collars and abutments. The movable cam ring is shifted relative to the fixed barrel to move an optical unit, the movable cam ring being fitted to the fixed barrel. Collars and abutments can be engaged with each other when the movable cam ring is in a predetermined positional relationship with respect to the fixed barrel. The collars and abutments preventing the movable cam ring from being disengaged from the fixed barrel and displaced in a direction along an optical axis relative to the fixed barrel.

Abstract: A method for preparing bromofluorenes includes a step of dispersing a compound selected from the group consisting of fluorene, fluorenone, and derivatives of fluorene and fluorenone in water to prepare a disperse system. Bromination is initiated by adding bromine Br2 into the disperse system. Thus, bromofluorenes can be efficiently and economically prepared without using any environmentally harmful organic solvent requiring a high cost to dispose of.