Abstract: The invention provides an article and process for producing electronic devices. More particularly the invention relates to an article and process for fabricating patterns of electrically conductive materials on non-electrically conductive substrates by laser ablation. Such an article and process find use in the production of RDIF devices, antennae, electrical circuits, microwave susceptors, contacts, leads, conductors, interactive displays, electrostatic shielding devices and the like. The process involves first providing an electrically conductive metal layer on an electrically non-conductive substrate. Then an electronic circuit is electrically connected to the electrically conductive metal layer.

Abstract: Substantially-accurate calibration of output impedance of a device-under-test (DUT) to within a predetermined range of allowable impedance. The DUT is part of a source series terminated (SST) serial link transmitter, in which two branches of parallel transistors each provide an impedance value when particular transistors of the parallel branch are turned on. The impedance value is added to a series-connected resistor to provide the output impedance. The DUT consists of one branch of parallel transistors in series with a resistor. Output impedance of the DUT is compared to the resistance of a reference resistor, and the comparator provides a control signal based on whether the output impedance falls within the pre-set percentage variance of the reference resistance. The control signal is processed by a FSM (finite state machine) that individually turns on or off the transistors within the parallel branch until the DUT impedance value falls within the desired range.

Abstract: The present invention stacks integrated circuits into modules that conserve board surface area. In a precursor assembly devised as a component for a stacked circuit module in accordance with a preferred embodiment of the present invention, one or more stiffeners are disposed at least partially between a flex circuit and an integrated circuit. In a two-high stacked circuit module devised in accordance with a preferred embodiment of the present invention, an integrated circuit is stacked above a precursor assembly. The two integrated circuits are connected with the flex circuit of the precursor assembly. The present invention may be employed to advantage in numerous configurations and combinations of integrated circuits in modules.

Abstract: A sensor assembly includes a sensing element electrically connected to a conductor of a flexible multiconductor cable using a conductive patch, which is electrically connected to the conductor. A method of forming a sensor assembly includes electrically connecting an electrically conductive patch to a sensing element and electrically connecting a conductor of a multiconductor cable to the electrically conductive patch.

Abstract: A flexible printed circuit improves data transfer rates by disposing ground wires in a ground plane proximate to signal wires disposed in a signal channel plane. One or more ground wires is associated with each signal wire pair or each signal wire for imaging of the return currents of the signal pairs. An overlapping alignment minimizes loop area between a ground wire and its associated signal wire. An offset alignment provides a reduced loop area and reduced breakage risk since movement of the flexible-circuit does result in compression of the signal wire and its associated ground wire. A combination of overlapping and offset alignment balances signal transfer effectiveness with breakage risk by offsetting ground and signal wires is stress sensitive regions and overlapping ground and signal wires in stress tolerant regions.

Abstract: A method and system for placing multiple loads in a high-speed system are disclosed. In one embodiment, the first load and the second load are placed on the first side and the second side of the printed circuit board, respectively. In addition, the first signal pin of the first load is vertically aligned with the second signal pin of the second load with an offset; the terminating end of a trace, which is connected to a driver on the printed circuit board, the first signal pin, and the second signal pin are connected at a T-point. The printed circuit also includes the first decoupling capacitor on the second side and the second decoupling capacitor on the first side. The first decoupling capacitor is connected to the first power pin of the first load. Similarly, the second decoupling capacitor is connected to a second power pin of the second load.

Abstract: An electronic unit includes a case, a printed circuit board, a connector block, and a connector introducing portion. The case is selected from a waterproof case and a non-waterproof case. The connector block is mounted upon the printed circuit board. The connector block has a retaining projection that engages a mating connector. The connector introducing portion is integrally formed with the cases and yet separately from the connector block. The connector introducing portion of the waterproof case has a retaining projection that engages the mating connector. The electronic unit is assembled with the case selected from the waterproof case and the non-waterproof case, and with the printed circuit board and the connector blocks received in the case that has been chosen.

Abstract: Wirings 2B1 are formed by application of heat treatment after an ink jet system is used to discharge a conductive liquid L onto a provisional substrate 5 having a predetermined repellent property, bonding an insulating layer 4B1 to the wirings 2B1 with an adhesive material 3B1 therebetween, peeling and removing the provisional substrate 5, and bonding and fixing the wirings 2B1 together with the insulating film 4B1 to a main substrate 1 by an adhesive material 3B1.

Abstract: A method of fabricating an antenna connector is provided. The components of the antenna connector are mechanically assembled in an automatically operated workstation to effectively eliminate the labor/time consuming assembly process requiring assembly by hand as in the case of the prior art. The electrical connection between the coaxial cable and the terminal can be ensured and also the coaxial cable can be effectively secured to the housing so that the coaxial cable may not come loose. Thus, it is not only possible to effectively increase the production throughput, but also the reliability of the antenna connector may be effectively promoted.

Abstract: An electrical box is mounted on a wall stud, and a wiring panel is installed within the electrical box so as to partition the interior of the electrical box into a user inaccessible wiring compartment and a user accessible module compartment. A protective cover is attached to the wiring panel so as to protect the wiring panel during a makeup phase of wall panel installation and painting. After the makeup phase, the protective cover is removed from the wiring panel and a module having a user operable electrical function is mounted to the wiring panel within the user accessible module compartment.

Abstract: A mounting structure includes a first electronic component, a second electronic component, and an adhesive. The first electronic component includes at least one protruding electrode including a protruding member and at least one electrically conductive layer. The protruding member is formed of resin. The at least one electrically conductive layer is disposed on the protruding member. The second electronic component has a facing electrode electrically conductively in contact with the at least one protruding electrode. The adhesive is used to adhere the first electronic component and the second electronic component to each other. The protruding member has a first area and a second area. The first area has the at least one electrically conductive layer provided thereon. The second area does not have the at least one electrically conductive layer provided thereon. The first area of the protruding member is squashed more than the second area.

Abstract: A method for mounting an electronic component on a substrate includes: forming an Au bump (24) on a surface of an electrode (20) of a substrate (10); placing an Sn-based solder sheet (26) on the Au bump; subjecting the Sn-based solder sheet and the Au bump to reflow soldering, to thus form an Au—Sn eutectic alloy (28); smoothing the eutectic alloy; and bonding an electronic component (30) on a surface of the smoothed eutectic alloy.

Abstract: A compliant contact structure and contactor card for operably coupling with a semiconductor device to be tested includes a substantially planar substrate with a compliant contact formed therein. The compliant contact structure includes a portion fixed within the substrate and at least another portion integral with the fixed portion, laterally unsupported within a thickness of the substrate and extending beyond a side thereof. Dual-sided compliant contact structures, methods of forming compliant contact structures, a method of testing a semiconductor device and a testing system are also disclosed.

Abstract: A tape substrate includes IC lands electrically connected to pins of a driver IC (integrated circuit), circuit board terminal lands electrically connected to an external circuit board, test lands for testing the driver IC mounted on the tape substrate, and a plating terminal used for plating the land. The test lands are arranged in a matrix. The plating terminal is disposed so as to surround the IC lands, the circuit board terminal lands, and the test lands.

Abstract: A method for affecting an impedance of a portion of an electrical circuit loop in an electrical circuit apparatus includes providing an electrical circuit apparatus having at least a portion of an electrical circuit loop including at least one of at least one trace and at least one via, and providing a layer of magnetic material disposed adjacent at least one of the trace and the via. The trace and the via are operatively connected together to provide electrical communication. Dielectric material is disposed in an operative relationship adjacent at least one of the trace and the via. The layer of magnetic material is disposed in operative relationship near at least one of the trace and the via to affect the impedance of at least one of the trace, the via and the portion of the circuit loop formed by the trace and the via.

Abstract: An electric device includes an electric element, such as a wound film capacitor, with power input and output leads. The electric element includes a coating layer of parylene that provides moisture resistance and low gas and moisture permeability to protect the electric element from short and long term moisture degradation effects. A known case layer is located adjacent to the coating layer. The case layer is a metal, epoxy-based, silicone-based, or polymer material that encapsulates the coating layer and the electric element to protect the coating layer and electric element from physical damage.

Abstract: Forming an inlay comprising an antenna wire having two end portions and a site for a transponder chip, comprises: mounting the wire to a surface of substrate; and leaving the end portions of the antenna wire free-standing, as loops adjacent terminal areas of a site on the substrate for the transponder chip. With the transponder chip installed on the substrate, the free-standing loops are repositioned to be substantially directly over the terminals of the transponder chip, in preparation for interconnection of the loops to the terminals of the transponder chip, then are bonded to the terminals. An embedding tool for mounting the wire on the substrate may embed the wire in or adhesively place a self-bonding wire on a surface of the substrate. The substrate may have two transponder chips, and function as a secure inlay. An anti-skimming feature is included in the inlay.

Abstract: A tool for making the semiconductor package accurately contact with the terminals of a electrical connector, comprises a body with a through hole for passing through the semiconductor package thereof, a plurality of the latching members mounted on the body and a guiding member, the guiding member is received in the body and could move up and down relative to the body. The guiding member of the invention is a floatable model to decrease the damage of the semiconductor package while loading.

Abstract: A method of manufacturing LED light string includes the steps of forming an LED light body from multiple serially connected printed circuit boards, fixing the LED light body to a base, and connecting a light-transmissible shell to the light body to form a cluster lamp; preparing a power cord, to which multiple lamp sockets are serially connected; fitting multiple cluster lamps to the lamp sockets on the power cord, so that the LED light bodies are made to emit light. A lampshade is detachably engaged with each lamp socket. The lampshade and the lamp socket may be differently designed to create romantic feeling. The number of LED light bodies on each cluster lamp and the number of cluster lamps on one LED light string may be varied as desired to increase the brightness of the light string while reduce the manufacturing cost of the LED light string.

Abstract: A method for assembling a washing machine is provided. The method includes providing a mode shifter including a solenoid, coupling a basket and an agitator to the mode shifter, and coupling a motor to the mode shifter. The solenoid selectively allows the motor to rotate at least one of the basket and the agitator. The method also includes affixing a motor controller to the motor, and electrically coupling the motor controller to each of the mode shifter and the motor. The motor controller is in operational control communication with the mode shifter and the motor.

Abstract: An adjustable driver pin connector compression tool comprising a body that is configured for receiving a plurality of different sized connectors. A sliding head assembly is slidably mounted within the interior of the body. The sliding head assembly being operatively coupled to a driver pin bolt moveable between at least two fixed driver pin positions.

Abstract: A method for producing a pH measuring probe includes: providing an electrode wire protruding out of both sides of a recording device, the electrode wire being fixed to the recording device with the first end thereof, placing a glass tube over a second end of the electrode wire until reaching a cavity of the recording device, the glass tube and the recording device being fixed together; providing another electrode wire protruding from both sides of a base plate including a recess for the recording device, the other electrode wire being fixed to the base plate with its end protruding; providing a casing comprising first and second openings, the casing and base plate being sealed together, forming the housing; and guiding the glass tube through the recess in the base plate until it protrudes out of an opening in the casing and the recording device is inserted into the base plate.

Abstract: A method is provided for fitting waterproof seals onto outer peripheries of end portions of electric wires. The method feeds seals along the axis line of the wire and into a seal cavity. A passage forming member forms a feeding passage to feed the seal into the seal cavity with a posture to receive the electric wire. The seal then is locked in the seal cavity. The wire then is moved along the axis line and into the seal.

Abstract: An implantable lead body for a medical device with improved conductor lumens separates and insulates conductors while permitting access to the conductors through the implantable lead outer surface. The implantable lead comprises a lead body, a stylet lumen, at least one conductor lumen, and at least one axial slit in the lead body. The lead body has a proximal end, a distal end, an internal portion, and an external portion. The stylet lumen is formed in the internal portion. The conductor lumen is formed in the internal portion and positioned near an outer surface of the internal portion such that there is only a web between the conductor lumen and the outer surface of the internal portion. The axial slit is formed in the lead body distal end between the conductor lumen and the outer surface of the internal portion.

Abstract: Power supplied to an information handling system electronic component through a circuit board has component package inductance parasitic effects compensated by configuring connections to the electronic component to have increased parasitic capacitance. For instance, power and ground vias that connect a processor to power and ground planes of the circuit board are aligned to create a desired parasitic capacitance that reduces the impact of parasitic inductance relating to signal compensation, power delivery and high speed decoupling. The desired distributed capacitance is modeled by altering the radius associated with the equivalent line charge of the power via, the distance associated with the line charges between power and ground vias, and the via barrel length.

Abstract: A method of fabricating an inductive coil having inner and outer winding portions formed from one or more metal sheets. The method includes wrapping a fiber strand around an outer surface of the inner winding portion, positioning the outer winding portion around the inner winding portion, and electrically coupling the inner winding portion to the outer winding portion to form an electric circuit.

Abstract: A wiring harness manufacturing method and a wiring harness manufacturing apparatus is provided, wherein manufacturing costs of a wiring harness is reduced. The wiring harness manufacturing apparatus (1) has a pair of wire stocking units (10a, 10b), a pair of cutting units (11a, 11b), a pair of joining units (12a, 12b), and a case insertion unit (13). Painting devices (14,15,16) are attached to one wire stocking unit (10a). Painting devices (17,18,19) are attached to one cutting unit (11a). Painting devices (18,19) are attached to one joining unit (12a). The painting devices (14,15,16,17,18,19) color the electric wire.

Abstract: An object of the present invention is to provide a wiring harness job-order production method and a wiring harness job-order production system, wherein a space for producing a wiring harness is reduced and the production efficiency of the wiring harness is improved. The wiring harness job-order production system 1 has a wiring harness assembling portion 15, an electric wire stock portion 13, and a parts stock portion 14. The wiring harness assembling portion 15 outputs wire amount data DT1 to the electric wire stock portion 13 when the wiring harness assembling portion 15 receives an order from a wiring harness ordering side 38. The wiring harness assembling portion 15 outputs parts amount data DT2 to the parts stock portion 14 when the wiring harness assembling portion 15 receives an order from the wiring harness ordering side 38. The electric wire stock portion 13 conveys a non-colored electric wire toward the wiring harness assembling portion 15.

Abstract: A method of manufacturing a magnetic head carries out a testing step, in which the magnetic head is heated, quickly and with a low operation cost and therefore can reduce delays in the manufacturing process and the need to repeat the manufacturing process. The method includes a row bar holding step of holding at least one surface in a lengthwise direction of a row bar using a holding jig with a lower thermal expansion coefficient than the row bar, a wire bonding step of connecting, using wires, connection terminals of respective magnetic heads on the row bar and test terminals for electrically connecting the connection terminals for test purposes, a heating step of heating the row bar, and a functional characteristic testing step of testing functional characteristics of the respective magnetic heads via the test terminals and the wires.

Abstract: The present invention involves a water heater and method of manufacturing the same. The water heater includes a tank assembly and a base assembly. The base assembly includes a heater assembly, a control unit, a control circuit and at least one temperature sensor. The base assembly is a separate module that has at least the heater assembly and control unit mounted thereto.

Abstract: A connection component for a semiconductor chip includes a substrate having a gap over which extends a plurality of parallel spaced apart leads. The ends of the leads are adhered to the substrate either by being bonded to contacts or being embedded in the substrate. The connection component can be formed, in one embodiment, by stitch bonding wire leads across the gap. In another embodiment, a prefabricated lead assembly supporting spaced apart parallel leads is juxtaposed and transferred to the substrate. The connection component is juxtaposed overlying a semiconductor chip whereby leads extending over the gap may have one end detached and bonded to an underlying chip contact.

Abstract: A method for establishing electrical contact includes nonrigidly applying force to a semiconductor substrate in directions substantially normal to a plane of the semiconductor substrate includes a first member with an electrically conductive element and a first attractive element and a second member that includes a support element and a second attractive element. The first and second attractive elements may be attracted to one another to secure the first and second members of the electrical connector to the semiconductor substrate in a manner that facilitates communication between the electrically conductive element of the first member and one or more semiconductor devices carried upon the semiconductor substrate. The electrical connector may be used in stress testing of semiconductor devices or to otherwise establish an electrical connection between one or more semiconductor devices, a ground, and a power source.

Abstract: Provided is an electrical connector having first and second surfaces and configured to establish electrical communication between two or more electrical devices. The electrical connector includes an insulative housing and a resilient, conductive contact retained in an aperture disposed from the first surface to the second surface. To contact the electrical devices, the contact includes a center portion from which extends two diverging, cantilevered spring arms that project beyond either surface of the electrical connector. To shorten the path that current must travel through the contact, one spring arm terminates in a bellows leg that extends proximate to the second spring arm. When placed between the electrical devices, the spring arms are deflected together causing the bellows leg to press against the second spring arm. For retaining the contact within the aperture, the contact also includes retention members extending from the center portion that engage the insulative housing.

Abstract: Embodiments of the invention provide a method for easily and reliably neutralizing charge in an assembly process for an actuator head suspension assembly used in a magnetic disk device. In one embodiment, a head suspension assembly includes a wire trace that includes a laminated structure of a metal layer, a first dielectric layer, a conductor layer, and a second dielectric layer. The conductor layer includes an exposed portion exposed from the second dielectric layer. The suspension assembly also includes a head/slider supported by the metal layer. An actuator assembly includes an actuator arm and a flexible printed circuit board. The exposed portion of the conductor layer is immersed in a charge neutralizing solvent. The head suspension assembly is mounted to the actuator arm. A terminal of the wire trace is connected to a terminal of the flexible printed circuit board.

Abstract: A method for mounting a coil onto a stator for a rotary electric machine. The method includes forming a coil piece by winding wire having a flat cross section into a single row lamination state including wire layers that are aligned along a line that is perpendicular to flat surfaces of the wire. The coil piece is formed so that a first portion to be inserted in the slot and a second portion that is not inserted in the slot appear alternately along the coil piece. The method also includes displacing the wire layers at the first portion from one another to change the single row lamination state to a connectively laminated stat e in which the wire layers at the portion to be inserted in the slot each adjacent pair of the wire layers partially overlap with respect to a direction perpendicular to the flat surfaces of the wire.

Abstract: A microelectronic package is fabricated by a process which includes folding a substrate. A substrate is folded by engaging a folding portion of the substrate with a die so that the folding portion pivots with respect to a first portion of the substrate.

Abstract: A method for manufacturing a probe card includes a first contact formation step of forming a first contact on a first surface of a first sacrificial substrate, a second contact formation step of forming a second contact on a first surface of a second sacrificial substrate, a signal transmission line formation step of forming a signal transmission line in the base substrate, a first contact joining step of attaching the first surface of the first sacrificial substrate to the base substrate and joining the first contact to the signal transmission line, and a second contact joining step of attaching the first surface of the second sacrificial substrate to the base substrate and joining the second contact to the signal transmission line.

Abstract: A three-dimensional computer infrastructure cooling system is provided. The three-dimensional computer infrastructure cooling system includes at least one compute, storage, or communications brick. In addition, the three-dimensional computer infrastructure cooling system includes at least one coldrail to facilitate the removal of heat from the at least one compute, storage, or communications brick. Also, the three-dimensional computer infrastructure includes a brick-internal carrier within the at least one compute, storage, communications brick, wherein the brick-internal carrier is attached to the at least one coldrail. Moreover, the three-dimensional computer infrastructure includes a power dissipating electronic element within the at-least-one compute, storage, or communications brick, wherein the power dissipating element is attached to the brick-internal carrier.

Abstract: A solution for protecting an electronic device from an electrical surge using a mounting structure is provided. In particular, the mounting structure comprises a conductive material and is electrically connected to the protected electrical device. The conductive material and/or mounting structure can have one or more properties that prevent the mounting structure from adversely impacting operation of the electronic device during normal operation, but enables the mounting structure to provide an alternative electrical path during the electrical surge.

Abstract: In wire cross-linking process, after microwave is launched into the inside of the waveguide coaxial converter, the coated wire is inserted into the wire insertion pipe. The coated wire is cross-linked by high frequency heat and a coating insulator is adhered well to an electric conductor by heat shrinking.

Abstract: An intermediate portion of the outer insulation of a shielded electrical cable is removed near an end of the cable. A remaining small segment of the outer insulation at the cable end is moved axially inward along the cable to bunch up an exposed conductive braid of the cable. The bunched up braid is pinched to form a flattened, bell-shaped element on two opposite sides of inner conductive wires of the cable. The inner wires are attached to electrical terminals and the terminals are inserted into an insulator mounted within a conductive connector shield. The flattened elements are simultaneously aligned between opposite crimp arms extending from sides of the connector shield. The arms are crimped onto the flattened elements using an ultrasonic/vibration type crimping process or a shear lock crimping process. Since the flattened braid elements extend away from the cable, the crimping process is offset from the inner wires.

Abstract: The present disclosure relates to a telecommunications cable having a jacket including a feature for allowing post-extrusion insertion of an optical fiber or other signal-transmitting member. The present disclosure also relates to a method for making a telecommunications cable having a jacket including a feature for allowing post-extrusion insertion of an optical fiber or other signal-transmitting member.

Abstract: The fabrication of a semiconductor integrated circuit device involves testing using a pushing mechanism that is constructed by forming, over the upper surface of a thin film probe, a reinforcing material having a linear expansion coefficient (thermal expansion coefficient) almost equal to that of a wafer to be tested; forming a groove in the reinforcing material above a contact terminal; placing an elastomer in the groove so that a predetermined amount projects out of the groove; and disposing a pusher and another elastomer to sandwich the pusher between the elastomers. With the use of such a probe, it is possible to improve the throughput of wafer-level electrical testing of a semiconductor integrated circuit.

Abstract: A probe card for production testing of semiconductor imaging die includes a stiffener supported on a bottom side of the probe card. The top of the stiffener is substantially flush with a top surface of the probe card. A light passage through the stiffener features non-reflective surfaces. Surfaces surrounding the light passage are arranged to avoid casting any shadows on the imaging die being tested. The arrangement provides a low profile probe card. A source of light used to illuminate the imaging die through the light passage can be placed close to the imaging device under test, providing few false negatives and more consistent results from wafer to wafer.

Abstract: The present invention relates to a method for forming an active area or flat panel in an X-ray detector device. The method comprises forming at least one flat form factor panel in a first size on a substrate of a second size and extending at least one contact of the at least one flat form factor panel. The method further comprises trimming the substrate to the first size forming the at least one flat panel.

Abstract: A wire processing apparatus includes a microwave generator, a microwave transmitter, a waveguide coaxial converter and a wire insertion pipe, and the wire insertion pipe is disposed in the wireguide coaxial converter. In wire recycling process, after a tip end of a coated wire is inserted into the wire insertion pipe, microwave is launched into the inside of the waveguide coaxial converter. The tip end of the coated wire is separated into a decomposed coating insulator and a molten electric conductor by microwave. In wire cross-linking process, after microwave is launched into the inside of the waveguide coaxial converter, the coated wire is inserted into the wire insertion pipe. The coated wire is cross-linked by high frequency heat and a coating insulator is adhered well to an electric conductor by heat shrinking.

Abstract: A method of making a windshield having first and second outer layers and a conductive bar, an electrical connector, and an intermediate layer positioned between the outer layers. The method includes the step of sinking the conductive bar and the electrical connector into a surface of the intermediate layer so as to be at least substantially flush with the surface. After sinking the conductive bar and the electrical connector into the surface, the first outer layer is engaged with the surface of the intermediate layer. Additionally, the second outer layer is engaged with a second surface of the intermediate layer.

Abstract: A method of assembling and providing an electric power apparatus. The method uses a heat resistant housing having a structure adapted to accommodate and retain a power circuit card and also including a bracket adapted to accommodate and constrain a rigid conductive member. A power circuit card having an electrical terminal is placed into the housing and a rigid conductive member into the bracket. The rigid conductive member is flow soldered to the electrical terminal, thereby exposing the heat resistant housing to heat and creating a solder bond. Finally, the rigid conductive member is affirmatively connected to the housing. The bracket constrains the rigid conductive member so that the act of affirmatively connecting does not weaken the solder bond.

Abstract: A brush assembly (10) for a miniature electric motor has a beryllium copper strip brush arm (14) and a graphite material brush head (12) moulded to an end thereof. The brush arm (14) has a number of apertures. The brush head (12) has a number of projections which pass through the apertures and form one or more caps (24) on the reverse side of the brush arm to secure the brush head (12) to the brush arm (14). A method of forming the brush assembly is also provided.

Abstract: A cable assembly comprises a plurality of electrical or fiber-optic cables, a spacer, and a collar. The cables are arranged lengthwise in a bundle, which includes a segment having a cross-sectional arrangement organized into a plurality of columnar sections of contiguous cables. Each columnar section has at least one cable. The spacer is disposed between adjacent columnar sections of cables and thus forms a dividing line between the adjacent columnar sections. The spacer spans substantially entirely across a cross section of the segment of the bundle in one direction. The collar is disposed entirely around the bundle and the spacer along at least a portion of the segment. The collar is sufficiently tight such that the collar and the spacer cooperate to hold the adjacent columnar sections in substantially fixed relative positions within the cross-section of the bundle.

Abstract: An optical memory device has grooves for guiding a light spot and pits for serving as track number indicators. The width W.sub.1 and depth d.sub.1 of the grooves and the width W.sub.2 and depth d.sub.2 of the pits are so selected that 2D(W.sub.1, d.sub.1)=1+D(W.sub.2, d.sub.2) where D(W.sub.1, d.sub.1) and D(W.sub.2, d.sub.2) are respectively the reflectivity of the groove and the pit.