Abstract: An optical receiver is provided with an optical-signal-receiving section and a controlling section. The optical-signal-receiving section incorporates a photodetector. The photodetector has an APD. Through a passivation film, a photoconductor is placed on a portion of a surface of the APD which remains unoccupied by an optical-signal-receiving area of the APD. When this structure is employed, the signal for controlling the avalanche multiplication factor of the APD can be obtained from the photoconductor. Consequently, the signal can be obtained with a simple structure. Furthermore, the photoconductor has a good linearity of the output current even to a weak lightwave. As a result, the output current I for controlling the avalanche multiplication factor of the APD can be obtained with high accuracy.

Abstract: The present invention provides an optical receiver that uses an avalanche photodiode (APD) whose multiplication factor m is controlled to compensate the temperature dependence thereof. An optical module of the present invention includes a light-receiving device in addition to the APD. The light-receiving device may be a semiconductor thin film or a PIN photodiode, and is disposed in front of the APD. Accordingly, the light-receiving device receives a portion of signal light, and transmits a rest portion thereof. The APD receives the rest portion of the signal light. The bias voltage applied to the APD is so controlled that a first photocurrent generated in the light-receiving device and a second photocurrent generated in the APD maintain a constant ratio.

Abstract: The present invention is to provide a laser driving circuit having a comparably short time constant, accordingly, can follow fluctuations with a short time interval. The circuit of the present invention provides a feedback transistor in addition to a driver transistor for driving the laser diode and a photodiode for detecting a portion of the optical output of the laser diode. The feedback transistor controls, by receiving the information derived from the photo current generated in the photodiode, the current flowing in the driver transistor and the laser diode. The time constant of the feedback loop, i.e., the laser diode, the photodiode, the feedback transistor, the driver transistor and the laser diode, is far smaller than that of the APC loop. Therefore, the feedback control for the short time constant phenomena may be carried out.

Abstract: An optical receiver includes an avalanche photodiode (APD) having a light-receiving area provided on a face of a first substrate, the light-receiving area receiving a part of signal light; a photodetector having a light-receiving area provided on a face of a second substrate, the light-receiving area receiving the other part of the signal light; and a mounting member having a principal plane on which the APD and the photodetector are mounted. Due to this structure, crosstalk between the APD and the photodetector does not occur and an avalanche multiplication factor of the APD can be controlled on the basis of the output current of the photodetector.

Abstract: An optical receiver includes a PIN photodiode (PIN-PD) having an incident surface for receiving signal light, the PIN-PD transmitting a part of the signal light to the surface opposite to the incident surface, and an avalanche photodiode (APD) having an incident surface for receiving light transmitted through the PIN-PD. In the optical receiver, the ratio of the quantity of signal light detected by the PIN-PD and the ratio of the quantity of signal light detected by the APD are not affected by the polarization state of the signal light incident on the optical receiver, and accordingly the avalanche multiplication factor of the APD is suitably controlled on the basis of the signal light detected by the PIN-PD.

Abstract: An optical receiver includes a light-receiving part and a control part. The light-receiving part includes an APD, a PIN-PD, and a branching optical device. First signal light is incident on the light-receiving part and is divided into second signal light and third signal light which are incident on the APD and the PIN-PD, respectively, by the branching optical device. Due to this structure, the third signal light is incident on the PIN-PD without the quantity thereof being varied depending on the polarization state of the first signal light. The control part generates a supply voltage at which a desired avalanche multiplication factor is obtained in the APD on the basis of the output current from the PIN-PD. According to the above-described structure, the avalanche multiplication factor of the APD is accurately controlled on the basis of the output current of the PIN-PD.

Abstract: A problem of the present invention is to provide a semiconductor laser module for making precise temperature control possible. A semiconductor laser module 1 according to the present invention has a Peltier element 4, a thermistor 5 for detecting the temperature of the Peltier element 4, and a differential amplification circuit 6 for generating a control signal according to the detection signal from the thermistor 5 so that the surface temperature of the Peltier element 4 conforms to a set temperature. A parallel compensating circuit 12 for generating a compensating signal for compensating for a delay in temperature variation in the Peltier element 4 with respect to the input of current signal to the Peltier element 4 branches and is connected to the output portion of the differential amplification circuit 6. The compensating signal is sent to an addition circuit 9 and detection correction signal obtained by adding the detection signal of the thermistor 5 and the compensating signal is generated.

Abstract: The lens barrel with an adjustable focus comprises an external mounting unit, an optical unit and a control unit including a focusing motor and the like. The external mounting unit comprises a fixed frame covering the optical unit, a distance ring, an outer circumferential cover, a zoom ring, a back end cover. The optical unit contains a plurality of frame member units that respectively support a plurality of lens groups. Furthermore, after the unitized optical unit is inserted into the fixed frame, the distance ring, outer circumferential cover, zoom ring, back end cover and the like are successively engaged with the outer circumferential part of the fixed frame from the rear side, so that these parts are easily assembled.

Abstract: The present invention provides an optical module able to reduce the power consumption thereof. The optical module, the package of which has a type of CAN or a co-axial shape, includes a Peltier device, a block, a laser diode (LD) and a photodiode. The block, mounting the LD on the side surface thereof, has a surface for reflecting the light emitted from the light-reflecting facet of the LD, and is mounted on the Peltier device. The photodiode, installed outside the Peltier device, receives the light emitted from the LD and reflected by the surface of the block. Since the photodiode is mounted outside the Peltier device, the cooling efficiency of the Peltier device may be enhanced, which saves the power consumption of the optical module.

Abstract: The present invention provides a semiconductor laser module that reduces a shift of the output wavelength after the laser diode is practically operated. The laser module comprises the semiconductor laser, a thermistor, a thermoelectric cooler, a heater and a controller. When the temperature of the laser diode is out of a preset range, the heater is supplied a current for simulating the self-heating of the laser diode. After the temperature of the laser diode falls within the preset range, the current supplied to the heater is shut off and the laser diode is practically driven by providing the bias and the modulation currents thereto.

Abstract: An optical transmitter apparatus includes a plurality of optical transmitter modules and a host controller. A module controller in each module determines whether the modulation current of a laser diode in the module is an anomaly, and also determines whether the temperature of the laser diode is an anomaly. If the modulation current or the temperature of the laser diode has an abnormal value, the module controller generates and sends an alarm signal from an alarm-outputting terminal. The alarm-outputting terminals of the modules are connected to an alarm-receiving terminal of the host controller in a wired-OR connection.

Abstract: A liquid infusion apparatus for fixing an outer cylinder of a syringe and a driver for pushing a plunger in a predetermined direction so as to exhaust liquid in the syringe, an incremental linear encoder arranged along the feeding axis of said driver for pushing the plunger, a detector of said incremental linear encoder mounted on a slider portion of the driver for pushing the plunger so as to generate a signal indicating a moving quantity of the plunger, and a sensor provided in the vicinity of a liquid exhaust port of the outer cylinder for setting along the feeding axis a remaining liquid quantity small section so as to generate a signal about a position of the plunger at the remaining liquid quantity small section.

Abstract: A light-emitting module according to the present invention contains a Peltier element driver, and a signal processor for controlling the Peltier element driver. The Peltier element driver is mounted on a first substrate, which directly attaches to the inner bottom surface of the housing, while the signal processor is mounted on the other substrate spaced to the first substrate. The first substrate and the other substrate are vertically integrated within the housing. This arrangement enables to encase the Peltier element driver and the signal processor in the housing with effective thermal dissipation.

Abstract: A solar cell includes a first semiconductor layer that is p-type, and a second semiconductor layer that is n-type formed over the first semiconductor layer. The solar cell includes a layer A made of a semiconductor different from the first semiconductor layer and the second semiconductor layer or an insulator between the first semiconductor layer and the second semiconductor layer. The band gap Eg1 of the first semiconductor layer and the band gap Eg2 of the second semiconductor layer satisfy the relationship Eg1<Eg2. The electron affinity &khgr;1 (eV) of the first semiconductor layer and the electron affinity &khgr;2 (eV) of the second semiconductor layer satisfy the relationship 0≦(&khgr;1−&khgr;2)<0.5, and the average layer thickness of the layer A is 1 nm or more and 20 nm or less.

Abstract: A problem of the present invention is to provide a semiconductor laser module for making precise temperature control possible.

Abstract: A solar cell with good characteristics and high reliability is provided that includes a semiconductor comprising at least one element from each of groups Ib, IIIb, and VIb. A method of manufacturing the same also is provided. The solar cell includes a conductive base, a first insulating layer formed on one principal plane of the base, a second insulating layer formed on a second principal plane of the base, and a light-absorption layer disposed above the first insulating layer. The light-absorption layer is formed of a semiconductor comprising at least one element from each of groups Ib, IIIb, and VIb.

Abstract: A lens barrel in accordance with the present invention has a stationary frame, a cam frame, a first lens frame, and a second lens frame. The cam frame has an external cam formed on the external surface thereof and an internal cam formed on the internal surface thereof. The first lens frame is freely movable in directions along an optical axis relative to the stationary frame when driven by the external cam of the cam frame. The second lens frame can freely slide in the optical-axis directions with its rotation restrained by the internal surface of the first lens frame when driven by the internal cam of the cam frame.

Abstract: A body frame, which is a lens barrel device, comprising two semi-circular torus-shaped lens frames, respectively, mounting thereto a forward-group lens and a rearward-group lens, and two guide shafts fixed to one of the lens frames and slidably inserted into a sleeve fixed to the other of the lens frames and into a slot, the two lens frames being supported to advance and retreat relative to each other. When a jig is used to assemble the lens frames, the two lens frames are mounted to the jig while the forward-group lens, the rearward-group lens and the two guide shafts are inserted into the jig with gaps therebetween, the jig being in a state, in which the forward-group lens, the rearward-group lens and the two guide shafts are retained in a predetermined position, and an adhesive is filled into and fixed to the respective gaps to complete assembly. Such lens body frame can ensure optical performance without being affected by accuracy of parts such as lens frames, guide shafts, photographing lenses and so on.

Abstract: A method of attenuating an unwanted electric field radiation caused by electrostatic induction on an internal conductive coating of a cathode ray tube by a pulse voltage generated by a deflection circuit is provided. A reverse pulse voltage, which is reverse in polarity to the pulse voltage of the deflection circuit, is impressed on an external conductive coating of the cathode ray tube and electrostatic induction induces a pulse voltage on the internal conductive coating which is reverse in polarity to a pulse voltage of the deflection yoke induce on the internal conductive coating through an electrostatic capacitance existing between the internal conductive coating and the external conductive coating so that an unwanted electric field radiation from the front screen of a cathode ray tube is attenuated.

Abstract: A zoom lens barrel wherein its cam ring has three sets of three cam grooves for advancing or retracting a first group frame, a focus frame and third group frame. The three cam grooves include a cam follower introducing groove connected to ends of two cam grooves for the focus frame and a third group frame and a joint groove for joining two cam grooves for the first group frame and the focus frame. When inserting a cam follower of the first group frame into the cam groove, after it is inserted into the introducing groove, it is passed through the cam groove for the focus frame and then, passed through the joint groove and fit to the cam groove for the first group frame. Further, when inserting the cam followers of the focus frame and third group frame into the cam groove, after it is inserted from the introducing groove, it can be fit to the focus frame and third group frame separately.