An analog circuit includes a pair of peak-hold circuits that generate peak signals indicating the peak values of a differential pair of input signals, a first differencing circuit such as a transconductance amplifier that takes the difference between the input signal values, a second differencing circuit such as a transconductance amplifier that takes the difference between the two peak signal values, and a combining circuit such as a resistor circuit that additively combines the outputs of the differencing circuits in such a way as to compensate for direct-current offset in the input signals. Advantages of this circuit structure include reduced power consumption and simplified implementation in an integrated circuit. Low pass filters, capacitor discharging circuits, and unbalanced circuit elements can be used to obtain further advantages.

1. Field of the Invention
The present invention relates to circuits used in communication equipment such as optical communication equipment and mobile communication equipment. These circuits include an optical receiving circuit, an optical transmitting circuit, an automatic gain control amplifier circuit, an automatic frequency compensation amplifier circuit, and a limiting amplifier circuit used for clock recovery. The invention relates in particular to an analog summing and differencing circuit used in a main amplifier and level discrimination circuit in the optical receiving circuit, in the part of the optical transmitting circuit that detects light emitted for monitoring purposes, in the amplitude-detecting part of the automatic gain control amplifier circuit and automatic frequency compensation amplifier circuit, and in a limiting amplifier, limit comparator, and offset compensator in the limiting amplifier circuit.
2. Description of the Related Art
As shown in FIG. 1, an optical receiving circuit includes a photodetector (PD), a preamplifier (P-Amp), n main amplifiers (M-Amp), where n is an integer equal to or greater than one, and a level discrimination circuit (L-Dis). The photodetector PD is reverse-biased by a voltage Vbias, and converts a received optical signal to a current signal Ip. The preamplifier converts the current signal Ip to a pair of differential voltages VAp, VAn. VAp is sometimes referred to as the non-inverting phase or positive phase, and VAn as the inverting phase, opposite phase, or negative phase, but the simpler terms positive voltage and negative voltage will be used for brevity below, with the understanding that they are merely convenient names and do not imply positive or negative algebraic values.
The n main amplifiers compensate for the direct-current (dc) offset of the differential voltages VAp, VAn, and amplify these voltages in n stages to a differential voltage level sufficient to drive the level discrimination circuit. The level discrimination circuit converts the final amplified differential voltages VCp(n), VCn(n) to a positive logic signal Qp and a negative logic signal Qn. The main amplifiers are described in, for example, U.S. Pat. Nos. 5,612,810, 5,875,049, and 5,892,609 (and corresponding Japanese Unexamined Patent Application Publications No. 08-84160, 09-289495, and 10-84231).
FIG. 49 shows the general structure of the main amplifier described in U.S. Pat. No. 5,612,810. This main amplifier includes an offset compensator 101a comprising an analog summing and differencing circuit (SUM/DIF CKT), and a differential amplifier Amp1. The offset compensator 101a includes a pair of peak-hold circuits PH1, PH2 and a pair of adders ADD1, ADD2. The adders ADD1, ADD2 constitute the summing and differencing part of the circuit. FIGS. 50 and 51 shows specific examples of the circuit configuration of the offset compensator 101a in FIG. 49.
In FIG. 49, peak-hold circuit PH1 senses the peak of the negative differential output voltage VAn of the preamplifier (cf. FIG. 1) and outputs a negative peak value VAnp; peak-hold circuit PH2 senses the peak of the positive differential output voltage VAp of the preamplifier and outputs a positive peak value VApp. Adder ADD1 outputs an offset-compensated positive differential voltage VBp by adding the positive differential voltage VAp and negative peak value VAnp; adder ADD2 outputs an offset-compensated negative differential voltage VBn by adding the negative differential voltage VAn and positive peak value VApp. The differential amplifier Amp1 amplifies the offset-compensated differential voltages VBp, VBn, and outputs a positive differential voltage VCp and a negative differential voltage VCn.
In the analog summing and differencing circuit in FIG. 50, adder ADD1 adds differential voltage VAp and peak value VAnp through a pair of summing resistors R2, R1 and outputs an offset-compensated positive differential voltage VBp; adder ADD2 adds differential voltage VAn and peak value VApp through a pair of summing resistors R3, R4 and outputs an offset-compensated negative differential voltage VBn.
If the resistance values of the summing resistors R1–R4 in FIG. 50 are related so that R1=R2 and R3=R4, the differential voltages VBp, VBn are given by the equations below.VBp=(VAnp+VAp)/2, VBn=(VAn+VApp)/2  (1)Accordingly, the adders ADD1, ADD2 can also be regarded as averaging circuits. Differencing is performed by supplying the outputs of adders ADD1, ADD2 to the differential inputs of the next-stage differential amplifier Amp1.
The analog summing and differencing circuit in FIG. 51 includes a balanced negative feedback amplifier Amp2 with a feedback resistor R5 connected between its inverting output and non-inverting input, and another feedback resistor R6 connected between its non-inverting output and inverting input. The positive differential voltage VAp and negative peak value VAnp are added through summing resistors R2, R1, and their sum becomes the non-inverting input of amplifier Amp2; the negative differential voltage VAn and positive peak value VApp are added through summing resistors R3, R4, and their sum becomes the inverting input of amplifier Amp2. The inverting output and non-inverting output of amplifier Amp2 are output as an offset-compensated positive differential voltage VBp and negative differential voltage VBn. The analog summing and differencing circuit in FIG. 51 replaces the adders ADD1, ADD2 in FIG. 49. Subtraction is performed by input to the differential input terminals of differential amplifier Amp1.
The main amplifier in FIG. 49 does not use negative feedback to compensate for offset, and is not affected by the relative rate of occurrence of '1' and '0' values, but can compensate for the differential dc offset voltage generated in the preamplifier, so stable operation and high gain can be obtained, even in a multistage configuration in which the last stage or stages perform a limiting operation.
In the main amplifier in FIG. 49, differential voltages VBp, VBn are related as indicated in the equation below.VBp−VBn=K((VAp+VAnp)−(VAn+VApp))  (2)
K in equation (2) is the gain (or attenuation ratio) in the analog summing and differencing circuit. The first term on the right indicates the value of VBp, the peak of which is the sum of the peak of pulse signal VAp and the peak-hold value VAnp (the peak value of pulse signal VAn). The second term on the right indicates the value of VBn, the peak of which is the sum of the peak of pulse signal VAn and the peak-hold value VApp (the peak value of pulse signal VAp). Subtraction of VBn from VBp means that these signals become differential inputs. The respective peak values of VBp and VBn are both equal to the sum of the peak values of the pulse signals VAp, VAn. Furthermore, since VAp and VAn are differential signals with identical amplitude, the amplitude values of VBp and VBn are identical. VBp and VBn therefore have the same peak value and amplitude, but are reversed in phase. Accordingly, VBp and VBn are offset-compensated differential signals.
FIG. 52 shows the general structure of the main amplifier described in U.S. Pat. No. 5,892,609. The reference voltage generator (REF-VOLTAGE-GEN) in this main amplifier has the same output dc voltage bias as the preamplifier (cf. FIG. 1). Input of the pair of peak-hold outputs VApp, VAnp to a differential input amplifier Amp2 with gain 0.5 produces a voltage VM in which one-half of the voltage offset of the differential voltages VAp, VAn is added to the output dc voltage bias, (corresponding to the median amplitude of the positive differential output VAp). This voltage VM then becomes a reference voltage VBn for the positive differential voltage VAp.
FIGS. 53 and 55 show the general structure of two main amplifiers described in U.S. Pat. No. 5,892,609, using like reference characters to indicate like elements. FIG. 54 shows a specific example of the circuit configuration of the offset compensator 101b in FIG. 53, comprising resistors R1–R6, bipolar transistors Q1–Q4, and constant-current sources Is1, Is2.
The main amplifiers in FIGS. 53 and 55 input an appropriate combination of the differential voltages VAp, VAn and peak-hold voltages VApp, VAnp to an amplifier with differential inputs and a wide input range (where widening the input range lowers the gain).
The main amplifier in FIG. 53 includes an offset compensator 101b comprising an analog summing and differencing circuit, and a differential amplifier Amp1. The offset compensator 101b includes a pair of peak-hold circuits PH1, PH2, a pair of amplifiers Gm1, Gm2 with differential voltage input and differential current output, and a pair of resistors R1, R2. The amplifiers Gm1, Gm2 and resistors R1, R2 constitute the summing and differencing part of the circuit.
Peak-hold circuit PH1 senses the peak of the negative differential voltage VAn from a preamplifier (cf. FIG. 1) and outputs a negative peak value VAnp; peak-hold circuit PH2 senses the peak of the positive differential voltage VAp from the preamplifier and outputs a positive peak value VApp. Amplifier Gm1 receives the positive differential voltage VAp from the preamplifier as its non-inverting input and the output VApp of peak-hold circuit PH2 as its inverting input, and outputs a positive differential current Io1p and negative differential current Io1n according to the differential input voltages VAp, VApp. Amplifier Gm2 receives the output VAnp of peak-hold circuit PH1 as its non-inverting input and the negative differential voltage VAn from the preamplifier as its inverting input, and outputs a positive differential current Io2p and negative differential current Io2n according to the differential input voltages VAnp, VAn. Resistor R1 converts the sum of the positive differential currents Io1p and Io2p to a positive output voltage VBp. Resistor R2 converts the sum of the negative differential currents Io1n and Io2n to a negative output voltage VBn. The differential amplifier Amp1 amplifies the offset-compensated positive output voltage VBp and negative output voltage VBn, and outputs a positive differential voltage VCp and a negative differential voltage VCn.
The main amplifier in FIG. 55 includes an offset compensator 101c comprising an analog summing and differencing circuit, and a differential amplifier Amp1. The offset compensator. 101c includes a pair of peak-hold circuits PH1, PH2, and a pair of amplifiers Din1, Din2 with differential voltage input and single-ended voltage output. The amplifiers Din1, Din2 constitute the summing and differencing part of the circuit.
Amplifier Din1 receives the positive differential voltage VAp from the preamplifier (cf. FIG. 1) as its non-inverting input and the output VApp of peak-hold circuit PH2 as its inverting input, and outputs a voltage VBp according to the differential input voltage. Amplifier Din2 receives the negative differential voltage VAn from the preamplifier as its non-inverting input and the output VAnp of peak-hold circuit PH1 as its inverting input, and outputs a voltage VBn according to the differential input voltage.
If differential input is regarded as subtraction and a T-network current sum is regarded as addition in FIGS. 53 and 55, then in FIG. 53, differential voltages VBp, VBn are related as indicated in the equation below.
                                                                        VBp                -                VBn                            =                              K                (                                                      (                                          VAp                      -                      VApp                                        )                                    +                                      (                                          VAnp                      -                      VAn                                        )                                                  )                                                                                =                              K                (                                                      (                                          VAp                      +                      VAnp                                        )                                    -                                      (                                          VAn                      +                      VApp                                        )                                                  )                                                                        (        3        )
In FIG. 55, differential voltages VBp, VBn are related as indicated in the equation below.
                                                                        VBp                -                VBn                            =                              K                (                                                      (                                          VAp                      -                      VApp                                        )                                    -                                      (                                          VAn                      -                      VAnp                                        )                                                  )                                                                                =                              K                (                                                      (                                          VAp                      +                      VAnp                                        )                                    -                                      (                                          VAn                      +                      VApp                                        )                                                  )                                                                        (        4        )
Equations (3) and (4) are the same as equation (2). Accordingly, VBp-VBn includes compensation for the dc offset of differential voltages VAp, VAn.
FIG. 56 shows the general structure of the level discrimination circuit described in U.S. Pat. No. 6,151,150 (and corresponding Japanese Unexamined Patent Application Publication No. 10-163828). This level discrimination circuit includes an offset compensator 104a comprising an analog summing and differencing circuit, and a comparator Comp1. The offset compensator 104a includes a pair of peak-hold circuits PH1, PH2, a pair of adders ADD1, ADD2, and a pair of voltage sources generating a reference voltage Vr and an offset voltage Voff. These circuit elements compensate for the dc offset of the differential voltages VCp, VCn and output differential voltages VEp, VEn. The adders ADD1, ADD2 constitute the summing and differencing part of the circuit. The comparator Comp1 compares the differential voltages VEp, VEn, and outputs a positive logic signal Qp and a negative logic signal Qn (one of the two logic signals, either Qp or Qn, may be omitted).
Photoelectric current flows in the photodetector PD (cf. FIG. 1) when the photodetector PD receives '1' data, and does not flow when the photodetector PD receives '0' data or does not receive any optical signal. A period during which photoelectric current does not flow will be referred to below as an extinction period, and a period during which photoelectric current flows and '1' data is received will be referred to as a light-receiving period.
If the offset compensator of the level discrimination circuit has the same general structure as the offset compensator of the main amplifier, when the same values of the differential voltages VAp, VAn continue over a long extinction period, the differential output voltages VCp, VCn, of the main amplifier and the differential output voltages VEp, VEn of the offset compensator of the level discrimination circuit are output with offset voltage compensation and zero amplitude, and are related as indicated in the equation below (where the tilde '˜' indicates approximate equality).VCp−VCn˜VEp−VEn˜0
If VEp−VEn˜0 as in the above equation, output of the positive logic signal Qp and the negative logic signal Qn becomes indeterminate or unstable.
In the offset compensator 104a in FIG. 56, input of the offset voltage Voff to adder ADD2 enables compensation for the dc offset of the differential voltage signals VCp, VCn to take place without having the logic signals Qp, Qn become indeterminate or unstable during long-period extinction. That is, if VCp−VCn˜0 over a long extinction period, then VEn>VEp because of the offset voltage Voff, stabilizing the logic signals at Qp='0', and Qn='1'.
FIG. 57 shows the general structure of an automatic gain control amplifier circuit (AGC amplifier circuit). This AGC amplifier circuit includes a variable gain amplifier 16a, a peak-hold circuit PH, and a gain control amplifier 26a. The variable gain amplifier 16a, the variable gain of which is externally controllable, amplifies an input voltage VF according to the controlled gain and outputs a voltage VG. The peak-hold circuit PH senses the peak value of this voltage and outputs the peak value VGp. The gain control amplifier 26a receives the peak-hold voltage VGp as its inverting input and a reference voltage Vr as its non-inverting input, and controls the gain of the variable gain amplifier according to the peak-hold voltage VGp.
In the AGC amplifier circuit in FIG. 57, when the amplitude level of the input voltage VF increases, the gain control amplifier 26a decreases the gain of the variable gain amplifier 16a, thereby maintaining the output voltage VG of the variable gain amplifier 16a at a constant amplitude level, even if the amplitude level of the input voltage VF varies.
FIG. 58 shows the general structure of an automatic frequency compensation amplifier circuit (√f-AGC amplifier circuit), using the same reference characters as in FIG. 57 for similar elements. This √f-AGC amplifier circuit includes a variable frequency characteristic amplifier 17a, a peak-hold circuit PH, and an equalization characteristic control amplifier 27a. The variable frequency characteristic amplifier 17a amplifies an input voltage VF according to an externally controllable gain-frequency characteristic, and outputs a voltage VG. The equalization characteristic control amplifier 27a receives the peak-hold voltage VGp as its inverting input and a reference voltage Vr as its non-inverting input, and controls the gain-frequency characteristic of the variable frequency characteristic amplifier 17a according to the peak-hold voltage VGp.
When a pulse signal is transmitted on a (metallic) cable, if the cable is long, high frequency components are attenuated with what is generally termed a √f characteristic, degrading the pulse waveform. It is necessary to compensate by varying the receiving frequency characteristic of the pulse receiving circuit according to the length of the cable (the gain at high frequencies must increase to compensate for the √f characteristic). This compensation process is also referred to as equalization.
In the √f-AGC amplifier circuit in FIG. 58, when the amplitude level of the input voltage VF decreases because of pulse waveform degradation, the equalization characteristic control amplifier 27a increases the high-frequency gain of the variable frequency characteristic amplifier 17a, thereby keeping its output voltage VG at a constant amplitude level and maintaining a fixed pulse waveform, even if the input voltage signal VF is degraded.
The √f characteristic compensation method, which controls the peak of the output voltage of a variable frequency characteristic amplifier as is done in the √f-AGC amplifier circuit in FIG. 58, is suitable for a signal with relatively few low-frequency components. Such signals are generated by balanced codes such as the alternate mark inversion (AMI) code illustrated in FIG. 41A, the code mark inversion (CMI) code illustrated in FIG. 41B, and the Manchester code illustrated in FIG. 41C.
FIGS. 59A and 59B show the general structure of two optical transmitter circuits. Each optical transmitter circuit includes a light-emitting element (laser diode) LD, a switching circuit CUR-SW, driving current generating circuits IP, IB, and a light emission control circuit 118.
FIG. 60 shows a specific example of the circuit configuration of the light emission control circuit 118. The light emission control circuit 118 includes a monitor photodetector PDM, a preamplifier, a reference voltage circuit, a peak-hold circuit PH, and a light emission control amplifier C-Amp. The preamplifier includes a pair of impedance elements Zp and a differential amplifier (DIFF-AMP). The differential amplifier DIFF-AMP includes a differential amplifying stage (D-AMP) with a pair of resistors R1, R2, a pair of bipolar transistors Q1, Q2, and a current source Is1, and a buffer stage (BUFF) with a bipolar transistor Q3 and a current source Is2. The reference voltage circuit includes a variable resistor R3, a bipolar transistor Q4, and a pair of current sources Is3, Is4. The impedance elements Zp convert current to voltage, as indicated in FIG. 59C
The light-emitting element LD emits light according to a driving pulse current Ip and driving bias current Ib, and transmits an optical signal. The monitor photodetector PDM converts a received monitor light signal from the light-emitting element LD to a monitor current signal. The preamplifier (which, like the preamplifier 16a in FIG. 57, may have externally controllable gain) converts the monitor current signal to a voltage VG. The peak-hold circuit PH senses the peak value of this voltage and outputs the peak value VGp.
In the optical transmitter circuit in FIG. 59A, the driving pulse current generating circuit IP generates a driving pulse current Ip according to a control voltage VC, and the driving bias current generating circuit IB feeds the light-emitting element LD a driving bias current Ib that is independent of the control voltage VC. The switching circuit CUR-SW switches the driving pulse current Ip on and off according to a transmit data signal D, and outputs the switched driving pulse current Ip to the light-emitting element LD. The light emission control amplifier C-Amp compares the peak value VGp with a reference voltage Vr and varies the light emission control voltage VC so as to decrease the driving pulse current Ip if VGp is greater than Vr, or increase the driving pulse current Ip if VGp is less than Vr.
In the optical transmitter circuit in FIG. 59B, the driving pulse current generating circuit IP generates a driving pulse current Ip independent of the control voltage VC, and the driving bias current generating circuit IB feeds the light-emitting element LD a driving bias current Ib according to the control voltage VC. The switching circuit CUR-SW switches the driving pulse current Ip on and off according to the transmission data signal D, and outputs the switched driving pulse current Ip to the light-emitting element LD. The light emission control amplifier compares the peak value VGp with a reference voltage Vr and varies the light emission control voltage VC so as to decrease the driving bias current Ib if VGp is greater than Vr, or increase the driving bias current Ib if VGp is less than Vr.
FIGS. 61 and 62 show the general structure of two limiting amplifier circuits included in a clock recovery circuit. The limiting amplifier circuit 119A in FIG. 61 includes m differential amplifiers Lim(1) to Lim(m) (where m is an integer equal to or greater than one), and a comparator Comp. The limiting amplifier circuit 119B in FIG. 62, which also performs duty cycle compensation, adds a duty compensation circuit to the limiting amplifier circuit 119A. The duty compensation circuit includes a pair of averaging circuits Me1, Me2, a differential amplifier Amp, a resistor Rt, and a capacitor Ct. The clock recovery circuit also includes a tuning tank (TANK) and, in FIG. 61, a capacitively coupled amplifier Dout that converts the single-ended output of the tuning tank to a differential signal.
FIG. 63 shows signal waveforms in the clock recovery circuit in FIG. 61. The tuning tank in the clock recovery circuit outputs a clock component signal (tank output signal T-out) synchronized to a tank driving trigger signal (T-trigger). The clock component signal T-out is a damped oscillation signal and has an approximate sine waveform. The clock component signal T-out has high amplitude when the tank driving trigger signal T-trigger drives the tank frequently, and low amplitude when the tank driving trigger signal T-trigger drives the tank infrequently.
In the clock recovery circuit in FIG. 61, the tank output signal is converted to differential voltages VSp(1), VSn(1) in the differential output amplifier Dout. These differential voltages VSp(1), VSn(1) are amplified and limited in the limiting amplifier circuit 119A, from which recovered clock signals (logic signals) Qp, Qn are produced. The m differential amplifiers Lim(1) to Lim(m) amplify and limit the differential voltages VSp(1), VSn(1) and output differential voltages VUp(m) (also denoted VSp(m+1)) and VUn(m) (also denoted VSn(m+1)). The comparator Comp compares voltage VSp(m+1) with voltage VSn(m+1), and converts VSp(m+1) and VSn(m+1) to the logic signals Qp, Qn.
In the limiting amplifier circuit 119B in FIG. 62, the averaging circuit Me1 senses the mean value Qpm of recovered clock signal Qp, and the averaging circuit Me2 senses the mean value Qnm of recovered clock signal Qn. The differential amplifier Amp receives the mean value Qpm as its non-inverting input and the mean value Qnm as its inverting input, and increases the bias voltage of the inverting input of the first differential amplifier Lim(1) if Qpm is greater than Qnm, or decreases the bias voltage if Qpm is less than Qnm, so as to compensate for variations in the duty cycle of the recovered clock signals Qp, Qn. The time constant of capacitor Ct and resistor Rt stabilizes the duty cycle compensation.
FIGS. 64A, 64B, and 64C show waveforms in a main amplifier. FIG. 64A shows waveforms of the differential voltages VAp, VAn output from the preamplifier. FIG. 64B shows waveforms of the offset-compensated differential voltages VBp, VBn. FIG. 64C shows waveforms in which high frequency components (noise components) have been removed from the waveforms in FIG. 64B by a low pass filter.
Photoelectric current flows in the photodetector PD (cf. FIG. 1) in the optical receiving circuit during light-receiving periods (while receiving '1' data), and does not flow during extinction periods (while receiving '0' data or no optical signal). The thermal current noise generated by the photodetector PD varies according to the current value, so the noise level is higher during the reception of '1' data than during the reception of '0' data. Accordingly, as shown in FIG. 64A, the waveforms of the differential voltages VAp, VAn output from the preamplifier include more output noise during the reception of '1' data, when photoelectric current flows in the photodetector PD, than during the reception of '0' data, when photoelectric current does not flow in the photodetector PD. The peak-hold voltages VApp, VAnp of the differential voltages VAp, VAn therefore appear to be significantly greater than the true peak values when '1' data is received, because a relatively high noise amplitude is added to the true peak values, but VApp, VAnp are close to the true peak values when '0' data is received and the noise amplitude is relatively low.
In the offset compensators in the main amplifiers discussed above, the differential voltages VAp, VAn shown in FIG. 64A and the peak-hold voltages VApp, VAnp of VAp and VAn are added and subtracted to perform offset compensation, producing the waveform shown in FIG. 64B. After the waveform in FIG. 64B is passed through a low pass filter and high frequency noise is removed, the waveform shown in FIG. 64C is obtained.
In the waveform in FIG. 64C, the signal level differs depending on whether '1' or '0' data is being received, because the dc offset corresponding to the apparent increase of the peak value due to noise persists unnecessarily even after the noise itself has been filtered out. As a result, the minimum light receiving performance is greatly degraded. It would be desirable to have an offset compensator that does not leave this unnecessary dc offset.
In particular, practical operation of the main amplifier in FIG. 52 is greatly restricted, because differential amplifier Amp2 must have the same output dc voltage bias as the preamplifier, and a single-stage differential input amplifier such as an npn transistor amplifier does not have a large output dynamic range in the direction in which the output potential is lower than the input bias voltage.
If the main amplifier in FIG. 52 is to be implemented in an integrated circuit (IC), it is easy to achieve ratio accuracy, such as equal gain, but it is difficult to ensure an absolute value such as gain=0.5. For IC implementation, it would also be desirable to reduce the power consumption of the amplifier in the offset compensator. Accordingly, for IC implementation, it would be desirable to have an offset compensator with low power consumption and with a circuit that is easy to fabricate.
Furthermore, in an optical receiving circuit including the main amplifier above, n main amplifiers must be dc-coupled, and in dc coupling a level shift circuit must be included to control the dc level, which varies in the main amplifiers. It would also be desirable to have an offset compensator that does not need this type of level shift circuit but can obtain a balanced differential signal even from a simple preamplifier, such as a capacitively coupled amplifier, in which the bias voltage varies depending on the '1' to '0' ratio.
In the offset compensator in the level discrimination circuit in FIG. 56, the summing and differencing part must receive two mutually offset reference voltages as inputs, and the power supply generating the offset voltage Voff must be floated. Furthermore, the adders ADD1, ADD2 must add and subtract three values, which significantly complicates the circuit configuration. Accordingly, it would be desirable to have a level discrimination circuit that does not need a reference voltage and has a simpler circuit configuration.
In the conventional optical receiving circuits described above, dc offset is compensated in the offset compensators of the main amplifiers, so that the '1' and '0' pulse widths in the outputs Qp, Qn of the comparator in the level discrimination circuit do not differ (pulse intervals of one type are not longer than pulse intervals of the other type), while in the offset compensator of the level discrimination circuit described above, an offset voltage Voff is added to maintain Qp='0', and Qn='1' during extinction periods. Addition of this offset voltage, however, reduces the effect of offset compensation in the offset compensators in the main amplifiers. Accordingly, it would also be desirable to have a level discrimination circuit that does not require the addition of an offset voltage Voff and can thus avoid degradation of the time-slot width ratio of the comparator outputs Qp, Qn.
In general, the output of an amplifier is the combination of a dc bias component with a signal amplitude component, and the dc bias component varies with variations in the temperature and power supply. In the AGC amplifier circuit in FIG. 57, the peak value of the combined sum of the dc bias component and the signal amplitude component is sensed, so control of the signal amplitude is inaccurate and a constant amplitude cannot easily be maintained. Accordingly, it would be desirable to have an AGC amplifier circuit that senses and controls only the magnitude of the amplitude component.
For the same reason, it is difficult to compensate accurately for frequency characteristics in the √f-AGC amplifier circuit in FIG. 58. Accordingly, it would be desirable to have a √f-AGC amplifier circuit that senses and controls only the magnitude of the amplitude component.
In the light emission control circuits in FIGS. 59A and 59B, the dc level of the preamplifier output varies according to the temperature and the power supply. In the specific example of the circuit configuration of the light emission control circuit 118 in FIG. 60, the preamplifier includes a differential amplifier, and the reference voltage Vr input to the light emission control amplifier is generated by a circuit analogous to the differential amplifier, so variations in the dc level of the preamplifier output are compensated for by similar variations in the reference voltage Vr, both variations being caused by the same temperature and power supply variations. Even this circuit configuration, however, cannot remove the effect of the offset voltage generated in the differential amplifier, so light emission control fails to keep the amplitude of the light emission constant. Accordingly, it would be desirable to have a light emission control circuit that can accurately maintain a constant light emission amplitude in an optical signal.
In the limiting amplifier circuit 119A in FIG. 61, each differential amplifier Lim(1)−Lim(m) is a potential source of dc offset. This has little adverse effect on the '1' and '0' duty cycle of the output if the input to each differential amplifier has a large amplitude and the differential amplifier operates as a switching element, but if the input has a small amplitude and the differential amplifier operates as an active amplifier, the '1' and '0' duty cycle of the output is degraded according to the ratio of the magnitude of the input and the magnitude of the above offset (cf. FIG. 63). That is, the degree of degradation of the '1' and '0' duty cycle of the output varies according to the number of the differential amplifiers Lim(1)−Lim(m) that operate as switching elements.
The limiting amplifier circuit 119B in FIG. 62 attempts to compensate for this offset and thereby mitigate the degradation of the output duty cycle. This circuit 119B functions effectively when all m differential amplifiers Lim(1)−Lim(m) operate as active amplifying elements. When a differential amplifier operates as a switching element due to high input amplitude, however, the difference between its risetime characteristic and falltime characteristic becomes a major factor degrading the '1' and '0' duty cycle of the output. The operation of the circuit 119B in FIG. 62 then becomes unstable, because it attempts to compensate for factors other than the risetime-falltime difference that causes the duty cycle degradation. Unstable operation may also occur if the feedback time constant (the product of capacitance Ct and resistance Rt) is too small. Jitter may occur if this time constant is too large, however, because variations in the tank output level (envelope) cannot be tracked. Accordingly, it would be desirable to have a limiting amplifier circuit that can avoid both unstable operation and jitter.

Analog summing and differencing circuit, optical receiving circuit, optical transmitting circuit, automatic gain control amplifier, automatic frequency compensation amplifier, and limiting amplifier


The developer delivering device includes a first delivering path, a second delivering path, a helical delivering blade disposed in the second delivering path, and a developer breaking member disposed in a connecting portion of the first delivering path and the second delivering path. The developer breaking member includes a breaking portion disposed opposite to a side wall of the second delivering path in a developer delivering direction of the second delivering path, a contact portion that is in contact with the helical delivering blade and extended in the developer delivering direction between the breaking portion and a center of the rotation of the helical delivering blade, and a coupling portion. The breaking portion has a first breaking portion and a second breaking portion. The contact portion has a first contact portion and a second contact portion. The coupling portion couples the first contact portion to the second contact portion.

1. Technical Field
The present invention relates to a developer delivering device and an image forming apparatus.
2. Related Art
In a related-art electrophotogaphic type image forming apparatus such as a copying machine or a printer, a residue such as a developer, a corona product or paper powder which remains on a surface of an image holding member in a formation of an image is collected and delivered.

Developer delivering device and image forming apparatus


According to an aspect of the invention, implantable or insertable medical devices are provided which contain the following: (a) one or more porous regions comprising pores and (b) one or more therapeutic agents which are (i) contained within the porous region, (ii) disposed beneath the porous region, or (iii) both. Moreover, the porous regions are capable of undergoing a change in configuration, such that the pores undergo a change in configuration, upon subjecting the porous regions to activating stimuli.

The in-situ delivery of therapeutic agents within the body of a patient is common in the practice of modern medicine. In-situ delivery of therapeutic agents is often implemented using medical devices that may be temporarily or permanently placed at a target site within the body. These medical devices can be maintained, as required, at their target sites for short or prolonged periods of time, in order to deliver therapeutic agents to the target site.
It is known that the sizes and shapes of pores within a porous material are related to the release rate of drugs from, and the access of bodily fluids to, that material. As a general rule, once pores are formed in a particular material, the pore size and shape are locked in.

Medical devices having porous regions for controlled therapeutic agent exposure or delivery


A perforated laminate comprising at least first and second layers and apertures extending through at least the first layer. The first layer is a nonwoven or formed film material, and the second layer comprises an absorbent structure. The at least first and second layers are primarily joined at the periphery of the perforated apertures. The laminate is particularly useful as a topsheet for an absorbent article, such as a disposable diaper or sanitary napkin. Also described are various materials and methods used to create such laminates.

There has been a need to develop improved topsheets for absorbent articles that are able to recognize the type of fluid discharge and determine whether such fluid should be absorbed entirely by the layer underneath or be redirected along the topsheet surface. This is particularly important for both absorbent sanitary napkins and adult and baby diapers. In the case of sanitary napkins, for example, current products on the market typically only absorb discharged menstrual fluid, and rarely absorb body sweat that remains between the pad and the body. This limitation can create significant discomfort for the wearer. Several patents describe the use of apertures, different material compositions, and laminate structures as a mean to address such issue. However, there is a continuing need for improved perforated laminates for use in absorbent articles.


A method and arrangement for correlating time in different time bases used by interconnected units by timestamping a reference event with a time determined with respect to a first time base. A message unit provides the time to a second interconnected unit that uses a second time base. A translation device is configured to calculate a difference between the time measured by the first time base and in the second time base. The difference is used to translate a time measured by the first clock to a time in a different time base at run time.

The present disclosure relates to a fixed and/or moveable system, in particular in or for vehicles, for example cars. The system operates with common or related time bases for indication of the time of detected or generated events in the system, and/or in a system or systems connected to this.
The present disclosure also relates to a device for effecting the establishment of functions carried out by two or more units (nodes) comprised in the system in a fixed and/or moveable system, in particular in or for vehicles, for example cars. The device can relate to arrangements for detection, control, analysis and/or simulation of comprised units.
The use of systems of this type in, for example, vehicles, is already known and reference can accordingly be made, among other things, to the patent applications and patents submitted by and granted to the same applicant as the present applicant. In the respective systems, the message and information (data) transmissions are carried out using or in accordance with protocols of a known type, which can be of a standardized type, for example Universal Serial Bus (USB), Controller Area Network (CAN), Local Interconnect Network (LIN), Ethernet, IEEE 802.11x, Infrared (IR), Wireless USB (WUSB), etc.
With this type of system, there are problems in determining events and/or time functions without relatively complicated and bandwidth-intensive arrangements. There is, for example, a desire to be able to determine the occurrence of the events and/or give indications of the time so that the normal traffic can be utilized to indicate the relevant time and/or occurrence of the event, for example, without extra hardware needing to be involved. The object of the disclosure is, among other things, to solve this problem. There is a need, in the respective module units, to be able to operate with preferably small resources with the object of simplifying the construction of the units. There should also be great freedom of choice in the construction of systems and their relationships. This disclosure also solves this problem.
A major problem in distributed embedded control system is to synchronize the generation of events in different nodes to each other in a timely manner, e.g., reading sensor values, execution of movements, releasing of power etc. The main solution to this problem is to create a global time and synchronize clocks at each node. Usually the time synchronization is made at the communication level. Typical examples are TTCAN, TTP and FlexRay protocols in the vehicle industry and SERCOS in the factory automation industry. All of these communication protocols are time triggered and it is a common opinion that safety critical distributed embedded control systems have to be based on a time triggered communication. An alternative to synchronizing clocks is to have each module relying on its own local clock and have a time translator recalculating the time of each clock to a common global time, but it has been regarded impossible to do in real time.
U.S. Pat. No. 5,896,524 suggests a method to recalculate clock readings by associating event pairs related to each other. However, such conventional methods cannot be used in realtime (e.g., see column 1, line 65 through column 2, line 4). What is needed is a method and apparatus that calculates the relationship between local clocks at run time. What is further needed is to calculate the relationship between local clocks and a global time base at run time.
U.S. Patent Application Publication US2006-0143345A1 shows that, in realtime systems at run time, it is more efficient to use different time domains within the system, wherein each time domain is created according to the need of cooperating nodes, rather than to rely on a global time. However, a global time may be better used for analyzing a system.
Each system in which the disclosure can be used can be regarded as individual, one or more series or sequences of events that are related to each other in time and space. There can be different time descriptions and time frames within one and the same system. Smaller systems can be comprised in the system, which in turn can, now or later, be comprised in other systems. During the first stage, the "drawing board" stage, of a system development, it is expedient to relate all the events to one and the same time frame, for example related to the physically defined second. The degree of coordination that is required of the different events in order for the required system function to be achieved can be analyzed in a first stage. In a second stage, an analysis of the relationship of the individual events to each other can indicate that other time frames and the utilization of knowledge concerning the association of different events to each other can simplify the design of the final system and the description, verification and validation of the same. The disclosure simplifies these development processes.
For analysis or verification of systems, there is a need not only to timestamp events that have occurred, but also to know with what precision and/or accuracy the timestamping is carried out.
It can happen in systems that different parts of the system relate events to different time bases, which in turn are related to each other.
Analysis and monitoring instruments of different types for vehicles are often based on standard computers with operating systems, for example a personal computer (PC) with WINDOWS XP®. The operating system (OS) simplifies the development of the software at the price of precision of timestamping of external events. Therefore special units are introduced between the PC and the bus system that, among other things, comprise a clock for timestamping of incoming time messages. For example, with the utilization of the program CANANALYZER from the company VECTOR, a CANCARDXL from the same company is connected to the PC. The CANCARDXL has a local clock and can timestamp messages from two CAN busses. If there is a need for several CAN busses, an additional CANCARDXL unit must be connected to the PC and the two CANCARDXL units must be connected to a coordination unit via a coaxial cable arrangement in order to synchronize their local clocks to a common time. By utilizing the disclosure, timestamping can be carried out with great precision, utilizing only components to be found as standard in the PC.

Method and arrangement for correlating time bases between interconnected units


The present invention relates to receiver equipment with AC-coupled receiver circuits and AC coupling filters. A switch connected between a first stage and a second stage among the receiver circuits is adapted to switch from a high coupling corner frequency, for rapid settling of a signal during preparation of data reception, to a low corner frequency, for low signal distortion during data reception. The receiver circuits are adapted to use known properties in the signal to perform the switch at a time when the short term DC-components of the signal are as low as possible.

It is desirable to use AC coupling between circuit stages e.g. amplifiers and mixers, in a receiver circuit in order to prevent unwanted DC signals caused by circuit DC bias voltages and mismatches from being propagated down the receiver chain.
It is also known to switch from a high coupling corner frequency, for rapid settling of a signal during preparation of data reception, to a low corner frequency, for low signal distortion during data reception, in receiver equipment with AC-coupled receiver circuits and AC coupling filters.
In receiver equipment with AC-coupled receiver circuits, where it is desired to switch from a high coupling corner frequency for rapid settling during e.g. amplifier gain programming to a low corner frequency for low signal distortion during data reception it is known that the properties of the signal are problematic when designing an AC coupling circuit for a signal with low frequency components during the preparation of data reception.
In practice this mean that the switched circuit suffers from a similar trade-off to the unswitched: in order to have reasonable settling times, it is necessary to have a reasonably high corner frequency when preparing for reception. However, the low frequency components of the signal mean that it is necessary to switch to a very much lower corner frequency for signal reception. The high initial corner frequency means that the coupling is sensitive to short term DC components, and the low final corner frequency leads to a very long settling time for the transient thus generated by the AC coupling switch.


The present invention discloses a multi-component intraocular lens implanted in an optical system of a human eye, including one or more foldable removable components, each component being foldable. One component acts as a base lens, including a flange with a slot. Another component acts is an optical assembly that may include a top lens joined to or integrated with a mid lens. The top lens, the mid lens or the optical assembly may include at least one projection that engages the slot of the base lens. The top and mid lenses are manufactured from a material having adhesive properties, wherein the top and mid lenses adhere to each other free of any material or substance being present therebetween.

1. Field of the Invention
This invention relates to a method for correcting the optical system of an eye using an intraocular lens system. Particularly, this invention relates to a method of correcting focusing abnormalities and optical aberrations measured by wave front or similar technology to quantify optical aberrations in the optical system of the eye, using a laser, or other apparatus and/or methods of fabricating or modifying a lens, for the optical system of an eye having a foldable, interchangeable intraocular lens system provided therein.
2. Description of Related Art
The field of refractive surgery has evolved rapidly during the past few decades. Current procedures and methods used by refractive surgeons may not satisfy the total refractive needs of the patient. Particularly, the most commonly performed refractive surgical procedures, such as, for example, cataract extraction with intraocular lens implantation, in addition to the most recently popularized corneal refractive surgical procedures, such as eximer laser photoblation, exhibit limitations. One reason for the limitations is the lack of post-operative refractive accuracy. The lack of post-operative refractive accuracy renders the commonly known refractive surgical procedures uncompetitive with currently available non-surgical alternatives for patients, for example, glasses and contact lenses. Further, because refractive surgery requires local or general anesthesia and incisions into the eye, a need exists for decreasing the trauma resultant from the surgery.
Recently, a need has arisen for efficient treatment of presbyopia, or the diminished power of accommodation of the eye. Presbyopia is a condition which typically affects a large number of people as they age, with the severity of the condition varying depending on the person. Difficulties arise in treating presbyopia because typically once a person manifests symptoms of presbyopia, the symptoms worsen as the person ages. As a person's condition worsens, a different, usually more powerful, lens is required to correct the condition. Conventional techniques for replacing an intraocular lens each time the patient's vision deteriorates do not always present a practical or cost-effective approach. Recent developments in the field of refractive surgery have made intraocular treatment of presbyopia a feasible course of treatment for those patients that desire or need improved vision, however a need exists for more precise techniques and devices for use in refractive intraocular surgery.
Patients suffering from eye trauma or other eye afflictions may have the iris or other portions of the eye distorted, destroyed, or discolored. Currently, such patients are typically prescribed cosmetic contact lenses. Cosmetic intraocular lens replacement is emerging as a viable alternative, however a need exists for more efficient intraocular lens replacement in order to minimize eye trauma and establish cosmetic intraocular lens replacement as a safe and effective alternative to cosmetic contact lenses and other non-surgical treatments. As surgical techniques become more effective, safer, and less painful, patients may choose to have elective lens replacement surgery to change the color, structure, or shape of their eyes. By providing a minimally invasive method for lens replacement as described in an embodiment herein, the surgeon is able to limit the drawbacks of the procedure.
Current procedures and methods for refractive surgery require the performing surgeon to execute the procedure with a high level of skill and experience. Currently, methods and procedures for carrying out refractive surgery involving intraocular lenses generally require direct visualization of the intraocular lens assembly within the eye. Such visualization, although not outside the scope of a surgeon skilled in the art, increases the degree of difficulty of the procedure, thus increasing the chance that a surgical error or other problem will arise in the surgical procedure, leading to unwanted complications. Thus, a need exists for intraocular lens assemblies and systems whose structures provide less complex methods of insertion into and extraction from the eye.
Currently, refractive cataract surgeons performing the most common refractive surgical procedure, i.e., routine cataract surgery, obtain refractive accuracies in a +/−0.75 to +/−1.00 diopter (D) range. However, the industry has established goals of obtaining refractive accuracies in the +/−0.25 D range. Therefore, there is a need in the industry to provide a more accurate alternative to the current procedure. Furthermore, analyses of current corneal refractive technologies indicate the presence of a significant amount of preexisting or naturally occurring post-operative, as well as preoperative, image distortion (optical aberration) or degradation, particularly under low light conditions, such as when driving at night.
Due to the practical limits of performing intraocular surgery, as well as the biological and physical behavior of the human eye during and after various types of intraocular surgery, predictability at the +/−0.25 D accuracy level with a single surgical procedure is difficult to achieve as a practical matter. Furthermore, factors such as biometry errors, variable wound healing, and capsular contraction around the intraocular lenses contribute to decreasing the likelihood of achieving the desired refractive accuracy. Accordingly, practitioners in the industry have found that an adjustable intraocular lens (IOL), hereinafter referred to as the MC-IOL (multi-component) or C-IOL (compound), following lens extraction surgery provides a plurality of desirable options for refractive surgeons and patients.
An adjustable IOL allows fine tuning of the initial refractive result by exchanging at least one of the optical elements of the lens implant. As a result, accuracies in the +/−0.25 D range are readily attainable. Furthermore, patients are provided with an opportunity to exchange the "old" lens components with new and hopefully more accurate components. Such an objective is obtainable if the surgeon has an effective, efficient, and safe method of performing lens element exchanges. Additionally, months and/or years after the refractive surgical procedure, if the optical properties of the inserted IOL, for example, the multifocality, become problematic, the surgeon should have the ability to safely exchange the undesirable optical elements of the IOL to correct any optical aberrations that the patient will not or cannot tolerate.
In 1990, the inventor of this application developed a multi-component intraocular lens, hereinafter referred to as the MC-IOL (FIG. 1), for use following clear lens or refractive cataract surgery, wherein the optical properties of the MC-IOL can be modified at any post-operative time. The base intraocular lens component of the MC-IOL is shown in FIG. 1. The mid lens attaches to the top of the base lens and holds the third component of the MC-IOL, the top lens, in place.
The base intraocular lens 10 and the mid lens 20 each have securing flanges 16, 18 and 20, 24, respectively, extending therefrom. The MC-IOL also comprises at least one top lens 30, as illustrated in FIG. 1. The top lens 30 is positioned on top of the mid lens 20. See FIGS. 1-2.
The MC-IOL also includes projections (or haptics) 11 and 13 which securely hold the MC-IOL in the tissue of the human eye. The above-described structure permits the base intraocular lens 10 to form a platform upon which the mid lens 20 is placed, and to hold the top lens 30. During routine cataract surgery, the MC-IOL replaces the crystalline lens of the human eye. Once a patient's eye has healed after such a surgery, the surgeon reenters the eye and replaces, if necessary, and more than once, the top lens 30 and the mid lens 20 to modify the optical characteristics of the eye until the desired levels for each optical characteristic are attained.
FIGS. 3A-3B illustrate an assembled compound intraocular lens, hereinafter C-IOL, used with a preexisting lens within the human eye. The C-IOL has two components similar to the mid lens (FIGS. 4A-4B) and the top lens (FIGS. 5A-5B) components of the MC-IOL. FIG. 5A also illustrates the axis orientation mark 85 used in some embodiments of MC-IOL lenses to aid in positioning and orienting the lens. The preexisting lens can be the crystalline lens of the eye with the C-IOL placed in the sulcus (FIG. 6) or in the anterior chamber angle (FIG. 7) of the eye's optical system. However, the C-IOL can also be used with a conventional IOL, as well as with an accommodating IOL, and mounted in the sulcus (FIG. 8), in the anterior chamber angle (FIG. 9), in the anterior chamber with posterior chamber fixation (FIG. 10) or in the anterior chamber with iris fixation (FIG. 11). Thus, a surgeon modifies the optical characteristics of the optical system of the eye by using the mid and top lenses in tandem with the preexisting conventional IOL implant or crystalline lens of the eye.
The C-IOL and MC-IOL provide numerous enhanced features. For example, the C-IOL and MC-IOL can each be structured as a monofocal or multifocal optical system, correct astigmatism, as well as comprise ultraviolet light-absorbing, tinted, or other such chemically treated materials.
It should be understood that there are various reasons why an adjustable MC-IOL or C-IOL is more desirable than a single component implant. In order to achieve all the permutations and combinations of the astigmatism, multifocality, and spherical correction needed to achieve emmetropia would take an inventory of over ten thousand lenses, whereas with the MC-IOL (multiple components) concept, an inventory of about one hundred components would be necessary. With anterior chamber lenses, progressive encapsulation or engulfment of the lens haptics by uveal tissue in the angle often occurs 1-2 years post-operatively. The engulfment typically makes the removal of the lenses and their haptics more difficult. Exchange of iris fixated anterior chamber lenses does not typically guarantee precise position or orientation. Posterior chamber lenses similarly cannot be removed because of posterior capsule fibrosis. Easy removal and exchangeability is critical for any customized emmetropic system, which can be provided by a specially designed multicomponent lens system.
Therefore, based on the above, a MC-IOL having three elements rather than one permits refractive customization and adjustability for all refractive errors, as well as for all patients, while using a minimal number of lens elements or parts and requiring little customization on the part of the manufacturer. Thus, it has become very important in the refractive surgery art to be able to individualize and/or customize surgery such that the surgeon can easily and safely, as well as accurately, modify the refractive power of an intraocular lens implant.
For example, U.S. Pat. No. 5,288,293 to O'Donnell, Jr. discloses a method of modifying a single IOL. O'Donnell suggests that the refractive power of a single IOL may be varied before implantation so that the changes can be made in situ by the ophthalmologist after determining the extent of correction required to improve the vision of the patient before the lens is made. However, the surgical implantation procedure itself may create additional optical aberrations which cannot be anticipated preoperatively and thus the primary lens implant cannot account for these optical aberrations.
As such, it may be argued that if a lens can be modified before being implanted, as suggested by O'Donnell, Jr., it should be possible to modify the implanted lens by removing the implanted lens, modifying the lens, and then reimplanting the modified lens into the optical system of the eye. However, the design of current intraocular lenses typically makes such a procedure difficult and impractical. Furthermore, after a period of time with normal healing, it becomes physically dangerous and/or nearly impossible to the patient to have the implanted lens removed once the eye tissue takes hold on the capsular fixation holes of the lens. Therefore, such an argument is not realistic, practical, or safe. A single component intraocular lens, which in general is not designed to be removed and with only two optical surfaces, cannot accurately allow for compensation of sphere, cylinder, cylindrical axis, and all forms of optical aberrations that may be discovered after the initial implantation. However, the MC-IOL typically will have four removable optical surfaces which can compensate for these optical properties.
The inventor of this application invented the previously discussed MC-IOL and C-IOL that are designed specifically to permit the easy exchange of optical elements at a post-operative period without risk to the human eye or to the patient, beyond the risk of ordinary intraocular surgery. The easy exchangeability of optical elements is critical because the actual surgery of implanting the lens in the first place, as well as variances in the manner in which the eye heals after implantation, potentially create distortions which may not stabilize for several months after the operation. Therefore, the ability to measure and to compensate for the distortion(s) optimally takes place several months after surgery and cannot typically be predicted prior thereto. Since the same surgical wound is used for both the primary and secondary operations, additional distortion due to wound healing would not be anticipated as a result of the second operation.
Furthermore, the ability to exchange optical elements of a multicomponent or compound intraocular lens can be economical compared to removing, modifying, and re-implanting a single component lens, as well as easier to perform.
The MC-IOL has four surfaces available for modification, two plano and two convex. Preferably, the modification is made only to the plano surfaces to avoid interfering with the convex side which may already be used for correction of astigmatism (cylinder) or used as a multifocal lens surface. The same preference applies to the CIOL, which has two surfaces available for modification, one plano and the other convex.
The inventor of this application also developed a system for correcting optical aberrations in the MC-IOL, as described, for example, in U.S. Pat. No. 6,413,276, for conducting measurements to determine any residual or new aberrations present in an operated eye after the biological healing parameters have stabilized, as well as to correct any errors in sphere, cylinder, or cylindrical axis, and for modifying one, two, or more existing lens elements within the implanted optical system based on the conducted measurements.
In conventional multi-component intraocular lens designs, the surgical procedure required to implant the intraocular lens components requires a high level of surgeon skill. For example, implantation of the removable component of the lens requires the surgeon to directly visualize the placement of the lens in order to match the notches with the flanges. Further, removal of the removable lens component requires a special forceps tool for grabbing the base lens, and releasing the tabs holding the sandwich and cap lens together with the base lens (see, for example, the system described in U.S. Pat. No. 5,968,094).
Historically intraocular lens systems used a rigid one piece poly methyl methacrylate (PMMA) lens. The PMMA lens is approximately six millimeters in diameter. Because the PMMA lens is rigid, insertion of the PMMA intraocular lens generally requires a seven or eight millimeter incision to be inserted into the eye. In contrast, a flexible or foldable lens can be manipulated and compacted to a much smaller size. Once compacted, the multi-component intraocular lens can be delivered using a relatively smaller incision, for example, about three millimeters or less. By using a smaller incision, the patient reaps optical and practical benefits. From an optical standpoint, any time incisions are made to the cornea, the cornea loses some of its natural globularity due to imperfections caused by the incisions and the resultant trauma. The imperfections in the cornea lead to induced astigmatism, or optical aberrations caused by irregularities in the shape of the cornea. By minimizing the size of the corneal incision, a surgeon may also minimize the amount of induced astigmatism. Even though the three-component design simplifies the process of correcting induced astigmatism, minimizing the amount of induced astigmatism remains a primary goal for all intraocular surgeries.
As a practical matter, by making a smaller incision, the surgeon reduces the amount of actual trauma to the eye, thus reducing the occurrence of complications and decreasing the time for recovery. These advantages are further realized if the surgeon is able to perform the intraocular surgery using an incision small enough to heal without the use of stitches, wherein the incision is small enough to allow the eye's natural ocular pressure to hold the incision together during the healing process.
The inventor's application Ser. No. 11/698,875 overcame the above-described drawbacks of the related art. FIGS. 12-16 illustrate the invention disclosed in the '875 patent application.
For example, FIG. 12A shows a top or plan view of an intraocular foldable base lens 100, which is similar to the MC-IOL base lens illustrated in FIG. 3. The base lens 100 attaches to the eye by at least one haptic 120 and while the base lens 100 in FIG. 12A can be secured to the eye by at least one haptic, it is preferable that at least two haptics 120 be used. As shown in FIG. 12A, each haptic 120 extends outward from the base lens 100, and is tilted from between 10 to 20 degrees, in either direction, relative to a plane taken across the base lens, preferably having a 15 degree positive tilt.
As shown in FIG. 12B, as well as later in FIG. 24, the base lens 100 (1000, FIG. 24) can also include one or more flanges 105 (1005, FIG. 24) disposed on and extending outwardly away from the body of the base lens 100 (1000, FIG. 24). Each flange 105 (1005, FIG. 24) can also have a slot 110 (1100, FIG. 24) designed or configured to receive or accept an assembly of a top lens 300 (3000, FIG. 24) and a mid lens 200 (2000, FIG. 24) therein. Each flange 105 (1005, FIG. 24) and slot 110 (1100, FIG. 24) is an essential feature to the design of base lens 100 (1000, FIG. 24). The MC-IOL concept allows for adjustments or enhancement operations, beyond its use in primary cataract, clear lens, surgery to compensate for any miscalculation or any biological variability or any change in the condition of the eye over time after the primary operation. In order for these surgical adjustments to be workable, the surgeon must have easy access to the front lens assembly 200, 300 (2000, 3000 FIG. 24). To assure this, the front lens assembly 200, 300 (2000, 3000 FIG. 24) must be left out of the capsule, in the sulcus. On the other hand, the base lens 100 (1000, FIG. 24) is left in the capsule. In the primary surgery after the MC-IOL is inserted and the edges of the capsule are placed between the haptics 210, see FIG. 14A (2100, FIG. 24) of the front lens assembly 200, 300 (2000, 3000 FIG. 24) and the base lens 100 (1000, FIG. 24), the vertically extending flanges 105 (1005, FIG. 24) and their corresponding slots 110 (1100, FIG. 24) allow a space between the haptics 210, see FIG. 14A (2100, FIG. 24) of the front lens assembly 200, 300 (2000, 3000 FIG. 24) and the base lens 100 (1000, FIG. 24) so that a special instrument, referred to as a capsule snare, allows the surgeon to place the front lens assembly haptic 210 (2100, FIG. 24) above the edges of the capsule (6-7 mm capsulorrhexis necessary in the primary surgery) thus capturing the capsule between the haptics 210 and 120 (2100 and 1200 of FIG. 24). The remaining capsule "cellophane wraps" around the edges, the haptics 120 (1200, FIG. 24) and the edges of the base lens 100 (1000, FIG. 24) during the healing process after the cataract, clear lens, surgery. The "cellophane wrapping" makes it extremely difficult and dangerous for the surgeon to gain access to any surface of the base lens 100 (1000, FIG. 24) after the primary surgery heals, which is necessary for enhancement operations. The vertically extending flanges 105 (1005, FIG. 24) and corresponding slots 110 (1100, FIG. 24) position the front lens assembly 200, 300 (2000, 3000, FIG. 24) in front of or away from the "cellophane wrapped" posterior capsule, that is, in the sulcus, making surgical removal and replacement of the front lens assembly 200, 300 (2000, 3000, FIG. 24), very safe and technically simple.
Put another way, the flanges 105 (1005, FIG. 24) and slots 110 (1100, FIG. 24) are necessary features of the MC-IOL design to assure easy removal and replacement of the front lens assembly 200, 300 (2000, 3000, FIG. 24) during an enhancement operation. Without the vertical flange 105 (1005, FIG. 24), the edges and haptics 210 (2100, FIG. 24) are inaccessible to the surgeon due to capsule contracture around the edges and haptics 120 (1200, FIG. 24) of the base lens 100 (1000, FIG. 24), that is, the normal healing process. The structural configuration of the flange 105 (1005, FIG. 24) and corresponding slot 110 (1100, FIG. 24) position the base lens assembly 200, 300 (2000, 3000, FIG. 24) in front of the capsule, in the sulcus, which allows or facilitates easy access for the surgeon to remove and the replace the front lens assembly 200, 300 (2000, 3000, FIG. 24) during an enhancement operation any time during the life of the patient after the primary operation has healed.
The base lens in FIG. 13 is similar to the base lens 100 (FIGS. 12A-12B), except for a groove 130 being defined therein that extends along the entire outer periphery, and a plurality of attachment points 140, which serve to attach the optical region 150 to the base lens.
The foldable MC-IOL disclosed in the inventor's '875 application includes two or more additional refractive components, i.e., a top lens 300 and a mid lens 200. The mid lens 200, which typically allows spherical adjustments, is illustrated in FIGS. 14A-14B, while the top lens 300 (FIG. 15) carries the astigmatic correction and has an orientation projection 305. The mid lens 200 may include at least one projection 210 extending away from the body of the mid lens 200 and may have varying lengths depending on the shape and number of projections. The mid lens 200 also includes a side portion 250 which extends upward, and terminates at a lip 225, as illustrated in FIG. 14B. The side portion 250 and lip 225 extend along the outer circumference of the mid lens 200, thereby defining a notch 230.
Prior to insertion into the eye, the top lens 300 engages the notch 225 of the mid lens, such that a seal is formed between the notch 225 and the top lens 300, and which holds the mid lens 200 and the top lens 300 together as a single assembly (FIG. 16). The top lens 300 is oriented so that, when the top lens 300 is inserted into the mid lens 200, raised projections or notches 305 of the top lens 300 face the mid lens 200 or may also project away from the mid lens 200. The notches or projections 305 can provide directional and axial orientation for the top lens, similar to the axis orientation marks 85 of FIG. 5.
The lens manufacturer assembles the mid lens 200 and the top lens 300 to a predetermined axis orientation to correct the astigmatism, and then the surgeon, outside the eye assembles the front lens assembly 200, 300, and the base lens 100 and inserts the completed assembly into the eye as one folded piece such that the mid lens 200 is sandwiched between the base lens 100 and top lens 300. Alternatively, the surgeon inserts the top lens 300 and the mid lens 200 assembly into the eye and then attaches the assembly to the base lens 100 by sliding a projection 210 of the mid lens 200 into a slot 110 of a corresponding flange 105 of the base lens 100, the latter two step assembly allows for a smaller surgical incision. Once the first projection 210 is in place in the corresponding first slot 110, if more projections are present in the mid lens 200, then the surgeon adjusts the mid lens 200 and the top lens 300 until the other projection(s) 210 line up with the other slot(s) 105. Once all projections 210 have been inserted into their corresponding slots 110, the assembly of the top lens 300 and the mid lens 200 is secured in the base lens 100, and the procedure is completed.
In the event that the assembly formed by the mid lens 200 and the top lens 300 requires replacement, the surgeon may perform a disassembly procedure as discussed herein. First, a cannula containing visco elastic material would be introduced into the eye and positioned at the interface between the lens assembly (mid lens 200 and top lens 300) and the base lens 100. The injection of visco elastic causes the mid 200/top 300 lens assembly to elevate, thus disengaging the projections 210 from the slots 110 in the base lens 100. The original lens assembly would then be removed from the eye, and a new lens assembly placed into the eye and attached to the base lens 100 similar to as described above in the primary operation.
The inventor's application Ser. No. 12/000,364 taught a different orientation of the mid lens and top lens than the orientation disclosed in the inventor's '875 application. For example, the '364 application inverted or reversed the order of the mid lens and top lens such that the top lens is placed on top of the base lens and the mid lens then positioned on top of the top lens such that the three components are oriented in an order where the base lens is most posterior relative to the patient's eye. The top lens is then placed on the base lens and the mid lens arranged on the top lens such that the mid lens is most anterior relative to the patient's eye and the top lens is arranged between or in the middle of the base and mid lens.
Moreover, while the inventor's '875 application teaches the mid lens includes a notch with which a projection of the top lens engages to securely maintain the mid/top lens assembly, the inventor's '364 application joins the top and mid lenses to each other using a joining means, such as, for example, a medical adhesive that is applied in at least one location where the mid lens interfaces with the top lens.
Further, the inventor's '364 application teaches a feature wherein the haptic of the mid lens has projections extending anteriorly and posteriorly that capture the top lens (circular configuration) and retain the top and mid lens (circular configuration) as an optical assembly.
As shown in FIGS. 17A-21, the inventor's '364 application discloses a medical adhesive MA is used to join the mid lens 200′ and top lens 300′, respectively, together as a single, integrated unit or assembly. For example, FIGS. 17B and 18 illustrate how the medical adhesive MA is applied to the inner surface 250a of a side portion 250′ of themid lens 200′ and/or an outer peripheral surface 350a of the top lens 300′ to securely retain the mid lens 200′ and top lens 300′ together. Alternatively, as shown in FIGS. 19-21, the inventor's '364 application teaches that the medical adhesive MA can also be applied along an upper surface of the mid lens 200″ and/or an entire lower surface of the top lens 300″, either entirely or in select, discrete locations thereon, which directly opposes the upper surface of the mid lens 200″ to join the top and mid lenses 300″ and 200″ into a single unit or assembly.


A semiconductor device includes connector leads which have an offset portion supported by the primary surface of a semiconductor chip on which electronics circuitry is formed into an integrated circuit. The offset portion is disposed near the contact pads for connecting the electronics circuitry. The remaining portion of the connector leads far from the contact pads is spaced from the primary surface by an adhesive strip of electrically insulative material. Bonding wires connect the connector leads to the contact pads. The total thickness of the package is reduced to accomplish a thinner and flatter semiconductor device.

1. Field of the Invention
The present invention relates to a semi-conductor device comprising a semiconductor chip on which electronics circuitry is formed into an integrated circuit (IC) and a package enclosing the semiconductor chip therein.
2. Description of the Background Art
The type of package molded with synthetic resin, electrically insulative, for enclosing an integrated circuit therein is advantageous in compactness and easy handling. A sort of synthetic resin package for an integrated circuit is known as the thin small outline package (TSOP). The thin small outline package includes a semiconductor chip having a primary surface on which contact pads are formed and in parallel to which connector leads extend outwards with the end portion thereof, nearer to the contact pads, secured on the primary surface by means of electrically insulative, adhesive strips. The contact pads are connected by bonding wires with the connector leads. The connecting portions of the bonding wires and the connector leads are encapsulated and sealed by a synthetic resin package together with the entire semiconductor chip. The electronics circuitry formed on the semiconductor chip is interconnected to the contact pads, which are electrically interconnected to the connector leads through the bonding wires. The electronics circuitry may ultimately be interconnected to a utility device, which will be coupled to the connector leads.
With the type of comiconductor device mentioned above, the bonding wires bonded to the contact pads formed on the primary surface of the semiconductor chip and the ends of the connector leads have such a sufficient length as to form an arc between the contact pads and the bonded ends of the connector leads. The bonded end portions of the connector leads are at the height, from the primary surface of the semiconductor chip, which height is substantially equal to the sum of the thickness of the adhesive strip and the thickness of the connector lead. The arcuate portion of the bonding wires extends over the height. That part of the synthetic resin package which covers the bonded end portions of the connector leads and the contact pads has to be of the thichness which is sufficiently longer than the height of the peak of the arc from the primary surface of the semiconductor chip. That requirement is a hindrance to minimizing the thickness of the synthetic resin package of a semiconductor device, and hence producing a compacter, or thinner, semiconductor device.

Semiconductor device having the inner end of connector leads displaced onto the surface of semiconductor chip


Embodiments of the invention include a breast nipple areola complex tattoo stencil comprising first, second and third stencil sections. The first stencil section defines an areola area. The second stencil section defines a nipple area and tubercle areas. One or more registration elements on the first and/or second stencil sections enable registration of the second stencil section to the first stencil section. The third stencil section defines one or both of a nipple shading area and a nipple highlight area. One or more registration elements on the third and/or second stencil sections enable registration of the third stencil section to the second stencil section.

The nipple areolar complex (NAC) is comprised of the nipple and the areola. The areola contains Montgomery's Tubercles which are sebaceous glands that appear as pale mounds. The areolar skin, which has a darker pigmentation than the surrounding skin, is anchored to the underlying breast with circular muscle fibers. These muscle fibers create a contrast of color variation on the overlying pigmented skin.
Mastectomy as a treatment for breast cancer commonly involves removal of the NAC. Following implant or autologous breast reconstruction, the NAC can be reconstructed. Tattooing can be performed to create the appearance of the areola and nipple. Shading and coloring can be used to create the appearance of a three dimensional structure. An actual three dimensional structure mimicking a nipple can be created by local flaps and fat grafting a mound, and the three dimensional structure can be tattooed. Color variations of the areola are sometimes recreated by tattooing alternating colors in concentric circles. These tattooing procedures are often done free-hand. Templates having circular openings (e.g., that are cut from adhesive-backed dressings) are sometimes used in connection with the nipple tattooing procedures (e.g., to define the areola).
There remains a continuing need for improved methods and devices for cosmetic and reconstruction surgery. Devices and methods that can enhance the appearance and efficacy of anatomic structures tattooed on a patient are desired. Such devices and methods for breast reconstruction procedures would be particularly useful.

Mayo Foundation for Medical Education and Research


An infusion wire that can be used either as a guidewire or an infusion catheter having a tapered core wire within an infusion lumen formed of the aligned lumens of the conduit of a proximal connector housing, an inner sheath in a proximal infusion wire portion and a distal coil wire in a distal infusion wire portion. The inner sheath is formed either of a polyimide tube or a wire reinforced polyimide tube, at least in a proximal section thereof In a fixed core wire embodiment, the core wire proximal end is attached to the connector housing, and the core wire distal end is connected to the distal end of the distal wire coil. An outer sheath is attached to the connector housing and formed over the inner sheath and the distal wire coil. A plurality of infusion side holes are formed in a distal infusion segment of the outer sheath in fluid communication with the infusion lumen. At the junction of the inner sheath and the distal wire coil, a radiopaque wire coil of a material having a higher radiopacity than the distal wire coil is formed into a plurality of radiopaque wire coil turns of substantially the same pitch, inner lumen diameter and outer diameter as the distal wire coil. The distal wire coil is space wound with distally increasing coil spacings. The distal core wire portion extending through the distal wire oil is tapered distally either continuously or in a stepped manner.

1. Field of the Invention
The present invention relates to medical catheters and guidewires commonly used in the placement of catheters in a patient's vascular system, and particularly to infusion wires that can be used both as a guidewire or an infusion catheter.
2. Description of the Background Art
Medical catheters and guidewires are devices that can be navigated through narrow body passages, typically blood vessels, until the distal end section is in a desired location. Guidewires are typically used for introduction of a catheter over the guidewire in order to perform a medical procedure in a blood vessel or body organ. For example, guidewires are employed to traverse blood vessels to reach a desired site. Then a catheter is advanced over the guidewire to a desired orientation with respect to the site for delivery of a drug or agent or for a performing a therapeutic or diagnostic function.
Cardiovascular guidewires typically have a solid core wire and are dimensioned to be received within a catheter lumen as the catheter is advanced over the guidewire. One very common guidewire construction has an elongated, flexible, helical coil having a proximal end and a distal end, the latter being inserted into the patient's vascular system. The internal core wire typically extends through the coil lumen with the proximal and distal ends of the core wire attached to the proximal and distal ends of the coil. A physician controls the advancement and resulting position of the distal end of the guidewire by manipulations performed at the proximal end outside the body. Then, a catheter is advanced over the guidewire, which may be left in place or withdrawn during a procedure using the guidewire.
In order to advance the catheter over the guidewire, it must be uniform in outer diameter or have only step down diameter reductions and minimal diameter increases distally. In addition, both catheters and guidewires are preferably constructed with radiopaque markers that are have greater radiopacity and hence higher visibility under fluoroscopy than the bulk of the elongated catheter or guidewire body. These markers allow the physician to visualize the location of the distal end and/or intermediate point(s) along the elongated body within the patient's body. When both the guidewire and the catheter are provided with such markers, care must be taken that they are not so long on one or both device that they mask one another or are confusing. In this regard, it may not be desirable to make the entire wire coil in the distal segment or portion of a high density radiopaque material, because its bright appearance under fluoroscopy would mask any radiopaque marker(s) on the catheter being introduced over it.
Some guidewires are constructed of wire coil defining a guidewire lumen with an outer sheath surrounding or within the wire coil and are adapted for use both as guidewires and as infusion catheters and are referred to as infusion wires. An infusion wire having a number of advantages is disclosed in commonly assigned U.S. Pat. No. 5,554,114. The infusion wire body disclosed in the '114 patent employs a wire coil extending within or outside a sheath for containing the infused drug or agent. Further wire coil infusion wires are disclosed, for example, in U.S. Pat. Nos. 5,178,158, 5,184,627, and 5,211,636. These infusion wires are provided with either a distal axial open end hole or a closed distal end with infusion side holes and a lumen for conveying infusion fluids or body fluids between the proximal end and the end hole or side holes.
In order to operate as a guide wire and be advanced through a tortuous vascular pathway to a desired infusion site, it is necessary that the overall outer diameter be as small as possible and that the construction provide for ease of advancement and excellent steerability or torqueability from the manipulated proximal end to the distal end thereof. Moreover, the construction typically requires increasing flexibility in the intermediate and distal sections. In order to provide adequate infusion capabilities, the side wall thickness has to be minimized to maximize potential infusion volume. The side wall construction also has to withstand high fluid pressures during infusion.
In use, because of the narrow gauge, flexibility and column strength, the distal portion of an infusion wire can be advanced to a desired site in a blood vessel. Then, the physician can advance a catheter over the infusion wire to the site. Depending on the design, the physician can remove the infusion wire from the catheter lumen or leave it in place while conducting a procedure with the catheter. Drugs or agents can be infused from the proximal end of the infusion wire, through the infusion lumen, and out through the distal end lumen opening or through a plurality of side holes in the distal sheath and/or through spaces between exposed turns of distal wire coil, if any, during or following the procedure using the catheter. Alternatively, distal blood pressure may be monitored through a fluid column in the lumen. Typical uses of infusion wires to infuse thrombolytic agents into a thrombus in a blood vessel to dissolve it are described in the article by T. McNamara, M.D. et al. entitled "Coaxial system improves thrombolysis of ischemia" published in DIAGNOSTIC IMAGING (pp. 122-131, November 1991), and incorporated herein by reference in its entirety.
A particular infusion wire is disclosed in U.S. Pat. No. 5,322,508 wherein a partial length core wire is attached at the distal end of a metal hypotube infusion wire body and extends distally within a wire coil also attached at the distal end of the hypotube. Hypotube construction without a full length core wire may provide a maximal size cross-section, infusion lumen that may accommodate a relatively high infusion flow rate. However, the constriction at the attachment to the distal core wire extension before the distal infusion side holes negates the advantage imparted by the unobstructed hypotube lumen. Moreover, hypotube does not provide for a 1:1 torque transmission down the length of the infusion wire during twisting or rotational advancement.
A further U.S. Pat. No. 5,569,197 discloses a similar infusion wire to those disclosed in the above-referenced patents and McNamara article that uses a superelastic alloy as a particular hypotube material in the proximal portion of the infusion wire. A number of conventional uses of infusion wires, e.g., to guide balloon angioplasty and stent placement balloon catheters into a desired site, are also disclosed in the '197 patent.
Currently, there are two types of clinically used infusion wires, one having a closed end of the type disclosed in the '627 patent and another having an open end of the type disclosed in the '158 patent and sometimes referred to as a "convertible wire". The '158 and '627 patents describe infusion wires and convertible wires having full length, coiled wire bodies within outer sheathes with constant diameter infusion lumens. In each case, the proximal sections have a polyimide tube between the wire coil and the outer sheath to strengthen that section and allow increased infusate pressure. The convertible wire disclosed in the '158 patent delivers the infusate through a distal end hole of the infusion lumen. The infusion wire disclosed in the '627 patent has a closed distal end and a plurality of infusion side holes cut in the outer sheath which covers the wire coil. In both cases, the removable core wire supplies sufficient column strength for steerability as the convertible wire or infusion wire is advanced to the treatment site.
In use of these infusion wires and convertible wires, when infusion therapy is desired, the core wire must be completely removed, since it occupies the bulk of the infusion lumen and would increase flow resistance and decrease flow rate dramatically were it left in place. The handling of this core wire is bothersome to many physicians. In addition, because of the full length coil construction (and non-attached core wire), it has no steerability or torqueability. Physicians may desire to steer the distal end into another vessel after the infusion wire is already deployed. Without the ability to steer the tip, they often will be forced to withdraw the entire convertible wire, then place a regular guidewire at the desired site, follow it with an infusion catheter advanced over the guidewire, and then remove the regular guidewire and replace it with the infusion wire.
While the '636 patent discloses an integral core wire within the infusion lumen of an infusion wire, the depicted embodiments all have at least one full length outer wire coil and a coaxial sheath leaving a small cross-section area for the infusion of infusate at slow, steady rates. A high pressure drop is effected along the length of the infusion wire so that the slow infusion rate between the distal coil wire turns and the infusion pressure is relatively insensitive to the fluid pressure of the fluid entering the lumen at the proximal end.
Infusion wires require a small cross-section size (typically 0.038 inches or less in diameter) and preferably have a relatively stiff proximal infusion wire portion to transmit torque and allow the infusion wire to be pushed and steered through the vascular system to position the distal infusion wire portion at a desired site. Such infusion wires also preferably have a relatively flexible distal infusion wire portion in order to access small diameter and tortuous body vessels. The stiffness and flexibility are controlled by the construction employing a removable or permanent core wire, the coiled wire in at least the distal infusion wire portion and a variety of proximal portion side wall constructions as described above.
Infusion wires also require at least one impervious sheath extending from the proximal end to one or more infusion port at or near the distal end in order to contain the infusate fluid. The delivery of infusate along the distal portion of the infusion wires of these types is effected typically through infusate passageways including the infusion lumen space extending along the length of the infusion wire between the core wire and the coiled wire within the impervious sheath, referred to as the infusion lumen, and then through the spaces between the adjacent wire coil turns and through one or more side opening in the sheath in the distal portion. The cross-section area of the passageways affects the volume of infusate that can be delivered through the proximal and distal infusion wire portions. The conflicting demands for passageway cross-section area and sufficient stiffness and flexibility in the infusion wire portions are difficult to satisfy.
In order to deliver the infusate along the distal portion, the sheath may terminate proximally to the infusion wire distal end, leaving a side opening comprising number of exposed distal coil wire turns, as in the above-referenced '508 patent. Alternatively, one or more typically a plurality of slits or holes are formed through the impervious sheath, as in the above-referenced '627 patent through which the infusate is expelled laterally. In either case, the infusate may be unevenly expelled first through the spacings between wire coil turns and then through the sheath opening or openings.
It is also desirable to be able to manually shape at least the distal most section of the distal infusion wire portion into a curve for accessing blood vessels during introduction of the infusion wire. At times, the applied force can cause the distal infusion wire portion to kink.
An infusion wire with improved steerability, uniformity in infusate fluid delivery profile, enhanced capability to be shaped to ease introduction into difficult to access blood vessels, and retaining a high infusion flow rate would therefore be a great improvement.