A variable-speed regeneration compensating apparatus for a double azimuth 4-head type video tape recorder comprises first and second standard speed regenerating heads, first and second low speed regenerating heads, a standard speed regeneration head switching part, a standard speed regeneration envelope detecting part, a low speed regeneration envelope detecting part, an envelope comparing part, a standard speed recorded medium regeneration signal switching part, first and second time constant circuits, a time constant circuit switching part, and a low speed recorded medium variable speed regeneration compensating circuit. Compensation is provided not only to the case where the picture data having undergone a standard speed recording which is subjected to variable speed reproduction, but also to the medium having undergone a low speed recording, and therefore the stripe shaped optical noise is eliminated making the low speed recording/regenerating of video tapes easier.

A double azimuth 4-head type video tape recorder is well known in the field.
That is, a revolving drum faces a running recording medium, i.e., a video tape, at an inclined angle. This drum includes a pair of standard speed recording/regenerating heads which are oppositely disposed and separated by 180 degrees. In addition, the drum includes, on the outer circumferential surface thereof, a pair of low speed recording/regenerating heads which are separated by 180 degrees, and also separated by a small distance (about 2 minutes horizontal scanning distance) from the above mentioned standard heads. In total, 4 heads consisting of two pairs of standard speed and low speed recording/regenerating heads forming two sets respectively are installed separated by 180 degrees on the drum.
Of the pair of the standard speed recording/regenerating heads, one of them has +6 degrees azimuth (VHS method) or +7 degrees azimuth (B method) (the azimuth indicating the angle between the head running direction and the lengthwise direction of the magnetic cap of the head). Against this angle, the other head forms an azimuth of -6 degrees or -7 degrees. Thus there is seen a difference between the two azimuths adjacent to each recorded video track for forming a picture by means of the traces of the relative motions between the video tape and the heads.
That is, a video track is recorded in an azimuth of +6 degrees or +7 degrees by one of the heads, and the adjacent video track is recorded in an azimuth of -6 degrees or -7 degrees by the other head. Thus, during a regenerating operation of a single track, although a head partially faces adjacent tracks cross talk arising therefrom can be effectively inhibited. This is a known technique (NHK home video technique, Japanese Broadcasting Association Item 87).
The pair of the low speed heads are disposed on the circumferential surface of the drum and mutually separated by 180 degrees. One of them is disposed adjacent to one of the standard speed heads having an azimuth of +6 degrees or +7 degrees has an azimuth of -6 degrees or -7 degrees. The other low speed head is disposed adjacent to the other standard speed head having an azimuth of -6 degrees or -7 degrees has an azimuth of +6 degrees or +7 degrees.
Therefore, a variable speed regeneration can be carried out using the standard speed head thereby assuring low speed regeneration or a high speed regeneration of a video track of a video tape recorded in a standard speed (this will be called standard speed recorded medium). This is achieved by using the pair of the standard speed heads. In a variable speed regeneration operation, the recorded video track and the head scanning track do not correspond to each other, and therefore, the adjacent video track is included during the regeneration scanning.
Therefore, the low speed head of a narrow width (19f) (VHS method), facing a video track having a wide width (58f) (VHS method) and recorded by a standard speed head, can partially regenerate a wide width video track which is recorded with the corresponding azimuth inclination angle. This regeneratable portion almost corresponds to the portion which is impossible to regenerate by means of the standard speed head. Therefore, when a video tape which is recorded in the standard speed is to be regenerated, the picture data which corresponds to the unregeneratable portion during a variable speed regeneration is replaced with the regeneration picture data obtained from a low speed head which is simultaneously operating.
Thus the required compensation is achieved with this well known technique. (Television technology, electronic technology publication, volume of April, 1989, Items 54-58).
Assuming such a double azimuth 4-head type, and assuming the possibility of recording/regeneration by the two pairs of the heads, in the case where the recorded data is subjected to a variable speed regeneration using the pair of the standard speed heads, the stripe shaped or strip shaped optical noise can be replaced with a substitution picture data. This conventional method is illustrated in FIG. 6.
Referring to FIG. 6, a pair of standard speed regenerating heads SP1,SP2 are connected through a pair of separate pre-amplifiers 1,2 to an enlarged region analogue switching circuit 3 which is commonly used as a shifting means for the standard speed regenerating head. In the same way, a pair of low speed regenerating heads EP1,EP2 are connected through a pair of pre-amplifiers 4,5 to an enlarged region analogue switching circuit 6 which is well known and commonly used as a switching means for the low speed regenerating head, with this switching circuit 6 being operated so as to complement the switching circuit 3.
In addition to the illustrated components, the analogue switching circuits 3,6 receive regenerating head switching pulses SWP and compensating pulses SWP in a separately expressed order, so that the two switching circuits 3,6 should be able to perform compensatory switching operations. In relation with this, an example for the regenerating head switching pulses SWP is taken. That is, a state of "0" is maintained for the angular interval of 180 degrees where a first standard speed regenerating head SP1 and a second low speed regenerating head EP2 are facing to the video tape which performs relative motions.
As against this, the analogue switching circuit 3 switches the first standard speed regenerating head SP1 to the standard speed regenerating signal VSP1 through the pre-amplifier 1 in order to output a standard speed regenerating signal VSP. Meanwhile, the compensation regenerating head switching pulse SWP which is inverted by an inverter (not shown) is maintained in a state of "1", while, in response to this, the analogue switching circuit 6 switches a low speed regenerating signal VEP2 for the second low speed regenerating head EP2 so that a low speed regenerating signal VEP to be outputted.
Successively to the above operation, an inverse relation is established such that the regenerating head switching pulse SWP is in a state of "1", and the compensation regenerating head switching pulse SWP is in a state of "0", for the angular interval of 180 degrees of the drum in which the second standard speed regenerating head SP2 and the first low speed regenerating head EP1 are facing to the video tape which is performing relative motions. Consequently, the two analogue switching circuit 3,6 switches the standard speed regenerating signal VSP2 for the second standard speed regenerating head SP2 and the low speed regenerating signal VEP for the first low speed regenerating head EP1 in a separately expressed order before outputting them.
Thus the output terminals of the two analogue switching circuits 3,6 which switch the regenerating signals VSP,VEP are respectively connected to the input terminal of a next standard speed regenerating envelope detecting circuit 7 and to the input terminal of a low speed regenerating envelope detecting circuit 8 in a separately expressed order. Meanwhile, the output terminals of the two envelope detecting circuits 7,8 are connected to first and second input terminals of a comparator 9.
The output terminal of the comparator 9 is connected to operate an analogue switching circuit 10, while the switching circuit 10 is connected to a compensation regenerating signal output terminal 11 by selecting one of the output terminals of the analogue switching circuit 3 and the analogue switching circuit 6 in response to the regeneration signal switching pulse SSP of the comparator 9. Thus the switching circuit 10 forms a means for switching the regeneration signal for the standard speed recorded medium.
Now will be considered the case where picture data of a standard recording using the standard recording heads SP1,SP2 is subjected to a variable speed regeneration at triple speed using the low speed regenerating heads EP1,EP2. The operation of the conventional apparatus will be described referring to FIGS. 7A and 7B. FIG. 7A illustrates an overlapping of the scanning traces of the video head with the video tracks for the recording time during a triple speed regeneration, i.e., the scanning traces of the video head obtained by observing the relative motions of the video head from the non-magnetic face of the video tape. FIG. 7B illustrates the wave pattern of the conventional apparatus in time series.
Where video tracks a,b,c recorded by standard recording heads are subjected to a variable speed regeneration of a triple speed as shown in FIG. 7A, video head scanning traces d,e are formed by the standard speed regenerating head during the variable speed regeneration. Here, a video head scanning trace e is is produced by the second standard speed regenerating head SP2, while another video head scanning trace e' shown in dotted lines and having a narrow width is produced by the first regenerating head EP1.
The mutual positional relationship between the video head scanning traces e,e' is governed by the standard speed of the known double azimuth 4-head type paired heads, and by the widths and position heights of the low speed regenerating video heads (i.e., the heads SP2,EP1). During the recording, the axial inclinations of the scanning traces e,e' are steeper by about 3 times that of the axial inclinations of the standard speed video tracks a,b,c. The reason is that, in the variable speed regeneration of a triple speed, the regeneration is carried out at a speed 3 times the standard recording speed. The above principle is validly applied also to video head scanning traces d,d' which are succeeded in time series.
However, during the time when the second standard speed regenerating head SP2 and the first low speed regenerating head EP1 are moved in a fixed relation in accordance with the scanning traces e,e' of the two video heads which precede in time series, the regeneration head switching pulse SWP lies in a state of "1", and the compensating pulse for it lies in a state of "0" as already described [FIG. 7B (A)f]. In response to this, the analogue switching circuits 3,6 switch the regenerating signals VSP2,VSP1 of the second standard speed regenerating head SP2 and the first low speed regenerating head EP1, before outputting them.
The detail of the video head scanning trace e produced by the second standard speed regenerating head SP2 will be described for the case where the regeneration head switching pulse SWP is restored to a period of state "1" [FIG. 7B(A)f] and a variable speed regeneration is carried out in this period. The initial period of the relative motion between the tape and head forms a wedge shaped region XSP2 having a narrowing tail. As against this wedge shaped region, a gradually reducing regenerating signal VSP2 [FIG. 7B (B)h] is produced by the second regenerating head SP2.
A lozenge region YEP1 following the wedge shaped region XSP2 has an azimuth which does not correspond with that of the second standard speed regenerating head SP2, and, therefore, the regenerating signal VSP2 disappears [FIG. 7B(B)i]. Instead, the azimuth of the first low speed regenerating head EP1 which is moving simultaneously comes to be corresponded with the lozenge region YEP1, and, therefore, it gradually increases correspondingly with the lozenge region to stay at a certain value, while the lozenge shaped regenerating signal VEP1 [FIG. 7B(C)j] is regenerated by the first low speed regenerating head EP1.
Further, as against a wedge shaped region ZSP2 which has a thick tail, and which succeeds the lozenge region YEP1, the second standard speed regenerating head SP2 produces a regenerating signal VSP2 [FIG. 7B(B)k] which gradually increases correspondingly with the wedge shape having a thick tail. During the interval where the regeneration head switching pulse SWP stays in a state of "0" all in the same way, the first standard speed regenerating head SP1 and the second low speed regenerating head EP2 which are switched perform relative motions in accordance with the video head scanning traces d,d' succeeding in time series.
First, as against a wedge shaped region XSP1 having a thin tail, a gradually decreasing regenerating signal VSP1 [FIG. 7B(B)i] is regenerated by the first standard speed regenerating head SP1, and then, as against the lozenge shaped region YEP2, a lozenge shaped regenerating signal VEP2 [FIG. 7B(C)m] is regenerated by the second low speed regenerating head EP2. Then, as against the wedge shaped region ZSP1 having a thick tail, a gradually increasing regenerating signal [FIG. 7B(B)n] is regenerated by the first standard speed regenerating head SP1.
Thus, during the period when the regeneration head switching pulse SWP is in a state of "1", the regenerating signals VSP2 which are regenerated by the second standard speed regenerating head SP2 are supplied through the above described analogue switching circuit 3 to the standard speed regeneration envelope detecting circuit 7 in the form of standard speed regenerating signals VSP. Then the circuit 7 outputs standard speed regeneration envelope signals ESP which expresses the envelope of the regenerating signals VSP detected as above.
The regenerating signals VEP1 which are regenerated by the first low speed regenerating head EP1 are supplied through the above described analogue switching circuit 6 to the low speed regeneration envelope detecting circuit 8 in the form of low speed regenerating signals VEP. The circuit 8 outputs low speed regeneration envelope signals EEP expressing the envelopes of the regenerating signals VEP detected as above.
Then the succeeding comparator 9 receives the standard speed regeneration envelope signals ESP and the low speed regeneration signals EEP through the first and second input terminals, respectively, and then, compares the magnitudes of the two sets of the signals. Under this condition, during the period in which the regeneration head switching pulses SWP is in a state of "1", the gradually decreasing regeneration video signals VSP of the second standard speed regenerating head SP2 and the gradually increasing regeneration signals VEP1 of the first low speed regenerating head EP1 cross each other.
Then at the time point where the two values become equal each other [FIG. 7B(C)o], the relation of the magnitudes of the two regenerating envelope signals ESP,EEP are inverted, with the result that the regenerating envelope signals EEP become larger than the regenerating envelope signals ESP. Consequently, the regeneration signal switching pulse SSP which is for the standard speed recorded medium and which is outputted by the comparator 9 is shifted to a state of "1", and, in response to this, the analogue switching circuit 10 is switched over
In other words, the selected ones are inserted into the second standard speed regenerating video signals VSP2 [FIG. 7B(D)p], and then, the mixed signals are supplied to the compensated regenerating signal output terminal 11 in the form of compensated regenerating signals VSSP for the standard speed recorded medium.
During the period in which the succeeding regeneration head switching pulse SWP is in a state of "0", the second low speed regenerating signals VEP2 having greater envelopes are inserted into the first standard speed regenerating signals VSP1 [FIG. 7B(D)q] based on the same operation as described above, and then, the mixed signals are supplied to the output terminal 11 in the form of compensated regenerating signals VSSP for the standard speed recorded medium.
However, in the case where a picture data which is completely recorded by means of a low speed recording head is taken as the object of the concern, the compensating operations for continuous regenerations bring various undesirable results. Such undesirable phenomena will be described referring to FIG. 8A (which is equivalent to FIG. 7A), FIG. 8B (which is equivalent to FIG. 7B) and FIG. 9, which precisely enlarges the recess of the wave pattern.
Now it is assumed that the video tracks a,b,c, . . . i,j,k which have narrow widths and are recorded by low speed recording heads are continuously regenerated at a triple speed. Then, during the variable speed regeneration, video head scanning traces l,m having wide widths are formed by standard speed regenerating heads. Further, these wide video head scanning traces l,m, include video head scanning traces 1', m' having narrow widths and formed by the low speed regenerating heads which are operated simultaneously with the standard speed regenerating heads during the variable speed regeneration.
First, in response to the regeneration head switching pulse SWP [FIG. 8B(A)n] which is in a state of "1", the first low speed regenerating head EP1 which is performing a variable speed regeneration of a triple speed makes relative motions along the video head scanning trace m' which precedes in time series. As against the wedge shaped region QEP1 having a narrow end and appearing in the initial stage of the relative motions, the first low speed regenerating head EP1 regenerates regenerating signals VEP1 [FIG. 8B(B)o] having a gradually decreasing trend in correspondence with the wedge shaped region having a narrow end.
Following the wedge shaped region QEP1, the azimuth of a lozenge shaped region RSP2 does not correspond with that of the first low speed regenerating head EP1, and therefore, the regenerating signals VEP1 disappear [FIG. 8B(B)p]. In the meantime, there occurs an overlapping with the leading end portion of the wedge shaped region QEP1 having a narrow end, and therefore, there is regenerated a regenerating signal VEP1 [FIG. 8B(B)q] having a gradually increasing trend in correspondence with a wedge shaped region having a wide end.
In the meantime, the second regenerating head SP2 which performs relative motions along the video head scanning trace m regenerates strip shaped regions [(RSP2)+(R'SP2)] which have leading end portions divided from the narrow ended wedge shaped region TSP2 by the video head scanning trace m as an inclined boundary.
Further, in correspondence with a wide ended wedge shaped region USP2, the second regenerating head SP2 further regenerates another signal [FIG. 8B(C)r] having a substantially flat form, while, in correspondence with the inclined cut portion of the region R'SP2, the head SP2 regenerates a gradually decreasing regenerating signal VSP2 [FIG. 8B(C)s]. In the above cases, the azimuths of the regions QEP1,SEP1 do not correspond with that of the second standard speed regenerating head SP2, and therefore, the regenerating signal VSP2 is not implicated here.
Then, if the head switching pulse SWP is shifted to a state of "0.revreaction., then, in response to this, the first standard speed regenerating head SP1 and the second low speed regenerating head EP2 start the operations of a variable speed regeneration of a triple speed. Then they perform relative motions along the wide width video head scanning trace 1 which succeeds in time series. Thus, as against the regions PSP1, WEP2,XSP1, YEP2, ZSP1, the first standard speed regenerating head SP1 and the second low speed regenerating head EP2 respectively regenerate two regenerating signals VSP1,VSP2 [FIG. 8B(B)t, FIG. 8B(C)u] which increase and decrease in the same form as when the head switching pulse SWP is in a state of "1".
Thus, in the case where a picture data which is recorded in a low speed by the low speed recording heads EP1,EP2 is to be subjected to a variable speed regeneration, it is very difficult to form compensated regenerating signals simply by comparing the magnitudes of the envelopes of the regenerating signals VEP,VSP, as is apparent by the increasing/decreasing trends of the regenerating signals VEP,VSP as shown in FIGS. 8B and 8C. This is the principal difference from the case where a picture data which is recorded at a standard speed by means of the standard speed recording heads SP1,SP2 is subjected to a variable speed regeneration.
Further, in the case where a picture data which has been recorded at a low speed by means of the low speed recording heads is subjected to a variable speed regeneration, the low speed regenerating heads EP1,EP2 have to be justly used to obtain regenerating signals VEP, if a proper picture data is to be obtained. Therefore, its use usually should be confined to the case where the signals are damped by the regenerating signals VEP to such an extent that partial degradation of the picture data or cross talk occur.
Therefore, it is more desirable in terms of the picture quality to use the regenerating signals VSP which are regenerated by the standard speed regenerating heads SP1,SP2. However, the current regenerating signals VEP are very low in their signal level compared with the regenerating signals VSP which are regenerated by the standard speed regenerating heads SP1,SP2. Therefore, there exist differences in the envelopes of the regenerating signals VEP1, VEP2 regenerated by the first and second low speed regenerating heads EP1, EP2, while there exist also step differences between the levels of the wave centers of the two regenerating signals VEP1, VEP2.
Consequently, due to the current regenerating signals VEP regenerated by the first and second low speed regenerating heads EP1, EP2 and due to their envelopes, there are many difficulties in properly deciding the time of selecting the regenerating signals VSP which are regenerated by the first and second standard regenerating heads SP1, SP2.
FIG. 9 illustrates the wave patterns showing mainly the time relation between the regeneration signal switching pulses SEP for the low speed recorded medium, which are used in deciding the time of selecting the regenerating signals VEP1, VEP2 of the first and second low speed regenerating heads EP1, EP2 and the regenerating signals VSP1, VSP2 of the first and second standard speed regenerating heads SP1, SP2. The above described difficulties will be described in further detail referring to FIG. 9.
In this drawing, during the period when the regeneration head switching pulse SWP is in a state of "1", and when the first low speed regenerating head EP1 is performing a variable speed regeneration at triple speed [FIG. 9(A)a], the regenerating head EP1 obtains a regenerating signal VEP1 through the pre-amplifier 4, and this regenerating signal VEP1 has an amplitude-modulated wave pattern [FIG. 9(B)b] which is equivalent to the main body of the envelope of one side as shown in FIG. 8B schematically and extractively.
Meanwhile, during the time when the regenerating head switching speed regenerating head EP2 is performing continuously a variable speed regeneration at triple speed [FIG. 9(A)c], this time, the switched second low speed regenerating head EP2 obtains another amplitude-modulated wave pattern [FIG. 9(B)d] through the pre-amplifier 5, with this wave pattern succeeding the wave pattern of the first low speed regenerating head EP1.
Now a comparison will be made on the separate amplitude-modulated wave patterns [FIG. 9(B)b, FIG. 9(B)d] of the first and second low speed regenerating heads EP1, EP2. Generally speaking, the wave pattern (amplitude) [FIG. 9(B)V] of the first low speed regenerating head EP1 and the wave pattern [FIG. 9(B)W] of the second low speed regenerating head EP2 do not correspond each other, and particularly, the center position of the wave pattern [FIG. 9(B)X] of the former and the center position of the wave pattern [FIG. 9(B)Y] of the latter do not correspond.
FIG. 9C illustrates a state which is formed by extracting the envelopes of the regenerating signals VEP of the low speed regenerating heads EP1, EP2, after taking into account the above described non-correspondences. According to the wave pattern of this drawing, during the first half period as a state of "1" and during the second half period as a state of "0", the shape of the envelope, particularly the rising and falling slopes [FIGS. 9(C)e and 9(C)f] and the position of the envelope, particularly its minimum value [FIGS. 9(C)g and 9(C)h] exist in different forms. Because of these different existences, difficulties are encountered in the following period.
That is, this refers to a period in which the case is different from that of the regenerating signals VSP of the first and second standard regenerating heads SP1,SP2, and in which the case of the regenerating signals VEP of the first and second low speed regenerating heads shows a significant relative damping in the envelopes of the regenerating signals VEP of the low speed regenerating heads EP1,EP2.
In other words, this refers to the period in which the relative damping is significantly seen in the envelopes EEP of the regenerating signals VEP as shown in FIG. 9D, i.e., in the regeneration signal switching pulse (corresponding to SSP of FIG. 6) required for deciding the period for compensating the cross talks and degradations of the regenerating picture data by inserting the regenerating signals VSP of the simultaneously operating standard speed regenerating heads SP1,SP2.
That is, during this period, it is very difficult to form the regeneration signal switching pulse SEP for a low speed recorded medium by inverting to a state of "0" [FIG. 9(D)i]. Therefore, in the case where a variable speed regeneration is carried out using the low speed regenerating heads EP1,EP2 and using the low speed recorded medium, the stripe shaped or optical noises which appear on the regenerated picture can not be eliminated.

Variable-speed regeneration compensating apparatus for double azimuth 4-head type video tape recorder


A pneumatic tire having excellent wet performance and steering stability and noise reduction comprises a tread divided into two regions by a pattern center, at least one of which regions is provided with a plurality of main slant grooves each being comprised of a steep slope segment and a gentle slope segment. Furthermore, when such a region is equally divided by a phantom line parallel with the pattern center into a tread central zone and a tread side zone, a steeply slant auxiliary groove communicating two adjoining main slant grooves with each other and a gently slant auxiliary groove arranged between the adjoining two main slant grooves are arranged in the tread side zone.

1. Field of the Invention
This invention relates to pneumatic tires, and more particularly to a so-called high-performance pneumatic tire realizing improvements of wet performance and steering stability and reduction of noise without sacrificing other tire performances.
2. Description of Related Art
In order to simultaneously satisfy high wet performance and low noise, it is generally useful to adopt a so-called directional tread pattern defined by arranging in a tread portion circumferential grooves extending straight in a circumferential direction of the tire and a plurality of slant grooves extending obliquely in a direction of converging from each of ground contact ends of the tread toward a pattern center.
In order to further improve the wet performance, it is effective to render the slant groove into a steeply slant groove having a small inclination angle with respect to the circumferential direction of the tire. In this case, however, land portions defined by these steeply slant grooves have necessarily an acute portion, and hence the rigidity of the land portion lowers and steering stability is degraded.
In addition, it is effective to increase a negative ratio for improving the resistance to hydroplaning. However, the increase of the negative ratio undesirably increases the noise level.
In order to improve the steering stability, it is useful that the slant groove is a gently slant groove extending obliquely at a large inclination angle with respect to the circumferential direction of the tire, or the arranging pitch of the slant groove is made large to enlarge the land portion defined by these slant grooves. In this case, however, the gently slant groove causes the degradation of pattern noise and hence the sufficient drainage performance at the ground contact region of the tread, particularly central region thereof is not obtained.
In the conventional tire having the aforementioned tread pattern, it is difficult to simultaneously and balancedly establish the wet performance, steering stability and noise.

Pneumatic tire including main slant grooves and auxiliary grooves


An electric covering for a joint between a pair of electric cables, a device including such covering in elastically expanded condition on a rigid tubular support and electric cable joints including such covering. The covering includes at least two elastic sleeves of cross-linked polymeric material, a first radially inner sleeve at least partly of insulating material and a second radially outward sleeve. To permit the covering to be elastically expanded and encircling the rigid support for a long period of time, e.g. two years, the two sleeves have different mechanical properties and in particular, the material of the second sleeve has a residual deformation, which is applied by elongation over a period of time, which is less than the residual deformation, similarly applied, to the material of the first sleeve. The covering can also include a radially innermost stress grading, elastic third sleeve of cross-linked polymeric material, and the sleeves can be in contact and bonded together at their contacting surfaces.

The known devices for forming joints of cables are of the type in which at least a tubular covering, made of an electrically insulating material for at least a part of its thickness, surrounds the connection between the conductors and elastically tightens on the end portions of the cables which face each other in the joint.
Examples of known devices are described in the European Patent No. 149,032, in the German Patent No. 3,001,158 and in the Japanese Patent No. 54-49588.
All the known devices comprise a rigid tubular support on which a tubular covering for joints of cables is fitted in an elastically expanded condition and means for removing the support from the tubular covering in order to enable this latter to shrink elastically to embrace and tighten, always elastically, on the end portions of the two cables, which face or are adjacent each other, and thereby enclose the electrical and mechanical connection of the conductors of said cables.
The known devices have drawbacks which are linked to the above indicated known particular element of the devices themselves.
The known devices for forming joints have the diameter of the inner bore of the tubular support only a little greater than that of the outer diameter of the cables where the joints are to be formed so as to impose a stretching as small as possible, in the radial direction, on the elastically expansible tubular covering in order to avoid permanent plastic deformations which would prevent the tubular covering, once it is fitted on the connection between the conductors of the cables, from exerting the required tightening on the end portions of the cables.
The need of avoiding permanent plastic deformations in the tubular covering for joints of cables is in fact an essential need since if in a joint between cables the tubular covering enclosing the mechanical and electrical connection between the conductors of the cables has suffered a permanent plastic deformation in radial direction, the covering is no longer able to exert a sufficient compression on the end portions of the insulations of the cables embraced by said tubular covering. In these conditions, the joint runs the risk of becoming perforated under the action of the electric stresses applied to it during the use of the cable.
In fact, an insufficient radial pressure exerted by the tubular covering on the end portions of the insulations of the cables does not assure a complete absence of air bubbles or very small bubbles, between the surfaces in contact with each other and hence, does not assure a perfect tightness with respect to possible infiltration of traces of moisture between said surfaces.
Such requirements create difficult conditions for the above-mentioned elements of the devices for forming joints of cables, for the joints of cables, or for the tubular coverings of the joints due to the need, existing at present, for providing a plurality of rigid supports of diameters of different dimensions and related tubular coverings of diameters of different dimensions (to be fitted on the supports) in order to cover the wide range of diameters of the cables where the joints are to be made. The latter represents a drawback since it obliges the users to store a considerable number of sleeves and relative supports of different types in order to cover any possible situation.
To avoid risks of permanent deformation of the tubular coverings, the fitting of the coverings on the tubular supports is, at present, carried out immediately before effecting the joint. This is because a high elongation in radial direction maintained for a substantial period of time on a known tubular covering for joints fitted on a tubular support means results in the risk of causing in the covering a permanent plastic deformation in the radial direction which is greater the longer the time of application of said high elongation.
To effect the fitting of a tubular covering on a tubular support immediately before forming a joint means that the operation must be carried out in place with all the risks that this unavoidably involves because of the ambient conditions in the field which are difficult to control. Also, there is an unavoidable increase in the time for effecting the joints, and it is not possible to store the devices completely ready to apply to joints of electric cables.

Multi-layer elastic sleeves for electric power cable joints and joints therewith


A laser system for the marking of metallic and non-metallic materials comprising a laser oscillator (1), characterized in that said laser oscillator (1) comprises: an active optical means (13) of the crystal laser type, a laser pump (10) to provide a pump energy to said active optical means (13); a mirror (14) disposed upstream said active optical means (13); an optical switch (16), apt to provide a pulsed laser beam, disposed downstream said active optical means (13); a mode adaptor (18) coupled to said optical switch (16); a predetermined length single-mode optical fiber (19), coupled to said mode adapter (18); a Bragg Grating type reflector coupled to said optical fiber (19).

The sector of industrial marking using laser is in considerable expansion subsequent to the possibility of marking metallic and non-metallic materials with techniques such as surface or deep engraving of the material or through colour change of the material. In this sector solid state lasers excited by laser diodes (Diode-Pumped Solid-State, or DPSS) are conventionally used, with average powers generally below 100 W and operating with light pulse repetition obtained through the "Q-switching" technique. The laser beam, produced by diodes, is then sent, through suitable collimation optics, to the work surface. This transfer can take place in two ways: by moving the laser beam on a fixed sample using a system of galvanometric mirrors, or by moving the sample using a system of axes x-y-z on a fixed laser beam. The DPSS laser source is typically constituted by discrete optical components such as: mirrors, crystals, lenses and prisms. A laser diode for excitation, also called power pump diode, excites a suitably doped optical crystal. When population inversion takes place inside the crystal, a coherent and monochromatic electromagnetic radiation is generated at the wavelength corresponding to the emission transition of the doped crystal. This radiation is amplified inside the resonant laser cavity delimited by two mirrors: a mirror through which the pump beam is sent to the crystal, known as High Reflection Mirror (HR) and an Output Coupler (OC) mirror, thus giving rise to the laser radiation. Deconvolution of the emission spectrum of the crystal with the reflection and pass bands of said mirrors produces a highly monochromatic radiation (<0.1 nm). An acoustic-optical modulator, i.e. based on sound-light interaction, positioned inside the cavity produces a pulsed signal giving rise to Q-Switching. However, this solution presents some problems.
It is known that DPSS lasers are affected by the problem of thermal lens that causes a variation in the quality of the laser mode as a function of the intensity of the pump diode with which the crystal of the active material is irradiated. Consequently, the quality of the output beam, and therefore the quality of the industrial marking, depends on the output power. Moreover, the quality of the laser beam (known as Beam Quality Parameter, M2) depends on the optical length of the resonator, defined as the distance between the HR and OC mirrors. That is, by varying the optical length, the quality of the beam changes. The time duration of the pulses also depends on this length. It is possible to define the time duration of the laser pulse by varying the aforesaid length. By increasing this length the time duration of the pulses increases. This variation is not random, but is dependent on the stability parameters of the laser, which in turn are dependent on the optical properties of the OC and HR mirrors and on the length of the thermal lens. However, when obtaining a stable laser cavity, such as to guarantee pulses of long duration, the problem of optical stability (optical alignment) of the cavity must be tackled. We can conclude that with DPSS technology it is not possible to obtain a laser source with a long pulse duration and simultaneously high mode quality. Moreover, the reliability of the laser source is limited as it is constituted by discrete elements and the cost of the whole system is relatively high and cannot be significantly decreased, as the cost of the discrete components cannot be further reduced, given that they cannot be mass produced.
For industrial machining operations, the DPSS laser source must be kept close to the work surface, in a single and relatively voluminous system, as transfer of the beam from the laser to the surface occurs through propagation in the free space. An alternative technology to the above relates to the use of a pulsed fibre laser. In a particularly common configuration, the laser is constituted by an oscillator that pumps a power amplifier, both made completely in optical fibre. In this architecture, the laser wavelength is not generated by pumping an optical crystal, as is the case in DPSS technology, but an optical fibre, known as active fibre, suitably doped with rare earths. There are two types of fibre laser architectures that allow pulsed laser beams to be produced. The first uses a low power seeder diode (a few tens of mW) whose signal, electronically pulsed, must be amplified several times to reach a sufficient power value. In the second type the laser beam, again emerging from a lower power diode, is pulsed using a Q-Switch, connected with the fibre. The beam output from this chain is conveyed, through a further fibre, to the work surface, guaranteeing remote positioning of the laser beam. Compared with the DPSS laser, the fibre laser has undoubted advantages. The quality of the beam and consequently of the marking does not depend on the output power and on the repetition rate, i.e. the fibre laser is not dependent on the effect of the thermal lens. Unlike DPSS lasers, the high quality of the laser beam (M2≈1) is not dependent on the laser power and is established by the single mode of the fibre.
Optical fibre components already available and with relatively low costs are used, as these are used in the telecommunications sector and are readily available. The source is more reliable, as the laser beam always propagates in optical fibre and no discrete optics are involved, as instead is the case in DPSS lasers. Finally, the source can be positioned remotely with respect to the work surface, as the beam is conveyed towards it directly from the optical fibre, while in DPSS lasers the beam is propagated to the work surface in the air. However, it must be stated that this latter solution also has undeniable disadvantages or problems. The intensity and the shape of the laser pulse emerging from a fibre laser is greatly influenced by non-linear phenomena such as: Scattering, i.e. Stimulated Brillouin Scattering (SBS), Photodarkening, Amplified Spontaneous Emission (ASE), which occur in the optical fibre and, principally, in the oscillator, phenomena that are completely absent in DPSS lasers as the laser radiation is produced in a crystal. In particular, phenomena of scattering, such as Stimulated Brillouin Scattering, compete largely with the laser efficiency giving rise to pre- and post-pulses that are amplified in the subsequent amplification chain reducing the efficiency of the laser and producing signals that can counterpropagate in the chain of the fibre laser colliding with and damaging sensitive elements such as the pump diodes. It is not possible to compensate this loss of efficiency by increasing the length of the fibre, as the intensity of Stimulated Brillouin Scattering depends on this parameter. Therefore, the longer the active fibre is, the more probable all non linear phenomena are, as for example in fibre laser architecture composed of a plurality of amplification stages.
Moreover, fibre laser architecture which involves the use of the Q-Switch is complicated by the need to launch the signal emerging from the fibre in the Q-Switch and subsequently receive it in this fibre. This type of architecture has a complex optical design, the objective of which is to guarantee maximum launching and collection efficiency in the single-mode fibre. This complexity is inexistent in a DPSS cavity as the Q-Switch must be proportioned only to the dimension of the laser mode. The output light is not linearly polarized, as is the case in some DPSS lasers, a fact that prevents possible and effective frequency duplication of the output beam, particularly useful in the case of micromachining operations, such as the formation of solar cells. Moreover, this radiation has a spectral width greater than one nanometer (FWHM Full Width at Half Maximum) not suitable for harmonic conversion, which is instead possible with laser radiation emitted from a DPSS source.

Laser system for the marking of metallic and non-metallic materials


A short wavelength light source is provided with a fundamental wave light source for generating a fundamental wave, and a plurality of wavelength conversion elements made of nonlinear optical crystals having periodic polarization-inversion structures and adapted to convert a part of the fundamental wave into a second harmonic, and the nonlinear optical crystals of the plurality of wavelength conversion elements are different in material or composition. By converting the fundamental wave from the fundamental wave light source by the plurality of wavelength conversion elements, the generation of a thermal lens effect caused by light absorption can be suppressed to improve a high output resistance.

1. Technical Field
The present invention relates to a short-wavelength light source for converting a fundamental wave into a second harmonic using a wavelength conversion element.
2. Description of the Background Art
In the generation of a second harmonic utilizing a nonlinear optical effect, a coherent light as a fundamental wave from a fundamental wave light source can be converted into a second harmonic having a half wavelength. In this wavelength conversion, conversion efficiency can be improved and an high-output short wavelength light can be generated by an increase in the length of the wavelength conversion element or an increase in the power of the incident fundamental wave in the case of noncritical phase matching.
Here, in the wavelength conversion element using KTP as a nonlinear optical crystal, an increase in the power density of a fundamental wave or a second harmonic causes the generation of a color center called a gray track, whereby the fundamental wave and the second harmonic are absorbed. Upon the occurrence of the gray track, a local heat distribution is caused by absorption and the nonlinear optical crystal is destructively damaged. As a method for solving this, a method for dividing a crystal to obtain divided second harmonics is proposed in Japanese Unexamined Patent Publication No. H11-271823.
FIG. 29 is a construction diagram of a conventional short-wavelength light source. In FIG. 29, a part of a fundamental wave emitted from a fundamental wave light source 301 is wavelength-converted into a second harmonic H1 by a KTP crystal 302, thereby being separated into a fundamental wave F1 and the second harmonic H1 by a wavelength separating mirror 304. A part of the fundamental wave F1 is wavelength-converted into a second harmonic H2 by a next KTP crystal 303, and separated into a fundamental wave F2 and a second harmonic H2 by a wavelength separating mirror 305. In this way, by extracting the second harmonics in such a state where the power densities of the generated second harmonics do not exceed a specific value using a plurality of KTP crystals, efficiency is improved.
Japanese Unexamined Patent Publication No. 2007-94424 discloses a method by which a plurality of nonlinear optical crystals are arranged in a direction of a fundamental wave beam and the fundamental wave beam is incident on the respective nonlinear optical crystals via condensing optical systems for wavelength conversion.
Japanese Unexamined Patent Publication No. 2002-350914 discloses a method by which a plurality of nonlinear optical crystals are arranged in a direction of a fundamental wave beam and the fundamental wave beam is incident on the respective nonlinear optical crystals via condensing optical systems for wavelength conversion by the generation of a second harmonic or a sum frequency.
However, since the above conventional constructions require a plurality of nonlinear optical crystals and the second harmonics are emitted from different parts, a complicated optical system is required to use the second harmonics while multiplexing them, which has presented a problem of enlarging the light source. Further, since the output extracted from one nonlinear optical crystal is limited, many crystals are necessary to obtain a high output, which has caused a problem of making miniaturization and lower cost difficult. Since the maximum emission quantity of each beam is limited, there has been a problem of being difficult to realize a high-output single beam.
In the construction for wavelength-converting the fundamental wave beam by a plurality of wavelength conversion elements while condensing the fundamental wave beam by the condensing optical systems, there has been proposed a method for reducing the interference of beams generated by the wavelength conversion elements by rotating the polarizations of the beams generated by the respective wavelength conversion elements. However, there has been a problem of reducing conversion efficiency since the polarizations of the second harmonics generated by the respective wavelength conversion elements differ. Further, in the construction for causing the fundamental wave laser to be incident on different crystals and generating a short-wavelength light by the generation of a second harmonic or a sum frequency, the generation of a high-output second harmonic using a plurality of wavelength conversion elements is not considered.


An organic electroluminescent device includes first and second substrates spaced apart from and facing each other, an organic electroluminescent diode on an inner surface of the second substrate, a gate line formed on an inner surface of the first substrate in a first direction, a data line formed in a second direction crossing the first direction, a power supply line spaced apart from the data line and formed in the second direction, a switching thin film transistor at a crossing portion of the gate and data lines, a driving thin film transistor at a crossing portion of the switching thin film transistor and the power supply line, a connecting electrode connected to the driving thin film transistor, and an electrical connecting pattern corresponding to the connecting electrode and for electrically connecting the connecting electrode to the organic electroluminescent diode.

1. Field of the Invention
The present invention relates to a flat panel display device and more particularly, to an organic electroluminescent device and manufacturing method for the same.
2. Discussion of the Related Art
Liquid crystal display (LCD) devices have been most widely used in the field of flat panel display devices due to their lightweight and low power consumption. The liquid crystal display (LCD) device is not a light emitting element but rather a light-receiving element that needs an additional light source to display images. Accordingly, there is a technical limit in improving brightness, contrast ratio, viewing angle and enlarging the size of a liquid crystal display panel. For this reason, mush research has been ongoing in this field to develop a new flat panel display element that can overcome the aforementioned problems.
The organic electroluminescent device is one of the those new flat panel display elements. Because the organic electroluminescent device emits light, allows for a wide viewing angle and a large contrast ratio, the organic electroluminescent device is superior when compared to the liquid crystal display (LCD) device. In addition, an organic electroluminescent device does not need a backlight. Further, an organic electroluminescent device also has the advantages of being light weight, a thin profile and low power consumption. Moreover, the organic electroluminescent device can be driven with a low DC (direct current) and has a fast response time. Because the organic electroluminescent device uses a solid material instead of a fluid material, such as liquid crystal, an organic electroluminescent device is more stable if it receives an external impact. The solid material also has a wider range of operating temperatures as compared to liquid crystal.
The organic electroluminescent device also has an advantage in terms of production costs as compared to an LCD device. Specifically, a deposition apparatus and an encapsulation apparatus are all that is needed for manufacturing an organic electroluminescent device, while the liquid crystal display (LCD) device or Plasma display panels (PDPs) need many kind of apparatus. Thus, the manufacturing process for the organic electroluminescent device is very simple compared to the liquid crystal display (LCD) device or the plasma display panels (PDPs).
Organic electroluminescent devices may be classified into either a passive matrix-type device or an active matrix-type device. In the active matrix-type organic electroluminescent device, voltage applied to the pixel is also stored in a storage capacitor CST such that the voltage is maintained until a signal for the next frame is applied. Accordingly, the pixel can retain the signal until the next frame regardless of the number of the scan lines. The active matrix-type organic electroluminescent device can obtain an appropriate luminance with low direct current (DC). Further, the active matrix-type organic electroluminescent device has advantages, such as low power consumption and high resolution with a large screen size. A basic structure and an operational property of the active matrix-type organic electroluminescent device will be described hereinafter with reference to FIG. 1.
FIG. 1 is a circuit diagram of a pixel of a related art active matrix organic electroluminescent device. A basic structure and an operational property of the active matrix-type organic electroluminescent device will be described hereinafter with reference to FIG. 1. As shown in FIG. 1, a scan line 2 is formed in a first direction while signal and power supply lines 4 and 6, formed apart from each other and crossing the scan line 2, are formed in a second direction. The scan line 2 together with the signal and power supply lines 4 and 6 define a pixel region. A switching thin film transistor TS, such as an addressing element, is formed near an intersection of the scan and signal lines 2 and 4, and a storage capacitor CST is connected to the switching thin film transistor TS. A driving thin film transistor TD, such as a current source element, is connected to the switching thin film transistor TS, the storage capacitor CST and the power supply line 6. The driving thin film transistor TD is electrically connected to an anode electrode of an organic electroluminescent diode E that is driven by a static current. The anode electrode as well as the cathode electrode are components of the organic electroluminescent diode E. The switching thin film transistor TS serves to control a voltage applied to the driving thin film transistor TS and the storage capacitor CST serves to store a charge to maintain the voltage applied to the driving thin film transistor TS. The driving principle of the related art organic electroluminescent device will be described hereinafter.
When the switching thin film transistor TS is turned on, a data signal can be applied to the driving thin film transistor TD and the storage capacitor CST via the switching thin film transistor TS. When the driving thin film transistor TD is turned on, a current from the power supply line 6 can be applied to the organic electroluminescent diode E. The current passing through the driving thin film transistor TD then passes through the organic electroluminescent diode E such that the organic electroluminescent diode E can emit light. Because the degree in which driving thin film transistor TD is open depends on amplitude of the data signal, gray levels can be displayed by controlling an amount of current that passes through the driving thin film transistor TD. A data signal that is stored in the storage capacitor CST is continuously applied to the driving thin film transistor TD and accordingly the organic electroluminescent diode E can continuously emit light at a specified gray level until a signal for a next frame is applied.
FIG. 2 is a plan view of a pixel of a related art active matrix organic electroluminescent device. As shown FIG. 2, the pixel includes a switching thin film transistor TS and a driving thin film transistor TD. As also shown in FIG. 2, a gate line 37 is formed in a first direction, and a data line 51 and a power supply line 41, which are spaced apart from each other, are formed in a second direction. The gate line 37 crosses the data line 51 and the power supply line 41 and defines a pixel region P between the gate line 37, the data line 51 and the power supply line 41. A switching thin film transistor TS is formed near an intersection of the gate and the data lines 37 and 51 and a driving thin film transistor TD is formed near an intersection of the switching thin film transistor TS and the power supply line 41. The power supply line 41 and a capacitor electrode 34, which is connected to a semiconductor layer 31 of the switching thin film transistor TS, form a storage capacitor CST. A first electrode 58 is electrically connected to the driving thin film transistor TD. Although not shown in FIG. 2, an organic light emitting layer and a second electrode are sequentially formed over the first electrode 58. The area where the first electrode 58 is formed is defined as an organic light-emitting region L. The driving thin film transistor TD has a semiconductor layer 32 and a gate electrode 38. The switching thin film transistor TS has a gate electrode 35. Layered structures of the organic light-emitting region L, the driving thin film transistor TD and the storage capacitor CST will be described hereinafter with reference to FIG. 3.
FIG. 3 is a cross-sectional view along the line III-III′ of FIG. 2. In FIG. 3, a driving thin film transistor TD having a semiconductor layer 32, a gate electrode 38, and source and drain electrodes 50 and 52 is formed on an insulating substrate 1. A power electrode 42 extending from a power supply line (not shown) is electrically connected to the source electrode 50 and a first electrode formed of transparent conductive material is electrically connected to the drain electrode 52. A capacitor electrode 34 is formed under the power electrode 42 of the same material used to form the semiconductor layer 32. The power electrode 42 and the capacitor electrode 34 form a storage capacitor CST. An organic light-emitting layer 64 and a cathode electrode 66 are sequentially formed on the first electrode 58 to complete formation of an organic light-emitting region L. A buffer layer 30 is formed between the substrate 1 and the semiconductor layer 32. First, second, third and fourth passivation layers 40, 44, 54 and 60 respectively having a contact hole for electrical contacting in each layer are formed on the substrate 1. The first passivation layer 40 is formed between the storage electrode 34 and the power electrode 42 and serves as a dielectric substance. The second passivation layer 44 is formed on the power electrode 42 and the third passivation layer 54 is formed between the source electrode 50 and the first electrode 58. The fourth passivation layer 60 is formed between the driving thin film transistor TD and a second electrode 66.
FIGS. 4A to 4I are cross-sectional views illustrating processes of fabricating the related art active matrix organic electroluminescent device, and correspond to cross-sections along the line III-III′ of FIG. 2. The organic electroluminescent device may be manufactured using a photolithographic process in which thin films are patterned by exposing and then developing a photoresist, such as a photosensitive material. As shown in FIG. 4A, a buffer layer 30 is formed on an insulating substrate 1 with a first insulating material. Then, a semiconductor layer 32 and a capacitor electrode 34 are formed of polycrystalline silicon on the buffer layer 30 through a first photolithography process using a first mask.
Subsequently as shown in FIG. 4B, a gate insulating layer 36 and a gate electrode 38 are formed on the semiconductor layer 32 by sequentially depositing a second insulating material and a first metal material on the semiconductor layer 32 and then patterning the deposited material through a second photolithography process using a second mask. Then, as shown in FIG. 4C, a first passivation layer 40 is formed on the whole substrate on which the gate insulating layer 36 and the gate electrode 38 are already formed. A power electrode 42 is subsequently formed on the first passivation layer 40 in an area corresponding to the capacitor electrode 34 by depositing a second metal material on the first passivation layer 40 and then patterning it through a third photolithography process using a third mask.
As shown in FIG. 4D, a second passivation layer 44 having first and second contact holes 46a and 46b and a capacitor contact hole 48 is formed in the first passivation layer 40 by depositing a third insulating material on the first passivation layer 40 and then patterning it through a fourth photolithography process using a fourth mask. The first and second contact holes 46a and 46b expose portions at both sides of the semiconductor layer 32 and the capacitor contact hole 48 exposes a portion of the power electrode 42. The semiconductor layer 32 is doped with impurities such as boron (B) or phosphorus (P) to define a channel region 32a corresponding to the gate electrode 38, and source and drain regions 32b and 32c at both sides of the channel region 32a.
As shown in FIG. 4E, source and drain electrodes 50 and 52 are subsequently formed on the second passivation layer 44 by depositing a third metal material and then patterning it through a fifth photolithography process using a fifth mask. The source electrode 50 is connected to the source region 32b through the first contact hole 46a and is connected to the power electrode 42 via the capacitor contact hole 48. The drain electrode 52 is connected to the drain region 32c via the second contact hole 46b. The semiconductor layer 32, the gate electrode 38 and the source and drain electrodes 50 and 52 form a driving thin film transistor TD. The power electrode 42 and the capacitor electrode 34 are electrically connected to the source electrode 52 and a semiconductor layer (not shown) of a switching thin film transistor (not shown), respectively and form a storage capacitor CST using the first passivation layer 40 as a dielectric substance.
Referring to FIG. 4F, a third passivation layer 54 having a drain contact hole 56 is formed by depositing a fourth insulating material over the whole substrate 1 on which the source and drain electrodes 50 and 52 are already formed and then patterning it through a sixth photolithography process using a sixth mask. As shown in FIG. 4G, a first electrode 58 is then formed on the third passivation layer 54 in an area corresponding to an organic light-emitting region L by depositing a fourth metal material on the third passivation layer 54 and then patterning it through a seventh photolithography process using a seventh mask. The first electrode 58 is connected to the drain electrode 52 through the drain contact hole 56.
Then, as shown in FIG. 4H, a fourth passivation layer 60 having a first electrode exposure portion 62 exposes a first electrode portion corresponding to the organic light-emitting region L formed by depositing a fifth insulating material over the whole substrate 1 on which the first electrode 58 is already formed and then patterning it through an eighth photolithography process using an eighth mask. The fourth passivation layer 60 also serves to protect the driving thin film transistor TD from moisture and contaminants.
As shown in FIG. 4I, an organic light-emitting layer 64 contacting the first electrode 58 via the first electrode exposure portion 62 is formed on the substrate 1 over which the fourth passivation layer 60 is already formed. A second electrode 66 is subsequently formed on the organic light-emitting layer 64 and the fourth passivation layer 60 by depositing a fifth metal material over the whole substrate 1. If the first electrode 58 is used as an anode electrode, the fifth metal material should have a reflection property so as to reflect the light emitted from the organic light-emitting layer 64 and thus to display an image. In addition, the fifth metal material is selected from the metal materials having a low work function such that the second electrode 66 can easily give away electrons.
FIG. 5 is a cross-sectional view of a related art organic electroluminescent device. As shown in FIG. 5, a first substrate 70 on which a plurality of sub-pixels Psub are defined and a second substrate 90 are spaced apart from each other. An array element layer 80 having a plurality of driving thin film transistors TD corresponding to each sub-pixel Psub is formed on the first substrate 70. A plurality of first electrodes 72 corresponding to each sub-pixel Psub is formed on the array element layer 80. The plurality of first electrodes 72 respectively connects to the driving thin film transistors TD of the sub-pixels Psub An organic light-emitting layer 74 for emitting light of either red (R), green (G) and blue (B) colors from the sub-pixels Psub is formed on the first electrode 72. A second electrode 76 is formed on the organic light-emitting layer 74. The first and second electrodes 72 and 76, and the organic light-emitting layer 74 form an organic electroluminescent diode E. Light emitted from the organic light-emitting layer 74 passes through the first electrode 72. That is, the organic electroluminescent device is a bottom emission-type organic electroluminescent device.
The second substrate 90 is used as an encapsulating substrate and has a depressed portion 92 at a middle surface thereof and a moisture absorbent desiccant 94 for protecting the organic electroluminescent diode E from exterior moisture. The second substrate 90 is spaced apart from the second electrode 76 at a certain distance. A seal pattern 85 is formed on one of the first and second substrates 70 and 90 and later used to attach the first and second substrates 70 and 90.
Attaching the substrate having the array element layer and the organic electroluminescent diode to an additional encapsulating substrate completes the related art bottom emission-type organic electroluminescent device. If the array element layer and the organic electroluminescent diode are formed on the same substrate, then yield of a panel having the array element layer and the organic electroluminescent diode is dependent upon the individual yields of the array element layer and the organic electroluminescent diode. The yield of the panel is greatly affected by the yield of the organic electroluminescent diode. Accordingly, if an inferior organic electroluminescent diode that is usually formed of a thin film having a thickness of 1000 Å has a defect due to impurities and contaminants, the panel is classified as a defective panel. This leads to wasted production costs and material, thereby decreasing yield.
Bottom emission-type organic electroluminescent devices have the advantages of high image stability and variable fabrication processing. However, the bottom emission-type organic electroluminescent devices are not adequate for implementation in devices that require high resolution because bottom emission-type organic electroluminescent devices have a small aperture ratio due to the thin film transistor blocking some of the light transmission. Top emission-type organic electroluminescent devices have a large aperature ratio. In addition, since top emission-type organic electroluminescent devices emit light upward of the substrate, the light can be emitted without being blocked by the thin film transistor that is positioned under the light-emitting layer. Accordingly, design of the thin film transistor may be simplified in top emission-type organic electroluminescent device. In addition, the aperture ratio can be increased, thereby increasing operational life span of the organic electroluminescent device. However, since a cathode is commonly formed over the organic light-emitting layer in the top emission-type organic electroluminescent devices, material selection and light transmittance are limited such that light transmission efficiency is lowered. If a thin film-type passivation layer is formed to prevent a reduction of the light transmittance, the thin film passivation layer may fail to prevent infiltration of exterior air into the device.

This patent is subject to a terminal disclaimer.

Organic electroluminescent device comprising power supply line on same layer as gate line


The invention relates to a circuit arrangement for the electrical isolation of signal lines, with an input (IN) for applying an input signal, an output (OUT) for releasing an output signal, and an initial branch (1) with an opto-coupler (OK) for optically coupling the input (TN) to the output (OUT), such that the input (IN) and the output (OUT) are connected in electrically isolated fashion by a second branch (2) with a capacitor (C1).

In many applications the electrical isolation of circuits is necessary. For example, to permit flexibility in an application involving several sensors that are interconnected in a single apparatus, the outputs of these sensors should each be electrically isolated from a supply line. Furthermore, circuits that are positioned in surroundings exposed to the risk of explosion and that are designed with the so-called intrinsic safety type of protection must be electrically isolated from other circuits. Usually these circuits are isolated from each other by opto-couplers. Here a disadvantage rests in the fact that, for the transmission of fast alternating signals, the opto-couplers must be operated with a great deal of current in order for the output signal not to be delayed and distorted. In particular, the use of this and other known circuit arrangements is not possible for two-wire sensors with, e.g., a 4-20 mA interface, due to the lack of an appropriate current.
Known from U.S. Pat. No. 5,995,252 is a circuit arrangement with which fast alternating signals can be isolated with only a relatively small loss of power. Starting with an input, an input signal is applied over a capacitor and an ohmic resistor to two opto-couplers, one of which responds to positive and one to negative input signal portions. The outputs of the opto-couplers are merged and applied to a buffer, with an ohmic resistor connected in parallel to the buffer, in order to provide an output signal. A disadvantage rests in the fact that this circuit arrangement is only suitable for alternating current signals.

Circuit arrangement for the electrical isolation of signal lines


Circuits, methods, and apparatus that provide a precise phase shift for a read strobe or other signal. One embodiment provides a read strobe delay line including a series of delay elements, where inputs or outputs of at least some of delay elements are received by a multiplexer. One input of this multiplexer is selected as the read strobe signal. Further precision adjustment may be made in the delay of the read strobe signal by using a delay line in a reference delay-locked loop, where that delay line also includes a series of delay elements, and inputs or outputs of at least some of the delay elements are multiplexed.

The present invention relates in general to integrated circuit input/output (I/O) interfaces, and in particular to methods and circuitry for accurately phase shifting clock signals in a multiple-data-rate interface.
Various interfaces have been developed to increase data transfer rates and data throughput between integrated circuits. In a multiple-data-rate interface, two or more bits of data are transferred during each clock period. A specific example is double-data-rate (DDR) technology, which performs two data operations in one clock cycle and achieves twice the data throughput. This technology has enhanced the bandwidth performance of integrated circuits used in a wide array of applications from computers to communication systems. The DDR technique is employed in, for example, synchronous dynamic random access memory (SDRAM) circuits.
DDR interfaces process I/O data (also referred to as DQ signals) using both the rising edge and falling edges of a clock or read strobe signal DQS that functions to control the timing of data transfers. DQS is normally edge-aligned with DQ for a DDR interface operating in read mode (i.e., when receiving data at a memory controller). For optimum data sampling, DQS is delayed by one-quarter of a clock period so that there is a 90 degree phase shift between the edges of DQ and DQS. This ensures that the DQS edge occurs close to the center of the DQ pulse. It is desirable to implement this 90 degree phase shift in a way that is as accurate and as stable as possible. But typical phase shift techniques that use, for example, delay chains, are highly susceptible to process, voltage, temperature, and other variations. In addition, typical DDR timing specifications require a wide frequency range of operation from, e.g., 133 MHz to 200 MHz. This places further demands on the performance of the phase shift circuitry.
Also, it is desirable to be able to adjust the 90 degree phase shift. For example, printed circuit board traces may be mismatched such that a deviation from 90 degrees is needed.
Thus, what is needed are circuits, methods, and apparatus to provide for adjustments to the phase shift applied to a DQS or similar signal.

Precise phase shifting using a DLL controlled, multi-stage delay chain


Disclosed are a compound represented by formula (I), a resin including a structural unit derived from the compound, and a resist composition:

Patent Document 1 mentions resist compositions comprising a resin composed of each structural unit derived from the following compounds.

Patent Document 2 also mentions a resist composition comprising a resin composed of a structural unit derived from the following compound.

Patent Document 3 also mentions a resist composition comprising a resin composed of a structural unit derived from the following compound.

Patent Document 4 also mentions a resist composition comprising a resin composed of a structural unit derived from the following compound.

Patent Document 5 also mentions a resist composition comprising a resin composed of a structural unit derived from the following compound.

Compound, resin, resist composition and method for producing resist pattern

Abstract: wherein R1 represents an alkyl group which may have a halogen atom, a hydrogen atom or a halogen atom; A1 represents a single bond or *-A2-CO—O—; A2 and A3 represent an alkanediyl group; W represents a divalent monocyclic saturated alicyclic hydrocarbon group; R2 and R3 each represent a hydrogen atom or a hydrocarbon group which may have a fluorine atom, etc., R4 represents a hydrogen atom, —CH2— in the group may be replaced by —O—, —S—, etc., R2 and R3, or R2, R3 and R4 may be bonded each other to form a ring which may have a fluorine atom or an alkyl group.


A test set includes at least one signal input port, a test circuitry, a processor, a user-input device, and a display. The test circuitry couples to and receives signals from the at least one signal input port. The test circuitry then generates test data corresponding to the received signals. The processor couples to and receives test data from the test circuitry and generates test results. The processor also couples to and receives commands from the user-input device. The processor further operatively couples to the graphical display that receives and displays the test results from the processor. In one embodiment, the test set is capable of performing line qualification and connectivity testing. A modem module can be used to facilitate connectivity testing. The modem module can be a plug-in module with a common interface to the test set. The modem module can also contain a fingerprint value that identifies the module type and the software revision number to the test set.

This invention relates generally to test instrumentation, and in particular to a telecommunications transmission test set for testing digital communications networks.
The advent of digital communications networks, such as the Internet, has generated great demands for high-speed data services. Conventional telephone modems can provide a limited data rate (i.e., up to 56 Kbps) before reaching the limit of performance for that technology. Other technologies, such as cable modem, can offer a leap forward in performance but are typically premised on changes in architecture that requires large investments in the communications network infrastructure.
Digital subscriber line (DSL) is a technology that offers a solution to the demand for greater bandwidth. DSL offers data rates that can be substantially higher than that of a conventional telephone modem. Furthermore, DSL uses existing twisted copper pair lines that are deployed and prevalent throughout the world. DSL delivers a basic rate access of 128 Kbps (i.e., the ISDN rate). High speed digital subscriber line (HDSL), a variant of DSL, delivers a data rate of 1.544 Mbps (T1) in North America and 2.048 Mbps (E1) elsewhere. Asymmetric digital subscriber line (ADSL), another variant of DSL, delivers data rates of 1.5 to 9.0 Mbps on the downstream path and 16 to 640 Kbps on the upstream path. More advanced variants of DSL promise even higher data rates. Collectively, DSL and variants of DSL are referred to as xDSL.
xDSL technology typically consists of a pair of modems connected to two ends of one or more twisted wire pairs, depending on the xDSL variant. One modem resides at a central office and the other modem resides at the customer premises. The twisted wire pair(s) forms a local loop. Generally, the maximum data rate is determined by the length of the local loop and the line conditions.
Installation, maintenance, and repair of an xDSL connection typically require execution of two sets of test: (1) line qualification and (2) connectivity testing. Line qualification includes tests to determine the quality of a line transmission that, in turn, determines the maximum data rate that can be achieved by an xDSL modem. Conventionally, a transmission impairment measurement set (TIMS) is used to qualify a line for xDSL service. The TIMS measures impairments such as frequency response, broadband noise, and signal power. One example of a TIMS is the OneTouch Network Assistance from Fluke Corporation that provides testing of patch cable and fiber optic cable. Unfortunately, the OneTouch Network Assistance does not provide the traditional tests normally required for line qualification and connectivity testing.
Once a line has been qualified and an xDSL modem has been installed (i.e., at the central office), connectivity testing is performed to verify data transmission over the modem. To perform connectivity testing, xDSL plug-in cards can be used. Generally, xDSL is provided by a number of manufacturers, many with proprietary designs. Thus, an xDSL plug-in card of a particular manufacturer is installed in the test equipment and connectivity tests (e.g., bit-error-rate (BER) and loopback tests) are then performed. This scheme presents a challenge to service technicians and telecommunications operators who need to maintain an inventory of xDSL plug-in cards from various vendors. In addition, the technicians need to correctly select the appropriate xDSL plug-in card for the particular local loop being tested.
A number of other challenges arise in testing digital communications networks. Conventionally, multiple types of test equipment are required to perform the various tests necessary to qualify a line and to test connectivity. For example, one type of test equipment is used to qualify a line by performing various measurements (e.g., TDR, line impairment, and so on). Another type of test equipment is then used to perform connectivity tests. The use of multiple types of test equipment increases the cost for installation, maintenance, or repair of an xDSL connection since more equipment must be maintained. Furthermore, test setup and test time are increased.
To address the test needs of digital communications networks, some test equipment manufacturers integrate multiple tests into a single test gear. One example of such integration is the CERJAC HDSL Installer's Assistance from Hewlett-Packard Company. The CERJAC HDSL Installer's Assistance performs line coil detection and insertion loss measurements (to qualify a line) and BER and transmission loopback testing (for connectivity testing).
Another challenge in testing digital communications networks arises because the line qualification and connectivity testing are often performed in a mobile environment. The service technicians generally move from site to site to test the local loop. Furthermore, access to the local loop may be limited in certain instances. Conventional test equipment are generally bulky and cumbersome, and not well suited for a mobile environment. For example, although touted as being portable, the CERJAC HDSL Installer's Assistance weighs a hefty 15 pounds.
Yet another challenge in testing arises because of the numerous amount of information that needs to be collected and presented for analysis. During the testing process, measurements are made and the test results are provided to a service technician who then configures the xDSL connection accordingly. In some conventional test sets, the test results are conveyed through simple LEDs on the front panel. However, LEDs can only display a limited amount of information. For some tests (i.e., power spectral density and load coil detection tests to qualify a line), large amounts of information are generated. Conventionally, the information is displayed or printed using alphanumeric characters. However, an alphanumeric display can be difficult to decipher and prone to mistake in interpretation.
From the above, a telecommunications transmission test set that is lightweight and portable, provides a comprehensive suite of tests, and intelligently displays test results is needed in the art.

Telecommunications transmissions test set


The invention proposes a fluid coupling apparatus in which the turbine wheel (28) is coupled in rotation to a shaft (34) through an interposed hub (36) made in one piece in sheet metal, which comprises an internally toothed sleeve portion (70) and an externally splined cylindrical skirt portion (66), for coupling together in rotation the hub (36) and an output member (60) of a lock-up clutch (16) of the fluid coupling apparatus (10).

1. Field of the Invention
The present invention relates to a fluid coupling apparatus, especially for a motor vehicle transmission.
2. Description of the Related Art
The invention is concerned with an apparatus of the same type as that described and shown in the documents U.S. Pat. No. 4,875,562 and WO-A-94/07058.
In these known designs, such a fluid coupling apparatus is of the type comprising a turbine wheel which is coupled to a turbine wheel hub constituting a driven element, for rotation of the latter with the turbine wheel whereby to couple the latter in rotation with an output shaft, together with an impulse wheel which is coupled to a driving element for rotation with the latter, and of the type comprising a lockup clutch which is adapted to act between the driving element and the driven element, and which comprises two coaxial parts which are mounted for movement of one with respect to the other against the action of circumferentially acting springs, the said parts being an input part comprising a piston, and an output part which is extended radially inwardly by a radial plate element for coupling it in rotation with the hub of the turbine wheel.
A locking clutch, usually called a "lock-up" clutch, for the fluid coupling apparatus is interposed operatively between a driving element and a driven element, and includes a torsion damper, a piston which is mounted for axial movement with respect to the driven element, and at least one friction liner which is associated with the piston and which is adapted to be gripped between the piston and a counter-piston.
In the document U.S. Pat. No. 4,875,562, the piston is so configured as to constitute the input part of the torsion damper, and it carries a friction liner which is arranged to come into contact with the transverse wall of the housing of the fluid coupling apparatus, with this wall constituting the counter piston.
The housing is a sealed casing which is filled with oil, and it is arranged to be coupled in rotation to a driving shaft.
The output part of the damper is fixed to the turbine wheel of the fluid coupling apparatus.
The turbine wheel is fixed to a hub which is arranged to be coupled to a driven shaft for rotation of the latter with it.
Thus, the casing constitutes a driving element, while the hub of the turbine constitutes a driven element, and the lock-up clutch is adapted to act between the casing and the turbine wheel so as to form a bridging means between these latter.
In the document U.S. Pat. No. 4,875,562, the torsion damper includes the piston which retains the springs (or resilient members) externally, together with a guide ring, which may be of divided form, which is carried by the piston, and retains the springs on the inside by virtue of retaining lugs.
The input part thus consists of the piston and the guide ring, while the output part comprises an annular damper plate which is fixed to the turbine wheel.
The output damper plate has engagement lugs which penetrate between the circumferencial ends of two consecutive springs so as to act on these latter.
Each of these lugs penetrates radially between two engagement lugs which are associated with the piston and the guide ring, respectively.
In the document WO-A-94/07058, the guide ring and the damper plate have retaining portions for retaining the springs on the outside and on the inside respectively.
In addition, the damper plate and the guide ring have engagement lugs for acting on the circumferencial ends of the springs.
Because of the retaining means it is possible, after the springs have been fitted by snap fitting of the damper plate behind snap-fitting lugs, to create a unitary sub-assembly which cannot be lost, which is capable of being handled and transported, and which comprises the piston and the torsion damper, this sub-assembly being then able to be fitted in position on the turbine hub.
In the designs proposed in the two said documents, the structure of the turbine hub and the ways used for fastening and/or coupling in rotation the turbine wheel and/or the radial connecting plate element of the output part, are of particular complexity, and are expensive to carry out.
In the document U.S. Pat. No. 4,875,562, the hub of the turbine wheel is a heavy machined component which comprises a radially internal portion in the form of a sleeve, in which internal axial splines are machined. The hub includes a radial plate portion that extends radially outwardly, and on which the turbine wheel is fixed by a set of rivets in the vicinity of that portion of it which lies radially towards the inside, while its radially outward portion includes axial lugs which extend towards the torsion damper. The output part of the lock-up clutch is also guided on a machined cylindrical surface of the radially inner part of the hub of the turbine wheel.
In the document WO-A-94/07058, the output part includes a radial plate element for coupling in rotation, which extends radially inwardly towards an internally splined sleeve, at one end of which it is fitted by seaming, while the turbine wheel is fitted by riveting on a middle portion of the connecting plate portion, in the region of that part of the latter that lies radially towards the inside. In another design, the splined sleeve includes a radial connecting plate portion which is made in one piece and machined, with the radial plate element that connects the output part and the turbine wheel for rotation together being fixed by riveting to its radially outer periphery.

Fluid coupling apparatus, especially for a motor vehicle transmission


Messaging interfaces that may be used in conjunction with interactive pagers include a housing that contains a message processing circuit, a user interface, and a communications circuit that is used to forward the text messages between the message processing circuit and an interactive pager. The user interface may be used to forward messages between a user of the interactive pager and the message processing circuit. The user interface may be a keypad (or any other collection of user-selectable keys, buttons, menu items, etc.), a microphone, an internal speaker and/or an external speaker such as the speakers on an automobile stereo system.

In recent years, a large number of handheld wireless text messaging devices, which are also known as "interactive pagers", have been brought to market. These interactive pagers may be used to transmit and/or receive text messages that are displayed to a user on a display screen. Examples of devices that include a wireless text messaging capability are paging devices that include a reply capability, wireless e-mail devices such as the Blackberry devices marketed by Research in Motion Limited, various personal data assistants such as devices that use the Palm operating system and the Windows Pocket PC operating system and cellular telephones that include text messaging capabilities.
The above-mentioned interactive pagers use one or more of a wide variety of input devices for inputting text messages into the device. For instance, with cellular telephones, the telephone keypad typically is used to "type" in a text message. Other devices such as the Blackberry devices include an integrated keyboard which may be used to type in a text message, and with other devices the text message may be typed into a computer and then downloaded to the interactive pager. Additionally, many devices such as Personal Data Assistants include on-screen keyboards, external keyboards and/or handwriting recognition capabilities that allow a user to use a stylus to handwrite the text message on a screen, touchpad or the like. Many interactive pagers include more than one of the representative input devices discussed above and/or other input devices that are known in the art
Each of the above-mentioned input devices may have its own limitations. For instance, because most interactive pagers are relatively small, the keyboards and/or keypads provided on such devices typically have relatively small keys or "buttons." These buttons may be more difficult to use than, for example, the keys on a standard computer keyboard. Additionally, many input devices include only a twelve button numeric keypad which is used to input the text messages. Because a separate button is not provided for each possible alpha-numeric entry, such keypads are also typically more difficult to use than a standard computer keyboard. These small size interactive pagers may use relatively small display screens which may be difficult to read and/or may use extensive scrolling to read longer messages.

Car-safe messaging interfaces for interactive pagers and related methods


A menu of mutations was developed that is useful in fine-tuning the attenuation and growth characteristics of dengue virus vaccines.

Dengue virus is a positive-sense RNA virus belonging to the Flavivirus genus of the family Flaviviridae. Dengue virus is widely distributed throughout the tropical and semitropical regions of the world and is transmitted to humans by mosquito vectors. Dengue virus is a leading cause of hospitalization and death in children in at least eight tropical Asian countries (WHO, 1997. Dengue haemorrhagic fever: diagnosis, treatment prevention and control—2nd ed. Geneva: WHO). There are four serotypes of dengue virus (DEN-1, DEN-2, DEN-3, and DEN-4) which annually cause an estimated 50-100 million cases of dengue fever and 500,000 cases of the more severe form of dengue virus infection, dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS) (Gubler, D. J. & Meltzer, M. 1999 Adv Virus Res 53:35-70). DHF/DSS is seen predominately in children and adults experiencing a second dengue virus infection with a serotype different than that of their first dengue virus infection and in primary infection of infants who still have circulating dengue-specific maternal antibody (Burke, D. S. et al. 1988 Am J Trop Med Hyg 38:172-80; Halstead, S. B. et al. 1969 Am J Trop Med Hyg 18:997-1021; Thein, S. et al. 1997 Am J Trop Med Hyg 56:566-72). A vaccine is needed to lessen the disease burden caused by dengue virus, but none is licensed. Because of the association of more severe disease with secondary dengue virus infection, a successful vaccine must induce immunity to all four serotypes. Immunity is primarily mediated by neutralizing antibody directed against the envelope E glycoprotein, a virion structural protein. Infection with one serotype induces long-lived homotypic immunity and a short-lived heterotypic immunity (Sabin, A. 1955 Amer J Trop Med Hyg 4:198-207). Therefore, the goal of immunization is to induce a long-lived neutralizing antibody response against DEN-1, DEN-2, DEN-3, and DEN-4, which can best be achieved economically using live attenuated virus vaccines. This is a reasonable goal since a live attenuated vaccine has already been developed for the related yellow fever virus, another mosquito-borne flavivirus present in tropical and semitropical regions of the world (Monath, T. P. & Heinz, F. X. 1996 in: Fields B. N. et al. eds. Fields Virology Philadelphia: Lippincott-Ravan Publishers, 961-1034).
Several live attenuated dengue vaccine candidates have been developed and evaluated in humans or non-human primates. The first live attenuated dengue vaccine candidates were host range mutants developed by serial passage of wild type dengue viruses in the brains of mice and selection of mutants attenuated for humans (Kimura, R. & Hotta, S. 1944 Japanese J Bacteriology 1:96-99; Sabin, A. B. & Schlesinger, R. W. 1945 Science 101:640; Wisseman, C. L. Jr. et al. 1963 Am J Trop Med 12:620-623). Although these candidate vaccine viruses were immunogenic in humans, their poor growth in cell culture discouraged further development. Additional live attenuated DEN-1, DEN-2, DEN-3, and DEN-4 vaccine candidates have been developed by serial passage in tissue culture (Angsubhakorn, S. et al. 1994 Southeast Asian J Trop Med Public Health 25:554-9; Bancroft, W. H. et al. 1981 Infect Immun 31:698-703; Bhamarapravati, N. et al. 1987 Bull World Health Organ 65:189-95; Eckels, K. H. et al. 1984 Am J Trop Med Hyg 33:684-9; Hoke, C. H. Jr. et al. 1990 Am J Trop Med Hyg 43:219-26; Kanesa-thasan, N. et al. 2001 Vaccine 19:3179-88) or by chemical mutagenesis (McKee, K. T. Jr. et al. 1987 Am J Trop Med Hyg 36:435-42). It has proven very difficult to achieve a satisfactory balance between attenuation and immunogenicity for each of the four serotypes of dengue virus using these approaches and to formulate a tetravalent vaccine that is safe and satisfactorily immunogenic against each of the four dengue viruses (Kanesa-thasan, N. et al. 2001 Vaccine 19:3179-88; Bhamarapravati, N. & Sutee, Y. 2000 Vaccine 18 Suppl 2: 44-7).
Two major advances utilizing recombinant DNA technology have recently made it possible to develop additional promising live attenuated dengue virus vaccine candidates. First, methods have been developed to recover infectious dengue virus from cells transfected with RNA transcripts derived from a full-length cDNA clone of the dengue virus genome, thus making it possible to derive infectious viruses bearing attenuating mutations which have been introduced into the cDNA clone by site-directed mutagenesis (Lai, C. J. et al. 1991 PNAS USA 88:5139-43). Second, it is possible to produce antigenic chimeric viruses in which the structural protein coding region of the full-length cDNA clone of dengue virus is replaced by that of a different dengue virus serotype or from a more divergent flavivirus (Bray, M. & Lai, C. J. 1991 PNAS USA 88: 10342-6; Chen, W. et al. 1995 J Virol 69:5186-90; Huang, C. Y. et al. 2000 J Virol 74:3020-8; Pletnev, A. G. & Men, R. 1998 PNAS USA 95:1746-51). These techniques have been used to construct intertypic chimeric dengue viruses which have been shown to be effective in protecting monkeys against homologous dengue virus challenge (Bray, M. et al. 1996 J Virol 70:4162-6). Despite these advances, there is a need to develop attenuated antigenic dengue virus vaccines that specify a satisfactory balance between attenuation and immunogenicity for humans.

Development of mutations useful for attenuating dengue viruses and chimeric dengue viruses

The United States of America, as represented by the Secretary, Department of Health and Human Services