Optical fiber has a glass portion and at least one coating of crosslinked polymer material surrounding the glass portion, the coating being obtained by crosslinking a composition of (a) at least one radically crosslinkable oligomer containing at least two reactive functional groups and having a number average molecular weight lower than about 1,000, preferably between about 400 and about 900; (b) at least one cationically crosslinkable compound containing at least one reactive functional group; (c) at least one free radical photoinitiator; and (d) at least one cationic photoinitiator. Preferably, the coating is a secondary coating or, in the case of a ribbon of optical fibers, it is a common polymer coating known as a “common coating”.

1. Field of the Invention
The present invention relates to an optical fiber comprising at least one polymeric coating crosslinked in the presence of both radical and cationic photoinitiators.
More particularly, the present invention relates to an optical fiber comprising a glass portion and at least one coating of crosslinked polymer material surrounding said glass portion, said coating being obtained by crosslinking a composition comprising at least one radically crosslinkable oligomer containing at least two reactive functional groups; at least one cationically crosslinkable compound containing at least one reactive functional group; at least one free radical photoinitiator; at least one cationic photoinitiator.
Moreover, the present invention relates to a crosslinkable composition that may be applied as said coating.
2. Description of the Related Art
Optical fibers commonly consist of a glass portion (typically with a diameter of about 125 μm), inside which the transmitted optical signal is confined, and of a coating, typically polymeric, surrounding the glass portion for essentially protective purposes. This protective coating typically comprises a first layer of coating positioned directly on the glass surface, known as the "primary coating" or "primary" for short, typically having a thickness of between about 25 μm and about 35 μm. In turn, this primary coating is generally covered with a second layer of coating, known as the "secondary coating" or "secondary" for short, typically having a thickness of between about 10 μm and about 35 μm.
These polymer coatings may be obtained from crosslinkable compositions comprising oligomers and monomers that are generally crosslinked by means of UV irradiation in the presence of suitable photoinitiators. The two coatings described above differ, inter alia, in terms of the modulus of elasticity of the crosslinked material. As a matter of fact, whereas the material which forms the primary coating is a relatively soft material, with a relatively low modulus of elasticity at room temperature, the material which forms the secondary coating is relatively harder, having higher modulus of elasticity at room temperature. The combination of said two layers of coating ensures adequate mechanical protection for the optical fiber.
The optical fiber thus composed has a total diameter of about 250 μm. However, for particular applications, this total diameter may also be smaller; in this case, a coating of reduced thickness is generally applied.
In addition, where one and the same cable internally contains several optical fibers, the operator must be able to identify the different fibers with certainty, hence it is convenient to colour the various fibers with different identifying colours. Typically, an optical fiber is colour-identified by surrounding the secondary coating with a third coloured polymer layer, commonly known as "ink", having a thickness typically of between about 2 μm and about 10 μm, or alternatively by introducing a coloured pigment directly into the formulation of the secondary coating.
Optionally, the coloured fibers can be then combined into groups of several fibers, typically in the form of fiber optic ribbons, to facilitate their insertion into and recognition within a cable.
Typically from 4 to 24 optical fibers are arranged in parallel to form a fiber optic ribbon and are then covered with a single covering known as the "common coating", of composition and physical properties similar to those of the secondary coating.
Different crosslinkable compositions useful as coatings for optical fibers have been already disclosed.
For example, patent U.S. Pat. No. 5,262,450 relates to a radiation curable composition comprising about 50-90 parts by weight, preferably about 60-80 parts by weight, of a multifunctional acrylate monomer, suitably with 3-6 acrylates groups, preferably pentaerythritol triacrylate or trimethylolpropane triacrylate; about 10-50 parts by weight, preferably about 20-40 parts by weight, of a divinyl ether monomer having both a hydrophobic backbone and an abrasion-resistant moiety, which is preferably the divinylether of cyclohexane dimethanol, and a radiation curing initiator, suitably a cationic initiator, and preferably, in combination with a free radical initiator. The abovementioned composition is said to provides coatings which are abrasion and water-resistant which may be applied to glass, including fiberglass and glass fiber optics.
International Patent Application WO 97/18493 relates to a removable matrix for retaining one or more optical fibers which have an outermost layer made of a first polymer having a first initiator system, e.g. a free-radical initiated, ultraviolet curable acrylate polymer, the matrix comprising a second polymer having a second initiator system substantially different from the first initiator system, e.g. a cationically initiated, ultraviolet curable vinyl ether polymer. In a further embodiment, the matrix also comprises a partial adhesion promoting amount of a free-radical initiated, radiation curable polymer. The abovementioned matrix is said to permit an easy removal of the fibers from the ribbon.
International Patent Application WO 96/02596 relates to a vinyl ether-containing composition polymerizable by actinic, γ-ray, or electron beam radiation comprising: (a) an oligomer or a mixture of oligomers which are monofunctional, multifunctional, or a mixture of both monofunctional and multifunctional oligomers, and which have a reactive functionality selected from the group consisting of epoxy, acrylate, vinyl ether, maleate, or mixtures thereof; (b) monomers which are monofunctional, multifunctional, or a mixture of both monofunctional and multifunctional monomers, and which have a reactive functionality selected from the group consisting of epoxy, acrylate, vinyl ether, maleate, or mixtures thereof, wherein at least one of (a) or (b) must contain a vinyl ether functionality; (c) a photoinitiator, optionally including a sensitizer, selected from the group consisting of a cationic photoinitiator and a radical photoinitiator; and (d) a thermal oxidation stabilizer. A dual photoinitiator system, i.e having both radical and cationic photoinitiator, may be used. The above-mentioned composition is said to be useful both as a primary coating and as a secondary coating for an optical fiber.
Japanese Patent Application 2000-336127 relates to a photo-curable resin composition comprising: (a) an oligomer which has ethylenically unsaturated groups; (b) a cationically polymerizable diluent monomer; (c) a photo-cationic polymerization initiator; and (d) a photo-radical polymerization initiator. The abovementioned composition is said to have excellent curing properties with a low exposure to ultraviolet radiation, even in the presence of oxygen and, when used as a coating for an optical fiber, it is possible to achieve high productivity. Furthermore, the above mentioned composition is said to have excellent heat resistance and moisture resistance and, consequently, it is said to be particularly useful as a coating material for optical fibers.

Optical fiber with polymeric coating crosslinked in the presence of both radical and cationic photoinitiators


A sheet-like probe and a method of producing the probe. In the probe electrode structure bodies do not come out from an insulation film and achieve high durability, and in a burn-in test for a wafer having a large area and for a circuit device having to-be-inspected electrodes with small intervals, positional displacement, caused by temperature variation, between the electrode structure bodies and the to-be-inspected electrode can be reliably prevented for stable connection conditions. The sheet-like probe includes an insulation layer and a contact film provided with electrode structure bodies arranged on the insulation layer to be apart from each other in the surface direction of the insulation layer and penetratingly extend in the thickness direction of the insulation layer. The electrode structure bodies each are composed of a surface electrode section exposed to the front surface of the insulation layer.

For example, in an electrical inspection for a wafer on which a large number of integrated circuits are formed or a circuit device such as an electronic component, for example, a semiconductor device, there has been used a probe for an inspection which has inspection electrodes arranged in accordance with a pattern corresponding to a pattern of electrodes to be inspected in a circuit device to be inspected.
Conventionally, there has been used a probe for an inspection in which the inspection electrodes formed by a pin or a blade are arranged.
However, in the case in which the circuit to be inspected is a wafer having a large number of integrated circuits formed thereon, it is necessary to arrange a large number of inspection electrodes when fabricating a probe for an inspection to inspect the wafer. Therefore, the probe for an inspection is very expensive. Moreover, in the case in which the pitch of the electrodes to be inspected is small, it is hard to carry out the fabrication of the probe for an inspection itself.
Furthermore, a warpage is generally generated on the wafer and the state of the warpage is also varied for each product (wafer). For this reason, it is practically hard to cause each of the inspection electrodes of the probe for an inspection to come in contact with a large number of electrodes to be inspected in the wafer stably and reliably.
For the above reasons, in recent years, there has been proposed a probe for an inspection which serves to inspect an integrated circuit formed on a wafer, comprising a circuit board for an inspection on which a plurality of inspection electrodes is formed in accordance with a pattern corresponding to a pattern of electrodes to be inspected on a surface, an anisotropically conductive sheet disposed on a surface of the circuit board for an inspection and a sheet-like probe in which a plurality of electrode structures extended to penetrate in a direction of a thickness thereof is arranged in a flexible insulating sheet (for example, see Patent Document 1).
FIG. 39 is an explanatory sectional view showing a structure according to an example of a conventional probe card comprising a circuit board 85 for an inspection, an anisotropically conductive sheet 80 and a sheet-like probe 90.
In the probe card, there is provided a circuit board 85 for an inspection having a large number of inspection electrodes 86 formed in accordance with a pattern corresponding to a pattern of electrodes to be inspected in a circuit device to be inspected over a surface, and a sheet-like probe 90 is disposed on the surface of the circuit board 85 for an inspection through the anisotropically conductive sheet 80.
The anisotropically conductive sheet 80 has a pressurizing conducting portion exhibiting a conductivity in only a direction of a thickness or exhibiting the conductivity in only the direction of the thickness when a pressurization is carried out in the direction of the thickness. There have been known the anisotropically conductive sheets having various structures. For example, Patent Document 2 and the like have disclosed an anisotropically conductive sheet obtained by uniformly dispersing a metal particle in an elastomer (which will be hereinafter referred to as a "dispersion type anisotropically conductive sheet").
Moreover, Patent Document 3 and the like have disclosed an anisotropically conductive sheet obtained by unevenly distributing a conductive magnetic particle into an elastomer, thereby forming a large number of conductive portions extended in a direction of a thickness and an insulating portion for mutually insulating them (which will be hereinafter referred to as an "an uneven distribution type anisotropically conductive sheet") . Furthermore, Patent Document 4 and the like have disclosed the uneven distribution type anisotropically conductive sheet in which a step is formed between a surface of a conducting portion and an insulating portion.
The sheet-like probe 90 has a flexible insulating sheet 91 formed of a resin, for example, and has such a structure that a plurality of electrode structures 95 extended in a direction of a thickness is disposed on the insulating sheet 91 in accordance with a pattern corresponding to a pattern of electrodes to be inspected in a circuit device to be inspected.
Each of the electrode structures 95 has such a structure that a projected surface electrode portion 96 exposed from a surface of the insulating sheet 91 and a plate-shaped back electrode portion 97 exposed from a back of the insulating sheet 91 are integrally coupled through a short circuit portion 98 extended to penetrate through the insulating sheet 91 in a direction of a thickness thereof.
Such a sheet-like probe 90 is generally manufactured in the following manner.
First of all, a laminate material 90A obtained by forming a metal layer 92 over a surface of the insulating sheet 91 is prepared as shown in FIG. 40(a) and a through hole 98H penetrating in a direction of a thickness is formed on the insulating sheet 91 as shown in FIG. 40(b).
As shown in FIG. 40(c), subsequently, a resist film 93 is formed on the metal layer 92 of the insulating sheet 91, and furthermore, an electrolytic plating treatment is carried out by setting the metal layer 92 to be a common electrode. Consequently, the through hole 98H of the insulating sheet 91 is filled with a metal deposit so that the short circuit portion 98 coupled integrally with the metal layer 92 is formed, and furthermore, a projected surface electrode portion 96 coupled integrally with the short circuit portion 98 is formed on a surface of the insulating sheet 91.
Then, the resist film 93 is removed from the metal layer 92, and furthermore, as shown in FIG. 40(d), a resist film 94A is formed on the surface of the insulating sheet 91 including the surface electrode portion 96 and a resist film 94B is formed on the metal layer 92 in accordance with a pattern corresponding to a pattern of a back electrode portion to be formed, thereby carrying out an etching treatment over the metal layer 92. As shown in FIG. 40(e), consequently, an exposed portion in the metal layer 92 is removed so that the back electrode portion 97 is formed. Thus, the electrode structure 95 is formed.
Thereafter, the resist film 94A formed on the insulating sheet 91 and the surface electrode portion 96 is removed, and furthermore, the resist film 93 formed on the back electrode portion 97 is removed. Consequently, the sheet-like probe 90 is obtained.
In the probe for an inspection, the surface electrode portion 96 of the electrode structure 95 in the sheet-like probe 90 is provided so as to be positioned on an electrode to be inspected in the wafer over a surface of the wafer, for example, in the circuit device to be inspected.
In this state, the wafer is pressed by the probe for an inspection. Consequently, the anisotropically conductive sheet 80 is pressed by the back electrode portion 97 of the electrode structure 95 in the sheet-like probe 90.
Consequently, a conducting path is formed in a direction of a thickness between the back electrode portion 97 and the inspection electrode 86 of the circuit board 85 for an inspection over the anisotropically conductive sheet 80. As a result, an electrical connection between the electrode to be inspected in the wafer and the inspection electrode 86 of the circuit board 85 for an inspection can be achieved.
Then, a predetermined electrical inspection is executed for the wafer in this state.
According to such a probe for an inspection, the anisotropically conductive sheet 80 is deformed according to the degree of the warpage of the wafer when the wafer is pressed by the probe for an inspection. Therefore, it is possible to reliably achieve an excellent electrical connection for each of a large number of electrodes to be inspected in the wafer.
However, the probe for an inspection has the following problems.
In a process for forming the short circuit portion 98 and the surface electrode portion 96 in the method of manufacturing the sheet-like probe 90 described above, a plated layer formed by the electrolytic plating grows isotropically. As shown in FIG. 41, therefore, a distance W from a peripheral edge of the surface electrode portion 96 to that of the short circuit portion 98 is equivalent to a projection height h of the surface electrode portion 96 in the surface electrode portion 96 which is obtained.
Accordingly, a diameter R of the surface electrode portion 96 which is obtained exceeds a double of the projection height h and is considerably great.
For this reason, in the case in which the electrode to be inspected in the circuit device to be inspected is minute and is disposed at a very small pitch, a distance between the adjacent electrode structures 95 cannot be maintained sufficiently. As a result, in the sheet-like probe 90 which is obtained, the flexibility of the insulating sheet 91 is lost. For this reason, it is hard to achieve a stable electrical connection to the circuit device to be inspected.
In the electrolytic plating treatment, moreover, it is actually difficult to supply a current having an even current density distribution to the whole surface of the metal layer 92. Due to the uneven current density distribution, a growth speed of a plated layer is varied for each through hole 98H of the insulating sheet 91. Therefore, a great variation is generated in the projection height h of the surface electrode portion 96 which is formed and the distance W from the peripheral edge of the surface electrode portion 96 to that of the short circuit portion 98, that is, the diameter R.
In the case in which the projection height h of the surface electrode portion 96 has a great variation, it is hard to carry out a stable electrical connection to the circuit device to be inspected. On the other hand, in the case in which the diameter of the surface electrode portion 96 has a great variation, there is a possibility that the adjacent surface electrode portions 96 might be short-circuited.
In the foregoing, there is means for reducing the projection height h of the surface electrode portion 96. For the means to reduce the diameter of the surface electrode portion 96 which is thus obtained, there can be supposed means for reducing a diameter r of the short circuit portion 98 (which indicates the smallest length in the case in which a sectional shape is not circular), that is, a diameter of the through hole 98H of the insulating sheet 91. In a sheet-like probe obtained by the former means, however, it is hard to reliably achieve a stable electrical connection to the electrode to be inspected.
On the other hand, it is hard to carry out the formation itself of the short circuit portion 98 and the surface electrode portion 96 through the electrolytic plating treatment by the latter means.
In order to solve such problems, there have been proposed sheet-like probes obtained by disposing a large number of electrode structures having a tapered surface electrode portion which has a smaller diameter from a base end toward a tip respectively in Patent Document 5 and Patent Document 6.
The sheet-like probe described in the Patent Document 5 is manufactured in the following manner.
As shown in FIG. 42(a), there is prepared a laminate material 90B obtained by forming a resist film 93A and a surface side metal layer 92A on a surface of an insulating sheet 91 in this order and laminating a back side metal layer 92B on a back face of the insulating sheet 91.
As shown in FIG. 42(b), then, there is formed a through hole communicating with each of the back side metal layer 92B, the insulating sheet 91 and the resist film 93A in the laminate material 90B and extended in a direction of a thickness.
Consequently, a concave portion 90K for forming an electrode structure which has a tapered configuration adapted to a short circuit portion and a surface electrode portion in an electrode structure to be formed is provided on a back face of the laminate material 90B.
As shown in FIG. 42(c), subsequently, a plating treatment is carried out by setting the surface side metal layer 92A in the laminate material 90B to be an electrode so that the concave portion 90K for forming an electrode structure is thus filled with a metal to form a surface electrode portion 96 and a short circuit portion 98.
Then, the back side metal layer 92B in the laminate material is subjected to an etching treatment and is thus removed partially. Consequently, a back electrode portion 97 is formed as shown in FIG. 42(d). Thus, the sheet-like probe 90 is obtained.
Moreover, the sheet-like probe described in the Patent Document 6 is manufactured in the following manner.
As shown in FIG. 43(a), there is prepared a laminate material 90C obtained by forming a surface side metal layer 92A on a surface of an insulating sheet material 91A having a greater thickness than an insulating sheet in a sheet-like probe to be formed and laminating a back side metal layer 92B on a back face of the insulating sheet material 91A.
As shown in FIG. 43(b), then, there is formed a through hole communicating with each of the back side metal layer 92B and the insulating sheet material 91A in the laminate material 90C and extended in a direction of a thickness. Consequently, a concave portion 90K for forming an electrode structure which has a tapered configuration adapted to a short circuit portion and a surface electrode portion in an electrode structure to be formed is provided on a back face of the laminate material 90C.
By carrying out a plating treatment with the surface side metal layer 92A in the laminate material 90C set to be an electrode, subsequently, the concave portion 90K for forming an electrode structure is thus filled with a metal to form a surface electrode portion 96 and a short circuit portion 98 as shown in FIG. 43(c).
Subsequently, the surface side metal layer 92A in the laminate material 90C is removed, and furthermore, the insulating sheet material 91A is subjected to an etching treatment, thereby removing a surface side portion of the insulating sheet. As shown in FIG. 43(d), thus, the insulating sheet material 91 having a predetermined thickness is formed and the surface electrode portion 96 is exposed.
Then, the back side metal layer 92B is subjected to the etching treatment so that the back electrode portion 97 is formed. Thus, the sheet-like probe 90 is obtained as shown in FIG. 43(e).
According to such a sheet-like probe 90, the surface electrode portion 96 is tapered. Therefore, the surface electrode portion 96 having a small diameter and a great projection height can be formed in a state in which a distance from the surface electrode portion 96 of an adjacent electrode structure is maintained sufficiently. Furthermore, each of the surface electrode portions 96 of the electrode structure 95 is formed by setting, as a cavity, the concave portion 90K for forming an electrode structure which is provided on the laminate material. Consequently, it is possible to obtain the electrode structure 95 having a small variation in the projection height of the surface electrode portion 96.
In these sheet-like probes, however, the diameter of the surface electrode portion in the electrode structure is equal to or smaller than the diameter of the short circuit portion, that is, the diameter of the through hole formed on the insulating sheet. Therefore, the electrode structure slips from the back face of the insulating sheet. Consequently, it is hard to actually use the sheet-like probe.
In order to solve the problem, for example, there has been proposed a sheet-like probe which has a holding portion on the surface electrode portion side in the electrode structure which has a small diameter and a tapered configuration described in the Patent Document 7 and prevents the electrode structure from slipping from the back face of the insulating sheet.
The sheet-like probe described in the Patent Document 7 is manufactured in the following manner.
As shown in FIG. 44(a), there is prepared a laminate material 132 including five layers formed by a surface side metal layer 122, an insulating sheet 124, a first back side metal layer 126, an insulating layer 128 and a second back side metal layer 130.
As shown in FIG. 44(b), an opening portion 134 is provided on the second back side metal layer 130 in the laminate material 132 and the insulating layer 128 is subjected to etching through the opening portion 134 so that a through hole 136 is provided on the insulating layer 128.
Next, the etching is carried out over the first back side metal layer 126 exposed from the bottom portion of the through hole of the insulating layer 128, thereby exposing the insulating sheet 124 from the bottom portion of the through hole 136.
Then, the insulating sheet 124 is subjected to the etching via the through hole 136 of the first back side metal layer 126, thereby exposing the surface side metal layer 122 from the bottom portion of the through hole 136.
Thus, the metal layer and the resin layer (the insulating layer 128 and the insulating sheet 124) are mutually subjected to the etching, thereby forming a through hole 138 communicating with each of the second back side metal layer 130, the insulating layer 128, the first back side metal layer 126 and the insulating sheet 124 and extended in a direction of a thickness. Thus, a concave portion 90K for forming an electrode structure having a tapered configuration adapted to a short circuit portion and a surface electrode portion of an electrode structure to be formed is provided on the back face of the laminate material 132.
Subsequently, a plating treatment is carried out by setting the surface side metal layer 122 in the laminate material 132 as an electrode. As shown in FIG. 44(c), consequently, the concave portion 90K for forming an electrode structure is filled with a metal to form the surface electrode portion 96 and the short circuit portion 98.
Then, the surface side metal layer 122 in the laminate material 132 is removed, and the insulating sheet 124 is subjected to the etching treatment and is thus removed to expose the first back side metal layer 126 (FIG. 44(d)).
Thereafter, the first back side metal layer 126 is subjected to the etching treatment to form a holding portion, and the first back side metal layer 126 is subjected to the etching treatment and is thus removed partially, thereby forming the back electrode portion 97 and a support portion. As shown in FIG. 44(e), thus, the sheet-like probe 90 is obtained.
In the sheet-like probe obtained by such a manufacturing method, furthermore, the back face of the laminate material 90C is provided with the concave portion 90K for forming an electrode structure which has a tapered configuration adapted to the short circuit portion and the surface electrode portion in the electrode structure to be formed. Therefore, a tip diameter 92T of the concave portion for forming an electrode structure is smaller than a diameter of an opening portion 92H formed on the back face of the laminate material 90C.
In this fabrication process of the sheet-like probe described in the Patent Document 7, a through hole for forming the electrode structure is formed in a insulating layer made of polyimide or the like. As shown in FIG. 45, the through hole can be obtained by forming the pattern of a photoresist film 140 including an opening 140a in the section in which the through hole will be formed on one face of the second back side metal layer 130 and by immersing the whole sheet in an etchant and carrying out an etching, thereby forming the through hole in the insulating layer 128 and the insulating sheet 124 made of polyimide.
In this method, a through hole 142a is formed in such a manner that a surface side metal layer 122 that has been laminated on the insulating sheet 124 is exposed at the bottom of the through hole 81a, and the electrode structure is formed through the process in which an electrolytic plating is carried out using the surface side metal layer 122 as a common electrode.
However, in the case in which a through hole is formed by carrying out an etching to the insulating layer 128 and the insulating sheet 124 made of polyimide, as shown in FIG. 45, the through hole 142a is tapered, and the diameter of the through hole becomes smaller as the through hole is deeper. Accordingly, in the case in which a polyimide film with a large film thickness is used, a through hole is closed before the through hole reaches to the surface side metal layer 122, thereby preventing the through hole 142a from being formed.
More specifically, in the case in which a through hole for forming the electrode structure is tried to be formed in a insulating layer made of polyimide by etching processing as a conventional method, there is a problem of that the through hole 142a that reaches to the surface side metal layer 122 cannot be formed in the case in which an film thickness t1 of the insulating sheet 124 and an film thickness t2 of the insulating layer 128 of which the surface is covered by a photoresist film 140 is thicker.
An etching treatment angle θ in an etching treatment, which differs in processing conditions, is said to be in the range of 45° to 55° in general.
Consequently, the through hole 142a cannot be reliably formed in the insulating layer if the sum of the film thickness t1 and the film thickness t2 of the insulating sheet 124 and the insulating layer 128 is more than half of a diameter φ1 of an opening.
Therefore, to reliably form the through hole 142a, it is necessary to decrease an film thickness t1 of the insulating sheet 124 or an film thickness t2 of the insulating layer 128. Accordingly, there is a case in which it is difficult to form the surface electrode portion having a large projection height. In the case in which a thickness of the electrode structure of the sheet-like probe is decreased and, for instance, the periphery of an electrode to be inspected in a circuit device to be inspected is covered by an insulating layer having a large thickness, it may be difficult to connect the electrode structure and the electrode to be inspected.
In this manufacturing method, a thickness of the electrode structure is almost equivalent to the sum of a thickness of the insulating sheet 124 and a thickness of the insulating layer 128, and a thickness of the short circuit portion is equivalent to a thickness of the insulating layer 128. Consequently, to increase a thickness of the electrode structure, it is necessary to increase a thickness of the insulating layer.
The sheet-like probe with an insulating layer having a large thickness has an effect of a high durability in repeated use. However, for such a sheet-like probe, a deformation amount of the insulating layer in a direction of a thickness is decreased, thereby decreasing a moving amount of the electrode structure in a direction of a thickness.
In particular, to suppress a positional shift of the electrode structure in a planar direction thereof, the sheet-like probe having a shape supporting the insulating film by a metal support material tends to further decrease a moving amount of the electrode structure in a direction of a thickness.
A decrease in a moving amount of the electrode structure in a direction of a thickness for the sheet-like probe causes a concave and convex absorbing ability of a probe card using the sheet-like probe to be reduced.
More specifically, for a probe card, the sum of a concave and convex absorbing ability of an anisotropically conductive connector and a concave and convex absorbing ability of the sheet-like probe becomes a concave and convex absorbing ability of the probe card. Consequently, a decrease in a concave and convex absorbing ability of the sheet-like probe causes a concave and convex absorbing ability of the probe card to be reduced.
In the case in which an electrode to be inspected in a circuit device has a variation in height for the probe card having a reduced concave and convex absorbing ability, a large pressure is required to achieve an electrical connection of the probe card to each electrode to be inspected. Accordingly, since there is increased a compressive deformation amount of a conductive portion in an anisotropically conductive connector, a permanent deformation of a conductive portion in an anisotropically conductive connector occurs early and an electrical connection is made difficult, thereby requiring an exchange of the anisotropically conductive connector and increasing an inspection cost.
In addition, in the case in which an electrode to be inspected in a circuit device is a solder bump electrode having a large variation in height, it may be impossible to achieve an electrical connection of the probe card to each electrode to be inspected.
Therefore, it is desired to increase a moving amount of the electrode structure in a direction of a thickness for the sheet-like probe to obtain a probe card having a large concave and convex absorbing ability.
As a means of increasing a concave and convex absorbing ability, a sheet-like connector as shown in the Patent Document 8 is known for instance.
Such a sheet-like connector is an anisotropically conductive connector composed of a complex conductive sheet in which a tapered movable conductor adapted to a tapered through hole formed in an insulating sheet is formed movably in a direction of a thickness of an insulating sheet and two anisotropically conductive elastomer sheets disposed on one and another faces of the complex conductive sheet.
For such an anisotropically conductive connector having a complex conductive sheet, a movable electrode in the complex conductive sheet can be moved in a direction of a thickness. Therefore, in the case in which the movable electrode is pressurized in a direction of a thickness, the two anisotropically conductive elastomer sheets disposed on one and another faces of the complex conductive sheet are compressed and deformed linking to each other. As a result, the total concave and convex absorbing ability of the two anisotropically conductive elastomer sheets appears as a concave and convex absorbing ability of the anisotropically conductive connector, thereby obtaining a high concave and convex absorbing ability.
Moreover, a thickness required for obtaining the desired concave and convex absorbing ability can be ensured by the total thickness of the two anisotropically conductive elastomer sheets, and an individual anisotropically conductive elastomer sheet having a small thickness can be used, thereby obtaining a high resolution.
However, the above described anisotropically conductive connector has a following problem in practice.
For the above described anisotropically conductive connector, a movable conductor in the complex conductive sheet is supported by both the insulating sheet and the anisotropically conductive elastomer sheet. In the case in which the complex conductive sheet and the anisotropically conductive elastomer sheet are separated from each other, the movable conductor may slip from the insulating sheet. Consequently, it is extremely hard to actually use the complex conductive sheet individually.
Accordingly, in the case in which a failure occurs in either of the complex conductive sheet and the anisotropically conductive elastomer sheet in the anisotropically conductive connector, either of the complex conductive sheet and the anisotropically conductive elastomer sheet cannot be exchanged to new one but the whole anisotropically conductive connector must be exchanged to new one.
Moreover, to form the movable conductor and its projecting portion in the above described sheet-like connector, a laser processing is carried out from the side of the insulating sheet to a laminate material in which an insulating sheet material and an auxiliary layer for forming a projecting portion are laminated, and a tapered through hole is formed.
Therefore, as described in a formation of the concave portion 90K for forming an electrode structure shown in the Patent Document 7, the sheet-like connector has problems of a miniaturization in a diameter of a tip portion of the movable conductor in the case in which a processing is carried out to a laminate sheet having a large thickness and of ensuring an insulating property between adjacent movable conductors in the case in which an electrode pitch of a wafer to be inspected described later is decreased. As a result, there are problems in the case in which a sheet-like connector is used as a sheet-like probe for inspecting a wafer.
As an electrode pitch of a wafer to be an object to be inspected becomes shorter, a disposition pitch of an electrode structure of the sheet-like probe becomes shorter. Although a disposition pitch of the electrode structure is generally in the range of 100 to 120 μm at present, it is thought that the disposition pitch must be for instance less than 100 μm in the future and 80 μm or less in the further future.
On the other hand, to ensure an insulating property between adjacent electrode structures, a width of an insulating portion between the electrode structures must be for instance in the range of 40 to 50 μm (a difference between a disposition pitch of an electrode structure and a diameter φ1 of an opening).
In the case in which a thick polyimide film is used to ensure the strength of the polyimide film, a diameter φ1 of an opening must be larger to form a through hole by etching as described above. However, in the case in which a diameter φ1 of an opening is made larger while a disposition pitch of an electrode structure is kept constant, an insulating property between adjacent electrode structures cannot be ensured.
Accordingly, in the case in which a disposition pitch of an electrode structure is made smaller, a thickness of a polyimide film is restricted. For instance, in the case in which a disposition pitch of an electrode structure is 120 μm and a diameter φ1 of an opening of a through hole is 70 μm, a thickness t of a polyimide film to be used must be 35 μm or less. In addition, in the case in which a diameter φ2 of an opening at a bottom side is made a certain level or more, the thickness t must be further less.
If the insulating layer 128 with a thickness of 50 μm is tried to be used to make the strength of the insulating layer 128 higher, a diameter φ1 of an opening of a through hole must be 100 μm or larger, thereby preventing an insulating property between adjacent insulating layers of electrode structures to be manufactured from being ensured. Consequently, it is impossible to make a diameter of an opening larger corresponding to a thickness of the insulating layer 128.
In the case in which an electrode structure is formed in a tapered through hole 142a as shown in FIG. 45, since a diameter φ2 of an opening at an end side in an etching direction is smaller, an electric resistance value increases. Accordingly, it is preferable that a diameter φ2 of an opening at the small diameter section is as large as possible.
Moreover, in the case in which the diameter φ2 of an opening is small, the small diameter section affects the electric resistance value. As a result, there is a problem that a variation of electric resistance values between electrode structures formed in the sheet-like probe may become larger.
Patent Document 1: Japanese Laid-Open Patent Publication No. 1995-231019
Patent Document 2: Japanese Laid-Open Patent Publication No. 1976-93393
Patent Document 3: Japanese Laid-Open Patent Publication No. 1978-147772
Patent Document 4: Japanese Laid-Open Patent Publication No. 1986-250906
Patent Document 5: Japanese Laid-Open Patent Publication No. 1999-326378
Patent Document 6: Japanese Laid-Open Patent Publication No. 2002-196018
Patent Document 7: Japanese Laid-Open Patent Publication No. 2004-172589
Patent Document 8: Japanese Laid-Open Patent Publication No. 2001-351702

Sheet-like probe, method of producing the probe, and application of the probe


A semiconductor laser device according to the present invention has a semiconductor substrate, an active layer formed on the semiconductor substrate and made of a compound semiconductor containing phosphorus, a guide layer formed on the active layer and made of a compound semiconductor a dopant diffusion preventing layer formed on the guide layer and made of a semiconductor compound containing arsenic, and a clad layer formed on the dopant diffusion preventing layer and made of a compound semiconductor containing a dopant.

The present invention relates to a semiconductor laser device and to a method for fabricating the same. More particularly, it relates to an increase in the output of the semiconductor laser device.
Recent years have seen rapid widespread use of DVD (Digital Versatile Disk) devices in the fields of AV (Audio-Video) equipment, PCs (Personal Computers), and the like. In particular, great expectations have been placed on the use of recordable DVD devices (such as DVD-RAM and DVD-R) as large-capacity memory devices embedded in PCs and the like and as post-VTR (Video Tape Recorder) devices.
As pickup light sources for the foregoing DVD devices, red semiconductor lasers at wavelengths in the 650 nm band have been used. With the recent increases in the density and capacity of an optical disk, a pick-up light source capable of performing a particularly high output operation over 80 mW has been in growing demand to allow a higher-speed write operation with respect to the optical disk.
If a semiconductor laser device is increased in output, however, the problem is encountered that the output thereof is saturated. The problem is conspicuous when the semiconductor laser device is operating at a high temperature. This is because an AlGaInP-based material composing the p-type clad layer of the red laser has a limitation in that it cannot provide a sufficiently large band barrier against electrons in the conduction band. Under high-temperature and high-output operating conditions, therefore, overflowing electrons are increased and a component of an injected current which does not contribute to light emission is increased.
In suppressing the overflow of electrons, it is effective to increase the concentration of a p-type impurity in the p-type clad layer and enlarge the band barrier against the electrons. i.e. accomplish high-concentration doping of the p-type clad layer with a p-type impurity.
However, the influence of solid-phase diffusion cannot be ignored in the AlGaInP-based material because of the diffusion coefficient of the p-type impurity which is generally high therein. It has been reported that the diffusion coefficient of Zn, e.g., in an AlGaInP-based material is 1×10−13 to 6×10−13 cm2s−1, which is about two orders of magnitude higher than that of Zn in an AlGaAs material used for the infrared laser. The influence of solid-phase diffusion becomes more conspicuous in the case of high-concentration doping since the diffusion coefficient of the impurity is directly proportional to the square of a doping concentration.
FIG. 3 shows a SIMS profile of an active layer and a clad layer in a conventional semiconductor laser device. As shown in FIG. 3, Zn has been mixed in the active layer though it has not been doped with an impurity intentionally. This results from the diffusion of an impurity used to dope the p-type clad layer in the active layer during the processes of crystal growth, thermal treatment, and the like for fabricating the semiconductor laser device. Similar impurity diffusion also occurs during the operation of the semiconductor laser device. If the impurity is diffused in the active layer, a nonradiative recombination center may be formed to degrade the characteristics of the semiconductor laser device. The production of a crystal defect reduces the lifespan of the semiconductor laser.
Due to the impurity diffusion in the active layer described above, the doping of the p-type clad layer with the p-type impurity at a high concentration has been difficult.
As a method for suppressing impurity diffusion in the active layer, therefore, Japanese Unexamined Patent Publication No. 2000-286507 discloses one which provides an undoped spacer layer between the p-type clad layer and an optical guide layer such that an impurity is absorbed in the spacer layer. If the doping concentration of the p-type clad layer of an AlGaInP-based semiconductor laser device is to be increased by using the method, the spacer layer for suppressing impurity diffusion should have a sufficiently large thickness. As the thickness of the spacer layer is increased, however, a series resistance is increased so that an operating current is increased disadvantageously or it becomes difficult to obtain a desired beam configuration under the influence of the spacer layer.

Semiconductor laser device and method for fabricating the same

Matsushita Electric Industrial Co., Ltd.


The invention relates to a method of reducing polarization dependence in planar optical waveguides using index and coefficient of thermal expansion (CTE) matched material between the optical waveguide core and the cladding layer. For coupled mode devices such as the directional coupler or mode conversion horn polarization sensitivity has been linked to birefringence in the cladding, since their operation is dependent on co-propagation of fundamental and higher order mode(s), which are not as strongly confined to the waveguide core. Polarization sensitivity can be reduced by reducing the CTE mismatch between the core and cladding, or by moving the birefringence away from the core/cladding boundary, or both. To accomplish this, silica material, or similar material for refractive index (RI) and CTE matching is applied between the core and cladding to waveguide features where significant transmission occurs in the cladding.

Planar lightwave circuits (PLC) are optical devices including planar optical waveguides formed on a silicon wafer substrate, wherein the waveguides are made from transmissive media which have a higher refractive index than the outlying cladding layers in order to guide light along the optical path. PLCs are designed to integrate multiple components and functionalities into a single optical chip, primarily for the telecommunications industry.
In designing any optical device for fabrication on a PLC, the design and fabrication of the optical waveguides is very important. The dimensions of the waveguides, and the separation of one waveguide from another, influence the stress on the waveguide, and hence the birefringence exhibited by the waveguide. The waveguide birefringence may give rise to undesirable polarization dependence properties such as polarization dependent loss (PDL) and polarization dependent wavelength of the optical device. For most component manufacturers and their customers it is important for the waveguide birefringence (B) through the device to be as low as possible, ideally zero, where B is commonly defined as the difference between the effective refractive indices experienced by TM and TE polarized light.
Polarization dependence of waveguide devices originates from stress induced birefringence in the waveguide layers which perturbs the desired index profile of the waveguide and leads to a difference in the effective modal index for the two polarizations.
Stress birefringence can lead to a difference in the effective index of the waveguide modes for the two polarizations, which is particularly detrimental in phase sensitive devices such as an arrayed waveguide grating (AWG) or a Mach-Zehnder Interferometer (MZI). For example, in an AWG, birefringence in the waveguides of the phase array leads to a splitting in the transmission spectrum of the device for the two polarizations, termed polarization dependent wavelength (PDW), resulting in an unacceptable polarization dependent loss if the PDW is large.
Polarization dependence in these devices is generally believed to be the result of differences of the thermal expansion properties between layers in the device structures causing stresses during the manufacturing process. Asymmetric stress in the waveguide cores results in birefringence.
U.S. Pat. No. 6,826,345 to Fan Zhong et al. issued Nov. 30, 2004 discloses a solution for birefringence in phase sensitive devices comprising a top cap layer of selected thickness on the top surface of the waveguide to reduce stress differences in the waveguide core. The method is said to reduce or substantially eliminate birefringence in an AWG device. For these devices, the polarization dependence is perturbed mainly by changes in the stress induced birefringence close to the center of the waveguide mode. The top cap does not cover the sidewalls of the waveguide core. Birefringence in the cladding layer is not considered.
Polarization dependence (such as PDL) is also of importance in devices that are not phase sensitive such as directional couplers, splitters and parabolic horns. For these devices, several factors can influence the polarization dependence of the design. However, it has been found that the stress, and hence birefringence, in the cladding is the more dominant factor in limiting the polarization sensitivity of the device than the waveguide core birefringence. This is particularly true for coupled mode devices such as the directional coupler or mode conversion horn. In both these examples, operation of the device is essentially dependent on co-propagation of fundamental and higher order mode(s), which are not as strongly confined to the waveguide core.
It is known in the prior art to dope the cladding to match its CTE to that of the substrate for the purposes of reducing waveguide birefringence (A. Kilian, J. Kirchhof, B. Kuhlow, G. Przyrembel and W. Wischmann 'Birefringence free planar optical waveguide made by FHD through tailoring of the overcladding' Journal of Lightwave Technology) but heavy doping affects the environmental stability of the device and the cladding to core stress is still present.
A further problem affecting the performance of planar waveguides is that during formation of the cladding and waveguiding layers gas pockets can be trapped under subsequent consolidated layers. Gas also becomes trapped between closely spaced waveguides such as directional couplers, Y splitters and similar structures. Such gas pockets disrupt the optical properties of the PLC layers. In an application by Kymata Limited, publication number GB 2,355,078 A, published Apr. 11, 2001, this problem is addressed by providing a composite cladding layer including a cladding interface between the waveguide core and an outer cladding portion. The cladding interface portion has a lower consolidation temperature than the outer cladding portion. Both cladding layers are consolidated together. Dopant ions are used to lower the softening temperature and maintain the refractive index. Doping is also suggested to match the thermal coefficient to that of the buffer layer. Birefringence in the cladding layer is not recognized as a source of PDL, however, and because the CTE is not matched between the core and cladding interface, the cladding interface does not separate the refractive index from the birefringence.
Accordingly, a method for reducing PDL in planar waveguide structures remains highly desirable.

Reduction of polarization dependence in planar optical waveguides


A device for the illumination of a display, in particular of a transmission display of a motor vehicle, comprises an areal lighting means for an at least substantially uniform illumination of the total display in combination with at least one light emitting diode for an illumination of a respective individual display, in particular of a transmission position display offset in comparison with the uniform illustration of the total display, in particular a more intensive illustration of a respective individual display, in particular of a transmission position display.

A problem of such illumination devices is a uniform illumination of the total display with a simultaneously offset illumination of a respective display position or single display such as in particular a transmission display, in particular a brighter illumination of a respective display position or single display such as in particular a transmission display.


A system and method include an object supported on a moveable support, an optical system that transmits radiation onto the object, a support having an aperture therethrough, a sensor system coupled to the support, and a control system coupled to the sensor system and the moveable support. The sensor system is arranged with respect to the aperture to measure a surface of the object and send measurement signals to the control system, such that the control system generates control signals received and used by the moveable support to ensure that the surface of the object receiving light transmitted by the optical system through the aperture is in a focus plane of the optical system.

1. Field
The present invention relates to a lithographic apparatus and a method for manufacturing a device.
2. Related Art
A lithographic apparatus is a machine that applies a desired pattern onto a substrate or part of a substrate. A lithographic apparatus can be used, for example, in the manufacture of flat panel displays (FPDs), integrated circuits (ICs) and other devices involving fine structures. In a conventional apparatus, a patterning device, referred to as a mask or a reticle, can be used to generate a circuit pattern corresponding to an individual layer of a complete multilayer device. This pattern can be transferred onto a substrate by imaging onto a layer of radiation-sensitive material (resist) provided on the substrate.
Instead of a circuit pattern, the patterning means can be used to generate other patterns, for example a color filter pattern or a matrix of dots. Instead of a mask, the patterning device can comprise a patterning array that comprises an array of individually controllable elements. The pattern can be changed more quickly and for less cost in such a system compared to a mask-based system.
A typical substrate can be round a round silicon wafer or a rectangular glass plate. Typically lithographic imaging systems have insufficient field to expose the full area of a substrate. To overcome this limitation the substrate can be scanned underneath image field, while the mask or reticle is synchronously scanned through the illumination beam. In this way, the pattern is transferred to a larger area of the substrate. If the scanned exposure region covers the full width and length of the substrate then exposure can be completed with a single scan. Otherwise, the substrate is stepped either laterally or in the scan direction, and the exposure process repeated until the entire substrate is exposed.
Alternatively the moving reticle or mask can be replaced by a stationary mirror array where the pattern is electronically generated by moving the mirrors as the resist coated substrate is scanned.
In order to properly pattern the substrate, the resist needs to be in a focal plane of a projection system. This is typically achieved through use of combination of a complex multi-axis metrology measurement system that controls the motion of the substrate stage often in 6 degrees of freedom, and separate sensors that measure the location of the substrate surface. The metrology components used to measure substrate position in the direction orthogonal to the substrate plane are expensive, and may occupy volume, which conflicts with space needed for other tool components.
Therefore, what is needed is a system and method that accurately measure a surface of an object, while reducing a number and/or complexity of devices in the system.

Lithographic apparatus and device manufacturing method utilizing a metrology system with sensors


Described herein include systems, methods, and apparatuses for the remote medium access control (MAC) in communication networks, for example, in cable networks. In particular, the disclosure describes a network architecture including a switch configured to communicate with remote MAC layer devices over first connections (e.g., digital fiber connections); the remote MAC layer devices configured to communicate with remote physical (PHY) layer devices over second connections (e.g., second digital fiber connections); and the remote PHY layer device configured to communicate with customer premise equipment devices over a third connection (e.g., analog coaxial connections).

A variety of service providers, such as cable providers and satellite providers, may connect user devices to one or more networks, such as cable networks and/or the Internet. A provider may provide cable and/or Internet access to a residence via devices such as headend devices that includes a computer system and databases required for the provisioning of content. The headend may include cable modem termination system (CMTS), which can send and receives cable modem signals on a cable network, for example, to provide Internet services to cable subscribers.

Remote medium access control (MAC) based networks


The invention relates to the field of microalgae culture and specifically relates to a trap-type carbon supplement device and carbon supplement method for cultivating microalgae in an open pond. The trap-type carbon supplement device for cultivating microalgae in an open pond, comprises a trap-type container, a partition plate and a gas distributor, wherein the gas distributor is positioned at the culture solution inlet of the trap-type carbon supplement device; the thickness of the trap-type carbon supplement device on the side of the culture solution inlet is 0.5-2 times of the depth of the culture solution in the open pond; the gap between the lower end of the partition plate and the bottom of the trap-type container is 0.5-2 times of the thickness of the trap-type carbon supplement device on the side of the culture solution inlet; the upper end of the partition plate is higher than the wall of the trap-type container; and the width of the partition plate is matched with the trap-type container. The carbon supplement device of the invention can make the gas-liquid contact time longer and reduce the depth of the trap-type container, therefore it can reduce the flow resistance of the liquid in the carbon supplement device and save energy consumption.

Microalgae can produce a variety of chemical products by fixing carbon dioxide through photosynthesis. Some microalgae can produce aliphatic hydrocarbons, for example, the hydrocarbon production of botryococcus can reach 15%-75% of dry cell weight; some microalgae can accumulate glycogen; some microalgae can accumulate glycerol, wherein the lipid content of many microalgae can reach 60% or above of the dry cell weight. The average combustion heat of fuel oil obtained by pyrolysis of algae biomass can be up to 33 MJ/kg. Microalgae can be cultured in seawater, salty water or semi-salty water, avoiding scrambling for land and freshwater resources with crops, and can be cultured with waste water. So, microalgae could be an important source to obtain biological resources in regions lack of freshwater or with barren land. Therefore microalgae are expected to be important sources for future energy and chemical products.
The carbon in microalgae cells accounts for more than a half of the dry cell weight of the cells, and the algae cells can fix carbon dioxide as their own components through photosynthesis in growing process, so that the supply of carbon sources should be assured in the culture medium in the algae culture process. The inorganic carbon sources in the algae culture medium exist in three forms, namely HCO3−, CO32− and free CO2. The ratio of the three forms of carbon sources in water varies with the pH value of the culture medium. If NaHCO3 is used as the carbon source, with the dissociation of HCO3− and the utilization of CO2, the pH value of the culture medium rises continually, more than half of the added NaHCO3 is converted to Na2CO3 which could not be utilized by algae, resulting a waste and considerable consumption of carbon source; moreover, the medium is difficult to be recycled because of the rise of its pH value. If CO2 is used as the carbon source, which is directly utilized by the microalgae, then the problem that the pH value of the culture medium rises can be avoided, which is beneficial for maintaining an desirable culture environment and allows the medium to be used repeatedly or for an extended period.
Cultivation in an open pond is a traditional and simple mode of microalgae culture, and is also recognized as a mature microalgae culture technology currently. It has the advantages of having a simple construction and being easy to operate, and has been applied to commercial production of spirulina, chlorella and Dunaliella salina (Chaumont D., J. Appl. Phycol., 1993, 5:593-604; Richmond A., Progress in Physiological Research, Vol.7, Biopress, Bristol., 1990, 269-330; Borowitzka L. T., Bioresource Technology, 1991, 38: 251-252). However, the depth of the culture solution in a traditional open pond is usually kept at 20-30 cm, if the CO2 is directly aerated into the open pond in a bubbling way, due to the very short residence time of the bubbles in the culture solution, the absorption efficiency of the CO2 is very low- only 13%-20% of the CO2 is absorbed (Becker E W, Microalgae: biotechnology and microbiology, Cambridge University Press, Cambridge, 1994, pp 293).
Ferreira et al. (Ferreira B S, Fernandes H L, Reis A and Mateus M. Microporous hollow fibers for carbon dioxide absorption: mass transfer model fitting and the supplying of carbon dioxide to microalgae cultures. Journal of Chemical Technology and Biotechnology, 1998, 71: 61-70) utilized a hollow fiber membrane to enhance gas-liquid mass transfer, so as to improve the absorption efficiency of the CO2, but the method is high in cost, and the hollow fiber membrane is prone to be fouled.
As for the method of L I Yeguang, H U Hongjun, ZHANG Liangjun and CHEN Zhixiang (Study on CO2 supply technique for spirulina production, Journal of Wuhan Botanical Research, 1996, 14 (4): 349-356), a gas-cover in size of several square meters is arranged on the surface of microalgae culture solution, and carbon dioxide gas is introduced into the gas-cover, so that the carbon dioxide is transferred into the culture solution through the water surface shrouded by the cover. The problems with this method are as follows: the specific interfacial area for gas-liquid exchange is small; the mass transfer rate is lowered down due to accumulation of oxygen and nitrogen in the gas-cover, and the oxygen and nitrogen need to be ventilated frequently, so part of the carbon dioxide in the gas-cover is wasted; for a gas source containing low-content carbon dioxide, the absorption efficiency of the carbon dioxide is very low; when the pressure in the gas-cover is slightly higher, the gas may leak out from the edge of the gas-cover through the liquid surface outside the gas-cover. Groove type carbon supplement method (CN200610018771.9, Device for Supplementing Carbon Dioxide into Microalgae Cultivation Pond) is as follows: a deep groove is dug and located beside a culture pond to enable the culture solution to flow through the deep groove, a gas sparger is arranged at the bottom of the groove, through which the carbon dioxide is supplied into the culture solution. The method may disrupt the spatial layout of the traditional open pond; and furthermore, the culture solution in the groove is not mixed well, the bottom of the groove becomes a dead zone for mass transfer after being saturated with carbon dioxide after a period of sparging, and then the deep groove does not function as a mass exchanger.
CONG Wei et al. (CN200510126465.2, Carbon Supply Device for Large-scale Culture of Microalgae and its Application and Use) develop a trap type carbon supplement device comprising a trap-type container; a partition plate and a gas distributor as shown in FIG. 1 for directly supplementing CO2 into the culture solution in an open pond, wherein the culture solution can form a circulation in the trap type carbon supplement device, thereby the time for gas-liquid contact is greatly prolonged; moreover, gas is supplied from the bottom of the trap type carbon supplement device; so that the absorption efficiency of CO2 is greatly improved. However, the carbon supplement device increases the flow resistance in the open pond, thereby resulting in increased electrical energy consumption for driving the fluid with a paddle wheel under the same flow velocity, and relatively more construction workload. According to the carbon supplement device disclosed in Patent Application No. CN200510126465.2, a gas distributor is positioned at the bottom of the trap-type carbon supplement device, as shown in FIG. 1, no matter whether the partition plate is mounted on the left side(upstream side), in the middle or on the right side(downstream side) in the trap-type container, only a part of the volume of the carbon supplement device (the upstream side or the downstream side of the partition plate) functions as a gas-liquid exchanger, so the utilization of the volume of the carbon supplement device is not high. If the regions on both sides of the partition plate in the carbon supplement device can become gas-liquid exchange regions, then the depth of the trap-type container of the carbon supplement device can be reduced to about one half of its present depth without loss of absorption efficiency of carbon dioxide, so that the flow resistance of the fluid in the trap-type carbon supplement device is reduced and thus energy consumption is saved.

Trap-type carbon replenishing device for culturing microalgae of opened pool and carbon replenishing method thereof

Institute of Process Engineering, Chinese Academy of Sciences


A pressure vessel, or pressurizable canister is described herein. The canister has a hollow, thin-walled, cylindrical, metal shell. The preferred metal is aluminum, because light weight is a consideration for the vessel. Two end caps are mechanically sealed to the respective distal ends of the metal shell tube by the process of electromagnetic pulse forming. The two end caps are made of a high strength, ductile thermoplastic. The preferred plastic is DELRIN.RTM., which is fabricated from an acetal resin. The plastic end caps are injection molded, and can include reinforcing threads. The end caps are each cylindrically shaped, and have at least one circumferential recess to accommodate the metal of the shell tube as it deforms about the end caps. The tube shrinks into the recess of the end caps, and forms a mechanical seal therewith. An O-ring seal is disposed within at least one circumferential recess of each end cap, to further the ability of the mechanical seal to hold a pressure of at least approximately 300 psi.

The art of fabricating containers and vessels has its roots in antiquity. In modern times, containers and vessels of all types, shapes, and sizes, are fabricated to meet the needs of a rapidly expanding world economy. The present invention is concerned with the manufacture of light weight canisters, capable of storing materials under a pressure of at least approximately 300 psi.
The typical method of fabricating pressure-type canisters is to weld a pair of distally placed closure elements, or end caps, to a metal shell body. Light weight, aluminum canister tube bodies, however, are not conducive to welding. Aluminum welding must be performed in an expensive, inert atmosphere of argon to prevent an oxide coat from forming and interfering with the weld process. More importantly, aluminum tends to anneal and weaken when subjected to welding temperatures, thus necessitating a thicker shell body. The thicker shell adds weight and cost to the finished product, and defeats the light weight objective. The thicker tube shell has the further disadvantage of reducing the amount of material that can be stored in the canister.
The current invention is for a light weight aluminum canister that forms a mechanical seal with its end caps by the method of electromagnetic forming. Electromagnetic forming is a well known process, wherein an electric coil is placed around a metal body, and is thereafter electrically pulsed to create a magnetic field that shapes the metal. In the present application, coils are placed about the distal ends of the shell tube. The coil is then electrified with a high energy voltage pulse of short duration, which magnetically forms and mechanically seals the shell body about the end caps. A typical electromagnetic forming process is described in U.S. Pat. No. 3,837,755, issued to BENOIT et al on Sep. 24, 1974, entitled "Multi-Piece Rod for Control and Structural Members"; and U.S. Pat. No. 4,523,872, issued to ARENA et al on Jun. 18, 1995, entitled "Torsion Resistant Grooved Joint".
The end caps used in the pressure canister of this invention can be formed from a variety of metallic or non-metallic materials. In the preferred embodiment of the inventive canister, the end cap material is a plastic material. A suitable plastic that has been chosen with the required attributes light weight, of strength and ductility is DELRIN.RTM.. DELRIN.RTM. is an injection moldable thermoplastic, fabricated from an acetal resin. It can be injection molded with reinforcing fibers to provide greater strength and ductility.


An oscillator unit is configured such that a frequency adjustment unit of a synthesizer used by a controller is smaller than a frequency variation tracking capability of a demodulator connected to an output side of a frequency converter. This structure successfully combines the temperature compensation control of an oscillator unit and the receiving process of a high-frequency receiving device. Accordingly, an oscillator unit with large temperature coefficient is applicable to high-frequency receiving devices.

FIG. 7 is a circuit diagram of a conventional reference oscillator. In reference oscillator 100 in FIG. 7, oscillator 101 is, for example, an AT-cut quartz crystal. Driver circuit 102 connected in parallel to oscillator 101 is configured, for example, with a CMOS inverter. Load capacitances 103 and 104 are connected to oscillator 101 and ground.
In general, the reference oscillator used for a reference frequency of communications devices, such as mobile phones, or high-frequency receiving devices, such as TV sets, require frequency stability against ambient conditions. In particular, frequency stability against temperature changes is one important performance. For example, TV sets require stability of at least ±60 ppm or less is required in a use temperature range. A structure of reference oscillator 100 is effective for achieving this performance, and crystal oscillator 101 is an essential device for equipment requiring highly accurate frequency stability.
However, crystal oscillator 101 has a structure of suspending an oscillating portion in midair while holding a part of crystal piece cut to a predetermined shape. Accordingly, downsizing is difficult. In addition, a device having the above structure needs to be manufactured one by one. This makes cost reduction difficult.
To redeem the disadvantage of reference oscillator 100 made of crystal, an oscillator using a silicon oscillator utilizing a semiconductor manufacturing process has been disclosed. A reference oscillator employing a silicon oscillator is configured in the same way as that in FIG. 7. However, since a temperature coefficient of silicon material is large, an oscillation frequency varies in line with a temperature change. Therefore, a temperature sensor is used for detecting a change in ambient temperature so as to apply temperature compensation control for retaining a constant frequency.
FIG. 8 is a block diagram of a conventional oscillator unit. In FIG. 8, conventional oscillator unit 201 includes reference oscillator 202 for generating a reference oscillation signal, synthesizer 204 for outputting a local oscillation signal based on the reference oscillation signal output from this reference oscillator 202, temperature sensor 205 for detecting temperature, and controller 206. Controller 206 adjusts a frequency of the local oscillation signal output from synthesizer 204 based on a detection result of temperature sensor 205. This controller 206 applies temperature compensation control for adjusting output frequency of synthesizer 204 based on a temperature detection result of reference oscillator 202 detected by temperature sensor 205. This prior art is disclosed, for example, in Patent Literature 1.
A temperature coefficient of silicon oscillator (not illustrated) in reference oscillator 202 is 30 ppm/° C., which is large. Therefore, a frequency adjustment level output from controller 206, corresponding to the detection result of temperature sensor 205, becomes large. As a result, a frequency variation in the local oscillation signal output from synthesizer 204 becomes large.
On the other hand, in a high-frequency receiving device, a frequency of high-frequency signal received is converted to an intermediate frequency signal, using the local oscillation signal obtained by converting a signal output from the oscillator. This is demodulated in a later process. Stable frequency without variation is thus demanded for this intermediate frequency signal. Accordingly, in case of using the oscillator in the high-frequency receiving device, a demodulator may not be able to demodulate if frequency greatly varies in the intermediate frequency signal as a result of temperature compensation control. Therefore, the oscillator unit using an oscillator with large temperature coefficient cannot be used in a field of high-frequency receiving devices, such as mobile phones and broadcast receiving tuners, even if a temperature compensation control circuit is added.
Patent Literature 1: U.S. Pat. No. 7,145,402

Oscillator, and receiving device and electronic device using the oscillator


The upper electrode 31 has a hole 35 extending from an upper surface 33 to a lower surface 34, a bolt 36 is inserted from the upper surface 33 of the upper electrode 31 into the hole 35, and secured in a lower electrode 32 by a screw. A gap 51 between an inside of the hole 35 and a straight body portion of the bolt 36 allows the upper electrode 31 to slide in all directions in a placement surface (upper surface of the lower electrode 32 in contact with the lower surface 34 of the upper electrode 31 in FIG. 2) that is a contact surface with an upper surface of the lower electrode 32, thereby providing an effect of preventing occurrence of a crack or a break in a U rod that can be expanded and contracted in all directions during a vapor phase growth process.

A Siemens method is known as a method for manufacturing polycrystalline silicon that is a raw material of monocrystalline silicon for manufacturing semiconductors or silicon for manufacturing solar cells. The Siemens method is a method of bringing a material gas containing chlorosilane into contact with a heated silicon core to grow polycrystalline silicon from vapor phase on a surface of the silicon core using a CVD (Chemical Vapor Deposition) method.
In growing polycrystalline silicon from vapor phase by the Siemens method, two vertical silicon cores and one horizontal silicon core are assembled into an inverted U-shape in a reactor of a vapor phase growth device, and opposite ends of the vertical silicon cores are secured to a pair of metal electrodes placed on a base plate via a pair of core holders.
Next, a current is applied from the metal electrodes to heat the silicon cores to a temperature range of 900° C. to 1200° C. in a hydrogen atmosphere, and a material gas, for example, a mixed gas of trichlorosilane and hydrogen is supplied from a gas nozzle into the reactor. Then, silicon is grown from vapor phase on the silicon core, and a polycrystalline silicon rod having a desired diameter is formed into an inverted U-shape. After the reactor is cooled, the polycrystalline silicon rod is taken out of the reactor.
In recent years, with increasing diameter of a polycrystalline silicon rod, a crack or a break easily occurs in the polycrystalline silicon rod during vapor phase growth or cooling of the polycrystalline silicon rod.
This may be because, in growing a polycrystalline silicon rod by a Siemens method, a temperature difference occurs between a center and a surface in a growing direction (radial direction) of the silicon rod during or after vapor phase growth, and this causes stress by thermal expansion or contraction of the polycrystalline silicon rod.
If the polycrystalline silicon rod breaks and falls in the reactor, heavy metal contamination occurs due to contact with an inner wall of the reactor and metal that constitutes a base plate or a metal electrode, and also it takes time to collect the collapsed polycrystalline silicon rod and clean the base plate to significantly increase an operation cycle time, thereby significantly reducing productivity.
Various proposals have been made to prevent occurrence of such a crack or a break of a polycrystalline silicon rod.
For example, Japanese Patent Laid-Open No. 8-45847 (Patent Literature 1) proposes a mounting tool of a carrier member (core) including at least one spring element provided between a current lead portion (metal electrode) and an electrode holder (holding tool of core holder), wherein the spring element allows movement of the electrode holder with respect to the current lead portion and also absorbs the movement.
Japanese Patent Laid-Open No. 2006-16243 (Patent Literature 2) proposes that a seed holding electrode including a carbon seed holder and a metal electrode, in which the seed holder and the metal electrode are joined by fitting in a tapered shape, and a noble metal sheet is joined therebetween in a rubbing manner, is used to prevent a break of polycrystalline silicon or a carbon component used in the seed holding electrode due to thermal strain generated in a cooling step after production of polycrystalline silicon.
Japanese Patent Laid-Open No. 2006-240934 (Patent Literature 3) proposes that a carbon holder, in which ends of a silicon core are electrically connected to electrodes via conductive holders holding the silicon cores and at least one holder is slidable on an electrode surface both to left and right in a direction of a line connecting opposite ends of an inverted U-shaped silicon core, is used to reduce occurrence of cracks in a polycrystalline silicon rod.

Carbon electrode with slidable contact surfaces and apparatus for manufacturing polycrystalline silicon rod


There is disclosed a salt of a polymer having charged anionic functionalities used as a dispersant in a dispersion solution containing a pigment and used for forming a first pigment layer. A substance which forms a salt with a polymer having charged anionic functionalities is mixed into a solution applied on the pigment layer, and/or mixed into a developing solution. The formed layers are patterned and thus a display screen is obtained.

1. Field of the Invention
The present invention relates to a method of manufacturing a display screen having a color filter, which is used in a cathode ray tube, a liquid crystal display element or the like.
2. Description of the Related Art
Conventionally, a filter pattern which is made by patterning a pigment layer into a predetermined pattern, is used in various fields. A color filter used in a liquid crystal display apparatus is a typical example of the filter pattern.
Further, as disclosed in, for example, U.S. Pat. No. 2,959,484 or 3,114,065, which is directed to a color cathode ray tube, a phosphor film with an optical filter which has a structure in which an optical filter of a color which corresponding to the color emitted by a phosphor film is provided in a front side of the phosphor film, that is, between the inner surface of the face plate of the panel and the phosphor film, is known. Usually, a plurality of phosphor films having emitting colors of red, blue and green are formed in a dot manner or a stripe manner on the inner surface of the face plate of a color cathode ray tube. As electron beams collide with these phosphor films, the phosphor films emit light, thus displaying an image. A filter-applied phosphor film is designed to achieve an improvement of image display characteristics such as contrast and color purity, and has a structure in which a filter pattern which transmits a light beam of the same color as the color emitted from the phosphor film itself, is provided between the face plate and the phosphor film. With this structure, of the external light made incident, the green and blue components can be absorbed by a red pigment film, the green and red components can be absorbed by a blue pigment film, and the blue and red components can be absorbed by a green pigment film. With use of filter-applied phosphor films, the contrast and the color purity of the display apparatus can be enhanced. For the formation of such a filter film, generally, a pigment film is applied on a substrate, and then an exposure and development are carried out on the film for patterning. During the patterning, a portion of the pigment film, which should remain as a desired pattern is required to have a sufficient adhesion property with respect to the substrate, whereas the other portion is required to have a sufficient removal property. Further, the pigment film is required to have a transparence, and it is required that pigment particles are dispersed uniformly without being gathered irregularly.
However, the bond between pigment particles and that between the pigment and the substrate are, in practice, relatively strong, and therefore some excessive portions of the pigment film are, in many cases, not removed in the development step, but remain on the substrate as residues. In order to avoid this, the following attempt was made. That is, the development was carried out before the pigment film was dried. However, this attempt entails another problem in which a good patterning cannot be carried out. That is, a sharp-edged pattern cannot be obtained. In other words, the boundary between the portion to remain and the portion to be removed after an exposure cannot be formed sharp.
In the case where such a filter is applied between a phosphor film and a substrate, first, a filter film is patterned as the exposure and development are repeated for each color by means of a slurry method. Then, on the filter film thus obtained, a phosphor which emit the same color as that of the filter film is patterned, as the exposure and development are repeated for each color by the slurry method. Thus, the above case involves a great number of production steps, making it complicated.
Under such circumstances, a method in which a phosphor film is applied on a pigment film, and patterning of these two layers is carried out by one exposure, is conventionally proposed (Jap. Pat. Appln. KOKAI Publication No. 52-77578 or No. 5-266795).
However, in the above-described method in which the patterning of the phosphor layer and the pigment layer is carried out by only one exposure, the phenomenon that the first film is dissolved while the second film is applied, easily occur. If the first layer is completely hardened in order to avoid the above drawback, the first film cannot be easily dissolved and removed by the development, which is carried out after the formation of the second layer. As a result, it is difficult to form the identical pattern in the pigment film and the phosphor film. Thus, in the case of the patterning by only one exposure, it is desirable that the two contradicting properties, namely, the dissolving property and the development property, be satisfied at the same time, and therefore this method involves a limited condition for work. As a result, phosphor layers with color filters, which have a uniform quality, cannot be obtained.


A ferroelectric memory device being short in the bit line direction. The ferroelectric memory device is structured including a first word line extending in the first direction; a plurality of element regions arrayed in the first direction on both sides of the first word line; a plurality of ferroelectric capacitors connected to the respective element regions and driven by the first word line. Each of the element regions preferably has a stair-like shape when seen in a plane view and the first word line is preferably arranged bent between the element regions.

1. Technical Field
The present invention relates to a ferroelectric random access memory device, display drive IC, and electronic equipment.
2. Related Art
Ferroelectric Random Access Memory (FeRAM) devices are used for storing information using the hysteresis that can be seen between the polarization and electric field of ferroelectric materials, and have been a focus of attention from the viewpoints of speed, lower power consumption and non-volatility.
For these FeRAM devices, just as other memory devices, the high-level integration or miniaturization of memory cells has been a longstanding problem.
For example, Japanese Patent Laid-Open Publication No. 2002-170935 describes a FeRAM where active regions to be connected to a predetermined bit line are arranged in a line along the bit line; and discloses a technique for reducing the area of a FeRAM cell by devising the shape and arrangement of plate lines, word lines and active regions.
However, with conventional FeRAM structures, the length of the bit line (direction) is long and there is a problem in that the size of the FeRAM is large.
Meanwhile, FeRAMs have been used in various electronic equipment because of their speed, low power consumption and non-volatility. For example, with a display drive IC in a display device, because of the connection to the display, the wiring spacing is sometimes set larger than the ordinary design rule (for example, the smallest wiring spacing).
Accordingly, in addition to pursuing high-level integration or miniaturization of a FeRAM device, it is also necessary to achieve high-level integration of memory cells while maintaining allowed wiring spacing.

Ferroelectric random access memory device, display drive IC and electronic equipment


Methods and apparatus for interfacing a memory device with a host device are disclosed. According to one aspect of the present invention, an apparatus which enables a non-volatile memory device to communicate with a host device includes a body and an element. The body has a boundary, and the element is arranged to move at least partially within the body. The element includes an interface which may be coupled to the host device when the element is in a first position with respect to the body. The element is also arranged to receive the non-volatile memory device and to move the non-volatile memory device and the interface with respect to the body. In one embodiment, when the element is in the first position with respect to the body, the interface at least partially extends past the boundary associated with the body.

1. Field of Invention
The present invention relates generally to mass digital data storage systems. More particularly, the present invention relates to systems and methods for enabling a flash memory card to interface with a host device.
2. Description of the Related Art
The use of non-volatile memory systems such as flash memory storage systems is increasing due to the compact physical size of such memory systems, and the ability for non-volatile memory to be repetitively reprogrammed. The compact physical size of flash memory storage systems facilitates the use of such storage systems in devices which are becoming increasingly prevalent. Devices which use flash memory storage systems include, but are not limited to, digital cameras, digital camcorders, digital music players, handheld personal computers, and global positioning devices. The ability to repetitively reprogram non-volatile memory included in flash memory storage systems enables flash memory storage systems to be used and reused.
Some devices which use flash memory storage systems, e.g., flash memory cards, include slots into which the flash memory cards may be inserted to enable data to be exchanged between a flash memory card and the device. Other devices, however, require the use of an adapter which accepts a flash memory card and is coupled to a device to enable data to be transferred between the flash memory card and the device. Many adapters include a slot into which a memory card may be inserted, and a connector which allows the adapter to be connected to a host device. For example, an adapter may include a slot that accepts a memory card such as a Secure Digital card or a MultiMedia card, and a Universal Serial Bus (USB) connector. An adapter that is coupled to a host device is generally effective in enabling data to be read from or written to a memory card inserted within the adapter by the host device.
Often, an adapter is only coupled to a host device when data is to be transferred between the host device and a memory card inserted into the adapter. Decoupling an adapter, e.g., an adapter that includes a USB connector, for a host device when the adapter is not in use enables a USB port associated with the host device to be freed for other uses.
When an adapter is decoupled from a host device, the connector on the adapter is typically exposed, as conventional adapters typically include connectors which protrude from the adapter. An exposed connector may be damaged relatively easily and, hence, may affect the performance of the adapter. In the event that there is a significant amount of damage to an exposed connector, the adapter may no longer usable. To protect a connector from damage caused by particles becoming lodged in the connector or damage that results in pins associated with the connector being bent, caps are sometimes placed over the connector when the adapter is not in use. In other words, a cap may be used to cover the pins of a connector. While a cap is generally effective in protecting a connector, a cap may be accidentally dislodged from the connector when the adapter is being transported, thereby exposing the connector to elements which may cause damage to the adapter. In addition, even with a cap in place, a connector may be damaged, e.g., the housing of the connector may be bent, when excessive force is applied to the connector.
Like a connector, a memory card may be damaged if the memory card is not properly protected. For example, if a memory card is being transported when the memory card is not protected by a sleeve or a case, the pins of the memory card may be damaged. In the event that the pins of a memory card sustain relatively significant damage, then the memory card may become unusable, and substantially any data stored on the memory card may be lost. It is fairly common for a memory card to remain inserted in an adapter when the memory card is not in use, e.g., a user may leave a memory card in an adapter when the adapter is uncoupled from a port on a host device. However, many adapters are arranged such that when a memory card is inserted in an adapter, part of the memory card may protrude from the adapter. When a memory card inserted in an adapter partially protrudes out of the adapter, the memory card may be damaged when the adapter is being moved from one location to another location.
Since adapters which allow memory cards to interface with host devices are highly portable, adapters are often transported. As such, when a part of a memory card inserted in an adapter and a connector that is a part of the adapter are exposed, the memory card and the connector may be damaged. Damage incurred by a memory card may be disastrous when the contents stored in memory of the memory card are effectively lost, while damage incurred by a connector may affect the reliability of the connector and, hence, the adapter, as discussed above.
Therefore, what is needed is a method and a system which protects both a memory card inserted into an adapter and a connector of the adapter from being damaged when the adapter is being transported. That is, what is desired is an adapter which is configured to protect both a memory card inserted into the adapter and a connector of the adapter when the adapter is not coupled to a host device.


A method for storing respiring produce, particularly bananas, during ripening is disclosed. The method allows bananas to remain in the ripened condition for an extended period of time while, at the same time, having improved sweetness and taste characteristics. In this method, during ripening, the produce is maintained in a gas medium which comprises oxygen and carbon dioxide and has the following characteristics:

During banana storage, starting at the moment of harvesting until delivery to the distribution network and directly to the consumer, it is necessary to pack bananas for different modes of storage, at various points in the process.
Bananas are usually harvested when they are unripe (green), and stored at a temperature of between 56° F. and 59° F. They can be stored in such a way for a sufficiently long time.
To activate the banana ripening process, the temperature is usually increased to between 60° F. and 62° F. and/or the composition of the gas medium surrounding the bananas is changed by adding ethylene to it. Ethylene, combined with an increased temperature, contributes to the beginning of the banana ripening process.
However, for the bananas to not ripen too quickly, or not spoil, their ripening process is usually conducted at a lower temperature, and in a gas medium characterized by a specifically selected composition.
Different innovations are known from the Prior Art that relate to methods for bananas storage and packing.
In U.S. Pat. No. 5,556,658, "Method for packaging, storing and ventilating produce", Raudalus et al, issued Sep. 17, 1996, a container system is described that is intended for transportation and storage of bananas. The system includes the external tare, internal container and a flexible bag positioned inside the container, in which the bananas are placed. The container has holes for ventilation, while the flexible bag has means for opening and closing. Such a design provides for the required ventilation and temperature for banana storage. The ability to open the bag allows ethylene to be delivered inside the bag, which activates the banana ripening process.
In U.S. Pat. No. 6,617,711 "Method of producing a container of bananas and method of transferring bananas", Rodriguez et al, issued Apr. 8,1997, a method for manufacturing a container for transportation and storage of bananas is described. The method utilizes a flexible internal container that is inserted into the external tare prior to placing banana clusters into it. The banana clusters are placed in layers, with gaps between them created with filling gaskets. Such placement of bananas can provide for ventilation and an even temperature throughout the entire inner space of the container.
In U.S. Pat. No. 6,013,293, "Packaging respiring biological material with atmosphere control member", De Moor, issued Jan. 11, 2000, packaging is described which provides for a required gas composition during storage of fruits and vegetables and other respiring biological materials. Part of the packaging is made as a gas-permeable membrane, which has selective properties, ie, lower oxygen-permeability as compared to carbon dioxide. The membrane provides optimum conditions for storing bananas because oxygen is delivered into a package from the external environment, while carbon dioxide, which is released during the ripening process, is removed from the packaging.
However, known methods do not provide for a long-term process for storing bananas during ripening, nor do they improve the flavor characteristics at earlier ripening stages.

This patent is subject to a terminal disclaimer.

Method for storing bananas during ripening

Abstract: PR=ratio of oxygen to carbon dioxide=(20.94−B)/C=from about 1.8 to about 3.8; wherein B is the percentage (by weight) of oxygen in the gas medium and C is the percentage (by weight) of carbon dioxide is the gas medium, and the percentage (by weight) of oxygen (in the gas medium) is from about 1.0 to about 6.0, and the percentage (by weight) of carbon dioxide in the gas medium is from about 3.0 to about 10.0.