An applicator comprising:

The present invention relates to an applicator usable as a writing tool or as a cosmetic tool, and particularly relates to an applicator that comprises a reservoir of cylindrical or any other shape for holding therein an amount of an ink or a cosmetic liquid such that an applying tip may be soaked with the ink or liquid to apply same to any desired surface.
The present applicant has disclosed in the Patent Laying-Open Gazette No. 9-323495 a free-inking applicator (viz., a writing tool) improved such that ink can smoothly be supplied enabling a continuous writing. This applicator for a writing use comprises a cylindrical ink reservoir and a fiber bundle tip, wherein the ink effluent from the reservoir flows through said tip due to capillary action. The applicator further comprises a valve assembly disposed in a distal region of the ink reservoir. Characteristically, this valve assembly is composed of a spherical valve body and a valve chamber that has a valve seat for supporting the valve body normally resting thereon. The valve seat has a forward opening and the valve body is movable fore and aft within the valve chamber. A spring urges the valve body towards the seat so that the tip disposed ahead the valve assembly has its rear end kept in contact with a forward portion of the valve body.
In the prior art applicator of the described structure, the spring disposed in the valve chamber forces the valve body to stop the forward opening lest any amount of ink should flow out of the applicator not being used. If however the tip is pressed against a paper sheet or the like to apply the ink thereto, then such a pressure to the tip will automatically push the valve body rearwards. As a result, the tip will be soaked with the ink continuously and at a moderate flow rate. Thus, the ink is prevented from trickling down in drops from the tip, but never causing the user to discontinue his or her writing motion for intermittent feed of the ink to the applying tip. There is no fear of any excessive amount of ink that will disable smooth and fine writings.
FIGS. 2 to 5 in the Gazette 9-323495 show the prior art examples wherein the applying tip has its proximal end of a diameter larger than that of the forward opening of the valve chamber. The valve body has a distal portion protruding forwards through the opening so as to contact the proximal end of the tip. The ink effluent through this opening is thus surely absorbed by and into this applying tip, thereby avoiding any dripping of the ink off said tip.
On the other hand, some of the known applicators comprise each an ink reservoir whose proximal or rear end is opened. A back-flow inhibitor such as a polybutene gel inserted in the rear region of the reservoir is capable of sliding therein in an axial direction. This inhibitor stopping the back-flow of ink does prevent ambient air from entering the reservoir""s deep region in which the ink is retained. As the amount of the ink held in said reservoir decreases, the inhibitor will gradually move forwards ensuring smooth feed of ink.
In such a prior art structure, it may be necessary to suppress the flow ate of ink. For this purpose, the valve body may have to be of a diameter slightly less than the inner diameter of the valve chamber in order to reduce clearance between said body and the inner periphery of said chamber. In spite of those diameters nearly equal to each other, the valve body must surely seal the valve seat with the forward portion of said body sufficiently protruding from the forward opening out of the valve chamber when the applicator is not in use. To meet this requirement, it may be necessary for the valve seat to be of a concave shape precisely commensurate with the outer periphery of the valve body. However, such a machining of a material for the valve chamber is extremely difficult.
The valve body may, for convenience"" sake, be a so small ball that the ordinary caulking process is feasible to form such a valve seat as providing a sufficient forward protrusion of the valve body and a reliable sealing effect thereof An enlarged clearance around this body will raise the ink flow rate to an undesirable extent to cause the ink dripping. If viscosity of the ink and back-flow inhibitor is considerably low, then this drawback will become severer.
Therefore, a primary object of the present invention is to provide an applicator as well as an ink- or liquid-feeding mechanism incorporated therein, wherein its valve assembly is easy to manufacture and assemble, with the ink or liquid being capable of application to a foreign article at a moderately suppressed flow rate.
As discussed hereinbefore, the prior art writing tool is constructed such that a writing pressure causes a valve body to be retracted a little distance to open the valve assembly to thereby provide a small clearance through which an ink is dispensed. For ensuring a smooth flow-out of the ink, it is of a viscosity of about 100 mPaxc2x7s (viz., centipoise) or less. In order to prevent a superfluous discharge of the ink having such a low viscosity of 100 mPaxc2x7s or less, a highly viscous follower is disposed in the reservoir behind and in contact with a column of the ink. The follower will exert a viscosity resistance for the ink column so that the ink flows out through the opened valve at an appropriate rate.
Usually, the prior art followers are blocks of a polybutene gel. The present inventors have confirmed through their experiments that the polybutene gel would drastically change its viscosity in response to ambient temperature. In an atmosphere of a temperature of 5xc2x0 C. corresponding to the winter room temperature, the polybutene gel will show a viscosity of about 100,000 mPaxc2x7s. In another atmosphere of a temperature of 35xc2x0 C. corresponding to the summer room temperature, that gel will show a considerably lowered viscosity of about 35,000 mPaxc2x7s or less. If the follower must merely serve as a back-flow inhibitor, then such a polybutene will suffice. However the follower has to serve also as a flow regulator for controlling the flow rate of an ink or the like liquid commencing to flow out in response to small distance displacement of the valve body. Thus, there has been observed a problem that a drastic change in viscosity due to change in temperature would undesirably result in variation of flow rate of the ink or liquid to be applied, to such a degree as causing the ink dripping or scratchy writings.
Therefore, a second object of the present invention is to provide a liquid applicator whose valve body is movable a small distance to open the valve to smoothly flow out the liquid having a viscosity of 100 mPaxc2x7s or less at a moderate rate, without being adversely affected by any actual temperature change in living atmospheres. Reliable performance free from any liquid dripping or scratchy application has to be afforded herein.
Further in the described prior art applicators, an idle long elapse of time after used once has caused the applying tip to dry up. This is because the valve in the applicator not being used is closed to seal up the ink in the reservoir not to flow towards the tip. Even if the valve is opened again, the ink effluent from the reservoir will advance forwards merely at a limited and considerably low-rate, failing to dissolve the dried ink and thus making it impossible to use the applicator any longer.
Therefore, a third object of the invention is to provide an applicator of the type that a liquid slowly exudes from a reservoir into an applying tip and improved such that even a long-term non-use might not dry up the said tip.
In the prior art writing tools, the spring has a sufficient biasing force so as to urge the valve body to firmly close the opening in the valve chamber, regardless of structure and/or size of the valve opening and the valve body. It is a matter of course that even such as strong biasing force is weaker than a writing pressure, because the valve body should be retracted a small distance when the tools are used. If the spring has an excessively high xe2x80x98spring constantxe2x80x99 (or more adequately xe2x80x98spring modulusxe2x80x99), then actual biasing forces would vary among the springs undesirably due to slightly poor precision in dimension of molded members or in works for assembling them, impairing the performance of the writing tools. It is experimentally known that the writing pressure is usually 120 gf (viz., xe2x80x98gramxc2x7forcexe2x80x99) or so in the conventional marking pen type of the writing tools. Accordingly, the biasing force is to be about 100 gf or less for the springs, and springs having a xe2x80x98spring constantxe2x80x99 of about 0.01 kg/mm have been employed for the purpose of quality assurance. In this case, the biasing force of finished products may be included in a range of 100xc2x110 gf even if a dimensional error of about 0.1 mm were found in relevant members or parts. A maximum permissible value of the spring constant has been about 0.04 kg/mm.
As discussed just above, spring constant of the springs urging the spherical valve bodies or balls in the prior art has been designed as small as possible. However, as will be seen in FIG. 1(b) in the Gazette 9-323495, the ball tends to collide with a rear stopper in the valve chamber, with a bump or clunk. This motion of the ball will give to the user""s hand an unpleasant feeling, when he or she uses the writing tool.
Therefore, a fourth object of the present invention is to provide an applicator of the type that a liquid slowly exudes from a reservoir into an applying tip when the tip is retracted a little by the writing pressure to open the valve, and of the following design. This applicator has to be improved such that a biasing member urging the valve towards its closed position has a biasing force that is balanced with the writing pressure only at an instant when the valve is opened. This structure will eliminate the feeling of collision, allowing the user to make a pleasant writing.
In addition to the drawbacks discussed above and inherent in the prior art applicators, there is another problem resulting from a structure that any ink pool is not formed outside the ink delivery opening in the valve. If the applying tip faces up for a long time while the applicator is used upside down, the valve kept open due to the writing pressure will allow an amount of ambient air to enter the valve chamber, from fore to aft. As a result, the ink and the back-flow inhibitor disposed behind same will tend to move back and to consequently flow out through the proximal opening of the ink reservoir, due to gravitational force.
Therefore, a fifth object of the present invention is to provide an applicator of the type that a liquid slowly exudes from a reservoir into an applying tip by means of a ink feed valve opened slightly when the applicator is used, and improved such that the ink is prevented from flowing back even when writing is done xe2x80x98downside upxe2x80x99.
It is still another problem that bubbles entrained in the ink reservoir of the prior art applicator will allow the back-flow inhibitor to slide in a reverse direction towards the proximal end, particularly when the distal end of the applicator is kept up.
Therefore, a sixth object of the present invention is to provide an applicator of the type that a liquid slowly exudes from a reservoir into an applying tip, with a back-flow inhibitor being disposed behind a column of the liquid for application. This applicator has to be improved herein such that the liquid is prevented from dripping down to impair the smooth and continuous writing property. In this applicator, the back-flow inhibitor has to be retained in position not to slip off the reservoir so that leakage of the liquid is prevented from flowing out from the reservoir proximal end.
Further, each of the prior art applicators has to be constructed such that the applying tip is held in place to be capable of being retracted a limited distance, with this tip""s rear end being kept in contact with a ball, i.e., a valve body. However, somewhat variation in dimension of the manufactured constituent members has sometimes caused the tip rickety fore and aft. Every time when the applicator is used repeatedly, the tip""s rear face will be pressed against the ball, producing a small dimple in the rear face due to plastic deformation thereof. In such an event, the tip would be become more rickety so that not only vibrations are produced in the writings, but also the writing feeling is impaired.
Therefore, a seventh object of the present invention is to provide an applicator of the type that a liquid slowly exudes from a reservoir into an applying tip when the applying tip is retracted by a writing pressure to open the valve, and improved such that the tip is protected from undesirable rickety movements.
FIGS. 2 to 5 in the Gazette 9-323495 shows the prior art examples wherein the valve chamber (viz., valve housing) is substantially of a cylindrical shape with a thick peripheral wall. A valve seat and a spring rest are formed in the inner peripheral surface of said cylinder. However, such a valve chamber causes lower manufacture efficiency and a higher production cost.
It may be possible to employ a thinner cylindrical valve chamber retained in an end plug disposed in distal end of the ink reservoir. In this case, a distal end of such a valve chamber will easily be caulked at its distal outer periphery to provide a valve seat tapered towards the distal end. Mass production of those valve chambers may be feasible at a lowered cost, though the applying tip must have a proximal end having a diameter relatively larger than that of the opening formed in each of such valve chambers. This structure intended to prevent the dripping of the ink would inevitably cause a certain problem that the tip""s proximal end face is forced against the constricted distal end of the valve chamber and/or against the spherical valve body of a reduced diameter. Consequently, a small dimple will be produced in said end face before long also in this case whereby the tip is rendered rickety. Further, the spherical valve body will come into a loose and idle engagement with an enlarged dimple, failing to be pushed back.
Therefore, an eighth object of the present invention is to provide an applicator of the type that a liquid slowly exudes from a reservoir into an applying tip, and improved such that the tip""s proximal end face is protected from deformation while affording a high efficiency in manufacture of the applicators.
It has been a further problem in the prior art applicators that the valve once opened with the writing pressure imposed to the tip sometimes tends thence to stand open, causing superfluous discharge of ink. In order to avoid this problem, a stopper may be formed in the applicator to restrict retraction of the tip. Such a stopper will however give an unpleasant bumping or clunking feeling to the user when the tip collides with the stopper. A means for biasing the valve body is necessitated in this case in addition to this body, making it difficult to lower manufacture cost below a certain limit.
Therefore, a ninth object of the present invention is to provide a novel structure for a delivery valve dispensing a liquid to be applied, wherein the valve is capable of opening in response to the writing pressure or by intentionally thrusting inwards the tip in an improved manner. In detail, this structure, that does not need any biasing means in addition to the valve body itself, has to be effective to avoid the dripping of the application liquid ink. It is further desirable and now possible to protect the users from any unpleasant bumping or clunking feeling when they begin writing.
The Utility Model Laying-Open Gazette No. 6-79586 discloses an example of the prior art applicators each having a valve assembly disposed in a distal region of the ink reservoir. Also in this type, an applying tip is movable a limited distance fore and aft, so that the tip may be retracted to push back a valve body to open the valve assembly, thereby feeding a liquid to the tip for the writing purpose. In its inoperative position, the valve stands closed to interrupt the feeding of said application liquid.
In order to prevent the tip from being retracted beyond a limit in one embodiment of this prior art, the distal end of reservoir will abut against a shoulder formed in the proximal portion of said tip, with said distal end thus serving as a stopper. In another embodiment, a valve receiver disposed in the reservoir may abut against a valve body that is being pressed back with the tip, with said retainer as an alternative stopper. In any case, collision takes place between the tip""s shoulder and the valve assembly""s distal face, or between the valve body and the receiver. Thus, a bumping or clunking feeling will be given the user, making him or her unpleasant.
Therefore, a tenth object of he present invention is to buffer the described collision so as to diminish such an unpleasant feeling of bumping or clunking.
The Patent Laying-Open Gazette No. 7-266782 discloses a slit valve that is opened by thrusting inwards a pen-point tip so that ink held in a reservoir is fed to this tip. The slit valve (i.e., resilient body 8) in the prior art writing tool is a cylinder having a bottom in which cutouts are formed. The distal face of the bottom inclusive of the cutouts is in a close contact with the proximal face of the pen-point tip. In this type structure, the ink pressure imparted to a bottom of the slit valve tends to open those cutouts in normal (viz., inoperative) state of each writing tool. However, the rear face of each pen-point tip will hinder the slit valve cutouts from opening, although the latter will be allowed to open by retracting the tip. This will cause the ink to flow from the reservoir to the tip so as to supply thereto said ink, thereby making the writing tool ready for use.
In this type prior art writing tool, the slit valve cutouts will open wider when the tip is pressed back deeper. Consequently, a superfluous amount of ink will flow through the valve undesirably remaining open, causing the ink to drip off the tip.
Therefore, an eleventh object of the present invention is to provide a structure simplified but effective to inhibit an ink or the like application liquid from dispensed even if the tip is pressed back excessively, so as to avoid he problem of ink dripping.
The Patent Laying-Open Gazette No. 62-78486 discloses a writing tool such as a fiber bundle pen or a correction pen as well as a cosmetic tool such as a manicure liquid applicator. Also, an applying tip may be pressed back to exude the liquid such as ink into this tip applying them to a foreign object. The applicator of this type comprises a liquid holding reservoir, an aperture formed in distal end of the reservoir and discharging the liquid, and a valve body for opening and closing the aperture. A biasing member always urges the valve body forwards to normally keep the aperture closed. The applying tip disposed ahead the reservoir has a rear end in contact with the valve body, so that the aperture will open to be supplied to and around the tip""s rear end when this tip is pressed back against resilient force of the biasing member. The tip""s rear portion will absorb the liquid thus fed thereto, with the liquid subsequently migrating forwards within said tip. In use, the distal or forward end of this applying tip may be put onto and dragged along a paper sheet or a nail, so as to apply the liquid thereto.
However in the described prior art applicators, an idle long elapse of time after used once has caused the applying tip to dry up. This is because the liquid feeding aperture in the applicator not being used is closed to seal up the liquid in the reservoir not to flow towards the tip""s proximal region. Even if the aperture is opened again by retracting the tip, this tip will scarcely absorb the liquid effluent from the reservoir, so that an excessive amount of the liquid falls down along the tip""s outer periphery, causing the dripping of said liquid.
Therefore, a twelfth object of the present invention is to provide a liquid applicator of the type that the liquid in a reservoir is fed to and around the proximal end of an applying tip in response to retraction thereof, and improved such that any long elapse of time after use does not cause dry up of said applying tip.
In general, the present invention provides an applicator constructed such that a valve body disposed in a valve chamber is urged towards an opening formed therein to close it to stop supply of a liquid such as an ink to an applying tip during nonuse of the applicator. The distal end of the applying tip can however be pressed on a paper sheet or the like to produce an application pressure forcing rearward displacement of the valve body to initiate supply of the liquid to the tip. Thus, any dripping or flooding of the liquid around the tip will not take place from or around the tip on one hand, and any interruption of use is not necessary for supplying the tip with the liquid.
In detail and to achieve the primary object set forth above, the applicator of the invention may comprise a flow restrainer disposed in the valve chamber and upstream of the valve body so as to move fore and aft a limited distance. In this case, the biasing member disposed behind such a flow restrainer will urge through the valve body through this strainer towards a valve seat. This structure simply uses the flow restrainer, in addition to the valve body, to be incorporated in the valve chamber. Thus, it is advantageous in that any surplus and intricate work is neither required in manufacture, nor complicating the machining of the liquid feed valve composed of the chamber, the seat and so on. Any excessive amount of the liquid of a low viscosity will be fed no longer to the applying tip.
In order to achieve the second object set forth above, the applicator of the invention may comprise a follower or back-flow inhibitor made of a viscous material whose viscosity shows no impermissible change in response to ambient temperature varying within a range of 5xc2x0 C. to 35xc2x0 C. This follower will serve to regulate flow rate of the application liquid whose viscosity is low and for example about 100 mPaxc2x7s or less. Such an applicator will work smoothly all the year around, never causing blurred writings (due to poor supply of ink) nor irregularly thickened strokes (due to excessive supply of ink). This advantage is afforded herein without needing any novel and additional structure, but simply by improving the back-flow inhibitor only.
In order to achieve the third object set forth above, the applicator of the invention may comprise an applying tip coated with a plastics or with a metal. This tip normally disposed inside an external cylinder of the applicator will now be protected from drying up, enabling storage thereof for a long time.
Alternatively, the third object may be achieved by forming a distal stopper for the reservoir entirely or partially with a gas-permeating material. The stopper of this material is exposed not only inside the reservoir but also around the tip. A solvent vapor emitted from the liquid remaining in the reservoir will be transmitted through the permeative material to around the tip. Such a simply improved feature will nevertheless be enough to suppress evaporation of the solvent out of the tip, thus preventing it from drying up.
Still another option is provided herein to achieve the third object, wherein at least the proximal portion of the tip is disposed inside the external cylinder together with valve assembly and reservoir. A first closed space is formed between the proximal portion and the cylinder, with a second one formed between the reservoir and the cylinder. Those first and second spaces communicate with each other, and an anti-drying agent is placed in the second space. By virtue of this feature, the applying tip disposed in the cylinder will be protected well from drying, enabling a long time storage of the applicator.
In order to achieve the fourth object set forth above, the applicator of the invention may comprise a biasing member urging the valve body towards its closed position. The xe2x80x98spring constantxe2x80x99 of the biasing member is selected herein such that the urging force thereof will increase almost abruptly, once the valve body is retracted a small distance. Such a suddenly increasing urging force will withstand well the writing pressure imparted to the tip, never producing any feeling of collision even when the tip is retracted, thus affording a natural and smooth touch.
In order to achieve the fifth object set forth above, the applicator of the invention may comprise a check valve between the feed valve and the reservoir. This check valve disposed behind the feed valve for moderately supplying an ink to the tip will operate to prevent the ink from flowing back and out of the proximal end of said reservoir.
In order to achieve the sixth object set forth above, the applicator of the invention may comprise an air inlet and an obstructer in relation to a back-flow inhibitor. This inhibitor, following the tail of the column of an application liquid within a reservoir so as to move forwards as the liquid is being spent, will slide forwards as in the prior art. The air inlet and the obstructer provided herein are formed in the rear end portion of the reservoir, so that the inhibitor can more smoothly advance forwards, while at the same time preventing it from moving backward even when the applicator is held upside down. Further, even if the reservoir has a fully opened rear end, the obstructer in the present invention will stop the inhibitor from slipping off through such a rear end, and thereby retaining the liquid never to escape through said end.
In order to achieve the seventh object set forth above, the applicator of the invention may comprise a second biasing member in addition to the first one already described above. This second biasing member urges the proximal end portion of the tip inwardly (viz., backward) with an elastic force weaker than that of the first biasing member acting on the valve body. By such a structure, the tip receiving two urging forces acting towards each other will no longer make a rickety motion. The weaker second biasing member will not cause any unintentional opening of the valve.
In order to achieve the eighth object set forth above, the applicator of the invention may comprise a tip stopper inhibiting the tip from retraction beyond a given limit. The valve chamber has its distal end region that may be a cylindrical portion located behind the proximal end of the tip, and is possibly constricted and tapered towards its distal extremity. The rear face of the tip will no longer tend to be collapsed, because neither the valve body nor the valve chamber""s distal end does impart to said face any intolerable force.
In order to achieve the ninth object set forth above, the applicator of the invention may comprise a valve body formed of an elastically compressible material and disposed in a valve chamber that is in turn defined between a valve stopper and a valve seat. A passage for allowing the application liquid to flow out of a reservoir and then into the chamber is formed in and through the valve stopper. The valve body in this case will be compressed in a fore-and-aft direction, as the tip is retracted towards the reservoir. If the application is not in use, the valve body keeps the outlet aperture or opening of the valve chamber so as to interrupt ink feed. If however the valve body is pressed with a natural writing pressure imparted to the tip or by intentionally pressing back the tip, then the outlet opening in the valve seat will be opened to supply the ink from the reservoir to the tip at a moderate and proper low rate. Thus, this applicator can now be used to make smooth writings, without suffering from any problem of ink dripping. Further, the elastically compressible valve body will reduce the bumping or clunking touch that would make the users unpleasant. In addition, such a elastic valve body make it possible to dispense with any conventional biasing members such as a spring. Preferably, this applicator may be designed such that the valve body occasionally receiving a strong pressure exceeding a certain given limit will bear against an internal wall surface of the valve chamber so as to bring the valve into its closed position. This feature is advantageous in that any excessive pressure that might be applied to the writing tip would never give any superfluous amount of ink to said tip, during a continued operation of writing, thus preventing the problem of ink dripping.
In order to achieve the tenth object set forth above, the applicator of the invention may comprise a resistant member that prevent the tip from backward displacement beyond a given limit. This resistant member may be made from a buffering material such as a silicone rubber. In use, the tip being pressed back will collide with such a buffering resistant member, without giving rise to any unpleasant touch of bumping or clunking.
In order to achieve the eleventh object set forth above, the applicator of the invention may comprise a valve assembly interposed between an ink reservoir holding an application liquid and an applying tip disposed ahead the reservoir to be movable fore and aft. The valve assembly, that remains closed unless the applicator is used, will open in response to retraction of the tip within a given range so as to feed the ink from the reservoir to the tip. If however the tip is pushed back beyond the limit, then the valve assembly will be closed again. This means that usual writing pressure or intentional moderate pressure imparted to the tip will allow normal feed of ink thereto, while inhibiting ink feed when the tip is too strongly pressed back. Thus, fine writings or painted surfaces will be obtained, free from any defect that would otherwise be caused by the ink dripping or the like.
In order to achieve the twelfth object set forth above, the applicator of the invention may be constructed such that at least the proximal portion of the tip is disposed inside the external cylinder together with valve assembly and reservoir. A first closed space is formed between the proximal portion and the cylinder, with a second one formed between the reservoir and the cylinder. Those first and second spaces communicate with each other, and an anti-drying agent is placed in the second space. By virtue of this feature, the applying tip disposed in the cylinder will be protected well from drying, enabling a long time storage of the applicator. When use of the applicator is resumed after the long term storage, any blurred writings will not be made. This is because the liquid discharged through the feed opening is smoothly absorbed into the tip. Any dripping of the ink that is a hindrance to fine writings will not take place in this applicator.

Abstract: An applicator comprising:

Abstract: a reservoir for holding therein an application liquid;

Abstract: a valve assembly disposed in a distal region of the reservoir;

Abstract: a tip disposed in front of the valve assembly;

Abstract: the valve assembly comprising:

Abstract: a valve chamber having a forward opening;

Abstract: a valve body held in the chamber and movable fore and aft; and

Abstract: a biasing member for urging the valve body to be pressed against a circular rim around the opening so as to close it,

Abstract: the valve body having a distal portion in contact with a rear end of the tip,

Abstract: wherein the application liquid stored in the reservoir has a viscosity of 100 mPaxc2x7s or less, and the applicator further comprises a follower disposed in the reservoir and in rear of a column of the liquid so as to control flow rate of the liquid flowing out through the opening of the valve chamber, with the follower serving also as a back-flow inhibitor for the application liquid, and wherein a viscous material forming the follower shows the value of at highest xe2x80x982xe2x80x99 as the ratio of viscosity at 5xc2x0 C. to viscosity at 35xc2x0 C.


A backlight unit and an LCD employing the backlight unit are provided. The backlight unit includes: a base substrate; a plurality of point light sources arranged in two or more lines on the base substrate; a diffusion plate disposed over the plurality of point light sources to diffuse and transmit incident light; and at least one barrier rib forming two or more division areas by being disposed between the base substrate and the diffusion plate to be upright with respect to the base substrate between the lines and having a wall surface reflecting light incident from the plurality of point light sources, at least a portion of an end portion of the barrier rib being inserted into the diffusion plate.

1. Field of the Invention
The present invention relates to a backlight unit and a liquid crystal display employing the same and, more particularly, to a direct light type backlight unit having a sequential division lighting structure of division areas, and a liquid crystal display employing the same.
2. Description of the Related Art
A liquid crystal display (LCD), which is a type of flat panel display, is a light receiving type display that is not self-luminescent but forms an image using incident light from an outside source. A backlight unit is disposed at a rear of the LCD to irradiate light toward a liquid crystal panel.
A cold cathode fluorescence lamp (CCFL) is generally used as a light source of the backlight unit of the LCD. However, the CCFL has a comparatively short lifetime and a low color reproducibility. The CCFL is much more disadvantageous with respect to lifetime and color reproducibility than a light emitting diode (LED) and is also more disadvantageous in instant lighting than an LED.
Since the CCFL is poor at instant lighting, it is difficult to employ a backlight unit using the CCFL as a light source in a time-division LCD. The time-division LCD requires a backlight unit that can be division lighted to synchronize with a picture scanning time. A backlight unit using an LED as a light source can satisfy such a requirement.
The backlight units are generally classified, depending on the arrangement of light source, into direct light type backlight units in which light emitted from a plurality of light sources disposed right below a liquid crystal panel is irradiated toward the liquid crystal panel, and edge light type backlight units in which light emitted from a light source disposed on a sidewall of a light guide panel (LGP) is transmitted to a liquid crystal panel.
The direct light type backlight units may use, for example, an LED as a point light source. In the direct type backlight unit using the LED as a point light source, LEDs are arranged in a two-dimensional array. Especially, the LEDs are arranged in plural lines, each line having a plurality of LEDs arranged in a line.
The direct light type backlight unit using the LEDs as a light source can be used in a time-division LCD. Such a direct light type backlight unit is provided with a diffusion plate for diffusing light diverging from the LEDs to irradiate the diffused light toward a liquid crystal panel.
In the time-division LCD employing the direct light type backlight unit using the LEDs as a light source, the lighting areas of the LEDs are divided and the lighting areas of the LEDs are lighted in synchronization with a scan time of the liquid crystal panel.
However, in a case where light diverging from a selected one of the divided lighting areas invades an adjacent lighting area through the diffusion plate, when one picture is changed to another one, it is difficult to effectively remove the motion blur phenomenon such that an after-image remains.

Backlight unit and liquid crystal display employing the same, comprising at least one barrier rib between point light sources, substantially inserted into a diffusion plate


A continuous process for removing sulfate ions from a substantially water-insoluble organic phase containing phosphoric acid and sulfuric acid is described. The organic phase is treated countercurrently in a first zone with an aqueous solution originating in a third contact zone, the organic phase issuing from the first zone is treated in a second zone with an aqueous solution containing barium ions, then the resultant organic phase is treated in a third zone with water. The aqueous phase exiting from the second zone is separated from the BaSO.sub.4 precipitate, recharged with barium and recycled into the second contact zone. The phosphoric acid thus obtained is suitable for use in human foods and beverages.

1. Field of the Invention
The present invention concerns a process for the elimination of sulfate ions from impure phosphoric acid. More particularly, the present invention concerns the elimination of sulfate ions during the purification of impure phosphoric acid by means of a liquid-liquid extraction process. According to the invention, a purified and highly desulfated phosphoric acid is obtained from a raw wet process phosphoric acid, said purified acid being usable in the human food industry.
2. Description of the Prior Art
It is known to prepare phosphoric acid according to a wet process comprising the attack of a strong acid such as sulfuric acid on phosphate ore. After separation by filtration of the insoluble residue and of the gypsum formed, there is obtained an impure solution of phosphoric acid containing numerous anionic and cationic impurities, particularly sulfate ions originating from the excess sulfuric acid which is introduced during the attack on the ore so as to obtain maximum yields in the solubilization of the calcium phosphate. To obtain a relatively purified aqueous solution of phosphoric acid, a subsequent liquid-liquid extraction process is usually applied to the raw acid utilizing an organic solvent which is substantially insoluble in water, such as alkyl phosphates or aliphatic alcohols having 4 to 9 carbon atoms. In the course of this extraction, in view of the partition coefficient of the acids between the aqueous phase and the solvent phase, a considerable portion of the sulfate ions follow the phosphate ions into the organic phase. After washing the organic phase containing the acids with water or a dilute phosphoric acid, the organic phase is re-extracted with water to yield an aqueous solution of purified phosphoric acid, which still has a sizable sulfuric acid content. Thus, in French Pat. No. 1.531.487 in the name of Jean Goret and Louis Winand (corresponding to U.S. Pat. No. 3,607,029, incorporated by reference herein in its entirety and relied upon), there is obtained at the completion of the process, after extraction with tributyl phosphate in the presence of excess sulfuric acid (excess sulfuric acid being utilized in order to improve the yield in the extraction of the phosphoric acid), a phosphoric acid solution having an H.sub.2 SO.sub.4 content with respect to P.sub.2 O.sub.5 of 0.5% or 5000 ppm. Operating under critical conditions, this process provides at best a content by weight of SO.sub.4 --in relation to P.sub.2 O.sub.5 of 500 to 1000 ppm. However, the food industry increasingly requires a highly desulfated phosphoric acid containing less than 100 ppm SO.sub.4 by weight with respect to P.sub.2 O.sub.5. Such is notably the case for certain nonalcoholic beverages, since an SO.sub.4 content in excess of 100 ppm is prohibited by current legislation.

Process for obtaining a desulfated phosphoric acid for use in foods and beverages


.alpha.-Alkylstyrene impurities, such as isopropenylstyrene, are removed from styrene and nuclear alkyl derivatives of styrene, such as t-butylstyrene, containing the same by treatment with a strong acid cation exchange resin.

New techniques for separating mixtures of polymerizable monomers are widely sought. In the chemical industry, a high degree of purity in substances which are subjected to polymerization is necessary insofar as it permits the preparation of polymers of high molecular weight, a high reactivity of the polymerization system, a high yield of polymer, and a low consumption of catalyst. It is also necessary to control the influence of various impurities on the characteristics of the polymers. For example, as an impurity in t-butylstyrene, isopropenylstyrene is a polyfunctional monomer and acts as a cross-linking monomer when the t-butylstyrene is polymerized. For use as a polymerization monomer, it is desirable and usually specified that the t-butylstyrene contain not more than, and preferably less than, 50 ppm of isopropenylstyrene.
Various techniques have been suggested for purifying monomers, such as fractional or extractive distillation, crystallization and zone-wise fusion, extraction and treatment with compounds which react with some impurities in the monomers. Until now, there has been no acceptable way to remove small amounts of .alpha.-alkylstyrene, especially amounts below about 5000 ppm, from mixtures of styrene and .alpha.-alkylstyrene or derivatives thereof.
U.S. Pat. No. 2,215,569 teaches that mixtures of 25 percent styrene, 17-25 percent .alpha.-alkylstyrene and 50-58 percent isopropylbenzene may be treated with sulfuric acid at about 70 percent to 90 percent strength at ordinary temperatures so as to effect the polymerization of the .alpha.-alkylstyrenes leaving the styrene unchanged.
For the purpose of treating sytrene monomers containing .alpha.-alkylstyrene impurities, sulfuric acid having a concentration in a range of about 70 percent to about 90 percent removed the .alpha.-alkylstyrene impurities; however, continued contact with the sulfuric acid led to the polymerization of the desired styrenic monomer.
It is desirable to keep the concentration of impurities, such as .alpha.-alkylstyrene and nuclear alkyl derivatives thereof, to a minimum, since they will react to form undesirable branched products in polymerization mixtures with styrene and nuclear alkyl derivatives of styrene. Further, it is particularly desirable to have the desired polymerizable styrene monomer in a high degree of purity since this will enhance the economics of production, sale and use. In accordance with the present invention, separation of mixtures of polymerizable aryl-substituted mono-olefins is obtained by contacting the mixture with an appropriate ion exchange resin. This process requires very low power consumption; avoids polymerization of the desired monomer; does not modify the properties of the desired monomer; limits loss of chemicals due to successive manipulations; avoids inconveniences due to washing, disposal of a deleterious waste stream, or use of extensive heat.

Process for purifying aryl-substituted mono-olefins


When information is recorded on an optical disc of DVD+R type, a latest RSAT is recorded upon completion of recording of one title. When recording of the latest RSAT fails, previous RSAT address information that indicates an address in which a previous RSAT is recorded is stored in a lead-in area of the optical disc. When an optical disc is loaded for reproduction, it is checked if the previous RSAT address information is present in the lead-in area. If it is present, the previous RSAT address information is obtained. If the latest RSAT is not found in a predetermined location but the previous RSAT address information is present, reproduction from the optical disc of DVD+R type is started by using the previous RSAT.

1. Field of the Invention
The present invention relates to an optical disc recording/reproducing apparatus for recording information to an optical disc and reproducing information recorded on the optical disc, and particularly relates to recording control and reproduction control for an optical disc of DVD+R type.
2. Description of Related Art
In recent years, there has been a wide spread of DVDs (Digital Versatile Disc) as an optical disc capable of recording a large amount of video/audio data that of movies or the like. As these DVDs, various types are known such as a DVD-ROM containing information that is pre-recorded by a manufacturer and can not be rewritten by a user, a DVD-R or a DVD+R that allows the user to record information thereon only once, and a DVD-RW, a DVD+RW, or a DVD-RAM that allows the user to rewrite information thereon repeatedly. Information recorded on these DVDs can be reproduced by optical disc reproducing apparatuses (DVD players) or optical disc recording/reproducing apparatuses (DVD recorders), and information can be recorded on a DVD-R, a DVD+R, a DVD-RW, a DVD+RW, and a DVD-RAM by using optical disc recording/reproducing apparatuses (DVD recorders).
Here, among these types of optical discs, a description will be given of the conventional recording control and reproducing control for the DVD+R optical disk.
First, a description will be given of the recording control for the DVD+R optical disc performed by a conventional optical disk recording apparatus. When a DVD+R  optical disc is inserted in the apparatus and loaded therein (mounting process for reading out disc information), the optical disc is detected as a DVD+R optical disc. Then, recording on the DVD+R optical disc begins in +VR mode in response to recording key operation on a remote control unit or the preset time to begin the recording when the programmed recording (programmed video recording) is activated.
In this way, the recording on the optical disc begins, and the information to be recorded first is then recorded as a title T1 in the data area of the optical disc. When the title T1 has been recorded, an RSAT (Reserved Space Allocation Table) that indicates title information of the title T1 is recorded after the title T1. Then, information to be recorded next is recorded as a title T2 in the data area of the optical disc. When the title T2 has been recorded, an RSAT that indicates title information of the title T2 is recorded after the title T2. Further, information to be recorded next is recorded as a title T3 in the data area of the optical disc. When the title T3 has been recorded, an RSAT that indicates title information of the title T3 is recorded after the title T3. Thereafter, the recording will be repeated in a similar manner.
Next, a description will be given of the reproduction control for the DVD+R optical disc performed by a conventional optical disc recording apparatus.
When a DVD+R optical disc is inserted in the apparatus and loaded therein, the optical disc is detected as a DVD+R optical disc. Then, a list of titles recorded on the optical disc is displayed on a display apparatus as a reproduction list. When the user selects and decides a desired title to be reproduced from among the titles in the reproduction list by operating a remote control unit, the optical disc recording/reproducing apparatus reads out the RSAT for the selected title, analyzes the file system, the control information, and the like, and reproduces the selected title.
The conventional recording/reproducing apparatus records a title on the DVD+R optical disc under the recording control as described above or reproduces a title recorded on the DVD+R optical disc under the reproduction control as described above. However, if the recording of an RSAT for a specific title is failed after the title itself has been  successfully recorded on the DVD optical disc, the specific title certainly can not be reproduced and, further, all RSATs that were recorded prior to the recording of the specific title can not be obtained, thereby making the reproduction of all titles impossible because there is no way to search the locations of the RSATs recorded in the past.
It is to be noted that, when the recording of an RSAT is failed, it is possible to find the RSATs recorded in the past. However, to do so, it is necessary to repeat many times the process of reading out data sequentially in predetermined sector units starting from the inner track side of the optical disc and the process of comparing the data on a sector-by-sector or ECC-by-ECC basis to find if the read-out data is the data of the title information that is searched for. Therefore, an enormous amount of time is required, which makes the reproduction of all titles impossible in reality.
According to a conventional technique described in JP-A-2002-312940, positional information of an area to which data is written is updated and held in a memory every time recording is performed. Also, the positional information held in the memory and the actual positional information of an area of a disc medium on which data is written are compared. When it is determined that the two sets of data are not identical, then the positional information in the memory is recorded to a write-once read-many-times type disc medium, so that recovery is made possible even if recording of the recording management area fails. However, according to this conventional technique, when recording of a specific title on a DVD+R optical disc is completed but recording of the RSAT for this specific title is failed, all RSATs recorded in the past can not be retrieved. In this case, this conventional technique does not solve a problem, i.e., all of the titles can not be reproduced, which is the problem specific to the DVD+R optical disc.
According to a conventional technique described in JP-A-2006-107622, recording zones are sequentially formed from the lead-in area side to the lead-out area side on the DVD-R disc. If an ECC error occurs when video information is recorded in a zone after a completed zone, the readable and normal latest log information selected from between log information 1 and log information 2 is moved to a zone after the last zone.  However, according to this conventional technique, when recording of a specific title on a DVD+R optical disc is completed but recording of the RSAT for the specific title is failed, all RSATs recorded in the past can not be retrieved. In this case, this conventional technique does not solve a problem, i.e., all of the titles can not be reproduced, which is the problem specific to the DVD+R optical disc.

Optical disc recording/reproducing apparatus


An adjustable-height scoring rule includes a base member and a plurality of interchangeable scoring inserts which are detachably secured to the base member to adjust the height of the scoring rule. The base member includes insert-receiver for receiving the scoring insert. In one embodiment, the insert-receiver comprises a longitudinally-extending channel formed in the top of the base member. The scoring insert includes an insert portion that fits within the channel of the base member. In a second embodiment, the insert receiving means comprises a longitudinally extending boss, and the scoring insert includes a channel member that engages the boss on the base member.

Rotary cutting dies are widely used for manufacturing boxes, cartons, and interpak-die cuts. The rotary die includes a die cylinder and anvil cylinder mounted in parallel-spaced relation to one another. The cutting die includes a series of cutting rules for shaping a blank, and a series of creasing rules for producing fold lines in the blank where it is to be folded. The anvil cylinder is covered with a blanket of urethane or other resilient material. The cylinders rotate in opposite directions and the board is fed between the cylinders. The cutting die, in cooperation with the anvil cylinder, cuts out a blank from the sheet material and produces fold lines in the blank.
In operation, the size of the nip (the space between the cylinders) is adjusted depending on operating conditions. For example, the blanket surrounding the anvil will be relatively thick when new, but will wear over time. Wear on the blanket will therefore effect the size of the nip which in turn will effect the feed rate of the board passing between the die cylinder and the anvil cylinder. When the blanket is new, there is a tendency for the anvil to feed more board than is desired for each rotation of the anvil. To compensate for the excessive feed, the operator may move the cylinders closer together. Conversely, as the blanket wears, the amount of board fed between the cylinders will decrease. The operator will compensate for inadequate feed by moving the cylinders farther apart.
The adjustments made to compensate for the size of the blanket will also effect score quality. When the cylinders are moved closer together, the creasing rules may produce excessive scores or tend to cut the board. When the cylinders are moved further apart, the creasing rules will produce a light score.
The conditions of the paper will also effect the score quality. For example, when the board is dry, there is a tendency for the board to tear and a lighter score is needed. When the board is wet, it does not cut well and the operator will typically move the cylinders closer to improve the score quality.
In order to maintain a consistent score quality while making adjustments in the nip, it is sometimes necessary to replace the scoring rules with scoring rules of different heights. For example, when the cylinders are moved closer together and the size of the nip is reduced, a shorter scoring rule can be used to prevent excessive scoring and cutting of the board. Similarly, when the cylinders are moved further apart and the size of the nip is increased, a taller scoring rule is needed. Making such changes in the die requires die-makers tools, which are not always available to rotary die operators. Further, it takes a relatively large amount of time to replace scoring rules. This downtime significantly effects the productivity of the rotary die operation.
Accordingly, there is a need for a scoring rule in which the height of the rule can be adjusted relatively quickly by the rotary die operator.


To provide a substrate laminating apparatus and a substrate laminating method capable of laminating two substrates highly precisely while achieving low cost and saving space. The substrate laminating apparatus includes an upper-substrate camera group provided to a lower vacuum chamber for capturing an image of an upper substrate fixed to an upper vacuum chamber. The upper-substrate camera group captures images of a first upper-substrate alignment mark and a second upper-substrate alignment mark of the upper substrate fixed to the upper vacuum chamber by actions synchronized with the lower vacuum chamber. Thereby, it is possible to save the space and to lower the cost by reducing the number of mechanical components.

1. Field of the Invention
The present invention relates to a substrate laminating apparatus and a substrate laminating method used for laminating an optical substrate to a display device, for example, and to a stereoscopic display device.
2. Description of the Related Art
In accordance with the recent needs for sophisticated functions of display devices, there has been used a peculiar display device capable of providing stereoscopic image display and the like in which an optical substrate such as a lenticular lens substrate, a parallax barrier substrate, or a liquid crystal lens substrate is combined with a display panel that uses an electro-optical element such as a liquid crystal or an organic EL (electroluminescence).
As an example of such display device, a display device using a lenticular lens substrate will be described. FIG. 19A is a schematic perspective view of the lenticular lens substrate, and FIG. 19B is a schematic chart showing a structural example of the display device using the lenticular lens substrate and a stereoscopic display method.
As shown in FIG. 19A, one of the surfaces of the lenticular lens substrate 50 is constituted with a plane face and the other surface is constituted with cylindrical lenses 51. The cylindrical lens 51 has a cylindrical surface and a semicircular sectional shape, and a plurality of the cylindrical lenses are continuously provided in an extended manner in an x-direction and a parallel direction.
As shown in FIG. 19B, a left-eye pixel 65a and a right-eye pixel 65b are alternately disposed on a display panel 64 by corresponding to the focal points of each of the cylindrical lenses 51. When the left-eye pixels 65a and the right-eye pixels 65b are driven according to prescribed signals by a driving circuit, not shown, a left-eye image is formed in a left-eye region 70a and a right-eye image is formed in a right-eye region 70b, respectively, by the cylindrical lenses 51. This makes it possible for an observer to recognize a stereoscopic image. Needless to mention, it is also possible to display normal two-dimensional images by driving the left-eye pixels 65a and the right-eye pixels 65b with a same signal.
Further, as a display device using a lenticular lens substrate, there is a plural-image simultaneous display device which simultaneously displays a plurality of images. Through distributing different images for observing directions by the cylindrical lenses with the same method for achieving stereoscopic display described above, this display device becomes capable of simultaneously displaying images different from each other for a plurality of observes.
With such display device using the lenticular lens substrate, it is required to mount the lenticular lens substrate on the display panel with high precision in order to achieve high-quality stereoscopic display or plural-image simultaneous display. Particularly, for high-definition display devices loaded on recent terminal devices, it is required to achieve lamination with high precision in the order of μm which has not been required conventionally.
In order to achieve the lamination precision in the order of μm, it is necessary to form a mark of the optical substrate and a mark of the display panel in the order of μm, respectively. However, in general, it is difficult to form the marks with the precision of μm at the time of manufacturing the optical substrates by machining.
As an example of a lens mark forming and mark reading method for overcoming such issue, the method depicted in Japanese Unexamined Patent Publication 2012-013933 (Patent Document 1) will be shown (FIG. 20). As a mark for reading out the positional information of the lenticular lens substrate 50, at least one non-periodical flat part 54 with which the period of the cylindrical lenses changes is provided at an end part in a lens pitch direction as shown in FIG. 20A. FIG. 20B is an example of an image acquired by irradiating light to a contact part between the lenticular lens substrate 50 and a substrate head 58 and capturing the reflection light thereof. If a specific positional relation such as the non-periodical flat part 54 is clear, it is possible to read the pitch of a specific position on the lenticular lens substrate 50. In this manner, the positional information of the lens is read out from the luminance distribution of the reflection light, the panel mark of the display panel is captured via an another camera, and the positions are aligned in the manner of indirect alignment. In the meantime, in a case of direct alignment with which the panel mark of the display panel is read out via the lenticular lens substrate, the position of the panel mark is observed by being changed by the refraction effect generated by the lenticular lens. Thus, in regards to securing the precision, the indirect alignment is more useful than the direct alignment.
Further, in a case where the display panel and the optical substrate are constituted with highly rigid materials, air bubbles tend to be mixed at the time of lamination since rigid bodies are to be laminated. For preventing the mixture of air babbles, it is known to laminate the both under a reduced pressure that is lower compared to an atmospheric pressure as depicted in Japanese Unexamined Patent Publication 2012-133098 (Patent Document 2). As the lamination materials, an adhesive film called OCA (Optically Clear Adhesive) and an adhesive called OCR (Optical Clear Resin) are used in general.
In order to achieve the highly precise lamination with such reduced-pressure laminating apparatus, first of all, used is a vacuum chamber having high rigidity in which a door valve for moving in and out the display panel and the optical substrate and other part than the opening part called a gate valve are formed as a unified structure. Secondly, mechanism components having a driving system such as highly precise XYZ-axis guide and a linear scale are used in a camera that is used for measuring the positions of an upper table and a lower table and for measuring the positions of the display panel and the optical substrate.
Now, the outline of highly precise lamination done by the reduced-pressure laminating apparatus of the related technique will be described based on paragraphs 0012 to 0014 and the flowchart of FIG. 4 shown in Patent Document 2. In a vacuum chamber, an upper table and a lower table are disposed in parallel to be facing with each other vertically with a space provided therebetween. The door valve of the vacuum chamber is opened, a display panel and an optical substrate are inserted inside the vacuum chamber, either one (upper substrate) of the display panel and the optical substrate is held to the upper table by having its lamination surface facing downwards, and the other one (lower substrate) is held on the lower table by having its lamination surface facing upwards. When the upper and lower substrates are completely placed inside, the door valve is closed, and the inside of the vacuum chamber is evacuated. Further, in a state where the upper and lower tables are facing each other vertically with a space provided therebetween, alignment marks provided, respectively, on the optical substrate and the display panel, are read out by a plurality of position measurement cameras, and positions of the upper substrate and the lower substrate are aligned by a horizontal-direction (XYθ direction) movable mechanism that is provided on the lower table. Subsequently, the upper table is brought down by a driving motor, and the upper and lower substrates are laminated. The laminated substrates are sent out from the vacuum chamber by a transport mechanism through opening the gate valve of the vacuum chamber.
There is no specific technique shown in Patent Document 2 as a technique for reading out the alignment marks provided on the optical substrate and the display panel, respectively, by using the position measurement camera. However, for example, there are a technique (FIG. 4 of JP 4330912 B (Patent Document 3)) with which a camera is disposed on the outer side (atmospheric pressure side) of a vacuum chamber and alignment marks of the upper substrate and the lower substrate inside the vacuum chamber are captured through a window that is opened through the vacuum chamber and a technique (JP 4192181 B (Patent Document 4)) with which a vacuum-resistant camera is provided inside the vacuum chamber, and alignment marks are captured under a vacuum environment.
Further, devices for performing lamination by using an upper and lower vacuum chambers and manufacturing methods thereof are depicted in Japanese Unexamined Patent Publication 2008-286886 (Patent Document 6), Japanese Unexamined Patent Publication 2010-020068 (Patent Document 7), and Japanese Unexamined Patent Publication 2009-258582 (Patent Document 8).
However, in a case where lens lamination is performed by using the methods of the related techniques described above, there are following issues to be raised.
Patent Document 2 discloses a reduced-pressure laminating apparatus which has a vacuum chamber and laminates a display panel and an optical substrate under a reduced pressure. For performing such lamination of an optical sheet constituted with a lenticular lens substrate and a panel substrate, following structures cam be considered when the mark reading method (indirect alignment) shown in Patent Document 1 is employed.
The optical sheet is held on the upper table by having its lamination surface facing downwards, and the panel substrate is held on the lower table by having its lamination surface facing upwards. After evacuating inside the vacuum chamber, a position measurement camera is disposed under an alignment mark of the optical sheet through inserting the position measurement camera into a gap between the upper table and the lower table disposed in parallel with a space provided therebetween. Further, light is irradiated to a contact part between the upper substrate and the upper table, and the reflection light from the alignment mark is captured and read out. Then, the alignment mark of the display panel is read out, and the positions of the upper substrate and the lower substrate are aligned by a horizontal-direction (XYθ direction) movable mechanism that is provided on the lower table. Finally, the upper table is brought down by a driving motor, and the upper and lower substrates are laminated tightly.
The point of this structure is to use the vacuum-resistant camera shown in Patent Document 4 as the position measurement camera, to insert the position measurement camera into the space between the upper and lower tables, and to capture and read out the reflection light of the alignment mark. However, there are following issues with the mechanism constituted with such structure.
The camera that can bear the vacuum environment shown in Patent Document 4 used as the position measurement camera requires special exterior members as well as wirings such as a camera casing formed with stainless steel, a connector, and a jacket that covers the connector. Thus, such camera is a more complicated structure than a regular camera used in an atmospheric pressure, so that it is expensive. Therefore, the cost is increased further when a plurality of those cameras are to be used.
Further, because of the structure with which the position measurement camera is inserted into the space between the upper and lower tables, it is necessary to add a highly precise XY transport mechanism within the vacuum chamber for moving the position measurement camera in the horizontal direction (XY). It is more difficult for the transport mechanism used in vacuum to radiate the heat compared to the transport mechanism used in an atmospheric pressure, so that the cost for securing the heat radiation performance and the heat resistance performance is more increased.
Further, the moving stroke of the camera transport mechanism is greater at least than the plane size of the upper table. It is because the camera needs to be evacuated from the upper table so that the camera does not become an obstruction when the upper table moves up and down in a laminating action. Thereby, the transport mechanism whose plane size is larger than that of the upper table is structured in the periphery of the upper table. Thus, the vacuum chamber that houses the transport mechanism becomes considerably larger than the case of Patent Document 2 described above. The increase in the size of the vacuum chamber leads to the increase in the size and weight of the entire laminating apparatus. Thus, it is required to increase the size of the device frame and to take a measure for increasing the rigidity, so that not only the cost but also the installment space is increased.
As a measure thereof, there is considered following Improvement Plan 1. This is a plan which uses the camera generally used in an atmospheric pressure as the position measurement camera and employs the transport mechanism that moves the position measurement camera in an atmospheric pressure as shown in FIG. 20 and FIG. 21 of WO 2010/026768 (Patent Document 5). This Improvement Plan 1 will be described in the followings.
Inside the vacuum chamber, the upper table and the lower table are disposed in parallel by facing with each other vertically with a space provided therebetween. By the side of the vacuum chamber, provided is a camera transport mechanism constituted with a scalar-type robot, an XY parallel-direction direct robot, or the like in which a plurality of position measurement cameras are provided in the tip end of an arm-type supporting body. The door valve of the vacuum chamber is opened, a display panel and an optical substrate are inserted inside the vacuum chamber, the optical substrate is held on the upper table by having its lamination surface facing downwards, and the panel substrate is held on the lower table by having its lamination surface facing upwards. When the upper and lower substrates are completely placed inside, the camera transport mechanism is inserted from the opening part of the door valve in a state where the upper and lower tables are placed to face with each other with a space therebetween, and the position measurement camera is disposed under the alignment mark of the optical substrate. Further, light is irradiated to the contact part between the upper substrate and the upper table, and the reflection light from the alignment mark is captured and read out. Then, the alignment mark of the display panel is read out. When reading of the alignment marks is completed, the camera transport mechanism is drawn out from the opening part of the door valve, and the position measurement camera is taken out to the side of the vacuum chamber. Subsequently, the door valve is closed, and the inside of the vacuum chamber is evacuated. Then the positions of the upper substrate and the lower substrate are aligned by a horizontal-direction (XYθ direction) movable mechanism that is provided on the lower table. After the position alignment, the upper table is brought down by a driving motor, and the upper and lower substrates are laminated. The laminated substrates are sent out from the vacuum chamber by a transport mechanism through opening the gate valve of the vacuum chamber.
The point of Improvement Plan 1 is to provide the camera transport mechanism constituted with a scalar-type robot, an XY parallel-direction direct robot, or the like in which a plurality of position measurement cameras are provided in the tip end of an arm-type supporting body by the side of the vacuum chamber and to read out alignment marks in an atmospheric pressure. Thereby, it becomes unnecessary to employ the above-described vacuum-resistant camera and the transport mechanism used in vacuum, so that a certain effect can be expected to address the increase in the cost and expansion in the installment space regarding those.
However, with Improvement Plan 1, it is difficult to have the lamination precision within the order of μm. That is, the arm-type supporting body having the position measurement cameras in the tip end thereof is formed in a cantilever structure having its fulcrum on the outside of the vacuum chamber. Therefore, position shift and defocusing are generated in the position measurement camera by the oscillation of the surroundings transmitted to the camera transport mechanism, so that the alignment precision is deteriorated.
Based on the above, the reduced-pressure laminating apparatus shown in Patent Document 2 still faces issues in regards to the increase in the cost, expansion in the installment space, deterioration in the lamination precision, and the like, for laminating the optical sheet constituted with the lenticular lens substrate and the display panel substrate.
In the meantime, Patent Document 1 discloses a lens mark forming and mark reading method for an optical sheet constituted with a lenticular lens substrate as well as a laminating method of an optical sheet and a display panel. As shown in paragraph 0054, FIG. 1C, and FIG. 8B of Patent Document 1, the optical sheet and display panel laminating method is to laminate the optical sheet constituted with the lenticular lens to the display panel by tilting the sheet holding head with respect to the display panel. However, as the lamination started from the end part proceeds, the contact angle between the sheet holding head and the display panel becomes smaller gradually. Thus, there is a risk of having air bubbles inserted immediately before completion of the lamination, and it is expected that the rate of having the air bubbles inserted therein becomes greater as the optical sheet becomes larger.
Further, also disclosed in Paragraphs 0061 to 0063 and FIG. 1 of Patent Document 1 is a method which laminates the optical sheet to the display panel continuously from the end part of the optical sheet towards the end part on the opposite side by having the held optical sheet to be in contact with the display panel by using a sheet holding head having an arc-shape holding face and rotating the rotation shaft of the sheet holding head while relatively moving the display panel or the rotation shaft itself to synchronize with the rotation. With this method, the contact angle between the optical sheet and the display panel becomes always constant from the start of lamination to the end. Thus, it is expected that there is no risk of having air bubbles inserted immediately before completing the lamination as mentioned above. However, while a film-sheet type optical sheet formed with a material that can be bent smoothly without hindrance can be held to the arc-shape holding face, it is difficult to hold the optical sheet formed with a highly rigid material. For example, it is difficult with this method to laminate an optical sheet constituted with a lenticular lens substrate having a transparent plate such as glass as a base member.
Thus, there is considered following Improvement Plan 2 in which a vacuum chamber and a vacuum evacuation system are added to the sheet holding head and the panel stage shown in a first exemplary embodiment of Patent Document 1, and lamination is performed in a reduced pressure that is lower than an atmospheric pressure.
Specifically, the vacuum chamber is formed as a divided structure constituted with a pair of vertically divided cubic vacuum chambers, the sheet holding head is disposed inside of the upper chamber (upper vacuum chamber) that is one of the vacuum chambers, the panel stage is disposed inside the lower chamber (lower vacuum chamber) that is the other vacuum chamber, and a vacuum evacuation system is provided on the side face of the lower vacuum chamber. Further, as the lamination steps, a step of forming a closed space as a vacuum chamber by a contact between the upper vacuum chamber and the lower vacuum chamber when bringing the sheet holding head and the panel stage to become close vertically and then reducing the pressure inside the vacuum chamber (surroundings of the sheet holding head and the panel stage) by evacuation before performing lamination is added to the step of laminating the optical sheet to the display panel (see step 106 of paragraph 0033 of Patent Document 1).
With this Improvement Plan 2, it is expected to become capable of laminating the above-described optical sheet constituted with a lenticular lens substrate having a transparent plate member as a base material. Further, the inner size of the added vacuum chamber simply needs to be slightly larger than the plane size of the sheet holding head and the panel stage. Thus, it is estimated that expansion of the installment space by employing Improvement Plan 2 is relatively small.
However, the vacuum chamber added in Improvement Plan 2 is formed in a divided structure being divided into two vertically. Thus, compared to a unified-structure vacuum structure, there is such an issue in terms of the structure that the rigidity of the parts divided into two vertically is deteriorated. That is, through providing a piping apparatus of the vacuum evacuation system on the side face of the lower vacuum chamber, the compression force by the atmospheric pressure at the time of reducing the pressure works as a shear force on the side face (horizontal direction) of the lower vacuum chamber. This causes deformation of the lower vacuum chamber. The deformation of the lower vacuum chamber causes position shift of the panel stage. Further, the shear force deteriorates the alignment precision of the horizontal transport mechanism of the panel stage. Particularly, when the vacuum evacuation direction is roughly consistent with the direction along which the lamination precision is required, the lamination precision is deteriorated by vacuum evacuation before and after a curing process of an adhesive such as OCR, for example.
Further, in a case of indirect alignment shown in Patent Document 1, it is necessary to individually capture the images of each of the marks of the optical substrate and the display panel. For example, in a case where the imaging camera exists at a fixed position when capturing the image of the optical substrate as shown in FIG. 20B of the current Specification, it is necessary to provide a step of capturing the image while moving the optical substrate and to provide a highly precise transport mechanism in order to capture marks at a plurality of points within the optical substrate. This leads to the increase in the size of the device frame due to the added transport mechanism, so that not only the cost but also the installment space is increased.
Further, regarding the transport mechanisms, there necessarily exits shift (error) in the position called alignment precision in each of the mechanisms. It means that the position shift (error) of the transport mechanism is accumulated as the number of the transport mechanisms associated with the lamination precision is increased so that the lamination precision becomes deteriorated gradually. The laminating apparatus requires lamination precision in the order of μm. Therefore, it is desired to achieve the device structure having the reduced number of transport mechanisms as much as possible in order to implement and maintain the precision.
In Patent Documents 6, 7, and 8, shown is a structure using a direct alignment method, which includes a means for capturing images of marks on the substrate in a state where an optical substrate and a display panel are placed in parallel by facing with each other with a space provided therebetween. With this method, when the optical substrate is employed as the substrate as described above, the position of the panel mark is observed by being changed by a refraction effect of the optical elements (lenticular lenses, for example) on the optical substrate. Thus, this method is inferior to indirect alignment in regards to securing the precision.
Further, with the techniques disclosed in Patent Documents 3, 6, 7 and the second exemplary embodiment of Patent Document 8, it is required to provide a window of light-transparent glass opened through a vacuum chamber in accordance with the mark capturing position. Thus, when changing the panel size, it is necessary to add the light-transparent window and modify the size of the window so that the cost is increased. In the first exemplary embodiment of Patent Document 8, disclosed is a structure with which no light-transparent glass is provided in a vacuum chamber while providing a camera inside the vacuum chamber. However, as described in Patent Document 4, the camera that can bear the vacuum environment is expensive. Further, the third exemplary embodiment of Patent Document 8 shows a structure with which lamination is performed under the vacuum environment. However, when an adhesive film called OCA is used as a lamination material, there is a risk of having air bubbles inserted between the optical substrate and the display panel as described above.
Further, in the technique disclosed in Patent Document 7, the lens pitch direction and the vacuum evacuation direction are the same as shown in FIG. 4 thereof. However, the lens pitch direction is the direction along which the lamination precision is required. Therefore, with this technique, the lamination precision is deteriorated by the vacuum evacuation as described above.
It is therefore an exemplary object of the present invention to provide a substrate laminating apparatus and a substrate laminating method capable of making it possible to perform lamination with high precision when laminating two substrates while saving the cost and space, and to provide a stereoscopic image display device of high image quality, which is manufactured by using the substrate laminating apparatus and the substrate laminating method.

Substrate laminating apparatus, substrate laminating method, and stereoscopic display device


To prevent process defects and wafer damage caused by improperly positioned wafers, a system and method for detecting a position of a wafer determines whether the wafer is properly positioned before executing a process. The system includes a chuck plate preferably having a supporting part configured to support a lower face of the wafer and a guide part located on a perimeter of the supporting part. A sensing unit senses a positional state of the wafer on an upper portion of the supporting part. A controller receives a signal corresponding to the positional state of the wafer from the sensing unit, and determines whether the wafer is properly positioned. The controller then sends an output control signal to an outputting unit to notify an operator of the wafer position. In this manner, process defects are avoided and a fabricating yield and operating rate of a fabrication unit increases.

This invention claims priority from Korean Patent Application No. 2001-5339, filed Feb. 5, 2001, the contents of which are herein incorporated by reference in their entirety.
1. Field of the Invention
The present invention relates to a system and method for detecting a position of a semiconductor wafer and more particularly, to a system and method that determines whether the wafer is normally positioned before executing a process, to prevent process defects.
2. Discussion of Related Art
In facilities for fabricating semiconductor devices, a vacuum pressure environment is generally used to prevent pollution and maintain the purity of a wafer. Bake oven facilities, for example, typically use vacuum pressure conditions. In a bake oven, an outer housing is generally made of opaque material, such as metal, to provide durability and airtightness. Because of this, however, it is difficult to determine whether a wafer is properly positioned within the bake oven and whether the process was properly executed.
To perform a process, the wafer is first positioned on a chuck plate. A conventional procedure for placing the wafer on the chuck plate, and its attendant difficulties, will be described with reference to FIGS. 1 and 2. Referring to FIG. 1, a general robot unit (not shown) places a wafer W in position on an upper part of a chuck plate 10 inside a fabrication unit, such as a bake oven. The chuck plate 10 includes elevator pins 12 which move vertically up and down. As the wafer is placed in the fabrication unit, the elevator pins 12 are elevated to prop up and support a lower face of the wafer W. After the robot unit places the wafer W it is withdrawn. When the robot unit is retracted from the wafer W, the elevator pins 12 are lowered to bring the lower face of the wafer W to rest on the upper face of the chuck plate 10. The wafer W can be positioned and maintained on the upper face of the chuck plate 10 using special equipment, or the wafer W may be positioned and fixed using a general fixing unit (not shown) installed on the chuck plate 10. Once positioned, the wafer W receives a desired environmental condition (such as a temperature state, an electric characteristic, etc.) through a condition forming part 14 installed on the chuck plate 10.
Unfortunately, a wafer particle or other particle P may unseat a lower face of the wafer W from an upper face of the chuck plate 10. If the wafer W rests unevenly on the chuck plate 10, the environmental condition provided by the condition forming part 14 will not be properly applied to the wafer, thus resulting in a process defect.
Referring to FIG. 2, besides process defects resulting from particles unseating the wafer W from the chuck plate 10, defects may also result from poor alignment of the wafer W on the chuck plate 10. A procedure for positioning the wafer W on the chuck plate includes a series of steps. The robot unit conveys the wafer W to the chuck plate 10. The wafer W is then transferred from the robot unit to the elevated elevator pins 12. The elevator pins are then lowered to place the wafer in contact with the upper face of the chuck plate 10. During these steps, however, various kinds of shocks, vibrations, or the like may cause the wafer W to be placed off-center from a proper position on the chuck plate 10. If such an operation error occurs, a portion of the wafer may hang over an edge of the chuck plate 10. If the wafer W is improperly positioned in this manner, the process will be performed non-uniformly over the face of the wafer W. Furthermore, if the wafer W overlaps a previously positioned wafer on the chuck plate 10, not only will a pattern layer formed on the wafer W be damaged, but the next procedure will also be adversely affected.
A conventional solution to these problems is to form a transparent window in the fabrication unit to allow a user to see into a given portion of the unit. A window, however, does not readily permit a determination that the wafer W is unseated when its separation from the chuck plate 10 is minimal. Furthermore, the window only permits viewing of the wafer W from a specific, fixed position. It would be desirable in the industry to have a system and method for detecting semiconductor wafer position that would automatically correct certain defects in wafer positioning. It would also be desirable to have a system and method for detecting semiconductor wafer position that would permit detection of even minute displacements of the wafer from the chuck plate surface.
Accordingly, the present invention is directed to a system and method for detecting a position of a semiconductor wafer that substantially obviates one or more of the limitations and disadvantages of the related art.
A primary object of the present invention is to provide a system and method for detecting a position of a semiconductor wafer, in which process defects and wafer damage can be prevented to increase fabrication yield. The system and method preferably provide easy verification of wafer position to permit determination of whether the wafer has been properly transferred to a chuck plate, whether the wafer has been placed in the right position on the chuck plate, whether the wafer is folded, and whether the wafer is separated from the chuck plate.
In accordance with a preferred embodiment of the present invention, a system for detecting a position of a semiconductor wafer includes a chuck plate having a supporting part, for supporting a lower face of a wafer, and a guide part formed on an outer perimeter of the supporting part. A sensing unit senses a position of the wafer on an upper portion of the supporting part and transmits a sensing signal to a controller. The controller preferably receives the sensing signal, corresponding to the wafer position, from the sensing unit, and transmits an output control signal to an outputting unit based on the sensing signal. The outputting unit can include a bell unit for outputting alarm sound, a lamp unit for outputting light, a monitoring unit for supplying a video image, and/or a switching unit for selectively cutting off power applied for respective constructions of the fabrication facilities.
An upper side portion of an inner side wall of the guide part is preferably provided with an inwardly slanted face so as to direct a wafer positioned on the guide part toward a center of the chuck plate. The supporting part and the guide part can be formed integrally or assembled together in an operating relationship. If assembled from separate components, the guide part could be constructed to move up and down in relation to the supporting part in response to a driving control signal from the controller. It may also be desirable for the guide part to be provided in at least two segments arranged at given intervals along an outer perimeter of the supporting part. A lower part of the chuck plate can include a rotating unit configured to rotate the supporting part in response to a rotation control signal from the controller.
The sensing unit is preferably constructed having optical sensors. The optical sensors can be configured to supply irradiating probe light against an edge portion of the wafer positioned on the supporting part and to receive and sense an amount of light reflected or diffracted therefrom. In one configuration, the optical sensors can be installed between the guide part segments. Alternatively, the optical sensors can be installed in opposing pairs along the inner wall of the guide part, with each sensor in a pair being located on an opposite side of a center of the supporting part. A plurality of light emitting and receiving sensors could also be disposed in various vertical positions along the guide part inner wall.
A method of detecting a position of a semiconductor wafer is also provided. The method includes supporting an edge portion of the wafer on a guide part and placing the wafer on a supporting part. A position of the wafer on the supporting part is sensed using a sensing unit during a sensing operation. A measurement value obtained through the sensing operation is then compared with a determination value range to detect and output an adhesion state and a positional state of the wafer.
To sense the positional state of the wafer on the supporting part, the sensing unit can be constructed having light emitting and receiving sensors arranged in pairs opposite each other across the supporting part. A plurality of light emitting and receiving sensors can be disposed in various elevations along the guide part inner wall so as to sense the positional state of the wafer along an upper face of the supporting part. Alternatively, the light emitting and receiving sensors can be arranged in opposing pairs at a single elevation with the guide part configured to be raised or lowered in relation to the supporting part. In this configuration, the sensors can sense the positional state of the wafer on the upper face of the supporting part as the guide part elevates and descends.
Sensing the positional state of the wafer on the supporting part could also be accomplished by constructing the guide part with at least two segments arranged at given intervals along an outer perimeter of the supporting part. In this embodiment, the supporting part is configured to selectively rotate. The sensing unit includes an optical sensor that transmits probe light between the segments of the guide part against an edge of a wafer positioned on the rotatable supporting part. As the supporting part is rotated, the optical sensor senses an amount of light reflected or diffracted from the wafer to determine the positional state of the wafer on the upper face of the supporting part.

System and method for detecting position of semiconductor wafer