JP5162936B2 - Optical sheet feeding device - Google Patents

Description

  The present invention relates to a feeding device for an optical sheet such as a polarizing sheet used in a liquid crystal display panel.

  Conventionally, in the process of sticking a polarizing sheet to a liquid crystal display panel, as shown in Patent Document 1, the polarizing sheets stocked on the tray are taken out one by one from the tray and placed on the conveying means, and then moved to the sticking work position. And carry.

  At this time, since the polarizing sheet is made of a resin sheet that is thin and easily charged with static electricity, a plurality of polarizing sheets may be taken out of the tray while being overlapped and placed on the conveying means.

In order to prevent such overlapping feeding of the polarizing sheets, the supply device of Patent Document 1 detects the thickness of the extracted polarizing sheet by a thickness sensor, confirms that it is one sheet, and places it on the conveying means. ing.
JP 2003-228057 A

  However, the detection of the number of polarizing sheets by the thickness sensor as described above has a problem that it is not possible to accurately detect the overlapped feed if an inadvertent deformation such as warpage occurs in the polarizing sheet.

  An object of the present invention is to provide an optical sheet feeding device capable of always feeding one by one while preventing the optical sheet from being repeatedly fed.

The optical sheet feeding device according to claim 1 of the present invention includes a conveying unit that conveys an optical sheet along a predetermined path, a sheet supply unit that sequentially places the optical sheet on the conveying unit, and the conveying unit. A transmittance measuring means for measuring the light transmittance of the optical sheet placed on the means and outputting the measurement value signal; and the optical sheet measured according to the transmittance measured value measured by the transmittance measuring means. of determining the number, and a controller for outputting a control signal according to the determination result, possess,
The transport means comprises a base and a transport tape rotated in the longitudinal direction of the transport means along the surface thereof.
The optical sheet is placed so that the placement position on the transport tape is shifted to one side from the longitudinal center of the transport tape, and both end portions protrude from the transport tape, respectively.
The transmittance measuring unit measures the light transmittance of the optical sheet at the end of the optical sheet that protrudes from the transport tape, at the end closer to the center in the longitudinal direction of the transport tape. It is characterized by doing.
The optical sheet feeding device according to claim 2 is the optical sheet feeding device according to claim 1, wherein the sheet supply unit includes a suction pad for sucking the optical sheet,
When the controller determines that the number of the optical sheet is one based on the output signal, the controller releases the suction of the optical sheet by the suction pad, and when the controller determines that the number of the optical sheet is two or more, the controller The suction pad is raised without releasing the suction of the optical sheet.
The optical sheet feeding device according to claim 3 is the optical sheet feeding device according to claim 2, wherein the controller re-starts after determining that there are two or more optical sheets based on the output signal. In the measurement, when it is determined that there are two or more optical sheets, the suction pad is lowered to cause the optical tape that has been sucked to adhere to the transport tape.
The optical sheet feeding device according to claim 4 is the optical sheet feeding device according to any one of claims 1 to 3, wherein the base has a direction orthogonal to the longitudinal direction of the transport tape. A through-hole drilled at a predetermined angle is provided,
The transmittance measuring means includes a light-emitting element and a light-receiving element that are disposed in an opposing arrangement with the optical axes aligned with each other across the through-hole.

The optical sheet feeding device according to claim 5 is the optical sheet feeding device according to any one of claims 1 to 4 , wherein the measurement value result data output from the transmittance measuring means is an analog signal. It is characterized by being output.

The optical sheet feeding device according to claim 6 is the optical sheet feeding device according to any one of claims 1 to 5 , wherein the controller starts feeding by the sheet feeding means and is the first one. The light transmittance of the optical sheet is used as a reference value, and the number of conveyed optical sheets is determined.

  According to the optical sheet feeding device of the present invention, it is possible to reliably prevent the overlap feeding and always feed one sheet at a time.

  FIG. 1 is a top view showing a polarizing sheet feeding device as an embodiment of the present invention used in the manufacturing process of a liquid crystal display panel, and FIG. 2 is an explanatory view showing the configuration of the main part thereof.

  As shown in FIG. 1, the polarizing sheet feeding device of the present embodiment includes a stocker 2 for the polarizing sheet 1, a conveyor 3 for transporting the polarizing sheet 1 to a work position for attaching the polarizing sheet 1 to a liquid crystal display panel, and a stocker 2 for the polarizing sheet 1. , A loader 4 placed on the conveyor 3, a sensor unit 5 that measures the light transmittance of the placed polarizing sheet 1, and a controller that controls the feeding operation of the polarizing sheet 1 based on an output signal from the sensor unit 5 6 etc.

  The stocker 2 includes a rectangular bottom plate 21 and a pair of side plates 22 and 22 erected at diagonal corners thereof. Each side plate 22 has an L-shaped flat cross section, and regulates the diagonal corner position of the polarizing sheet 1 to form its stock.

  The conveyor 3 is arranged in parallel with the stocker 2 and includes a base 31 and an endless transport tape 32 that is rotated in the direction of the arrow along the surface thereof, as shown in FIG. The transport tape 32 has a two-layer structure in which an adhesive layer 322 is laminated on the surface of the base tape 321, and rotates along a predetermined path from the mounting position of the polarizing sheet 1 through a mounting position to a liquid crystal display panel (not shown). It is stretched by a plurality of support rollers 33 so as to be movable. The base 31 is provided with a through hole 311 for measuring light transmittance in the vicinity of the conveyance tape travel path at the position where the polarizing sheet 1 is placed. As shown in FIG. 3, the through-hole 311 is formed by being inclined at a predetermined angle in a direction orthogonal to the transport tape traveling direction.

  As shown in FIG. 1, the loader 4 includes a suction pad 41, a cylinder 42 that supports the suction pad 41, and a lift cylinder 42 that supports the suction pad 41 in parallel with the extending direction (traveling direction) of the transport tape 32. It comprises a linear movement mechanism 43 to be moved.

  The sensor unit 5 includes a light emitting element 51 and a light receiving element 52. The light receiving element 52 outputs a analog signal corresponding to the amount of received light. As shown in FIG. 3, the light emitting element 51 and the light receiving element 52 are disposed so as to face each other with their optical axes aligned with the inclined through hole 311 of the base 31 interposed therebetween. In this case, the light emitting element 51 is installed as close as possible to the through hole 311 at a position off the upper side in the vicinity of the mounting position of the polarizing sheet 1. In this way, by arranging the sensor unit 5 and the through hole 311 in an inclined manner, when the polarizing sheet 1 is placed on the placement position on the base 31 (shown by a broken line in FIG. 1), the light emitting element 51 becomes an obstacle. To avoid becoming.

  The controller 6 is a programmable controller (hereinafter referred to as PLC (Programmable Logic Controller)) including an input / output circuit, a CPU (Central Processing Unit), a memory, and the like. The output signal from 52 is processed to control the feeding operation of the polarizing sheet. The control operation based on this stored program will be described in detail later.

  An A / D converter 7 for converting an analog signal into a digital signal is interposed between the controller 6 and the light receiving element 52 of the sensor unit 5, and a warning indicator 8 is connected to the output side of the controller 6. .

  Next, the operation of the polarizing sheet feeding device configured as described above will be described.

  In FIG. 1, first, the cylinder 42 of the loader 4 is driven, the suction pad 41 is lowered, the uppermost sheet of the polarizing sheet 1 loaded on the stocker 2 is sucked and raised, and the linear movement mechanism 43 is driven. Then, the suction pad 41 on which the polarizing sheet 1 is sucked and held is linearly moved together with the cylinder 42 in the direction of the white arrow. When the polarizing sheet 1 to be sucked and held arrives above the placement position indicated by the two-dot chain line, the cylinder 42 is stopped, and the polarizing sheet 1 to be sucked is placed on the transport tape 32 by lowering the suction pad 41. . At this time, the adsorption state of the polarizing sheet 1 is maintained without being released. Therefore, the polarizing sheet 1 is held in a state where one side is adsorbed by the suction pad 41 and the other side is adhered to the adhesive layer 322 on the surface of the transport tape 32. Note that a transparent separate film (not shown) is attached to one side of the polarizing sheet 1, and this separate film side is attached to the adhesive layer 322 of the transport tape 32.

  The mounting position of the polarizing sheet 1 is set at a position where the portion held by the transport tape 32 is shifted to one side from the center in the longitudinal direction, as shown by a two-dot chain line. That is, the holding position is set so that the area of the part covering the upper side of the through-hole 311 is about 1/3 of the area of the part floating in the air on the opposite side. As a result, the degree of bending of the portion of the polarizing sheet 1 that covers the upper portion of the through hole 311, that is, the portion that measures the light transmittance, is less than that in the case where it is held at the central portion. Depending on the mounting position of the polarizing sheet 1, accurate and stable light transmittance can be measured.

  Next, light is emitted from the light emitting element 51, and the light transmitted through the polarizing sheet 1 and passing through the through hole 311 is received by the light receiving element 52. At this time, the light transmitting portion of the polarizing sheet 1 is always stably supported substantially horizontally as described above. Therefore, there is no problem that the amount of received light varies depending on the holding state of the polarizing sheet 1.

  The light receiving element 52 outputs an analog signal voltage photoelectrically converted according to the amount of light received. In this case, since the output signal voltage is analog, the dynamic range can be easily expanded to increase the resolution.

The analog signal voltage output from the light receiving element 52 with an expanded dynamic range is converted into a digital signal through the A / D converter 7 and input to the PLC 6. In the PLC 6, a digital signal indicating the light transmittance of the first (first) polarizing sheet 1 loaded is taken in as the light transmittance of one polarizing sheet, and this is placed at the mounting position. A reference value for determining the number of polarizing sheets is used. The light transmittance of the first polarizing sheet 1 as the determination reference value is set and displayed as “1” on the touch panel indicator of the PLC 6 . In this case, the display of the placed polarizing sheet 1 for determining the range and one is, when the reference value 1, a 0.85 to 1.15. In general, the light transmittance of one polarizing sheet is distributed between 30% and 50%. Therefore, if the distribution range is set to a range of ± 15% with respect to the reference value, 1 This is because there is no possibility of erroneously determining that the number of sheets is zero or two or more.

  When the setting of the determination range for determining one polarizing sheet 1 is finished, the suction by the suction pad 41 is released, and the first polarizing sheet 1 is transported downstream by rotating the transport tape 31 for a predetermined time. To do. The suction pad 41 whose suction has been released is raised and returned to the upper side of the original stocker 2 to start the suction of the next polarizing sheet 1.

  When the second polarizing sheet 1 is placed at the placement position where the updated transport tape 31 is rotated by the same polarizing sheet supply operation and waits, the measurement of the light transmittance is similarly started. In the measurement of the light transmittance, when the display of the PLC 6 is less than 0.85, the polarizing sheet is “none”, when the display is 0.85 to 1.15, “one sheet”, when larger than 0.85, “Two or more” is determined.

  When it is determined as “one sheet”, the suction of the polarizing sheet 1 by the suction pad 41 is released, and the transport tape 32 is rotated so that the polarizing sheet 1 at the placement position is released as in the case of the first polarizing sheet. It is transported a certain distance downstream.

  On the other hand, if it is determined that “None” other than “1” or “2 or more” is determined, a signal indicating erroneous supply is output to the warning indicator lamp 8 and a warning is displayed to stop the production line. . When the line is stopped, the operator visually discriminates whether the warning content is “None” or “2 or more”, and in the case of “2 or more” overlap feeding, the suction pad 41 is manually released from suction. Raise without. Thereby, since the lowermost polarizing sheet is adhesively held by the adhesive layer 322 of the transport tape 32, only the polarizing sheet superimposed thereon rises together with the suction pad 41. Thereafter, the light transmittance of the polarizing sheet 1 adhered and held on the transport tape 32 is measured again, and when it is determined to be “one sheet”, the light is transported downstream.

  If it is determined that “two or more sheets” are obtained even in the re-measurement of the light transmittance described above, the operator removes the polarizing sheet laminate from the transport tape 32 and lowers the suction pad 41 to remove the polarizing sheet that has been sucked. The conveyance tape 32 is adhesively held. Thereafter, the light transmittance is newly measured, and after confirming that it is “one sheet”, it is conveyed downstream. In this new light transmittance measurement, if it is determined that “two or more sheets” are determined, the separation operation is performed again by raising and lowering the suction pad 41 described above, and after confirming “one sheet”, the polarizing sheet is moved downstream. Transport to the side.

  If it is identified as “None” by visual inspection after the warning is displayed, the operation state such as the suction pressure of the suction pad 41 is inspected, and if it is confirmed that there is no abnormality, the polarizing sheet feeding process by this production line is resumed. .

  When the feeding of the polarizing sheet 1 loaded on the stocker 2 is completed, the stocker is changed and a feeding process for a new stacked polarizing sheet is started. At this time, the light transmittance of the first polarizing sheet is taken in as a new determination reference value, and the determination range is newly set automatically. Therefore, even when the type of polarizing sheet is changed and the light transmittance is greatly changed, the polarizing sheet is prevented from being repeatedly fed in the same process as in the case of the same type of polarizing sheet. Can be fed one by one.

  As described above, according to the polarizing sheet feeding device of the present embodiment, the number of polarizing sheets to be fed is determined by measuring the light transmittance thereof, so that the polarizing sheet is influenced by deformation states such as warping. It is possible to accurately determine the number of sheets and feed them one by one stably.

  In addition, since an analog signal voltage obtained by photoelectrically converting the amount of received light is output as an output from the light receiving element 52, a dynamic range of an output signal from the light receiving element 52 in feeding a type of polarizing sheet having a low light transmittance. Can be easily enlarged, and the number of fed sheets can be detected with high accuracy.

  Further, since the light transmittance of the polarizing sheet 1 to be fed first is taken as a judgment reference value, and the judgment range for judging the number of the polarizing sheets to be fed is automatically set based on this, the polarized light to be fed Sheet type switching can be easily performed by a simple operation of simply replacing the stacker 2.

The present invention is not limited to the above embodiment.
For example, one polarizing sheet used as a reference for determining the number of polarizing sheets to be fed is placed at a position different from the feeding line of the polarizing sheet, and the light transmittance of this reference polarizing sheet is always taken in and fed. It is good also as a structure which compares the light transmittance of the polarizing sheet which should be sent, and determines the number of sheets.

  Further, the conveying means is not limited to the endless belt type in the above embodiment, and various other conveying means such as a drum type can be adopted.

  In addition, the present invention is not limited to the polarizing sheet feeding device, and is naturally applicable to various other optical sheet feeding devices such as a phase plate.

It is a top view which shows the polarizing sheet feeding apparatus as one Embodiment of this invention. It is explanatory drawing which shows the principal part structure of the said base sheet feeding apparatus. It is typical sectional drawing which cuts and shows the said principal part by the III-III line in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Polarizing sheet 2 Stacker 21 Bottom plate 22 Side plate 3 Conveyor 31 Base 311 Through hole 32 Conveying tape 321 Base sheet 322 Adhesive layer 33 Support roller 4 Loader 41 Suction pad 42 Cylinder 43 Linear movement mechanism 5 Sensor unit 51 Light emitting element 52 Light receiving element 6 PLC (Programmable Logic Controller)
7 A / D converter 8 Warning indicator

Claims (6)

Conveying means for conveying the optical sheet along a predetermined path;
Sheet supply means for sequentially placing the optical sheets on the conveying means;
Transmittance measuring means for measuring the light transmittance of the optical sheet placed on the conveying means and outputting the measurement value signal;
In response to said transmission measurements made by transmittance measuring unit determines the measured number of optical sheets, and a controller for outputting a control signal according to the determination result, possess,
The transport means comprises a base and a transport tape rotated in the longitudinal direction of the transport means along the surface thereof.
The optical sheet is placed so that the placement position on the transport tape is shifted to one side from the longitudinal center of the transport tape, and both end portions protrude from the transport tape, respectively.
The transmittance measuring unit measures the light transmittance of the optical sheet at the end of the optical sheet that protrudes from the transport tape, at the end closer to the center in the longitudinal direction of the transport tape. An optical sheet feeding device characterized in that: The sheet supply means has a suction pad for sucking the optical sheet,
When the controller determines that the number of the optical sheet is one based on the output signal, the controller releases the suction of the optical sheet by the suction pad, and when the controller determines that the number of the optical sheet is two or more, the controller The optical sheet feeding device according to claim 1, wherein the suction pad is lifted without releasing the suction of the optical sheet. If the controller determines that the number of optical sheets is two or more even after re-measurement after determining that the number of optical sheets is two or more based on the output signal, the controller lowers the suction pad and sucks the optical The optical sheet feeding apparatus according to claim 2, wherein the sheet is adhesively held on the transport tape. The base is provided with a through hole that is drilled at a predetermined angle in a direction perpendicular to the longitudinal direction of the transport tape,
The said transmittance | permeability measurement means consists of the light emitting element and light receiving element which are installed in the arrangement | positioning which opposes each optical axis on both sides of the said through-hole, and to oppose. The optical sheet feeding device according to 1. The measurement result data outputted from the transmittance measurement unit, the optical sheet feeding apparatus according to any one of claims 1 to 4, characterized in that output an analog signal. Said controller, said sheet feeding means to start feeding by a reference value the light transmittance of the first optical sheet, any of claims 1 to 5, characterized in that to determine the number of optical sheets to be conveyed the optical sheet feeding apparatus according to an item or.

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