JPWO2008038567A1 - Method for manufacturing molded sheet and apparatus for manufacturing the same - Google Patents

Abstract

The method for producing a molded sheet according to the present invention is a method for producing a molded sheet by molding a resin into a sheet by pressing the resin between a pair of roll molds R1, R2, and a pair of rolls The step of adjusting the rotational phase of the pair of roll molds R1, R2 so that the distance between the rolls between the molds R1, R2 is constant, and the pair of roll molds R1, R2 in a state where the phases are synchronized And a step of making the rotational angular velocities of R2 substantially the same. Thereby, the thickness of a forming sheet can be controlled precisely.

Description

  The present invention relates to a method and apparatus for manufacturing a molded sheet, and more particularly, to a method for manufacturing an optical sheet that requires precise thickness control used in a rear projection television or the like.

  Conventionally, transmissive screens are generally used for rear projection televisions. A structural example of this transmission screen is shown in the schematic cross-sectional view of FIG. As shown in FIG. 8, the transmissive screen includes a Fresnel lens sheet 1 and a lenticular lens sheet 2. Usually, the transmission type screen is configured with the Fresnel lens sheet 1 and the lenticular lens sheet 2 in close contact with each other. In this specification, the incident side, the emission side, the incident surface, and the emission surface are the incident side, the emission side, the incident surface, and the emission of the light shown in FIG. Shows the surface.

  A structural example of the lenticular lens sheet 2 is shown in the sectional view of FIG. As shown in FIG. 9, the lenticular lens sheet 2 generally has a plurality of incident side lenses 21, and the incident side lenses 21 have a substantially cross-sectional shape. The plurality of incident-side lenses 21 are arranged on the light incident slope side, and are formed so that the distances between the lens valley portions 22 are equal. The image light passes through the Fresnel lens sheet 1 and is converged and emitted as parallel light. The converged parallel light is greatly diffused in the horizontal direction by the lenticular lens sheet 2. This makes it possible to observe an image in a wide visual field range in the horizontal direction.

  As shown in FIG. 9, a plurality of exit side lenses 23 are arranged on the light exit side of the lenticular lens sheet 2. A plurality of light absorbing layers 24 are provided between the plurality of exit side lenses 23, and the light absorbing layer 24 is made of a light absorbing material such as black ink. The plurality of light absorption layers 24 are provided in portions (non-light condensing portions 25) other than the light condensing portions of the respective incident side lenses 21. Thus, by providing the light absorption layer 24 on the light emitting side, the contrast in the bright room is improved. Further, in FIG. 9, the boundary portion 241 of the light absorption layer 24 is provided on the slope 251 of the non-light-collecting portion 25 in order to improve the external light contrast.

  Further, in the lenticular lens sheet 2 of the projection type video apparatus having a plurality of video light sources, it may be required to correct color unevenness. In this case, another lens is also provided in the condensing part of the incident side lens 21 on the light incident surface. In the following description, the light incident surface may be referred to as an HL surface, and the light absorption layer 24 may be referred to as a black stripe or BS.

  In such a lenticular lens sheet 2, the distance from the position of each incident side lens 21 provided on the light incident surface side to the exit side lens 23 (hereinafter, this may be referred to as inter-lens distance or sheet thickness). )is important. Specifically, if the sheet thickness is too thin or too thick, part of the transmitted light is blocked. As a result, the transmission efficiency is lowered or the intended emission pattern cannot be obtained. Therefore, it is necessary to precisely adjust the sheet thickness (see Patent Document 1).

  In particular, in recent years, the lenticular lens sheet 2 is required to have high definition, and the pitch needs to be further reduced. For example, the pitch of the conventional lenticular lens sheet 2 is about 0.7 to 1.0 mm, and the sheet thickness is about 0.8 to 1.2 mm. Therefore, the conventional lenticular lens sheet 2 is good with an accuracy of about ± 0.01 mm. On the other hand, in the recent lenticular lens sheet 2, a pitch of 0.3 to 0.1 mm is used, and the sheet thickness in that case is approximately 0.4 to 0.1 mm. Therefore, the recent lenticular lens sheet 2 is required to have an accuracy of less than ± 5 μm, and further less than ± 3 μm.

  Conventionally, the lenticular lens sheet 2 is manufactured by an extrusion molding method in which a thermoplastic resin is extruded using a roll molding die, a so-called 2P molding method in which an ultraviolet curable resin is laminated on a base sheet, or the like. In such a manufacturing method, the sheet thickness is controlled by the distance between the rolls between the pair of roll forming dies. The roll forming die performs engraving and surface treatment on the surface while rotating around the roll axis, thereby providing a predetermined uneven shape, mirror surface, and the like. Thereafter, the roll forming die is installed in a forming apparatus to form a sheet.

  The schematic diagram of FIG. 10 shows a state where the roll mold is installed in the molding apparatus. As shown in FIG. 10, the roll shaft 51 of the roll forming die 5 is set in parallel with a rotating shaft 52 that causes the forming device to rotate the roll forming die 5 in this state. The forming apparatus rotates the roll forming die 5 from this state. As shown in FIG. 10, the roll shaft 51 of the installed roll forming die 5 rotates in a state of being deviated from the rotation shaft 52 when actually rotating. Accordingly, the roll forming die 5 rotates around the rotation shaft 52 in an eccentric state, and the roll shaft 51 rotates around the rotation shaft 52.

As described above, the roll shaft 51 of the roll mold 5 in the state where it is installed in the molding apparatus and the rotary shaft 52 of the roll mold 5 that actually rotates at the time of manufacture cannot be exactly matched. For this reason, periodic rotation unevenness called run-out occurs in the distance between the rolls of the pair of roll forming dies 5. Moreover, periodic rotation unevenness also occurs due to the performance of a bearing or the like that supports the roll forming die 5. In accordance with this periodic unevenness, unevenness occurs in the sheet thickness. In particular, in recent lenticular lens sheets for which high definition is required, it is necessary to precisely control the thickness of the sheet, and a technique for controlling the distance between rolls more precisely is required.
JP-A-5-150371

As described above, in the conventional method for manufacturing a lenticular lens sheet, the roll axis of the roll mold and the rotation axis of the roll mold at the time of manufacture cannot be exactly matched. Therefore, there is a problem that the distance between the rolls of the pair of roll forming dies changes and it is difficult to precisely control the sheet thickness.
This invention is made | formed in view of the said subject, and it aims at providing the manufacturing method of the molded sheet which can control sheet | seat thickness precisely, and its manufacturing apparatus.

The method for manufacturing a molded sheet according to the present invention is a method for manufacturing a molded sheet by pressing the resin melted between a pair of roll molds to form the resin into a sheet shape, Adjusting the rotational phase of the pair of roll molds so that the distance between the roll molds is constant, and adjusting the rotational phase speed of the pair of roll molds And substantially the same step.
With such a configuration, the change in the distance between the rolls in the pair of roll forming dies can be minimized, so that the distance between the rolls can be kept constant and the sheet thickness can be precisely controlled.

  Furthermore, the method for manufacturing a molded sheet according to the present invention includes a step of detecting the distance between the rolls, and in the step of adjusting the rotational phase, the rotational phase is adjusted based on the detected distance between the rolls. is there.

Further, in the step of adjusting the rotational phase, the one roll forming die is moved away from the one roll forming die as one roll forming die approaches the other roll forming die.
With such a configuration, the change in the distance between the rolls in the pair of roll forming dies can be minimized, so that the distance between the rolls can be kept constant and the sheet thickness can be precisely controlled.

  Furthermore, when the diameters of the pair of roll molds are φ1 and φ2, respectively, and the rotational angular velocities of the pair of roll molds are S1 and S2, respectively, φ1 <φ2 and S1 <S2.

  The method for producing a lenticular lens sheet according to the present invention uses such a molded sheet as a lenticular lens sheet having a plurality of lenticular lenses and a plurality of convex portions. With such a configuration, the sheet thickness of the lenticular lens sheet can be precisely controlled.

The forming sheet manufacturing apparatus according to the present invention is a forming sheet manufacturing apparatus having a pair of roll forming molds that press the molten resin while rotating, and the distance between the rolls between the pair of roll forming molds is constant. Adjusting means for adjusting the rotational phase of the pair of roll forming dies, and rotation that makes the rotational angular velocities of the pair of roll forming dies substantially the same with the rotational phase adjusted by the adjusting means. And an angular velocity control means.
With such a configuration, the change in the distance between the rolls in the pair of roll forming dies can be minimized, so that the distance between the rolls can be kept constant and the sheet thickness can be precisely controlled.

  Furthermore, the molded sheet manufacturing apparatus according to the present invention includes a detecting unit that detects the inter-roll distance, and the adjusting unit adjusts the rotational phase based on the detected inter-roll distance.

The adjusting means moves the other roll forming die away from the one roll forming die as one roll forming die approaches the other roll forming die.
With such a configuration, the change in the distance between the rolls in the pair of roll forming dies can be minimized, so that the distance between the rolls can be kept constant and the sheet thickness can be precisely controlled.

  Furthermore, when the diameters of the pair of roll molds are φ1 and φ2, respectively, and the rotational angular velocities of the pair of roll molds are S1 and S2, respectively, φ1 <φ2 and S1 <S2.

  The apparatus for producing a lenticular lens sheet according to the present invention uses the molded sheet as described above as a lenticular lens sheet having a plurality of lenticular lenses and a plurality of convex portions. With such a configuration, the sheet thickness of the lenticular lens sheet can be precisely controlled.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method and manufacturing apparatus of a shaping | molding sheet which can control sheet | seat thickness precisely can be provided.

It is a plane schematic diagram which shows the example of 1 structure of the extrusion manufacturing apparatus which concerns on this invention. It is a figure for demonstrating the principle of the nonuniformity of the distance between the conventional rolls. It is a figure for demonstrating the principle of the nonuniformity of the distance between the conventional rolls. It is a figure for demonstrating the principle of the nonuniformity of the distance between the conventional rolls. It is a figure for demonstrating the principle of the nonuniformity of the distance between the conventional rolls. It is a figure for demonstrating the principle of the nonuniformity of the distance between rolls in this invention. It is a figure for demonstrating the principle of the nonuniformity of the distance between rolls in this invention. It is a figure for demonstrating the principle of the nonuniformity of the distance between rolls in this invention. It is a schematic diagram which shows one structural example of the measuring apparatus of the distance between rolls concerning this invention. It is a plane schematic diagram which shows an example of the state of a roll. It is a graph which shows an example of change of distance between rolls concerning the present invention. It is a graph which shows an example of change of distance between rolls concerning the present invention. It is a schematic sectional drawing which shows one structural example of the conventional transmission type screen. It is a schematic sectional drawing which shows one structural example of the conventional transmission type screen. It is a plane schematic diagram which shows an example of the state of a roll.

Explanation of symbols

10 ... Extrusion manufacturing equipment, 11 ... Die, 12, 13 ... Roll forming die,
14 ... roll, 15 ... resin, 151 ... lenticular lens sheet 30 ... roll distance measuring device, 31 ... laser light emitting part, 32 ... laser light receiving part,
33 ... Laser beam evaluation unit, 34 ... Rotational angular velocity control device 1 ... Fresnel lens sheet, 2 ... Lenticular lens sheet, 21 ... incident side lens,
22 ... Lens valley part, 23 ... Exit side lens, 24 ... Light absorption layer, 241 ... Boundary part,
25 ... Non-condensing part, 251 ... Slope 5 ... Roll mold, 51,52 ... Rotating shaft

The method and apparatus for producing a patterned sheet according to the present invention can be used for producing an optical sheet used in, for example, a rear projection television. In particular, the manufacturing method and the manufacturing apparatus can be suitably applied to manufacturing a lenticular lens sheet. In this embodiment, with reference to FIGS. 8 and 9 as appropriate, the lenticular lens sheet 2 will be described as an optical sheet. However, the present invention is not limited to this.
The best mode for carrying out the present invention will be described below with reference to the drawings.

First, the configuration of the extrusion manufacturing apparatus according to the present invention will be described with reference to FIG. FIG. 1 is a schematic plan view showing a main part of an extrusion manufacturing apparatus according to the present invention.
As shown in FIG. 1, the die 11 discharges molten resin 15. The resin 15 discharged from the die 11 passes through the air gap, and from the nip position between the roll forming die 12 as the first roll and the roll forming die 13 as the second roll, between the roll forming dies 12 and 13. To the roll gap provided in The resin 15 sent to the roll gap is pressurized in the roll gap between the roll molds 12 and 13.
Specifically, the resin 15 is pressed against the roll mold 13 because the roll mold 12 presses the roll mold 13 with a predetermined pressing force. As a result, the surface of the lenticular lens sheet and the back surface of the resin 15 are formed on the resin 15.

  When the resin 15 passes through the roll gap of the roll molds 12 and 13, it is cooled by the roll mold 13 that functions as a main cooling roll. The cooled resin 15 is taken out from the roll gap as a sheet-like resin on which irregularities of the lenticular lens sheet are formed. Thereafter, the resin 15 is sent to a roll 14 that functions as an annealing roll, and is sent to a winding device (not shown) as a lenticular lens sheet 151 for processing. Although not shown in FIG. 1, in the manufacturing apparatus 10, a printing process is performed as the lenticular lens sheet 151 immediately after being extruded. After the printing process is performed, the lenticular lens sheet 151 is sent to a winding device (not shown) and processed.

Next, with reference to FIG. 1, the appearance of fluctuations in the distance between rolls in the conventional manufacturing apparatus and the effects of the present invention will be described with reference to FIG. 1.
In the extrusion manufacturing apparatus 10 shown in FIG. 1, roll forming dies 12, 13 (hereinafter, these may be referred to as roll forming dies R1, R2) having the same roll diameter and the same rotational angular velocity are used. Yes. FIGS. 2 and 3 show how the distance between rolls of a lenticular lens sheet manufactured using these roll molds R1 and R2 varies.
Here, the meanings of the roll forming dies R1 and R2 mean a first roll forming die provided in the forming apparatus and a second roll forming die different from the first roll forming die. It does not mean the first roll forming mold and the second contacting roll mold.

  Generally, the roll mold is pivotally supported by a bearing member. Due to the dimensional accuracy of the bearing member and the like, the roll forming die causes a periodic displacement in the direction parallel to the rotation axis as it rotates. The accuracy standard of the bearing member is 5 to 4 μm even if it is a 5 to 4 grade bearing member having an excellent accuracy grade. For this reason, periodic rotation unevenness occurs in several μm.

  Furthermore, since the rotation axis at the time of manufacturing the roll forming die and the rotation axis when installed in the molding apparatus cannot be exactly matched, periodic rotation unevenness called run-out is also added.

  2A and 2B show periodic rotation unevenness of the roll forming dies R1 and R2. Here, the vertical axis in FIG. 2A indicates the distance from a predetermined reference position to the surface of the roll mold R1. As shown in FIG. 2A, periodic rotation unevenness with an amplitude A is generated every time the rotation period Ta is rotated. The roll forming die R2 is the same, and as shown in FIG. 2B, periodic rotation unevenness with an amplitude B is generated each time the rotation is performed at the rotation period Tb.

  The roll forming dies R1 and R2 are set at a predetermined interval and rotate. At this time, the distance between the rolls between the roll forming dies R1 and R2 is obtained by superimposing the rotation unevenness of FIGS. 2A and 2B. Therefore, the period of the periodic rotation unevenness is equal to the length of the molded sheet formed while the roll mold is rotated once.

  2C and 2D show an example of how the roll molds R1 and R2 are rotated. In FIG. 2C, the roll forming dies R1 and R2 are rotated at positions where the respective amplitudes become maximum. At this time, the non-uniformity in the distance between rolls has a maximum amplitude of (A + B). In FIG. 2D, the roll mold R1 rotates at a position where the amplitude is maximum in the positive direction, and the roll mold R2 is rotated at a position where the amplitude is minimum (maximum amplitude in the negative direction). . At this time, the non-uniformity in the distance between the rolls is the minimum | A−B | amplitude. Thus, the unevenness in the distance between rolls varies greatly depending on the phase of the rotational unevenness of the roll molds R1, R2.

  The present invention focuses on this point. Specifically, in the present invention, the roll forming dies R1 and R2 are rotated so that the respective displacement amplitudes cancel each other. More specifically, in the present invention, the rotational phase of the roll forming dies R1 and R2 is adjusted so as to minimize the variation in the distance between the rolls between the roll forming dies R1 and R2, and fixed to this rotational phase. Make the rotation angular velocity substantially the same. In the above example, adjustment is made so that the rotational phases of the roll molds R1, R2 maintain the state shown in FIG. 2D.

Here, even if the rotational angular velocities of the roll forming dies R1 and R2 are not exactly the same, it is only necessary that the effects can be exhibited.
In general, in a roll forming apparatus, a resin reservoir (hereinafter sometimes referred to as a bank) is provided for the purpose of applying tension to a sheet, or at a location where the roll and the resin are in contact with each other, so For the purpose of adjusting the shape, etc., it is usual to make a difference in the rotational angular velocities of the roll forming dies R1, R2. Hereinafter, the difference between the rotational angular velocities of the roll molds R1 and R2 expressed as a percentage may be referred to as a draw ratio.
When there is a difference in the rotational angular velocities of the roll forming dies R1 and R2, the state of the distance between the rolls alternately repeats the state shown in FIG. 2C and FIG. If the rotational angular velocity difference between the roll forming dies R1 and R2 is small, the beat period becomes very large. Therefore, the phase of the roll can be readjusted when the unevenness of the distance between the rolls becomes relatively large. In this invention, it is not limited to which rotation angular velocity of roll shaping | molding die R1, R2 is large. For example, in extrusion molding, the draw ratio of the roll molds R1, R2 is about 1% to 10%.

  More preferably, in the present invention, molding is performed by setting a slight difference in the rotational angular velocities of the roll forming dies R1, R2. In this case, the sizes of the roll diameters are changed approximately corresponding to the draw ratio. Thereby, the rotational angular velocities of the roll forming dies R1 and R2 can be made substantially the same, and the unevenness in the distance between the rolls can be set to the minimum amplitude as shown in FIG. 2D.

FIG. 3A and FIG. 3B show an example of how the roll forming dies R1 and R2 having the same roll diameter in the extrusion manufacturing apparatus according to the present invention are rotated. 3A and 3B, a slight difference is given to the rotational angular velocities of the roll molds R1 and R2, and the rotational angular velocities are made different.

However, as shown in FIGS. 3A and 3B, it is assumed that the rotational angular velocities are slightly different in the combination of roll forming dies R1 and R2 having the same roll diameter. Then, as shown in FIG. 3C, unevenness in the inter-roll distance is generated, which shows a “beat” phenomenon in which a relatively short first period and a relatively long second period are combined.
That is, the roll forming die R1 causes rotation unevenness with an amplitude A and a period Ta as shown in FIG. 3A. At the same time, the roll forming die R2 causes rotation unevenness with an amplitude B and a period Tb as shown in FIG. 3B. At this time, the non-uniformity in the distance between the rolls of the roll dies R1, R2 periodically changes with the maximum amplitude (A + B) and the minimum amplitude | A−B | as shown in FIG. 3C.
Note that fa and fb shown in FIGS. 3A and 3B are reciprocals of the periods Ta and Tb, respectively, and correspond to frequencies.

Next, the inter-roll distance measuring apparatus according to the present invention will be described. Here, a case where a lenticular lens sheet is manufactured as an example of a molded sheet will be described.
The schematic diagram of FIG. 4 shows a configuration example of the inter-roll distance measuring device according to the present invention. In FIG. 4, reference numeral 10 generally indicates the inter-roll distance measuring apparatus according to the present invention. As shown in FIG. 4, the inter-roll distance measuring device 30 includes a laser light emitting unit 31, a laser light receiving unit 32, and a laser light evaluation unit 33.

  The laser light emitting unit 31 emits laser light, and the laser light receiving unit 32 receives the laser light emitted from the laser light emitting unit 31. The laser beam evaluator 33 evaluates the intensity of the laser beam received by the laser receiver 31. The laser light emitting unit 31, the laser light receiving unit 32, and the laser light evaluating unit 33 function as a detecting unit that detects a positional shift periodically generated by the rotation of the roll forming dies R1 and R2. That is, the inter-roll distance measuring device 30 functions as this detection means.

  In the inter-roll distance measuring device 30, a part of the laser light emitted from the laser light emitting unit 31 is blocked by the roll forming dies R1 and R2. The laser light receiving unit 32 receives transmitted laser light other than the blocked laser light. The laser light receiving unit 32 inputs the received laser light to the laser light evaluating unit 33. The laser beam evaluation unit 33 evaluates the intensity of the input laser beam and calculates the distance between rolls of the roll forming dies R1 and R2 based on the intensity of the laser beam. Thereby, the distance between rolls of the roll molds R1, R2 is measured.

  The laser beam evaluator 33 controls the rotational phase of the roll molds R1, R2 based on the measurement result, and adjusts the distance between the rolls. Specifically, the laser beam evaluation unit 33 inputs the measurement result to the rotation angular velocity control device 34 that controls the rotation angular velocities of the roll forming dies R1 and R2. The rotation angular velocity control device 34 calculates the optimum rotation angular velocity of each of the roll forming dies R1 and R2 as described above based on the input measurement result. The rotational angular velocity control device 34 controls the rotational phase of the roll forming dies R1, R2 based on this rotational angular velocity. Thereby, the distance between rolls of the roll molds R1, R2 is adjusted. Therefore, the rotation angular velocity control device 34 functions as an adjusting unit that adjusts the distance between rolls detected by the distance measurement device 30 between rolls. At the same time, the rotational angular velocity control device 34 functions as a rotational angular velocity control means for making the rotational angular velocities of the roll molds R1, R2 substantially the same while the roll molds R1, R2 are in a synchronized state.

When such a distance measuring apparatus between rolls is used, the rotational phase alignment of the roll forming dies R1 and R2 can be efficiently performed as described below.
Specifically, a difference of several percent is applied to the rotational angular velocities of the roll forming dies R1 and R2, and the state in which the distance between the rolls varies as shown in FIG. 3C is reproduced. The roll-to-roll distance measuring device 30 measures the change in the distance between the rolls by observing two to three long cycles. The inter-roll distance measuring device 30 detects the position and timing at which the unevenness of the inter-roll distance is minimized from the measurement result. The inter-roll distance measuring device 30 makes the rotational angular velocities of the roll molds R1, R2 substantially the same in the rotational phase of the roll molds R1, R2 based on the detection result. As a result, it is possible to realize a state in which the unevenness in the distance between rolls is the smallest as shown in FIG. 2D.

In addition, the measuring method of the distance between rolls is not specifically limited to the said method. You may measure the thickness of the sheet | seat shape | molded by another method.
Although the position of the inter-roll distance measuring device 30 is not particularly described, for example, one position may be installed at the center position in the width direction of the sheet, or two positions may be installed near both ends. It is preferable to provide at a position where the thickness unevenness of the sheet to be formed is desired to be minimized.
Further, as shown in FIG. 5, since the rotation unevenness may be inclined with respect to the axis of the roll, the rotation phase is set so as to minimize the thickness unevenness of the entire sheet by providing a plurality of inter-roll distance measuring devices 30. It is more preferable to adjust.

  As described above, in the present invention, the rotational angular velocities of the roll forming dies R1 and R2 are made substantially the same, and the rotational phase is controlled to be the same phase. In other words, the roll mold R2 moves away from the roll mold R1 as the roll mold R1 approaches the roll mold R2. As a result, the non-uniformity in the distance between the rolls of the roll forming dies R1, R2 is minimized, so that the distance between the rolls can be kept substantially constant and the sheet thickness can be precisely controlled.

Examples of the present invention will be specifically described below.
<Example>
Using an acrylic / styrene copolymer resin, a lenticular lens sheet 2 having a pitch of 0.15 mm and a sheet thickness of 0.2 mm was manufactured by an extrusion molding method.
As the inter-roll distance measuring device 30, “Laser Line Gauge VG manufactured by Keyence Corporation” was used.

本実施例では、ロール間距離の周期変化は、表１に示す回転数、ドロー比から予想される短周期１２.３秒、長周期５．２分とほぼ一致している。このことから、ロール間距離の周期変化は、ロール成形型Ｒ１，Ｒ２それぞれの回転ムラが重畳して現れたものと推定される。このとき、ロール間距離の周期変化は、図６に示すように、およそ０．２±０．０１ｍｍ、すなわち２００±１０μｍであった。First, in order to match the rotational phase of the roll, a sheet was formed under the manufacturing conditions shown in Table 1 so that the change in the distance between the rolls shows a periodic change as shown in FIG. 3C. As a result, as shown in FIG. 6, the inter-roll distance showed a periodic change of about 12 seconds for a short period and about 5 minutes for a long period.

In this example, the cycle change in the distance between rolls is almost the same as the short cycle of 12.3 seconds and the long cycle of 5.2 minutes expected from the rotation speed and draw ratio shown in Table 1. From this, it is presumed that the periodic change in the distance between the rolls appears as the rotation irregularities of the roll forming dies R1 and R2 are superimposed. At this time, the period change of the distance between rolls was approximately 0.2 ± 0.01 mm, that is, 200 ± 10 μm, as shown in FIG.

Next, with respect to the periodic change in the distance between rolls shown in FIG. The result is shown in FIG. However, in FIG. 7, when the distance between rolls is 0.2 mm, that is, 200 μm, the vertical axis is 0 point, and the fluctuation from the 0 point is shown. As a result, as shown in FIG. 7, the distance between the rolls was about 0.2 ± 0.003 mm, that is, 200 ± 3 μm in a short period of about 12 seconds, and the fluctuation range was as extremely small as 6 μm.
As described above, in this embodiment, the change in the distance between the rolls can be made extremely small, whereby the sheet pressure of the lenticular lens sheet 2 can be precisely controlled.

  The present invention is used, for example, in the manufacture of optical sheets that require precise thickness control, such as those used in rear projection televisions.

Claims (10)

A method of producing a molded sheet by molding the resin into a sheet by pressing the molten resin between a pair of roll molds,
Adjusting the rotational phase of the pair of roll molds so that the distance between rolls between the pair of roll molds is constant;
And a step of making the rotational angular velocities of the pair of roll forming dies substantially the same in a state where the rotational phase is adjusted. Detecting the distance between the rolls further,
The method for producing a molded sheet according to claim 1, wherein in the step of adjusting the rotational phase, the rotational phase is adjusted based on the detected distance between rolls.   2. The step of adjusting the rotational phase includes moving the other roll forming die away from the one roll forming die as one roll forming die approaches the other roll forming die. Or the manufacturing method of the shaping | molding sheet | seat as described in any one of 2.   The diameters of the pair of roll forming dies are φ1 and φ2, respectively, and the rotational angular velocities of the pair of roll forming dies are S1 and S2, respectively, and φ1 <φ2 and S1 <S2. The manufacturing method of the molded sheet as described in any one of 1-3.   The method for producing a lenticular lens sheet, wherein the molded sheet according to any one of claims 1 to 4 is a lenticular lens sheet having a plurality of lenticular lenses and a plurality of convex portions. An apparatus for producing a molded sheet having a pair of roll molds that press the molten resin while rotating,
Adjusting means for adjusting the rotational phase of the pair of roll molds so that the distance between the rolls between the pair of roll molds is constant;
An apparatus for manufacturing a molded sheet, comprising: a rotation angular velocity control unit that makes the rotation angular velocities of the pair of roll forming dies substantially the same in a state where the rotation phase is adjusted by the adjustment unit. A detecting means for detecting the distance between the rolls,
The said adjustment means adjusts the said rotation phase based on the detected distance between rolls, The manufacturing apparatus of the molded sheet of Claim 6 characterized by the above-mentioned.   8. The adjusting device according to claim 6, wherein the adjusting means moves the other roll forming die away from the one roll forming die as one roll forming die approaches the other roll forming die. An apparatus for producing a molded sheet according to claim 1.   The diameters of the pair of roll forming dies are φ1 and φ2, respectively, and the rotational angular velocities of the pair of roll forming dies are S1 and S2, respectively, and φ1 <φ2 and S1 <S2. The manufacturing apparatus of the shaping | molding sheet as described in any one of 6 thru | or 8.   10. The apparatus for producing a lenticular lens sheet, wherein the molded sheet according to claim 6 is a lenticular lens sheet having a plurality of lenticular lenses and a plurality of convex portions.

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