JP2777833B2 - Projection screen manufacturing method and double-sided lenticular lens - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a transmissive or reflective projection screen used as a screen of a projection television or a microfilm reader, and a double-sided lenticular lens. .

(Prior Art) Transmissive projection screens and the like are widely used for the purpose of displaying film advertisements, projected television images, microfilm images, and the like. Usually, this type of projection screen is provided with a predetermined lens on an entrance surface or an exit surface so as to be bright when viewed from the observation side and to enlarge the viewing angle. For example, the use of a double-sided lenticular lens or fly's eye is disclosed in
No. 436, Japanese Utility Model Publication No. 52-4932, Japanese Patent Application Laid-Open No. 57-81254,
No. 57-81255 and JP-A-58-108523.

However, in order to obtain the desired characteristics of this type of screen, it is essential that the relative positions of the lenticular lenses or fly's eyes on both sides be accurately controlled. For example, lenticular lens pitch is 1mm
In the case of the degree, the positional deviation of both sides is required to be within ± 2%, that is, the positional accuracy of about ± 20 μm. If the error is not controlled within this range, the color balance will deteriorate,
Inconveniences such as narrowing of the visual field range and occurrence of color unevenness in the screen occur.

Most of the double-sided lenticular lenses currently in practical use are molded products of methacrylic resin, and the molding methods include roll forming of extruded plates, casting by cell casting, and compression molding by heating press. The technology is applied, and in each case, a method of directly or indirectly transferring a metal mold to a resin plate is adopted.

In order to make a double-sided lenticular lens accurately, A. The dimensional accuracy of the molds on both sides is high, B. The mold temperature during molding is uniform, and the molding shrinkage of the resin is uniform. It is required that the alignment is accurate and there is no backlash. For example, a 1-meter square screen pitch of 1 mm and a 1-mm thick double-sided lenticular lens are formed.
Assuming that the permissible accuracy of the lateral displacement and the plate thickness is within ± 2%, the positional accuracy of the double-sided lenticular lens is
The total error factors of A, B, and C must be kept within ± 2 μm both in the horizontal direction and in the thickness direction.

However, when examining the coefficient of linear expansion of the metal, steel: 1.1 × 10 ^-5 1 / ° C aluminum: 1.7 × 10 ^-5 〃 brass: 1.8 × 10 ^-5 、 When the temperature changes by ℃, steel 11μ, aluminum 17μ, and brass 18μ will be expanded and contracted, so mold accuracy (including factory temperature accuracy),
Extremely sophisticated equipment and technology will be required for controlling the molding temperature and positioning the double-sided mold.

In recent years, the trend toward large-screen televisions with higher definition has been strengthened, and lenticular lenses for screens have also been required to have finer pitches. It is not easy to make the positional deviation of the front and rear double-sided lenses of the lens plate much higher than the above-mentioned value.

For this reason, if a transparent cylindrical body in which the lenticular lens units of the incident surface and the exit surface are integrated is used for the lens unit, it is considered that at least the positional relationship between the lenticular lenses on both surfaces can be easily secured. For example, JP 47
Specific proposals have been made in JP-A-28925, JP-A-59-121647, JP-A-59-121648, and JP-A-59-123850.

(Problems to be solved by the invention) However, when a prototype of the screen proposed above is manufactured,
As can be seen immediately, in each case, the gap between the cylindrical lenses always occurs, and the straight rays leaking from them have a serious problem (such as see-through, hot band, etc.), and have good characteristics. It becomes practically impossible to provide a transmissive screen having the same.

This is because the accuracy of the diameter of the currently available transparent fiber cylindrical body has a variation of at least about ± several percent, and a gap is always generated simply by arranging these. Even if the columnar bodies are arranged while applying a pressing force to each other, a gap is formed as a result as long as there is no means for firmly fixing them.

Also, in JP-A-47-28925, a columnar elongated lens is arranged in layers, and a dark color coating is performed on the entire surface of the layer.
There is a description to scatter and emit light by providing an unpainted part, but the specific method is not specified, and considering that this type of product has not been put to practical use in the industry, the specific manufacturing method has been established. It is thought that it was not possible, and it was not feasible with the light from the gap.

In view of such a situation, the present invention provides a screen manufacturing method with excellent performance by arranging light-transmitting strands in parallel without gaps and integrating them in a sheet shape, and arranging the light-transmitting strands with high precision. It is intended to provide a lenticular lens.

(Means for Solving the Problems) That is, the present invention has been made to solve the above-mentioned problems. When melt-spinning a large number of plastic-based light-transmitting strands, the individual spinning nozzle holes are formed in a straight line. At the same time, at least the inlet side of the adjacent nozzle holes is brought close to each other at a small interval, and immediately after the molten resin is spun from the nozzle holes, a phenomenon that the translucent strands are enlarged in the radial direction to cause the translucent strands to intersect each other. A first aspect of the present invention is a method for manufacturing a projection screen, wherein a single or a plurality of obtained sheets are fused and integrated, taken out in a sheet shape, and a double-sided lenticular lens is obtained. When melt-spinning a conductive strand, the nozzles are formed by bringing the individual spinning nozzle holes into a straight line and making at least the inlet side of the adjacent nozzle holes close to each other at a small interval. A plurality of the fibers are arranged in parallel and in front and behind, and the phenomenon that the translucent strands immediately after the molten resin is spun out from each nozzle hole expands in the radial direction is caused to fuse together to form a tape shape. A projection screen characterized by alternately guiding the two to a converging roll, bringing them into close contact with each other, fusing the adjacent parts into a sheet form, and forming a double-sided lenticular lens with one or a plurality of the obtained sheets. A second lenticular lens is formed on the incident side surface so as to form a pair with the first lenticular lens on the observation side surface so as to face the first lenticular lens. In a double-sided lenticular lens in which a lens is formed, a pitch of the lens unit is 0.1 to 0.5 mm, and an external light absorbing portion is provided between the lens units of the second lenticular lens. There sided lenticular lens, characterized in that at to the third invention.

 Hereinafter, the present invention will be described with reference to the drawings.

The production method of the present invention, which is the first invention, is carried out by using a melt spinning technique.
FIG.

In the figure, (1) is an extruder, (2) is a die (1A)
And discharges the molten resin from a spinning nozzle hole. The arrangement of the nozzle holes at this time will be described later, but a metering pump such as a gear pump may be provided to secure the stability of the discharge amount of the molten resin.

The translucent strand discharged from the nozzle hole is taken into a sheet shape by a take-up roll (4) via a guide roll (3), and cut into a predetermined length by a cutter (5). A single sheet obtained in this way or a plurality of these sheets are connected in the width direction to form a double-sided lenticular lens.

The light-transmitting strand used in the present invention is a resin having a good light-transmitting property, for example, a thermoplastic polymer such as an acrylic polymer, a polycarbonate polymer, or a polyacrylate, a crosslinked silicon polymer, a crosslinked acrylate polymer, or an ionically crosslinked polymer. And the like. The thickness of the light-transmitting strand at this time varies depending on the size, application, and purpose of the screen, but is generally about 0.1 to 1.5 mm.In particular, according to the production method of the present invention, the light-transmitting strand has a thickness of 0.5 mm. Even in the case of mm or less, the positional accuracy of the front and back double-sided lenses can be maintained with high accuracy, which sufficiently contributes to the fine pitch of the screen.

The cross-sectional shape of the light-transmitting strand is not limited to a circular shape, and an oval shape, an oval shape, or the like can be selected according to optical characteristics.

The present invention, as described above, when melt-spinning a large number of plastic-based translucent strands, while arranging individual spinning nozzle holes in a straight line, adjacent nozzle holes are closely spaced at small intervals, It is characterized by causing a phenomenon that the translucent strands are fused and integrated with each other by causing a phenomenon of expanding in the radial direction immediately after the molten resin is spun out from the nozzle hole.

This point will be described below with reference to FIGS.

In this example, translucent strands having a substantially oval cross section are arranged in a sheet-like manner, and FIG. 2 shows a nozzle hole (2A) of a nozzle.
Is shown.

The nozzle holes (2A) are arranged in a straight line, and the adjacent nozzle holes (2A) have a small interval (2B) from the inlet side to the outlet side.
Is placed in close proximity. When the molten resin is spun from such a nozzle hole (2A), the spun light-transmitting strands (10) adhere to each other due to a radially enormous phenomenon (referred to as a balus effect) as shown in FIG. Wear and integrate.
FIG. 4 shows this state as a model, but it becomes enormous immediately after spinning from the nozzle hole (2A).

FIG. 5 shows another example of the nozzle (2). The nozzle hole (2A) has a taper at the tip end and the nozzle hole is in close contact with the outlet side. It can be made more stable.
This phenomenon affects the diameter of the nozzle hole (2A), the setting of the small interval (2B), the operating conditions of the extruder and the metering pump, and the temperature and viscosity of the molten resin. It is desirable to select optimal conditions.

When the small interval (2B) of the nozzle holes (2A) is set to a range of about 5 to 30% with respect to the nozzle diameter at the nozzle entrance, good adhesion by the bolus effect is good, and the translucent strands are fused to each other. Has been found to be suitable for If it is less than 5%, the cross-sectional shape of the resulting light-transmitting strand may change. Conversely, if it exceeds 30%, the light-transmitting strands are in close contact with each other or are less likely to be fused after the contact. is there.

Further, the sheet in which the light-transmitting strands are integrated as described above is generally stretched and further reduced in diameter to improve the strength, but in the production method of the present invention, this stretching step is performed in a sheet state. Will receive it.

6 to 8 show examples of another cross-sectional shape of a sheet in which light-transmitting strands used for a projection screen obtained by the method of the present invention are integrated, and these are all different types by a conjugate spinning method. Obtained by simultaneously spinning the materials of different colors).

6 and 7 show the translucent strand (1
FIG. 8 shows an example in which an external light absorbing portion (11) made of a material containing a light absorbing agent is provided between the strands on the observation side surface with respect to the light transmitting portion (10A) which is the main component of (0). This is an example in which a light-transmitting strand (10) is formed by a first light-transmitting portion (10B) and a second light-transmitting portion (10C) using materials having different refractive indexes.

9 to 11 show an example of the second invention of the present invention in which an extremely large number of light-transmitting strands are simultaneously spun. In the example of FIG. 9, two rows of nozzles (2) are used. , (2) are arranged in parallel, and below this, a converging roll (6) for winding the translucent strand is arranged.

In this method, one nozzle (2) is used for 20 to 20 nozzles.
A group of nozzle holes having about 100 nozzles as one unit is provided, and the light-transmitting strands (10) discharged in a tape shape in this unit are guided onto a converging roll (6), and each tape-like strand is further moved in the width direction. And connect it to a sheet.

At this time, the arrangement of the nozzle holes of the nozzle (2) is preferably configured as shown in FIG. 12 and FIG.

The nozzle unit of the group of linear arrays at this time is L,
The tape width after stretching When the number of rows is R and the interval between nozzles is P, Should be established, and if this is rewritten, Becomes For example, if L = 45 mm, L / D = 25 mm, and R = 2, the stretching ratio D ² is And from now on It can be seen that the interval P between the nozzles should be 5 mm.

As a result, when the focusing roll (6) rotates at a peripheral speed of 3.24 times the discharge speed from the nozzle hole, the stretching ratio can be increased to 3.24 times.
Can be reduced to 1 / 1.8 of the diameter of the nozzle hole. This allows a very large number of translucent strands (1
0) can be made close together to form a wide sheet, but when increasing or decreasing the number of light-transmitting strands (10) to be discharged, the width regulating rings (6) at both ends of the converging roll (6) can be used.
A).

It is desirable to adjust the temperature to an optimum temperature for winding and cooling the light-transmitting strand (10) by circulating hot water inside the focusing roll (6).

FIG. 10 shows an example in which three rows of nozzles (2), (2) and (2) in which nozzle holes are arranged in series are used, and the basic concept is the same as that of FIG.

In the case of manufacturing by this apparatus, first, a light-transmitting strand (10) is discharged from a nozzle hole of a nozzle, and is independently taken up by a high-speed rotating focusing roll (6).
Two guides (7A) and (7B) below the nozzle (2)
Is positioned horizontally. This guide (7A), (7B)
Is provided as shown in Fig. 11. The guides (7A) and (7B) are provided with concave grooves in which the pitch (TP) of the tape unit is shifted so as to partially overlap each other by TP / 3. When the focusing roll (6) is decelerated and stretched, the translucent strands (10) discharged from the three nozzles (2) pass through the tape shape into a sheet-like shape as in the case of FIG. It can be integrated. After the conditions (7A) and (7B) are stabilized, the guides (7A) and (7B) may be returned to the vertical position, but the nozzle holes of the nozzles need to be aligned with the positions shifted by the pitch (TP).

Further, as a method of omitting the guide as described above, it is preferable to arrange the nozzles (2) as shown in FIG.

That is, in this example, the nozzles (2) are arranged in five rows, and a group of linearly arranged nozzles is L = 45 mm, the tape width after stretching L / D = 15 mm, and the number of rows R = 5. That is, the stretching ratio is set to 3, Therefore, the interval P between the nozzle groups is preferably set to 30 mm.

By converging with a converging roll using a die having such a nozzle hole, a screen integrated into a sheet can be obtained without using a guide.

It is desirable that the screen obtained by the manufacturing method of the present invention use a double-sided lenticular lens composed of a single sheet over the entire width of the transmission screen, but when there is a restriction due to the manufacturing apparatus, the screen becomes a unit. A lenticular lens sheet having a predetermined width may be manufactured and connected in the width direction using a plurality of adhesives or adhesive tapes to form a double-sided lenticular lens.

According to such a manufacturing method of the present invention, the positional deviation of the lens on both the front and back surfaces of the double-sided lenticular lens can be easily and significantly improved. In particular, even for a double-sided lenticular lens with a fine pitch of 0.5 mm or less, which has been impossible in the past, it is possible to similarly increase the positional deviation of the front and rear surfaces of the lens.

In the double-sided lenticular lens of the present invention, for example, a first lenticular lens is formed on an incident side surface, and is opposed to the first lenticular lens on an observation side surface, as shown in FIGS. 14 and 15, for example. A high-definition double-sided lenticular lens having a pitch of 0.1 to 0.5 mm in a second lenticular lens so as to form a pair with each other, and external light between the lens units of the second lenticular lens. An absorbing section is provided.

It is particularly preferable that the double-sided lenticular lens has light-transmitting transparent columnar bodies adjacent to each other in a side-by-side relationship, and that the light on the incident side is closely adhered so as not to leak from the gap between the transparent columnar bodies. As an example, for example, in the same manner as in the method for manufacturing a screen using the translucent strands, the translucent strands cause a phenomenon in which the translucent strands expand in the radial direction, and a fused surface is formed on the outer surface thereof. And a sheet which is integrated by fusion.

According to such a manufacturing method, even in a fine pitch double-sided lenticular lens having a lens unit of 0.5 mm or less, it is possible to achieve high precision with a small positional shift between the front and rear surfaces of the lens.

In the double-sided lenticular lens of the present invention, if the lens pitch is less than 0.1 mm, sufficient high precision cannot be achieved, and if it exceeds 0.5 mm, sufficient high definition cannot be achieved, and more preferably 0.1 It is in the range of ~ 0.25mm.

As described above, a screen using a double-sided lenticular lens having a structure having an external light absorbing portion on the observation side can form high-contrast, high-performance image quality.

(Example) Hereinafter, an example of the present invention will be described.

Example 1 A double-sided lenticular lens was manufactured using an apparatus substantially as shown in FIG.

The nozzle holes used at this time had the shapes and arrangements shown in FIGS. 2 and 5, and three dies were arranged in parallel to make a total of 4100 holes. Then, a convergence roll was arranged at a position 200 mm below the die.

At this time, the interval (C) on the inlet side of the nozzle hole shown in FIG. 2 is 0.05 mm, the width (W) is 0.75 mm, and the length (T) is 0.90 m.
m and the nozzle pitch (NP) were 0.80 mm.

The methacrylic resin pellets are plasticized by a vent extruder according to a conventional method, the molten resin is supplied to the nozzle using a gear pump, and discharged from the nozzle hole tip at a speed of 0.2 m / min.
Using a guide having a TP of 24 mm as shown in FIG. 1, it was subdivided into a tape shape, these were alternately arranged on a collecting roll, and were taken up by a guide roll. At this time, the width between the width regulating rings of the collecting roll was 1.050 mm.

The collecting roll was initially operated at a peripheral speed of 3 m / min, but gradually decelerated to 1.8 m / min. The convergence roll was controlled by circulating warm water at 50 ° C., the space from just below the die to the convergence roll was covered with a duct, and the discharged translucent strand was gently exposed to warm air and taken off.

The lenticular lens sheet obtained in this manner is cut to a length of 800 mm, and the focal length is 1 m (length and width are 800 × 1.05
0mm) Fresnel lens and a diffusion plate of the same size with a thickness of 3mm. This screen was attached to a Pioneer 50 "projection television" SD-P 5020 "and observed. However, it was a high-quality screen with fine brightness and stable color tone.

By the way, when the cross section of this lenticular lens sheet was examined, it was in the state as shown in FIG. 3 and the width (W ') was 0.25.
mm, height (T ') 0.3 mm, R ₁ = 0.125 mm, R ₂ = 0.1 m
m.

Example 2 Polycarbonate resin having a nozzle hole having the same shape as that of Example 1 and having a refractive index of 1.6
(10B) in the figure, methacrylic resin with a refractive index of 1.49
Using a conjugate spinning device as shown in the figure (10C), the light-transmitting strand was discharged under the same conditions as in Example 1 and integrated into a sheet by a focusing roll and taken off.

When the optical characteristics of the obtained screen were measured by a gonio-photometer, a screen gain as shown in FIG. 16 was obtained, and it was confirmed that the screen had particularly excellent color balance.

(Effects of the Invention) The present invention has a configuration as described in detail above, but can provide a screen body having no gaps and being in close contact with each other, and is excellent in a bright, high-definition, high-quality projection screen. Can be manufactured efficiently.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of the first invention of the present invention, FIG. 2 is a bottom view showing a nozzle hole, FIG. 3 is a cross-sectional view showing a part of the obtained screen, FIG. FIG. 5 is a cross-sectional view showing a state in which a light-transmitting strand is discharged from a nozzle. FIGS. 6 to 8 are partially enlarged cross-sectional views of a screen showing another example. FIGS. FIG. 11 is a perspective view and a side view showing an example of the invention of FIG. 2, FIG. 11 is a partially enlarged plan view of a guide in FIG. 10, FIG. 12 and FIG. 13 are schematic views showing an arrangement of nozzle holes, FIG. FIG. 15 is a sectional view showing an example of the third invention of the present invention, and FIG. 16 is a graph showing transmission characteristics of a screen in the example. (1) Extruder (1A) Die (2) Nozzle (2A) Nozzle hole (2B) Small interval (3) Guide roll (4) Take-up roll (5) ) Cutter (6) Focusing roll (6A) Width control ring (7A), (7B) Guide (10) Translucent strand (10A) Translucent section (10B) (10C): a light-transmitting portion made of a material having a different refractive index (11): an external light absorbing portion (12): a first lenticular lens (13): a second lenticular lens

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-168112 (JP, A) JP-A-2-125242 (JP, A) JP-A 1-117179 (JP, A) JP-A 55-168 30401 (JP, A) JP-A-52-15615 (JP, A) JP-B-51-44217 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03B 21/62 G03B 21 / 60 D01D 5/253

Claims (7)

(57) [Claims] When melt-spinning a large number of plastic translucent strands, individual spinning nozzle holes are arranged in a straight line, and at least the inlet side of adjacent nozzle holes is brought close to each other at a small interval. , Immediately after the molten resin is spun from the nozzle hole, causing a phenomenon that the translucent strands are fused and integrated with each other by causing a phenomenon of enormous expansion in the radial direction, and are taken out in a sheet shape, and the obtained sheet is used alone or in plural. A method for producing a projection screen, comprising a double-sided lenticular lens. 2. The method for manufacturing a projection screen according to claim 1, wherein a plastic translucent strand having a non-circular cross section is melt-spun. 3. The light-transmitting strand according to claim 1, wherein each of the light-transmitting strands has a portion that provides an optical function different from a main portion in a part of the cross section. 3. The method for manufacturing a projection screen according to item 2. 4. A nozzle formed by melt-spinning a large number of plastic-based translucent strands, in which individual spinning nozzle holes are linearly arranged and at least the inlet sides of adjacent nozzle holes are closely spaced at a small interval. Are arranged in parallel and in front and behind, and a phenomenon that the translucent strand group immediately after the molten resin is spun out from each nozzle hole is radially enlarged to be fused and integrated with each other to form a tape shape. Along with this, the projection screen is characterized in that it is alternately guided on a converging roll, brought into close contact with each other, and the adjacent portions are fused together to form a sheet, and the obtained sheet is used as a double-sided lenticular lens with a single or a plurality of sheets. Production method. 5. A first lenticular lens is formed on a surface on an incident side, and a second lenticular lens is formed on a surface on an observation side so as to face the first lenticular lens and form a pair with each other. A double-sided lenticular lens, wherein the pitch of the lens unit is 0.1 to 0.5 mm and an external light absorbing portion is provided between the lens units of the second lenticular lens. 6. The double-sided lenticular lens according to claim 5, wherein a pitch of the lens unit is 0.1 to 0.25 mm. 7. A double-sided lenticular lens is formed by fusing a plurality of light-transmitting strands arranged in parallel, forming a fusion surface on each light-transmitting strand outer surface adjacent to each other, and fusing. The double-sided lenticular lens according to claim 5 or 6, wherein the lenticular lens is integrated in a sheet shape.