TWI689753B - Downward-facing prism optical sheet manufacturing method - Google Patents

Abstract

A downward-facing prism optical sheet including a substrate, a diffusion layer provided on top of the substrate, and a triangular prism layer provided beneath the substrate, wherein concave spacers disposed in a regular or an irregular manner are provided on the diffusion layer.

Description

Method for manufacturing down-pointed optical disc

The present invention relates to a method for manufacturing a downward-facing optical lens with a triangular triangular lens facing the light from the light source. The side surface type light emitting device is used as a backlight light source of a liquid crystal display (LCD) device.

In the surface light-emitting device, in order to improve the brightness of the viewer's visual direction (relative to the normal direction of the display screen), 珜鏡 optical sheet is used. For example, if the upward-facing optical film BEF (registered trademark) is used, the triangular triangular film is located on the opposite side of the light from the light source (refer to Japanese Patent Laid-Open No. 2010-72131 (Patent No. 5262490 ) Of Figure 7) to achieve a wider light distribution; on the other hand, if you use the downward-facing optical film, that is, the triangular triangular system is opposite to the light of the light source (refer to: Japanese Patent Laid-Open No. 9-197404 According to the gazette (Patent No. 3234843), a relatively narrow light distribution is realized. Therefore, in a high-resolution LCD device, if a side edge type light-emitting device using a down-pointing optical sheet is used as a backlight light source, there will be good results. In addition, the direct-type light-emitting device using the downward-facing optical sheet has a different light distribution angle because the angle at which light is emitted from the light guide plate is different from that of the side edge type.

FIG. 7 is a cross-sectional view of a side-surface type light-emitting device using a conventional downward-facing optical sheet.

In FIG. 7, a light source 2 composed of a plurality of light-emitting diode (LED) elements is provided, and the light source 2 is linearly (arranged in a row) arranged in an acrylic resin, polycarbonate resin, etc. The light incident surface 1a of the side surface of the light guide plate 1 is constituted. The reflective plate 3 is provided on the back surface 1b side of the light guide plate 1, and the downward facing optical sheet 4 is provided on the light exit surface 1c side of the front surface of the light guide plate 1. Also, on the back surface 1b of the light guide plate 1, a dot pattern 5 is formed.

The downward prism optical sheet 4 is composed of a substrate 41, a diffusion layer 42 formed on the substrate 41, and a triangular prism layer 43 formed under the substrate 41.

In FIG. 7, the light L from the light source 2 enters the light incident surface 1 a of the light guide plate 1 and is reflected by the back surface 1 b of the light guide plate 1 while being reflected between the back surface 1 b and the light exit surface 1 c in the light guide plate 1. The dot pattern 5 on the side scatters. This scattered light forms a uniform brightness distribution on the light guide plate 1, and emits light from the light exit surface 1c of the light guide plate 1, and enters the light toward the downward optical sheet 4. As a result, the light from the down-leaf optical sheet 4 has a narrow light distribution characteristic D.

FIG. 8 is a flowchart for explaining the method of manufacturing the down-faced optical sheet 4 of FIG. 7.

First, in the diffusion layer coating step 801, the diffusion layer 42 is coated on the base material 41 made of polyethylene terephthalate (PET). For example, as shown in FIG. 9, in a transparent resin composed of polycarbonate resin or the like, a resin 901 is poured in, and the base material 41 is moved while being smoothed by a scraper 902; The light diffusing particles 42b are dispersed, and the light diffusing particles 42b are made of acrylic resin or the like having a refractive index different from that of the transparent resin. As a result, the transparent resin becomes the transparent resin layer 42a. In this case, the light diffusion particles 42b have various diameters of, for example, 5 μm to 20 μm, and a sufficient light diffusion effect is exhibited in the diffusion layer 42 with a thickness of about 15 μm to 20 μm.

Next, in the triangular layer formation step 802, as shown in FIG. 10, a stamper 1001 forming a triangular triangular shape is adhered to the roll mold 1002; the roll mold 1002 is rotated toward the moving substrate 41, The liquid ultraviolet curing resin 1003 is poured onto the upstream side of the roll mold 1002, and the ultraviolet curing resin 1003 is cured by moving the substrate 41 while irradiating ultraviolet UV, so that the triangular prism layer 43 is on the substrate Formed on 41. In this case, the ultraviolet curing resin 1003 is formed while the squeegee 1004 is smoothed.

However, in the conventionally known downward optical sheet 4, as shown in the perspective view shown in FIG. 11 and the cross-sectional shape shown in FIG. 12, in the diffusion layer 42, the light diffusion particles 42b will agglomerate due to gravity and cause Get bigger. Not only that, but it is also difficult to control the thickness of the diffusion layer 42 to be uniform. In addition, in FIG. 12, (A) is a cross-sectional view, (B) is a cross-sectional photograph, and (C) is a cross-sectional enlarged photograph. Therefore, as shown in FIG. 13, in particular, light diffusion particles 42 b with a large diameter protrude to the surface of the diffusion layer 42 and are not evenly distributed. As a result, there is a problem that even if a uniform brightness distribution is achieved on the light guide plate 1, the screen of the LED panel on the upper side of the down optical sheet 4 may cause screen abnormalities such as flicker and glare.

In order to solve the above-mentioned problems, the manufacturing method of the downward-facing optical sheet of the present invention includes the following steps: a stamper is adhered to the roll die, and the convex die is regularly or irregularly formed with convex spacers; the roll die Rotate against the moving substrate and pour the liquid UV-curable resin containing light-diffusing particles onto the surface of the roll die, and then cure the UV rays from the substrate side while smoothing the UV-curable resin with a scraper The resin is irradiated with ultraviolet rays to harden the ultraviolet-curing resin to form a diffusion layer, and the diffusion layer has a through hole transferred by the convex spacer.

According to the present invention, in the ultraviolet curing resin, the aggregation phenomenon of the light diffusion particles due to gravity can be suppressed; not only that, but also the thickness of the diffusion layer hardened by the ultraviolet curing resin can be controlled to be uniform. Therefore, the light-diffusing particles do not protrude to the surface of the diffusion layer and are scattered, and it is possible to prevent screen abnormalities such as flicker and glare from occurring on the LED panel screen above the down-top optical sheet.

1: light guide plate

1a: incident surface

1b: back

1c: light emitting surface

2: light source

3: reflector

4, 4’: Downward optical film

41: substrate

42, 42’: diffusion layer

42a, 42’a: transparent resin layer

42b, 42’b: light diffusion particles

42’c: concave spacer

43: Triangle layer

5: dot pattern

501: stamping

501a: convex spacer

502: Roll die

503: UV curing resin

504: Scraper

901: resin

902: Scraper

1001: stamper

1002: Roll die

1003: UV curing resin

1004: Scraper

L: light

D: light distribution characteristics

UV: ultraviolet

801: Diffusion layer coating step

802: Steps for forming the triangular layer

401: Diffusion layer forming step

[FIG. 1] A perspective view showing an embodiment of the downward-facing optical sheet of the present invention.

[FIG. 2] FIG. 1 is a cross-sectional view of the downward-facing optical sheet of FIG. 1. (A) is a cross-sectional view, (B) is a cross-sectional photograph, and (C) is an enlarged cross-sectional view.

[Figure 3] Photo of the top surface of the diffusion layer in FIG.

[FIG. 4] A flow chart for explaining the manufacturing method of the downward-facing optical sheet of FIG.

[Fig. 5] An explanatory diagram of the steps of forming the diffusion layer in Fig. 4.

[FIG. 6] A graph showing the thickness of the diffusion layer manufactured by the manufacturing method of the flowchart of FIG. 4.

[Fig. 7] A cross-sectional view of a side-surface type light-emitting device using a conventionally known downward-facing optical sheet.

[FIG. 8] A flow chart for explaining the manufacturing method of the downward-facing optical sheet of FIG. 7.

[Fig. 9] An explanatory diagram of the diffusion layer coating step of Fig. 8.

[Fig. 10] An explanatory diagram of the step of forming triangular prisms in Fig. 8.

[Fig. 11] A perspective view of the downward-facing optical sheet of FIG. 7 shown in FIG.

[FIG. 12] FIG. 11 is a cross-sectional shape of the downward-facing optical sheet of FIG. 11, (A) is a cross-sectional view, (B) is a cross-sectional photograph, and (C) is an enlarged cross-sectional view.

[Figure 13] Photo of the top surface of the diffusion layer of FIG.

[Examples]

FIG. 1 is a perspective view showing an embodiment of the downward-facing optical sheet of the present invention, FIG. 2 is a sectional view of the downward-facing optical sheet of FIG. 1, (A) is a sectional view of FIG. 1, (B ) Is a section photograph, (C) is an enlarged view of the section.

In Fig. 1 and Fig. 2, the downward-facing optical sheet 4'is provided instead of the downward-facing optical sheet 4 in Figs. 11 and 12. In order to replace the diffusing layer 42 of the down-pointing optical sheet 4, the down-pointing optical sheet 4'is provided with a diffusion layer 42'.

The diffusion layer 42' is dispersed in the transparent resin layer 42'a, and the light diffusion particles 42'b are dispersed; and the diameter of the light diffusion particles 42'b is 0.01 μm or more and 2 μm or less; and is provided with, for example, 10 μm~ A concave spacer 42'c with a fixed depth of 15 μm and a diameter of 5 μm. The concave spacer 42'c may be arranged regularly or irregularly (randomly). The concave spacer 42'c is a through hole formed by transferring the convex spacer 501a of the stamper 501 of FIG. 5 described later. By using the manufacturing method of the convex spacer 501a, the squeegee 504, and the ultraviolet irradiation from the side of the base material 41, the thickness of the diffusion layer 42' is controlled to be uniform, not only that, but also the ultraviolet curing resin 503 is suppressed The coagulation phenomenon of the light diffusion particles 42'b caused by the gravitational force keeps the diameter of the light diffusion particles 42'b small. Therefore, as shown in FIG. 3, the light diffusion particles 42'b exist uniformly in the diffusion layer 42' without protruding to the surface of the diffusion layer 42'. As a result, as long as a uniform brightness distribution is achieved on the light guide plate 1, it is possible to suppress the occurrence of screen abnormalities such as flicker and glare on the screen of the LED panel on the upper portion of the down optical sheet 4'.

Fig. 4 is a flow chart for explaining the method of manufacturing the down-faced optical film 4'of Figs. 1 and 2. In FIG. 4, a diffusion layer forming step 401 is provided instead of the diffusion layer coating step 801 of FIG. 8.

In the diffusion layer forming step 401, as shown in FIG. 5, a stamper 501 is adhered to the roll die 502. The stamper 501 is formed regularly or irregularly with a fixed height of, for example, 10 μm to 15 μm and a diameter of 5 μm Convex partition 501a; the roll mold 502 is rotated toward the moving substrate 41, and the liquid ultraviolet (UV) hardening resin 503 is poured onto the surface of the roll mold 502, and the blade 504 is used to smooth out the ultraviolet rays The cured resin 503 is molded while irradiating ultraviolet rays from the base 41 side. On the diffusion layer 42', a concave spacer 42'c to which the convex spacer 501a of the stamper 501 is transferred is formed.

In addition, the ultraviolet curing resin 503 includes a transparent resin constituting the transparent resin layer 42'a, and light diffusion particles 42'b. At this time, in the stamper 501, the surface state of the portion where the convex spacer 501a is not formed is a concave-convex state (not shown), and the surface of the formed diffusion layer 42' becomes a concave-convex surface to prevent adhesion adhesion (Not shown). This prevents the diffusion layer 42' from adhering to the LED panel above it. For example, the uneven surface of the diffusion layer 42', which prevents adhesion, has an arithmetic average roughness (Ra) of 0.05 to 0.1 m, and its period (Sm) is random.

As shown in FIG. 6, the thickness of the diffusion layer 42' can be reduced due to the presence of the concave spacer 42'c, and the deviation thereof can be reduced.

In addition, the present invention can also be applied to any modification of the self-explanatory range of the above embodiment.

4’: Downward optical film

41: substrate

42’: Diffusion layer

42’a: transparent resin layer

42’b: light diffusion particles

42’c: concave spacer

43: Triangle layer

Claims (3)

A method for manufacturing a downward-facing optical sheet, the downward-looking optical sheet includes a substrate, a diffusion layer disposed on the substrate and containing light diffusing particles, and a triangular polygonal layer disposed under the substrate The manufacturing method of the downward-facing optical sheet includes the following steps: a stamper is attached to the roll mold, and the stamper is regularly or irregularly formed with convex spacers; the base material that makes the roll mold move toward Rotate and pour the liquid ultraviolet curing resin containing the light diffusing particles onto the surface of the roll die, and then irradiate the ultraviolet curing resin from the substrate side while smoothing the ultraviolet curing resin with a squeegee Ultraviolet rays are formed into the diffusion layer by curing the ultraviolet-curable resin, and the diffusion layer has a through-hole transferred by the convex spacer. For example, in the method of manufacturing a downward-facing optical sheet of claim 1, the surface state of the portion where the convex spacer is not formed in the stamper is a concave-convex state. For example, the manufacturing method of the downward-facing optical sheet of the second item of the patent application scope, wherein the unevenness has an arithmetic average roughness of 0.05 to 0.1 μm, and its period is random.

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