TW201730589A - Downward-facing prism optical sheet, side edge surface emitting device using same, and 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

Optical sheet facing downward, side edge type surface emitting device using the same, and manufacturing method thereof

The present invention relates to a downwardly-twisted optical sheet having a triangular ridge facing a light source from a light source, a side edge type surface light-emitting device using the optical sheet, and a method of manufacturing the same. The side edge type surface emitting device is used as a backlight source for a liquid crystal display (LCD) device.

In the surface emitting device, a 稜鏡 optical sheet is used in order to increase the brightness of the viewer's visual direction (with respect to the normal direction of the display screen). For example, if the glazing optical sheet BEF (registered trademark) is used, that is, the triangular ridges are located on the opposite side of the light from the light source (refer to Japanese Laid-Open Patent Publication No. 2010-72131 (Patent No. 5262490) Figure 7), in order to achieve a wider light distribution; in contrast, if the optical sheet is used, the triangular ray is opposite to the light source of the light source (refer to: Japanese Patent Laid-Open No. 9-197404) The bulletin (Patent No. 3234843)) achieves a narrower light distribution. Therefore, in a high-resolution LCD device, if a side-edge surface light-emitting device using a downward-facing optical sheet is used as a backlight source, there is a good effect. Further, in the direct-type surface light-emitting device using the optical sheet facing downward, since the angle at which light is emitted from the light guide plate is different from that of the side edge type, narrow light distribution cannot be achieved.

Fig. 7 is a cross-sectional view showing a side edge profile light-emitting device using a conventional squeezing optical sheet.

In Fig. 7, a light source 2 composed of a plurality of light-emitting diode (LED) elements is disposed, and the light sources 2 are arranged in a line (in a row) in an acrylic resin, a polycarbonate resin, or the like. The light incident surface 1a of the side surface of the light guide plate 1 is formed. The reflector 3 is provided on the side of the back surface 1b of the light guide plate 1. On the other hand, the optical sheet 4 facing downward is provided on the light-emitting surface 1c side of the front surface of the light guide plate 1. Further, a dot pattern 5 is formed on the back surface 1b of the light guide plate 1.

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

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

Fig. 8 is a flow chart for explaining a method of manufacturing the lower jaw optical sheet 4 of Fig. 7.

First, in the diffusion layer coating step 801, the diffusion layer 42 is applied onto the substrate 41 made of polyethylene terephthalate (PET). For example, as shown in FIG. 9, in the transparent resin made of a polycarbonate resin or the like, the resin 901 is poured, and the substrate 41 is moved while being smoothed by the blade 902; light diffusion is dispersed in the resin 901. The particles 42b are composed of an acryl-based 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-diffusing particles 42b have various diameters of, for example, 5 μm to 20 μm, and exhibit sufficient light diffusion effects in the diffusion layer 42 having a thickness of about 15 μm to 20 μm.

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

[Problem to be Solved by the Invention] However, in the conventional optical sheet 4, as shown in a perspective view of FIG. 11, and a cross-sectional shape thereof as shown in FIG. 12, in the diffusion layer 42, the light-diffusing particles 42b Aggregation will occur due to gravity and become larger. Not only that, it is also difficult to control the thickness of the diffusion layer 42 to be uniform. Moreover, 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, the light-diffusing particles 42b having a large diameter protrude to the surface of the diffusion layer 42 and are unevenly dispersed. As a result, even if a uniform luminance distribution is achieved on the light guide plate 1, the screen of the LED panel facing the upper portion of the optical sheet 4 is flickered, and the screen such as glare is abnormal. [Technical means to solve the problem]

In order to solve the above problems, the squint optical sheet of the present invention comprises: a substrate; a diffusion layer provided on the substrate; and a triangular enamel layer disposed under the substrate; and the diffusion layer is provided with a regularity or A concave spacer is irregularly arranged.

Furthermore, the side edge type surface light-emitting device of the present invention includes: a light guide plate; a light source; a light incident surface disposed on a side surface of the light guide plate; and the downward facing optical sheet disposed on the light exit surface of the light guide plate.

Furthermore, the method for producing a squeezing optical sheet of the present invention comprises the steps of: bonding a stamper to a roll die, forming a stamped portion in a regular or irregular manner; and causing the roll mold to face each other The liquid substrate is rotated and the liquid ultraviolet curable resin is poured onto the surface of the roll mold, and the ultraviolet curable resin is irradiated with ultraviolet rays from the substrate side to cure the ultraviolet curable resin to form a diffusion layer. [Effects of the Invention]

According to the present invention, since the concave spacer is provided in the diffusion layer, the diffusion phenomenon of the light diffusion particles due to the attraction force can be suppressed in the diffusion layer; not only that, the thickness of the diffusion layer 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 the image of the LED panel on the upper portion of the lower optical sheet from being flickered or glare.

[Embodiment] Fig. 1 is a perspective view showing an embodiment of a sinusoidal optical sheet of the present invention, and Fig. 2 is a cross-sectional view of the sinusoidal optical sheet of Fig. 1, (A) is a cross section of Fig. 1. Fig., (B) is a cross-sectional photograph, and (C) is an enlarged cross-sectional view.

In Fig. 1 and Fig. 2, the lower optical sheet 4' is disposed instead of the lower optical sheet 4 of Figs. The optical sheet 4' is placed down, and a diffusion layer 42' is provided instead of the diffusion layer 42 of the optical sheet 4 facing downward.

In the diffusion layer 42', the light diffusion particles 42'b are dispersed in the transparent resin layer 42'a, and the diameter of the light diffusion particles 42'b is 0.01 μm or more and 2 μm or less; and it is provided with, for example, 10 μm. A concave spacer 42'c having a fixed depth of 15 μm and a diameter of 5 μm. The concave spacers 42'c may be arranged regularly or irregularly (randomly). Due to the presence of the concave spacers 42'c, the thickness of the diffusion layer 42' is controlled to be uniform, and not only the aggregation of the light-diffusing particles 42'b caused by gravity is suppressed, but the light-diffusing particles 42' are caused. The diameter of b is kept small. Therefore, as shown in Fig. 3, the light-diffusing particles 42'b are uniformly present in the diffusion layer 42' without protruding to the surface of the diffusion layer 42'. As a result, as long as a uniform luminance distribution is achieved on the light guide plate 1, it is possible to suppress occurrence of flickering or glare of the screen of the LED panel on the upper portion of the lower optical sheet 4'.

Fig. 4 is a flow chart for explaining a method of manufacturing the lower cymbal optical sheet 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.

In the diffusion layer forming step 401, as shown in FIG. 5, a stamper 501 is adhered to the roll mold 502, and 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. The convex spacer portion 501a rotates the roll mold 502 toward the substrate 41 that moves, and the liquid ultraviolet (UV) hardening resin 503 is poured onto the surface of the roll mold 502, and the ultraviolet ray is smoothed by the squeegee 504. The cured resin 503 is molded by irradiating ultraviolet rays from the side of the substrate 41. In the diffusion layer 42', a concave spacer 42'c to which the convex spacer 501a of the stamper 501 is transferred is formed. Further, the ultraviolet curable resin 503 includes a transparent resin constituting the transparent resin layer 42'a and light diffusing particles 42'b. At this time, in the stamper 501, the surface state of the portion where the convex spacer portion 501a is not formed is in a concave-convex state (not shown), and the surface of the formed diffusion layer 42' is formed to prevent adhesion and adhesion. (not shown). Thereby, adhesion between the diffusion layer 42' and the LED panel of the upper layer is prevented. For example, the uneven surface of the diffusion layer 42' which is adhered to the adhesion is an arithmetic mean roughness (Ra) of 0.05 to 0.1 μm, and the period (Sm) thereof 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 variation can be reduced.

Further, the present invention is also applicable to any modification of the self-explanation range of the above embodiments.

1‧‧‧Light guide plate
1a‧‧‧Into the glossy surface
1b‧‧‧back
1c‧‧‧Glossy
2‧‧‧Light source
3‧‧‧reflector
4,4'‧‧‧Down Optics
41‧‧‧Substrate
42,42'‧‧‧Diffusion layer
42a, 42'a‧‧‧ transparent resin layer
42b, 42'b‧‧‧Light diffusing particles
42'c‧‧‧ concave compartment
43‧‧‧Triangular layer
5‧‧‧ dot pattern
501‧‧‧Molding
501a‧‧‧ convex spacer
502‧‧‧roller
503‧‧‧ UV curing resin
504‧‧‧Scraper
901‧‧‧Resin
902‧‧‧Scraper
1001‧‧‧Molding
1002‧‧‧roller
1003‧‧‧ UV curing resin
1004‧‧‧Scraper
L‧‧‧Light
D‧‧‧Light distribution characteristics
UV‧‧‧UV
801‧‧‧Diffusion layer coating step
802‧‧‧ triangular layer formation steps
401‧‧‧Diffusion layer forming step

Fig. 1 is a perspective view showing an embodiment of a squatting optical sheet of the present invention. Fig. 2 is a cross-sectional view showing the lower jaw 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. FIG. 3 is a top photo of the diffusion layer of FIG. 1. FIG. Fig. 4 is a flow chart for explaining a method of manufacturing the lower cymbal optical sheet of Fig. 1. Fig. 5 is an explanatory diagram of a step of forming a diffusion layer of Fig. 4. Fig. 6 is a drawing showing the thickness of a diffusion layer manufactured by the manufacturing method of the flowchart of Fig. 4. Fig. 7 is a cross-sectional view showing a side edge type surface light-emitting device using a conventional squeezing optical sheet. Fig. 8 is a flow chart for explaining a method of manufacturing the lower jaw optical sheet of Fig. 7. Fig. 9 is an explanatory view of a diffusion layer coating step of Fig. 8. Fig. 10 is an explanatory view of a triangular crucible forming step of Fig. 8. Fig. 11 is a perspective view showing the lower cymbal optical sheet of Fig. 7. Fig. 12 is a cross-sectional view showing the lower jaw 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. Fig. 13 is a top plan view of the diffusion layer of Fig. 11.

4'‧‧‧Down Optics

41‧‧‧Substrate

42’‧‧‧Diffusion layer

42'a‧‧‧Transparent resin layer

42’b‧‧‧Light diffusing particles

42'c‧‧‧ concave compartment

43‧‧‧Triangular layer

Claims (8)

A downward facing optical sheet comprising: a substrate; a diffusion layer disposed on the substrate; and a triangular layer disposed under the substrate; the diffusion layer being disposed in a regular or irregular manner a concave spacer. In the lower optical sheet of the first aspect of the patent application, the surface of the diffusion layer of the concave spacer is not present, and the uneven surface treated surface for preventing adhesion is formed. For example, the squeezing optical sheet of the second aspect of the patent application has an arithmetic mean roughness of 0.05 to 0.1 μm, and the periodicity thereof is random. The undulation optical sheet of the first aspect of the patent application, wherein the diffusion layer has a thickness of 10 to 15 μm; and the diameter of the light diffusion particles in the diffusion layer is 0.01 μm or more and 2 μm or less. A side edge type surface emitting device includes: a light guide plate; a light source; a light incident surface disposed on a side surface of the light guide plate; and a downward facing optical sheet as in the first aspect of the patent application, wherein the light guide plate is disposed on the light guide plate surface. A method for manufacturing a downward facing optical sheet, comprising: a substrate, a diffusion layer disposed on the substrate, and a triangular layer disposed under the substrate; The manufacturing method of the optical sheet includes the following steps: a stamper is adhered to the roll mold, and the stamper is formed with a regular spacer in a regular or irregular manner; the roll mold is rotated toward the moving substrate, and the liquid is rotated The ultraviolet curable resin is poured onto the surface of the roll mold, and the ultraviolet curable resin is irradiated with ultraviolet rays from the base material side to cure the ultraviolet curable resin to form a diffusion layer. The manufacturing method of the squeezing optical sheet of the sixth aspect of the invention, wherein the surface state of the portion where the convex spacer is not formed in the stamper is in a concave-convex state. The manufacturing method of the yoke optical sheet according to Item 7 of the patent application, wherein the unevenness state is an arithmetic mean roughness of 0.05 to 0.1 μm, and the period is random.