TWI417573B - Brightening the diffusion film - Google Patents

Description

Brightening diffusion film

The invention relates to a compound brightening diffusion film which is suitable for use on a display or a lighting device and has a diffusion and brightening effect.

The optical film used in the early stage of the display is generally designed to be a diffusion film that uniformly disperses the light source according to the properties of the optical film, and a brightness enhancement film that concentrates the light source, by stacking a plurality of diffusion films and brightness enhancement films. To make the light source evenly and brightly projected on the display panel. In recent years, a composite optical film having both a brightening and a diffusing function has appeared. There are many forms of such a composite optical film, and only one known optical film will be described below.

Referring to FIGS. 1 and 2, the conventional brightness enhancing diffusion film 1 comprises: a light transmissive substrate layer 11, a diffusion scratch resistant layer 12 bonded to a light incident surface 111 of the substrate layer 11, and a bonding and substrate layer 11 The diffusion enhancing layer 13 on one of the light exiting faces 112. The diffusion scratch-resistant layer 12 includes a substrate 121, and a plurality of diffusion particles 122 dispersed in the substrate 121, or may be a rugged structure for the purpose of avoiding scratches and overcoming the problem of adsorption between the films. The diffusion enhancing layer 13 has a plurality of hemispherical microlenses 131 which are disorderly arranged and have different heights. By utilizing the shape of the microlens 131 to condense and disperse and diffuse the fine particle structure, the brightening diffusion film 1 can simultaneously have the effect of brightening and diffusing.

Although the design of the conventional brightening diffusion film 1 can achieve the desired effect, it is necessary to mold the concave mother mold by electroforming, and then form the diffusion brightening layer 13, which causes trouble in manufacturing and also increases material cost. In addition, although the conventional brightening diffusion film 1 can achieve the purpose of diffusion and brightening by arranging the microlenses 131 of different heights, there are many slits 132 of different sizes between the adjacent microlenses 131. When the light-emitting surface 112 of the substrate layer 11 is sent out and passes through the diffusion-enhancing layer 13, the effect of the light passing through the microlens 131 and the slit 132 is inconsistent, and an inconsistent diffusion and a light-transmitting star sand effect are generated, and the display taste is lowered. According to the actual test by the inventors, the brightness of the brightness of the brightness-enhancing diffusion film 1 having such a structure is relatively poor, and the density of the lens for effective concentration is relatively low, that is, the effect of diffusion and concentration is relatively poor.

In addition, the US 7,286,280 B2 invention provides a brightness enhancing film for use in a backlight module. The brightness enhancing film is characterized in that a plurality of hemispherical microlenses which are adjacent to each other and have a large diameter are disposed on the surface of the film, and then in several phases. A small diameter microlens is refilled between the gaps between the adjacent large diameter microlenses. Although the aforementioned US invention patents have eliminated the gap as much as possible to avoid the influence of the gap on the uniformity of the light source projection, no matter how dense the large and small diameter microlenses are, there are still gaps, so the uniformity of the light source processing is also Not perfect. In addition to the aforementioned invention patents, there are similar disadvantages of US2006-0146562 and US 7,092,166, and are not explained one by one.

In addition, the US Patent No. 7,068,433 B2 discloses a FOCUSING SCREEN MASTER having a microstructure, which has a plurality of honeycombs and closely arranged microlenses, which utilize different heights and heights of the microlenses. The offset of the point position is used for focusing purposes. Although the honeycomb-shaped macro lens is suitable for use in the field of focusing the screen, the gap between adjacent macro lenses is not properly designed. The diffusion effect is still not ideal, so it is not suitable for direct use on backlight modules such as displays.

The object of the present invention is to provide a high uniformity diffusion brightening structure, and at the same time, use the shape design coordination of the structure to match the appropriate luminance gain ratio to achieve a brightening diffusion film with different use requirements.

The brightness enhancing diffusion film of the present invention is suitable for use in a display or a lighting device, and comprises: a substrate layer, and a light processing layer on a light emitting surface of the substrate layer, the light processing layer comprising a plurality of adjacent connections and substantially A regular hexagonal microlens with a contour and a plurality of bottom grooves surrounding the microlens. Wherein the microlenses each have an apex substantially at the geometric center, and an adjacent array pitch (pitch, hereinafter referred to as P) between the adjacent and parallel bottom grooves, and the radius of curvature r of the bottom groove is The array pitch P is 1/50 to 3/25, thereby increasing the haze and luminance gain ratio of the brightness enhancing diffusion film.

A second feature of the present invention is that the microlenses have a height H, and the aspect ratio (H/P) of the height H to the array pitch P is 20 to 60%, by controlling different depths and widths. In comparison, the double luminance gain ratio or the single luminance gain ratio of the brightness enhancement diffusion film can be increased, so that the brightness enhancement diffusion film is suitable for use in a display or a lighting device.

The invention has the beneficial effects of: providing a microlens adjacent to the adjacent hexagonal shape on the light-emitting surface of the substrate layer, and providing a bottom groove between the micro-lenses while limiting the radius of curvature of the bottom-grooves, The invention can be used to simultaneously brighten and diffuse the light source by using a single structure. In addition, the present invention can also increase the single- or double-brightness gain ratio by the combination of the aspect ratio (H/P) value, so that the brightness-increasing diffusion film is suitable for use in various occasions such as a display and a lighting device.

The foregoing and other objects, features, and advantages of the invention are set forth in the <RTIgt;

Before the present invention is described in detail, it is noted that in the following description, similar elements are denoted by the same reference numerals.

Referring to Figures 3 and 4, Embodiment 1 of the brightening diffusion film of the present invention comprises: a substrate layer 2, and a light processing layer 3 positioned above one of the light-emitting surfaces 21 of the substrate layer 2, wherein the substrate layer 2 further has A light-incident surface 22 for light entering, and the light-treating layer 3 of the first embodiment of the present invention includes: a plurality of regular hexagonal microlenses 31 closely arranged and protruding upward from the light-emitting surface 21, and surrounding the microlens 31 a plurality of first bottom grooves 32, a plurality of second bottom grooves 32', and a plurality of third bottom grooves 32". Each of the hexagonal microlenses 31 has six adjacent bottom grooves 32, A bottom edge 311 of one of 32', 32" and a vertex 312 positioned substantially at the geometric center.

Further, the first bottom recessed grooves 32 of the embodiment 1 of the present invention are parallel to each other on the opposite side of the positive hexagonal microlens 31, and each of the first bottom recessed grooves 32 has a center line 321 and two adjacent to each other. The width between the center lines 321 is the array pitch P (pitch), and each of the first bottom grooves 32 has a radius of curvature r. The second bottom groove 32' is also parallel to each other and forms an angle of 120 degrees with the first bottom groove 32. The third bottom grooves 32" are also connected to each other in parallel with the first one. Between the second bottom recesses 32, 32', and forming an angle of 120 degrees, the array pitch P of the second bottom recessed grooves 32' and the array pitch P between the third bottom recessed grooves 32" and the first undercut The array pitch P of the grooves 32 is the same, and further, the apex 312 of the microlenses 31 has a height H between the light exiting faces 21.

Referring to Table 1, the array pitch P of the first embodiment of the present invention is 43 μm, the height H of the microlens 31 is 17.8 μm, and the radius of curvature r of the bottom recesses 32, 32', 32" are all 3.0 μm. As a result, it is found that the single-sheet haze of the first embodiment of the present invention is 96.11%, the single-thickness gain ratio is 29.6%, and the double-thickness gain ratio is 44.0%, since the brightness-enhancing diffusion film has better haze. In addition, when two brightening diffusion film stacks are used, the measured double-thickness gain ratio is also as high as 44%, that is, by increasing the groove around the lens and appropriately controlling the aspect ratio of the microlens 31 (microlens 31). The height H is divided by the array pitch P) of the microlens 31 to obtain a better double-combined luminance and atomization effect. The aspect ratio (H/P) of the first embodiment of the present invention is 41.4% (17.8/43). This size limitation makes the brightness-enhancing diffusion film suitable for use on displays that require higher haze and double-brightness gain ratios. That is, the first embodiment of the present invention is compared with the conventional examples of FIGS. In addition to the diffusion layer with diffusing particles, the single haze used to represent the diffusion effect, and the representative bright Hui than double the gain of a plus are relatively conventional, and thus, compared with the conventional Example 1 Example known not only for producing this embodiment is simple, also it has the effect of diffusion and preferred gain ratio of bis Hui.

1. Luminance gain ratio test standard: TCO-03 test was carried out by a spectrophotometer manufactured by TOPCON Corporation and model SR-3A.

2. Haze test: The test of JIS K 7105 was carried out using a haze meter of the type NDH-5000 manufactured by NIPPON.

3. Microlens size measuring instrument: KEYENCE VK-9500.

Referring to Table 1, the configurations of Embodiments 2, 3, and 4 of the present invention are the same as those of Embodiment 1, and the array pitch P and the radius of curvature r are the same as those of Embodiment 1, but the height H of the microlenses 31 is changed, that is, The height H of the microlens 31 of the second embodiment of the invention was lowered to 15.52 μm, the height H of the example 3 was increased to 20.54 μm, and the height H of the example 4 was increased to 23.56 μm. It is known from the test results of Table 1 that when the height H of the microlens 31 is lowered, the single-thickness gain of the brightening diffusion film is relatively low, and conversely, the single-thickness gain ratio is increased, so that the brightness diffusion of the present invention When the film is to be used in a single use case such as a lighting device or the like, the microlens 31 having a large height H is selected to produce a preferable single luminance gain ratio.

On the other hand, the height H of the microlens 31 disclosed in Embodiments 2 and 3 of the present invention also has a good performance in terms of single haze and double luminance gain ratio, so the size range of the display of the embodiments 2 and 3. It is also suitable for use on the display screen of the display. Further, from the test results of Example 4, when the height H of the microlens 31 is larger than 23.56 μm, the double luminance gain ratio is remarkably lowered, but the single luminance gain is remarkably improved. Therefore, the proportional range of this embodiment 4 of the present invention is more suitable for use on a lighting device. On the other hand, if the brightness enhancing diffusion film of the present invention is to be used in a display, the preferred aspect ratio of the microlenses 31 is between 34 and 55%, which is a preferred combination embodiment range, and the aspect ratio is between 37.5~48% is the best embodiment of multiple combinations. Compared with the conventional technique, which is roughly a hemispherical microlens (approximately 49~50% aspect ratio), it has better multiple stacking luminance performance, for example, P= 47μm, H=22.9μm, single brightness 40.9%, aspect ratio 48.7%, can produce higher structure atomization ability to avoid glare and provide higher single brightness gain ratio to concentrate light to save energy.

Still referring to Table 1, the foregoing embodiment of the present invention investigates the influence of the height H of the microlens 31 on the luminance gain ratio and the haze, while the fifth and sixth embodiments of the present invention investigate the appropriateness of the radius of curvature r, that is, by implementation. The experimental results of Example 5 show that when the radius of curvature r is reduced to 1.95 μm, the test data of the brightness-enhancing diffusion film is ideal, so the brightness-enhancing diffusion film of this size is suitable for use in a display or a lighting device. From the test result of the embodiment 6, it is known that when the rate radius r is increased to 6.8 μm, the single haze and the double luminance gain ratio have a good performance, but the single luminance gain ratio is slightly poor, so Dimensional brightening diffuser film is suitable for use on displays.

Still referring to Table 1, the structures of Embodiments 7 and 8 of the present invention are also the same as those of Embodiment 1, in which the array pitch P of Example 7 is 30 μm, the height H of the microlens 31 is 12.8 μm, and the radius of curvature r is 2.0 μm. It is found from the test results that the brightness-spreading film having the above-mentioned proportional relationship is not inferior in the single haze and the double-brightness gain ratio. By the same token, in the eighth embodiment of the present invention, after the array pitch P, the height H and the radius of curvature r are simultaneously increased, the single haze and the double luminance gain ratio of the brightness enhancing diffusion film also have a good performance, so the foregoing size range is obtained. The brightening diffuser film is also suitable for use in display products.

As can be seen from the above description, the present invention utilizes a plurality of regular hexagonal microlenses 31, and a concave bottom recess 32, 32', 32" between adjacent microlenses 31, and defines such bottom recesses 32. The design of the radius of curvature r of 32', 32" is not only found in the conventional brightening diffusion film, and the foregoing design allows the brightness-enhancing diffusion film to generate a higher fog without using a diffusion structure such as a diffusion particle or the like. Degree and diffusion effect. In addition, the present invention can also increase the double luminance gain ratio or the single luminance gain ratio by the selection of the height H of the microlens 31. That is, when the present invention is used, for example, on a display, a combination of ratios having a preferred double luminance gain ratio can be selected, and when the present invention is applied to a lighting device, a ratio having a better single luminance gain ratio can be selected. The scope of the brightening diffusion film of the present invention is not only novel, but also allows the brightness-increasing diffusion film to be applied to different products in a manner of selecting different ratio ranges without deliberately designing the diffusion structure.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent.

2. . . Substrate layer

twenty one. . . Glossy surface

twenty two. . . Glossy surface

3. . . Light treatment layer

31. . . Microlens

311. . . Bottom edge

312. . . vertex

32. . . First bottom groove

321. . . Center line

32’. . . Second bottom groove

32"...the third bottom groove

P. . . Array spacing

r. . . Radius of curvature

H. . . height

Figure 1 is a schematic cross-sectional view of a conventional brightening diffusion film;

Figure 2 is a partial plan view of one of the conventional brightness enhancing diffusion films;

Figure 3 is a partial plan view of Embodiment 1 of the brightening diffusion film of the present invention; and

Figure 4 is a cross-sectional view taken along line 4-4 of Figure 3.

2. . . Substrate layer

twenty one. . . Glossy surface

twenty two. . . Glossy surface

3. . . Light treatment layer

31. . . Microlens

312. . . vertex

32. . . First bottom groove

P. . . Array spacing

r. . . Radius of curvature

H. . . height

Claims (7)

A brightness enhancing diffusion film comprising: a substrate layer having a light emitting surface; and a light processing layer disposed on the light emitting surface of the substrate layer and including a plurality of microlenses adjacent to the substantially hexagonal hexagonal shape And a plurality of bottom grooves surrounding the microlenses; wherein the microlenses each have an apex substantially at a geometric center, and have an array pitch P between two adjacent parallel bottom grooves, and the bottom The radius of curvature r of the groove is 1/50 to 3/25 of the array pitch P. The brightness-increasing diffusion film according to claim 1, wherein the microlenses have a height H, and the aspect ratio of the height H/array pitch P is 20 to 60%. The brightness-increasing diffusion film according to item 2 of the patent application is suitable for use in the case of double-stacking, wherein the radius of curvature r is 1.5 to 7.0 μm. The brightness-enhancing diffusion film according to item 3 of the patent application is suitable for use in the case of double-stacking, wherein the aspect ratio is 37.5 to 48%. The brightness-increasing diffusion film according to claim 4, wherein the array pitch P is between 30 and 60 μm. The brightness-enhancing diffusion film according to item 2 of the patent application is suitable for use in a single sheet, wherein the aspect ratio is 34 to 55%. The brightness-increasing diffusion film according to claim 6, wherein the array pitch P is between 30 and 60 μm.