WO2023102802A1 - 光学膜片组、背光模组及显示装置 - Google Patents

光学膜片组、背光模组及显示装置 Download PDF

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Publication number
WO2023102802A1
WO2023102802A1 PCT/CN2021/136657 CN2021136657W WO2023102802A1 WO 2023102802 A1 WO2023102802 A1 WO 2023102802A1 CN 2021136657 W CN2021136657 W CN 2021136657W WO 2023102802 A1 WO2023102802 A1 WO 2023102802A1
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Prior art keywords
light
optical film
sheet
prism sheet
diffusion sheet
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PCT/CN2021/136657
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English (en)
French (fr)
Inventor
黄建智
黄柏菖
张嘉尹
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瑞仪(广州)光电子器件有限公司
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Priority to PCT/CN2021/136657 priority Critical patent/WO2023102802A1/zh
Publication of WO2023102802A1 publication Critical patent/WO2023102802A1/zh

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    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00Optical elements other than lenses
    • G02B5/02Diffusing elements; Afocal elements
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00Optical elements other than lenses
    • G02B5/04Prisms
    • GPHYSICS
    • G02OPTICS
    • G02FOPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333Constructional arrangements; Manufacturing methods
    • G02F1/1335Structural association of cells with optical devices, e.g. polarisers or reflectors

Definitions

  • the disclosure relates to a film component and its application, and in particular to a film component applicable to a backlight module, and a backlight module and a display device using the film component.
  • a common backlight module mainly includes a light guide plate and several optical films.
  • the optical film can refract the light emitted from the light guide plate so that it emits light at a normal viewing angle.
  • such a backlight module cannot be applied to anti-peeping display products. Therefore, how to produce a good anti-peep effect by changing the matching design of the optical film and the light guide plate has become an active goal of the related industry.
  • the purpose of this disclosure is to provide an optical film set and a backlight module and a display device using the film assembly.
  • the optical film set Through the design of the optical film set, the amount of light emitted from the front viewing angle can be maintained and the amount of light emitted from the side can be reduced. Stray light from the light.
  • an optical film set which is configured to guide light from a light guide plate of a backlight module.
  • the optical film set includes a lower prism sheet and an upper prism sheet.
  • the lower prism sheet has a plurality of lower prism structures, and each lower prism structure extends along the first direction.
  • the upper prism sheet is disposed above the lower prism sheet, wherein the upper prism sheet has a plurality of upper prism structures, and each upper prism structure extends along a second direction, wherein the second direction is different from the first direction.
  • There is an included angle between the second direction and the extending direction of the light incident surface of the light guide plate ranging from 25° to 50° or from 130° to 155°, inclusive.
  • the above-mentioned second direction and the extending direction of the light incident surface of the light guide plate have an included angle ranging from 115 degrees to 140 degrees or from 220 degrees to 245 degrees, inclusive.
  • the above-mentioned first direction and the second direction are perpendicular to each other.
  • the above-mentioned optical film set further includes a lower diffusion sheet disposed below the lower prism sheet, and the lower diffusion sheet includes a plurality of diffusion particles, and these diffusion particles make the lower diffusion sheet have a 50% to 60% Haze of , with endpoint values inclusive.
  • the above-mentioned optical film set further includes an upper diffusion sheet disposed above the upper prism sheet.
  • the upper diffusion sheet contains a plurality of diffusion particles, and these diffusion particles make the upper diffusion sheet have a haze of 30% or less, and the endpoint values are included.
  • the above-mentioned optical film set further includes a lower diffuser and an upper diffuser.
  • the haze ratio of the lower diffusing sheet to the upper diffusing sheet is 1.6 to 6, and the endpoint values are included.
  • the above-mentioned lower diffusion sheet is disposed below the lower prism sheet, and the upper diffusion sheet is disposed above the upper prism sheet.
  • the lower diffusion sheet, the upper prism sheet, and the upper diffusion sheet in sequence, part of the light is emitted from the upper diffusion sheet along the front view direction, and the other part of the light is emitted from the upper diffusion sheet along the side view direction.
  • Light output wherein the ratio of the light output from the side view direction to the light output from the front view direction is less than 0.07.
  • the above-mentioned front view direction is parallel to the light emitting normal of the upper diffuser, and an included angle between the side view direction and the light emitting normal is greater than 45 degrees.
  • each of the above-mentioned lower prism structures and each of the upper prism structures is a strip structure.
  • the backlight module includes a light guide plate, a light source and the above-mentioned optical film group.
  • the light guide plate has a light incident surface and a light output surface.
  • the light source is adjacent to the light incident surface.
  • the optical film group is arranged above the light-emitting surface.
  • the display device includes a light guide plate, a light source, the above-mentioned optical film group and a display panel.
  • the light guide plate has a light incident surface and a light output surface.
  • the light source is adjacent to the light incident surface.
  • the optical film group is arranged above the light-emitting surface.
  • the display panel is arranged above the optical film group.
  • the optical film set disclosed in the present disclosure is mainly designed through the angle between the extension direction of the upper prism structure of the upper prism sheet and the light incident surface, and is matched with the extension direction of the lower prism structure of the lower prism sheet and the light incident surface.
  • the amount of light emitted from the side viewing angle is reduced to meet the optical requirements of the anti-peeping display.
  • the combination of the upper prism sheet and the lower prism sheet of the present disclosure can further achieve the effect of reducing the stray light emitted from the side viewing angle when the diffuser sheets with different hazes are matched.
  • FIG. 1 is a schematic diagram illustrating a device of a backlight module according to a first embodiment of the present disclosure
  • FIG. 2 is a front view illustrating a lower prism sheet according to a first embodiment of the present disclosure
  • FIG. 3 is a front view illustrating an upper prism sheet according to a first embodiment of the present disclosure
  • FIG. 4 is a comparison diagram showing the luminance of the front viewing angle and the luminous brightness of the side viewing angle generated by using the included angle design of the upper prism sheet according to the first embodiment of the present disclosure
  • FIG. 5 is a side view illustrating a lower diffusion sheet according to a first embodiment of the present disclosure
  • FIG. 6 is a device schematic diagram illustrating a backlight module according to a second embodiment of the present disclosure.
  • FIG. 7 is a device schematic diagram illustrating a display device according to an embodiment of the present disclosure.
  • FIG. 1 is a schematic diagram of a backlight module according to a first embodiment of the present disclosure.
  • the backlight module 100 of this embodiment mainly includes a light guide plate 110 , a light source 120 and an optical film set 200 .
  • the light source 120 mainly provides light to the light guide plate 110
  • the optical film set 200 is disposed in front of the light guide plate 110 .
  • the optical film group 200 is mainly used to reduce the amount of light emitted from the light guide plate 110 from a side viewing angle, and maintain the amount of light emitted from the light guide plate 110 from a front viewing angle, so that the backlight module 100 can be applied to Anti-spy display in product.
  • the light guide plate 110 has a light incident surface 111 and a light output surface 112 .
  • the light source 120 is adjacent to the light incident surface 111 , and the light provided by the light source 120 enters the light guide plate 110 from the light incident surface 111 of the light guide plate 110 , and then exits from the light exit surface 112 of the light guide plate 110 .
  • the optical film set 200 includes a lower diffusion sheet 210, a lower prism sheet 220, and an upper prism sheet 230, wherein the lower diffusion sheet 210, the lower prism sheet 220, and the upper prism sheet 230 are sequentially stacked on the light guide plate 110 in front of the light-emitting surface 112 .
  • FIG. 2 and FIG. 3 are respectively a front view illustrating a lower prism sheet and an upper prism sheet according to the first embodiment of the present disclosure.
  • the lower prism sheet 220 has a plurality of lower prism structures 221 , and each of the lower prism structures 221 is a strip structure extending along the first direction D1.
  • the upper prism sheet 230 has a plurality of upper prism structures 231 , and each upper prism structure 231 is a strip structure extending along the second direction D2.
  • the second direction D2 is different from the first direction D1.
  • the included angle ⁇ between the second direction D2 and the extending direction A1 of the light incident surface 111 of the light guide plate 110 .
  • the included angle ⁇ ranges from 25° to 50° or from 130° to 155°.
  • plane P2 includes the shaded area as shown in Figure 1 formed by the extension line P1 and the front view direction
  • the front view direction referred to here refers to the direction where the light rays are parallel to the upper prism sheet 230
  • the normal direction, and the side view direction refer to the direction having an included angle ⁇ between the aforementioned plane P2 and the front view direction.
  • FIG. 4 is a comparison diagram of the luminance of the front viewing angle and the luminance of the side viewing angle generated by using the included angle design of the upper prism sheet according to the first embodiment of the present disclosure.
  • the included angle ⁇ of the upper prism sheet 230 is in the range from 25 degrees to 50 degrees or from 130 degrees to 155 degrees (that is, in the range selected by the dotted box in FIG.
  • the overall backlight module 100 can produce a larger luminance at the front view angle and a smaller luminance at the side view angle, which makes the ratio of the light output of the light emitted from the side view direction to the light output of the light emitted from the front view direction (It can also be referred to as the proportion of light output from the side view angle) is small, for example, less than 0.07, which means that the angle ⁇ of the upper prism sheet 230 is within the range from 25 degrees to 50 degrees or from 130 degrees to 155 degrees (and includes the endpoints) value) design can reduce the amount of side light output.
  • Table 1 and Table 2 show the output results of the light L1 and the light L2 generated by the combination of the angle ⁇ of the lower prism sheet 220 and the angle ⁇ of the upper prism sheet 230 .
  • the included angle ⁇ of the upper prism sheet 230 ranges from 25 degrees to 50 degrees or from 130 degrees to 155 degrees, the proportion of light emitted from the side view angle is less than 10%, or even less than 7%. %, which meets the needs of anti-peeping products.
  • the included angle ⁇ of the lower prism sheet 220 can be designed within the range of 115° to 140° or from 220° to 245°, and includes the endpoint values;
  • the direction D2 is perpendicular to the first direction D1 of the lower prism structure 221 of the lower prism sheet 220 , so as to achieve the aforementioned effect of reducing the proportion of light output from side viewing angles.
  • the lower diffusion sheet 210 includes a plurality of diffusion particles 211 .
  • the lower diffuser 210 of the present disclosure can mainly reduce the stray light emitted from the side viewing angle (that is, the angle ⁇ between the front view direction and the side view direction is greater than 45 degrees), wherein the stray light refers to the diffusion caused by the diffusing particles Light, which belongs to light with no specific direction.
  • the parallel light L3 enters the lower diffusion sheet 210
  • a part of the light (such as light L4) will pass through the lower diffusion sheet 210 in parallel, and another part of the light (such as light L5) will be diffused and penetrate the lower diffusion sheet 210 through the diffusion particles 211.
  • the deviation angle of the ray L5 relative to the parallel ray L3 is greater than 2.5 degrees.
  • the ratio of the transmittance of the light L5 scattered through the lower diffuser 210 to the sum of the transmittances of the light L4 plus the light L5 can be defined as the haze of the lower diffuser 210 .
  • the lower diffuser sheet 210 has a haze of 50% to 60%, inclusive.
  • the haze of the bottom diffuser 210 is 0%, although it can achieve the same low proportion of light emitted from the side view angle, it cannot meet the light uniformity requirement of the light-emitting surface close to the light-incoming side; the haze of the current diffuser 210 is 90 %, although it can achieve a lower proportion of light emitted from the side viewing angle, it cannot meet the luminance requirements of the front viewing angle, and because more stray light is measured at the side viewing angle, it detracts from the anti-peeping effect of the product. Therefore, when the haze of the lower diffuser 210 is 50% to 60%, it can not only meet the anti-peeping purpose of the product, but also generate less stray light at the side viewing angle.
  • this disclosure utilizes 50% to 60%
  • the low-haze lower diffuser on the one hand, can meet the optical appearance required by customers, on the other hand, it can also reduce the generation of stray light, thereby meeting the needs of anti-peeping products.
  • the disclosed backlight module can also have different structural designs. Please also refer to FIG. 6 , which is a schematic diagram of a backlight module according to a second embodiment of the present disclosure.
  • the structure of the backlight module 300 of this embodiment is substantially the same as that of the backlight module 100 shown in FIG. 1 , the only difference being that the backlight module 300 further includes an upper diffusion sheet 440 .
  • the backlight module 300 mainly includes a light guide plate 310 , a light source 320 and an optical film set 400 .
  • the light source 320 mainly provides light to the light guide plate 310
  • the optical film set 400 is disposed in front of the light guide plate 310 .
  • the optical film group 400 is mainly used to reduce the amount of light emitted from the light guide plate 310 from the side view angle, and at least maintain the light output amount of the light emitted from the light guide plate 310 from the front view angle, so that the backlight module 300 can Applied to anti-peep display products.
  • the optical film set 400 includes a lower diffusion sheet 410, a lower prism sheet 420, an upper prism sheet 430 and an upper diffusion sheet 440, wherein the lower diffusion sheet 410, the lower prism sheet 420, the upper The prism sheet 430 and the upper diffusion sheet 440 are sequentially stacked in front of the light emitting surface of the light guide plate 310 .
  • the structures of the lower prism sheet 420 and the upper prism sheet 430 are substantially the same as those of the lower prism sheet 220 and the upper prism sheet 230 shown in FIGS.
  • the effect of the upper diffusion sheet 440 is to ensure that the product of the anti-peeping display has better optical taste, such as better uniformity, especially the haze of the upper diffusion sheet 440 is higher than that of the lower diffusion sheet 410. In this way, it can ensure that the light emitted from the upper diffuser 440 will not generate too much stray light, and further make the products using the optical film set of the present disclosure meet the anti-peeping property.
  • the lower diffusion sheet 410 and the upper diffusion sheet 440 have diffusion particles 211 such as shown in FIG. 5 , and these diffusion particles can make the lower diffusion sheet 410 have a haze of 50% to 60% (inclusive). , and the haze of the upper diffusion sheet 440 is lower than that of the lower diffusion sheet 410 , for example, 30% or less, and the endpoint values are included.
  • Table 3 shows that the angle between the prism structure of the upper prism sheet 430 and the extending direction of the light incident surface 311 of the light guide plate 310 ranges from 25 degrees to 50 degrees or from 130 degrees to 155 degrees.
  • the amount of stray light generated is still within the allowable range of the anti-peeping product. It can be seen from Table 3 that when the haze of the lower diffuser 410 is in the range of 50% to 60% and the haze of the upper diffuser 440 is less than 30%, less stray light can be generated.
  • the optical quality of the backlight module of this embodiment is also taken into account, for example, it has better uniformity.
  • FIG. 7 is a device diagram illustrating a display device according to an embodiment of the present disclosure.
  • the display device 500 of this embodiment includes a backlight module 100 and a display panel 510 as shown in FIG. 1 .
  • the display panel 510 is disposed in front of the backlight module 100 . Therefore, through the design of the optical film set 200 in the backlight module 100 , the display device 500 can also maintain the light output at the front viewing angle and reduce the light output at the side viewing angle, so details will not be repeated here.
  • the application of the backlight module 100 shown in FIG. 1 in the display device 500 is only used as an exemplary illustration, and is not intended to limit the present disclosure.
  • the backlight modules of other aforementioned embodiments (for example, the backlight module 300 shown in FIG. 6 ) can be applied to display devices to produce the same anti-peeping effect.
  • the optical film set of the present disclosure is mainly designed by the angle between the extension direction of the upper prism structure of the upper prism sheet and the light incident surface, and is matched with the extension direction of the lower prism structure of the lower prism sheet
  • the angle between the incident surface and the light incident surface is changed to reduce the amount of light emitted from the side angle of view while maintaining the amount of light emitted from the front angle of view, so as to meet the optical requirements of the anti-peep display.
  • the combination of the upper prism sheet and the lower prism sheet of the present disclosure can further achieve the effect of reducing the stray light emitted from the side viewing angle when the diffuser sheets with different hazes are matched.

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  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Nonlinear Science (AREA)
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Abstract

一种光学膜片组(200),其配置以将来自于背光模组(100)的导光板(110)的光线导出。光学膜片组(200)包含下棱镜片(220)及上棱镜片(230)。下棱镜片(220)具有多个下棱镜结构(221),且每一个下棱镜结构(221)沿着第一方向(D1)延伸。上棱镜片(230)设置在下棱镜片(220)的上方,其中,上棱镜片(230)具有多个上棱镜结构(231),且每一个上棱镜结构(231)沿着第二方向(D2)延伸,第二方向(D2)不同于第一方向(D1)。第二方向(D2)与导光板(110)的入光面(111)的延伸方向(A1)之间具有在从25度至50度或从130度至155度的范围内的夹角,且包含端点值。

Description

光学膜片组、背光模组及显示装置 技术领域
本揭露涉及一种膜片组件及其应用,且特别是涉及可应用于背光模组的膜片组件、及使用此膜片组件的背光模组及显示装置。
背景技术
一般常见的背光模组主要包含导光板与数张光学膜片,光学膜片可将从导光板射出的光线折射,使其以正视角出光。然而,此种背光模组并无法应用在防窥显示产品上。因此,如何通过改变光学膜片与导光板的搭配设计来产生良好的防窥效果,已成为相关业者积极努力的目标。
发明内容
因此,本揭露的目的在于提供光学膜片组及使用此膜片组件的背光模组及显示装置,通过光学膜片组的设计,可维持光线从正视角出光的出光量并降低光线从侧向出光的杂散光。
根据本揭露的上述目的,提出一种光学膜片组,其配置以将来自于背光模组的导光板的光线导出。该光学膜片组包含下棱镜片及上棱镜片。下棱镜片具有多个下棱镜结构,且每一个下棱镜结构沿着第一方向延伸。上棱镜片设置在下棱镜片的上方,其中,上棱镜片具有多个上棱镜结构,且每一个上棱镜结构沿着第二方向延伸,其中,第二方向不同于第一方向。第二方向与导光板的入光面的延伸方向之间具有范围从25度至50度或从130度至155度的夹角,且包含端点值。
依据本揭露的一实施例,上述的第二方向与导光板的入光面的延伸方向之间具有范围从115度至140度或从220度至245度的夹角,且包含端点值。
依据本揭露的一实施例,上述的第一方向与第二方向互相垂直。
依据本揭露的一实施例,上述的光学膜片组还包含设置在下棱镜片的下方的下扩散片,且下扩散片包含多个扩散粒子,这些扩散粒子使下扩散片具有50%至60%的雾度,且包含端点值。
依据本揭露的一实施例,上述的光学膜片组还包含设置在上棱镜片的上方的上扩散片。其中,上扩散片包含多个扩散粒子,这些扩散粒子使上扩散片具有30%以下的雾度,且包含端点值。
依据本揭露的一实施例,上述的光学膜片组还包含下扩散片与上扩散片。其中,下扩散片与上扩散片的雾度比值为1.6至6,且包含端点值。
依据本揭露的一实施例,上述的下扩散片设置在下棱镜片的下方,上扩散片设置在上棱镜片的上方。来自于导光板的光线依序通过下扩散片、下棱镜片、上棱镜片以及上扩散片后,一部分光线沿着正视方向从上扩散片出光,另一部分光线沿着侧视方向从上扩散片出光,其中从侧视方向出光的出光量与从正视方向出光的出光量的比值小于0.07。
依据本揭露的一实施例,上述的正视方向平行于上扩散片的出光法线,侧视方向与出光法线之间具有大于45度的夹角。
依据本揭露的一实施例,上述的每一个下棱镜结构与每一个上棱镜结构均为条状结构。
根据本揭露的上述目的,另提出一种背光模组。背光模组包含导光板、光源以及上述的光学膜片组。导光板具有入光面以及出光面。光源邻设于入光面。光学膜片组设置在出光面的上方。
根据本揭露的上述目的,又提出一种显示装置。显示装置包含导光板、光源、上述的光学膜片组以及显示面板。导光板具有入光面以及出光面。光源邻设于入光面。光学膜片组设置在出光面的上方。显示面板设置在光学膜片组的上方。
由上述可知,本揭露的光学膜片组主要是通过上棱镜片的上棱镜结构的延伸方向与入光面之间的夹角设计,并搭配下棱镜片的下棱镜结构的延伸方向与入光面之间的夹角变化,在维持光线从正视角出光的出光量的前提下,降低光线从侧视角出光的出光量,以符合防窥显示的光学需求。此外,本揭露的上棱镜片与下棱镜片的组合在搭配不同雾度的扩散片时,还 可进一步达到减少从侧视角出光的杂散光的效果。
附图说明
为了更完整地了解实施例及其优点,现在参照附图做出下列描述,其中:
图1是绘示依照本揭露的第一实施方式的背光模组的装置示意图;
图2是绘示依照本揭露的第一实施方式的下棱镜片的前视图;
图3是绘示依照本揭露的第一实施方式的上棱镜片的前视图;
图4是绘示依照本揭露的第一实施方式的利用上棱镜片的夹角设计所产生的正视角出光辉度与侧视角出光辉度的比较图;
图5是绘示依照本揭露的第一实施方式的下扩散片的侧视图;
图6是绘示依照本揭露的第二实施方式的背光模组的装置示意图;以及
图7是绘示依照本揭露的一实施方式的显示装置的装置示意图。
具体实施方式
请参照图1,其是绘示依照本揭露的第一实施方式的背光模组的装置示意图。本实施方式的背光模组100主要包含导光板110、光源120以及光学膜片组200。光源120主要可提供光线至导光板110中,且光学膜片组200设置在导光板110的前方。光学膜片组200主要用来降低从导光板110射出的光线从侧视角出光的出光量,并维持从导光板110射出的光线从正视角出光的出光量,以使背光模组100能够应用至防窥显示产品中。
如图1所示,导光板110具有入光面111与出光面112。光源120邻设于入光面111,且光源120所提供的光线从导光板110的入光面111进入导光板110中,再从导光板110的出光面112出光。在本实施例中,光学膜片组200包含下扩散片210、下棱镜片220及上棱镜片230,其中下扩散片210、下棱镜片220、及上棱镜片230依序堆叠在导光板110的出光面112的前方。
另请一并参照图2及图3,其分别是绘示依照本揭露的第一实施方式 的下棱镜片及上棱镜片的前视图。在本实施例中,下棱镜片220具有多个下棱镜结构221,且每个下棱镜结构221为条状结构,并沿着第一方向D1延伸。第一方向D1与导光板110的入光面111的延伸方向A1之间具有夹角α。上棱镜片230具有多个上棱镜结构231,且每一个上棱镜结构231为条状结构,且沿着第二方向D2延伸。其中,第二方向D2不同于第一方向D1。第二方向D2与导光板110的入光面111的延伸方向A1之间具有夹角β。在本实施例中,夹角β在从25度至50度或从130度至155度的范围内。由此,从导光板110的出光面112射出的光线依序通过下扩散片210、下棱镜片220与上棱镜片230后,一部分光线(例如图1的光线L1)沿着正视方向(或称正视角)从上棱镜片230出光,另一部分光线(例如图1的光线L2)沿着侧视方向(或称侧视角)从上棱镜片230出光。举例而言,当使用者面对如图1所示的背光模组100时,用户正视背光模组100的中心位置,此时在背光模组100的出光面上界定通过该中心位置的延伸线P1,则延伸线P1与正视方向所构成的平面P2(平面P2包含如图1的阴影区域)上具有侧视方向,其中,在此所指的正视方向是指光线平行于上棱镜片230的法线方向,而侧视方向是指在前述平面P2上与正视方向之间具有夹角θ的方向。
另请一并参照图4,图4是绘示依照本揭露的第一实施方式的利用上棱镜片的夹角设计所产生的正视角出光辉度与侧视角出光辉度比较图。由图4可知,当上棱镜片230的夹角β在从25度至50度或从130度至155度的范围内(也就是图4中的虚线方框所框选出的范围内)时,整体背光模组100可产生较大的正视角出光辉度以及较小的侧视角出光辉度,这使得从侧视方向出光的光线的出光量与从正视方向出光的光线的出光量的比值(也可称为侧视角出光占比)较小,例如小于0.07,这表示利用上棱镜片230的夹角β在从25度至50度或从130度至155度的范围内(且包含端点值)的设计,可使侧向出光量降低。
另请参照下表一与表二,表一与表二为下棱镜片220的夹角α与上棱镜片230的夹角β的角度搭配所产生的光线L1与光线L2的出光结果。
表一
Figure PCTCN2021136657-appb-000001
表二
Figure PCTCN2021136657-appb-000002
根据上表一及表二可知,当上棱镜片230的夹角β的范围为从25度至50度或从130度至155度时,侧视角出光占比均小于10%,甚至可小于7%,这可满足防窥产品的需求。由此可知,下棱镜片220的夹角α可设计在115度至140度或从220度至245度的范围内,且包含端点值;或使上棱镜片230的上棱镜结构231的第二方向D2与下棱镜片220的下棱镜结构221的第一方向D1互相垂直,来达到如前述的降低侧视角出光占比的效果。
另请参照图5,其是绘示依照本揭露的第一实施方式的下扩散片的侧视图。在一实施例中,下扩散片210包含多个扩散粒子211。本揭露的下扩散片210主要可减少从侧视角(即正视方向与侧视方向之间的夹角θ大于45度)射出的杂散光,其中,杂散光是指经过扩散粒子所造成的漫射光线,其属于无特定方向性的光线。当平行光线L3入射进入下扩散片210时,一 部分光线(例如光线L4)会平行穿透下扩散片210,另一部分光线(例如光线L5)则经由扩散粒子211作用而散射穿透下扩散片210,其中光线L5相对于平行光线L3的偏离角度大于2.5度。其中,散射穿透下扩散片210的光线L5的穿透率,与光线L4加上光线L5的穿透率总和的比值,可定义为下扩散片210的雾度。在本实施例中,下扩散片210具有50%至60%的雾度,且包含端点值。当下扩散片210的雾度为0%时,虽然能够达到同样较低的侧视角出光占比,但无法满足出光面靠近入光侧的光线均齐度需求;当下扩散片210的雾度为90%时,虽然能够达到较低的侧视角出光占比,但无法满足正视角的出光辉度需求,且由于在侧视角所测量到的杂散光较多,因此减损了产品的防窥效果。故下扩散片210的雾度在50%至60%时,既可满足产品的防窥目的,也可在侧视角产生较少的杂散光。须说明的是,相对于习知背光模组中用高雾度的下扩散片(例如90%雾度的下扩散片)容易产生较多的杂散光的情况,本揭露利用50%至60%的低雾度下扩散片,一方面可满足客户要求的光学外观,另一方面还能降低杂散光的产生,进而满足防窥产品的需求。
本揭露的背光模组亦可有不同的结构设计。另请参照图6,其是绘示依照本揭露的第二实施方式的背光模组的装置示意图。本实施方式的背光模组300的结构与图1所示的背光模组100的结构大致上相同,差异仅在于背光模组300进一步包含上扩散片440。如图6所示,背光模组300主要包含导光板310、光源320以及光学膜片组400。光源320主要可提供光线至导光板310中,且光学膜片组400设置在导光板310的前方。光学膜片组400主要是用来降低从导光板310射出的光线从侧视角出光的出光量,并至少维持从导光板310射出的光线从正视角出光的出光量,以使背光模组300能够应用至防窥显示产品中。
如图6所示,在本实施例中,光学膜片组400包含下扩散片410、下棱镜片420、上棱镜片430及上扩散片440,其中下扩散片410、下棱镜片420、上棱镜片430及上扩散片440依序堆叠在导光板310的出光面的前方。其中,下棱镜片420与上棱镜片430的结构与图1至图3所示的下棱镜片220与上棱镜片230的结构实质上相同,故于此不再赘述。在本实施例中, 上扩散片440的效果在于确保防窥显示的产品具有更佳的光学品味,例如更佳的均齐度,特别是上扩散片440的雾度比下扩散片410的雾度更低,如此可确保从上扩散片440射出的光线不会产生过多的杂散光,进一步使应用本揭露的光学膜片组的产品满足防窥特性。
在本实施例中,下扩散片410与上扩散片440具有例如图5所示的扩散粒子211,且这些扩散粒子可使下扩散片410具有50%至60%(包含端点值)的雾度、且上扩散片440的雾度比下扩散片410的雾度更低,例如30%以下,且包含端点值。另请参照表三,表三说明了基于前述的上棱镜片430的棱镜结构与导光板310的入光面311的延伸方向的夹角的范围为从25度至50度或从130度至155度的条件下,再搭配下扩散片410与上扩散片440的雾度变化,所产生的杂散光的量仍在防窥产品的容许范围内。由表三可知,当下扩散片410的雾度在50%至60%的范围内、并且上扩散片440的雾度为30%以下时,可产生较少的杂散光。此外,从表三的结果亦可推知,下扩散片410与上扩散片440的雾度比值范围在从1.6至6的范围内(且包含端点值)时,可满足防窥特性的产品,同时产生较少的杂散光之外,也兼顾了本实施例背光模组的光学品味,例如具有更佳的均齐度。
表三
Figure PCTCN2021136657-appb-000003
另请参照图7,其是绘示依照本揭露的一实施方式的显示装置的装置示意图。本实施方式的显示装置500包含如图1所示的背光模组100以及显示面板510。显示面板510设置在背光模组100的前方。由此,显示装置500通过背光模组100中的光学膜片组200的设计,同样可维持正视角出光量并降低侧视角出光量的目的,故在此不再赘述。其中,本案实施例以图1所示的背光模组100应用于显示装置500中仅用来作为示范说明,并非用 以限制本揭露。前述其他实施例的背光模组(例如图6所示的背光模组300均可应用于显示装置中,以产生同样的防窥效果。
由上述本揭露实施方式可知,本揭露的光学膜片组主要通过上棱镜片的上棱镜结构的延伸方向与入光面之间的夹角设计,并搭配下棱镜片的下棱镜结构的延伸方向与入光面之间的夹角变化,在维持光线从正视角出光的出光量的前提下,降低光线从侧视角出光的出光量,以符合防窥显示的光学需求。此外,本揭露的上棱镜片与下棱镜片的组合在搭配不同雾度的扩散片时,还可进一步达到减少从侧视角出光的杂散光的效果。
虽然本揭露的实施例已揭露如上,然其并非用以限定本揭露,任何所属技术领域人员,在不脱离本揭露的实施例的精神和范围内,应当可以做出些许更动与润饰,故本揭露的实施例的保护范围应当以所附的权利要求书所界定的保护范围为准。
【附图标记列表】
100:背光模组
110:导光板
111:入光面
112:出光面
120:光源
200:光学膜片组
210:下扩散片
211:扩散粒子
220:下棱镜片
221:下棱镜结构
230:上棱镜片
231:上棱镜结构
300:背光模组
310:导光板
311:入光面
320:光源
400:光学膜片组
410:下扩散片
420:下棱镜片
430:上棱镜片
440:上扩散片
500:显示装置
510:显示面板
A1:延伸方向
D1:第一方向
D2:第二方向
L1:光线
L2:光线
L3:光线
L4:光线
L5:光线
P1:延伸线
P2:平面
α:夹角
β:夹角
θ:夹角。

Claims (11)

  1. 一种光学膜片组,其配置以将来自于背光模组的导光板的光线导出,其中,所述光学膜片组包含:
    下棱镜片,其具有多个下棱镜结构,且每一所述下棱镜结构沿着第一方向延伸;以及
    上棱镜片,其设置在所述下棱镜片的上方,其中,所述上棱镜片具有多个上棱镜结构,且每一所述上棱镜结构沿着第二方向延伸,所述第二方向不同于所述第一方向,且所述第二方向与所述导光板的入光面的延伸方向之间具有夹角,其中,所述夹角在从25度至50度或从130度至155度的范围内,且包含端点值。
  2. 根据权利要求1所述的光学膜片组,其中,所述第二方向与所述导光板的入光面的延伸方向之间具有在从115度至140度或从220度至245度的范围内的夹角,且包含端点值。
  3. 根据权利要求2所述的光学膜片组,其中,所述第一方向与所述第二方向互相垂直。
  4. 根据权利要求1所述的光学膜片组,还包含下扩散片,所述下扩散片设置在所述下棱镜片的下方,其中,所述下扩散片包含多个扩散粒子,所述多个扩散粒子使所述下扩散片具有50%至60%的雾度,且包含端点值。
  5. 根据权利要求1所述的光学膜片组,还包含上扩散片,所述上扩散片设置在所述上棱镜片的上方,其中,所述上扩散片包含多个扩散粒子,所述多个扩散粒子使所述上扩散片具有30%以下的雾度,且包含端点值。
  6. 根据权利要求1所述的光学膜片组,还包含下扩散片及上扩散片,其中,所述下扩散片与所述上扩散片的雾度比值为1.6至6,且包含端点值。
  7. 根据权利要求6所述的光学膜片组,其中,所述下扩散片设置在所述下棱镜片的下方,所述上扩散片设置在所述上棱镜片的上方,其中,来自于所述导光板的光线依序在通过所述下扩散片、所述下棱镜片、所述上棱镜片以及所述上扩散片后,一部分的所述光线沿着正视方向从所述上扩散片出光,另一部分的所述光线沿着侧视方向从所述上扩散片出光,其中 从所述侧视方向出光的出光量与从所述正视方向出光的出光量的比值小于0.07。
  8. 根据权利要求7所述的光学膜片组,其中,所述正视方向平行于所述上扩散片的出光法线,所述侧视方向与所述出光法线之间具有大于45度的夹角。
  9. 根据权利要求1所述的光学膜片组,其中,每一所述下棱镜结构与每一所述上棱镜结构为条状结构。
  10. 一种背光模组,包含:
    导光板,其具有入光面以及出光面;
    光源,其邻设于所述入光面;以及
    根据权利要求1至9中任一项所述的光学膜片组,其设置在所述出光面的上方。
  11. 一种显示装置,包含:
    导光板,其具有入光面以及出光面;
    光源,其邻设于所述入光面;
    根据权利要求1至9中任一项所述的光学膜片组,其设置在所述导光板的所述出光面的上方;以及
    显示面板,其设置在所述光学膜片组的上方。
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