WO1996005466A1 - Source de lumiere plane mettant en ×uvre une couche de diffusion de la lumiere - Google Patents

Source de lumiere plane mettant en ×uvre une couche de diffusion de la lumiere Download PDF

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Publication number
WO1996005466A1
WO1996005466A1 PCT/JP1995/001608 JP9501608W WO9605466A1 WO 1996005466 A1 WO1996005466 A1 WO 1996005466A1 JP 9501608 W JP9501608 W JP 9501608W WO 9605466 A1 WO9605466 A1 WO 9605466A1
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WO
WIPO (PCT)
Prior art keywords
light
sheet
light source
height
curve
Prior art date
Application number
PCT/JP1995/001608
Other languages
English (en)
Japanese (ja)
Inventor
Michiko Takeuchi
Toshikazu Nishio
Taiji Ishii
Original Assignee
Dai Nippon Printing Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Dai Nippon Printing Co., Ltd. filed Critical Dai Nippon Printing Co., Ltd.
Priority to KR1019960701957A priority Critical patent/KR100215127B1/ko
Priority to US08/619,623 priority patent/US5944405A/en
Publication of WO1996005466A1 publication Critical patent/WO1996005466A1/fr

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
    • G02B6/0051—Diffusing sheet or layer
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0205—Diffusing elements; Afocal elements characterised by the diffusing properties
    • G02B5/021—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures
    • G02B5/0215—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures the surface having a regular structure
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0205—Diffusing elements; Afocal elements characterised by the diffusing properties
    • G02B5/021—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures
    • G02B5/0221—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures the surface having an irregular structure
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0273—Diffusing elements; Afocal elements characterized by the use
    • G02B5/0278—Diffusing elements; Afocal elements characterized by the use used in transmission
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
    • G02B6/0038—Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
    • G02B6/0053—Prismatic sheet or layer; Brightness enhancement element, sheet or layer
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0065—Manufacturing aspects; Material aspects

Definitions

  • the present invention relates to a surface light source useful for a backlight of a transmissive display device such as a liquid crystal display, a lighting advertisement, a $$ sign, and more particularly to a surface light source using a light diffusion sheet.
  • LCD liquid crystal display devices
  • a surface light source used for ⁇ 3 ⁇ 4 light is ⁇ ! ⁇ from one or both sides of a transparent light guide composed of a flat plate, and ⁇ : light is guided by total internal reflection inside The light propagates uniformly throughout the light plate, and ⁇ of the propagated light is converted to light less than the critical angle by the light scattering plate of the light guide 3 ⁇ 4®, and the tfc3 ⁇ 4 is emitted from the light guide plate surface ( Japan's National Opening of Japan 55-1 6 2 201).
  • a lens sheet having ⁇ on one surface and a smooth surface on the other surface is placed on the surface of the light guide plate of the surface light source of ⁇ ; With the separated surface facing up, the expanded tfc3 ⁇ 4light is uniformly and isotropically diffused within a desired angle range by using the light focusing action of the lens. No. 201).
  • Renzushi - bets when dispersing the light diffusing agent particles such as T io 2 used in combination with adefovir extinguishing transparent diffuser extinguishing transparent sheet) formed by the transparent resin, a single, vanishing Ade Using only a transparent diffuser laminated on the light guide (US Patent No.
  • the emitted light is emitted with respect to the normal direction of the light guide surface.
  • a relatively sharp distribution peaks at an angle of 60 degrees, the brightness increases in the 3 ⁇ 4g
  • the light adhesion between the lens sheet and the surface of the light guide plate generates an equal thickness interference fringe such as a Newton ring. There was also 3 ⁇ 4 ⁇ .
  • the light diffusing layer of the light guide 3 ⁇ 4® Attempts to correct and equalize the luminance distribution in the light guide by increasing and decreasing the 3 ⁇ 4t of the pattern closer to the light source and increasing the distance away from the light source;
  • the device of the first type has a drawback that the halftone dots of the light-diffusing layer can be seen through when viewed from the light-emitting surface side.
  • myself 2 there was also a drawback that the space and erasure of the entire optical office were doubled to J3 ⁇ 4 ⁇ .
  • An object of the present invention is to solve the above-mentioned problems ⁇ s and ⁇ , and to increase uniformity and high brightness only within a desired angle range without increasing the power, power, and the size of the ⁇ tm.
  • ⁇ to provide a surface light source with no variation in luminance depending on the location in the plane.
  • the object is to provide a transparent base material containing no light particles, having random fine irregularities on the surface, wherein the minute irregularities have a wavelength of light source light of £ Lh or less than ⁇ ⁇ ⁇ .
  • the surface roughness is plotted by plotting the percentage of the cumulative frequency distribution of the height of the minute irregularities on the vertical axis and the height of the minute irregularities on the horizontal axis to form a cumulative 3 ⁇ 4 ⁇ cloth curve of the height of the minute irregularities.
  • the segregation number distribution curve becomes a convex curve toward the lower side of the coordinates, and the average value of the height of the small irregularities is attained by a surface light source using a light sheet having a value larger than the intermediate value. Is done.
  • the diffusion sheet is located on at least one side of the side end surface, and is located on the light exit surface of an optical flat plate light guide or a light guide having a cavity, which has an emissive layer on S®. 3 ⁇ 4S can be provided.
  • the upper sheet has a light source housed therein, a rear wall of the light source, a projection wall for covering an image, and a front window of the lamp house having a window opened in front of the light source. It can also be provided to cover.
  • the surface of the light guide may be a flat surface having a surface roughness equal to or less than the wavelength of the light from the light source.
  • a convex or concave single-row sheet or a novel row sheet can be formed. Further, another similar diffusion sheet can be formed on the 3 ⁇ 4m sheet.
  • FIG. 1 is a perspective view showing an example of a type display device using the edge light type surface light source of the present invention.
  • FIG. 2 is a perspective view showing an example of a transparent device using the direct-type surface light source of the present invention.
  • FIG. 3 is an explanatory cross-sectional view of an example of the edge light type surface light source of the present invention, showing a case where a group is formed on B of the light diffusion sheet.
  • FIG. 4 is a perspective view showing an example of a lens sheet used in the present invention.
  • FIG. 5 is a perspective view showing another example of the lens sheet used in the present invention.
  • FIG. 6 is a perspective view showing still another example of the lens sheet used in the present invention.
  • FIG. 7 is a perspective view showing another example of the lens sheet used in the present invention.
  • FIG. 8 is a perspective view showing " ⁇ " in the case where the lens sheet used in the present invention is doubled.
  • Fig. 9 is a cross-sectional view showing that light travels from inside the light guide plate to the outside.
  • Figure 10 shows that ⁇ that oozes out of the light guide plate due to the tunnel effect reappears in the lens sheet. It is sectional drawing which shows becoming a traveling wave.
  • FIG. 11 is a cross-sectional view showing that when the optical rat sheet of the present invention is used, the light traveling from the light guide plate to the outside is partially partially reflected and partially reflected.
  • FIG. 12 is a diagram showing an example of the method for producing an ultraviolet-ray sheet of the present invention.
  • FIG. 13 is a perspective view showing an example of the light diffusion sheet of the present invention produced by the manufacturing method shown in FIG.
  • FIG. 14 is a cross-sectional view of a conventional edge light type surface light source without a lens sheet.
  • FIG. 15 is a perspective view of a conventional edge light type surface light source, showing a case where a lens sheet of a power plane is formed.
  • FIG. 16 is a cross-sectional view of FIG.
  • FIG. 17 shows the surface roughness of the longitudinal bow, that is, the depth R of the ⁇ ! Valley, taken as the percentage of the cumulative distribution, and the abscissa plots the ⁇ in the ⁇ to increase the ⁇ of the optical sheet according to the present invention.
  • FIG. 7 is a diagram showing a cumulative frequency distribution curve f (R) when the surface roughness, that is, the depth R of the ⁇ Si valley is taken.
  • FIG. 18 is a cross-sectional view of a molding die having the characteristics of the cumulative S ⁇ cloth curve f A (R) of FIG.
  • FIG. 19 is a cross-sectional view of ⁇ !! ⁇ !! having the characteristic of the contributory number distribution curve f B (R) of FIG.
  • FIG. 20 is a cross-sectional view schematically showing an undercut ⁇ K formed by aggregates of micro-clustered (spherical) particles of chromium metal when a chrome mat is applied to the roll for use.
  • FIG. 21 shows the relationship between the height of the light sheet according to the present invention, that is, the light M: the surface roughness of the sheet, and the distribution thereof, with the vertical axis representing the surface roughness, ie, the cumulative height R of the peak. ⁇ The percentage of the cloth is taken, and the horizontal axis is the surface roughness, that is, the peak height R.
  • FIG. 10 is a diagram showing a case where the cumulative distribution curve ⁇ (R) is convex downward from the cumulative distribution curve, and also satisfies the relationship of average value ⁇ intermediate value.
  • FIG. 22 is a partially enlarged measurement diagram of the optical sheet having the cumulative characteristics of FIG.
  • FIG. 23 shows the height of the optical sheet according to the present invention, that is, the surface roughness of the optical sheet and the distribution thereof, and the vertical axis represents the surface roughness, that is, the cumulative distribution of the peak height R.
  • the cumulative frequency distribution curve ⁇ (R) with the percentage taken and the surface roughness on the horizontal axis, that is, the peak height R, the cumulative frequency distribution curve ⁇ (R) is convex to the cumulative frequency distribution curve ⁇ . It is a figure showing the case where it is satisfied.
  • FIG. 24 is a partially enlarged measurement diagram obtained by stereoscopically viewing 3 ⁇ 4g of the light sheet having the cumulative number distribution characteristic of FIG.
  • FIG. 25 shows the height of the light m sheet according to the present invention, that is, the surface roughness of the light diffusion sheet, and the distribution thereof, and the vertical axis shows the surface roughness, that is, the cumulative sum of the peak height R.
  • the cumulative percentage of the cloth, with the horizontal axis representing the surface roughness, that is, the peak height R, is 2 ⁇
  • the average value of R StSlfc ⁇ Cloth curve or "T is a diagram showing the case where it consists of a convex part and a convex part on the upper side.
  • FIG. 26 is a partially enlarged view 61 of the light sheet having the cumulative ⁇ cloth characteristic of FIG.
  • FIG. 27 shows the ⁇ height of the optical sheet according to the present invention, that is, the surface roughness of the optical sheet, and the distribution thereof, and the vertical axis represents the surface roughness, ie, the cumulative distribution of the peak height R.
  • FIG. 28 shows the ridges of a right-angled isosceles triangular section having the cumulative frequency distribution characteristics of Fig. 27.
  • FIG. 7 is a partial enlarged view of ⁇ g of a light 3 ⁇ 4t3 ⁇ 4 sheet made in FIG.
  • FIG. 29 shows the height of the projections of the light diffusion sheet according to the present invention, that is, the surface roughness of the light diffusion sheet, and the distribution t state thereof.
  • ⁇ In the cumulative 3 ⁇ 4 ⁇ 3 ⁇ 4 distribution curve ⁇ (R), taking the percentage of the cloth and taking the surface roughness on the horizontal axis, that is, the height R of the peak, the cumulative distribution curve is convex upward to ⁇ and It is a figure which shows a case where it is convex and an average value ⁇ an intermediate value.
  • 3 0 is a stereoscopic phased partial enlarged measuring 3 ⁇ 4 ⁇ figure of the light diffusing sheet ⁇ with cumulative 3 ⁇ 43 ⁇ 4 number distribution characteristic of FIG. 2 9 0
  • FIG. 31 shows the height of the projections of the light diffusion sheet according to the present invention, that is, the surface roughness of the light diffusion sheet, and the distribution thereof, and the vertical axis represents the surface roughness, ie, the cumulative height R of the peak.
  • the cumulative distribution curve f (R) where the percentage of the cloth is taken and the horizontal axis is the surface roughness, that is, the height R of the peak, the cumulative distribution curve force ⁇ a convex curve downward over the entire area It is a figure showing a case.
  • FIG. 32 is a partially enlarged measurement diagram in which 3 g of the light diffusion sheet having the cumulative number distribution characteristic of FIG.
  • FIG. 33 is an angular distribution diagram of emission light luminance of the surface light source of the present invention ((Example 9, mi).
  • FIG. 34 is an angular distribution diagram of emission light luminance of the surface light source example 8) of the present invention.
  • FIG. 1 shows an edge light type surface light source according to the present invention.
  • reference numeral 1 denotes a light guide plate
  • the light guide plate 1 is a solid transient flat plate.
  • a light source for example, a linear light source 3 is provided along a side end surface of the light guide plate 1. Behind the light source 3, a reflector 5 is provided. The light emitted from the light source 3 is either directly or The light enters the light guide plate 1 and is internally reflected, for example, as shown in FIG. 3, or is emitted directly from the light guide plate 1 to the outside.
  • a light emitting layer 2 is provided on the back of the light guide plate 1. The surface of the light guide plate 1 on the side opposite to the 3 ⁇ 43 ⁇ 4 * layer 2 is formed as an outgoing surface.
  • the light sheet 8 is provided in contact with the light exit surface, and the light emitted through the light exit surface travels three times on the light sheet 8.
  • the light that has been applied to the light sheet 8 passes through the oversized display device 6 that has the lens sheet 4 attached.
  • a gap 9 is formed between the light diffusion sheet 8 and the light guide plate 1 and between the light SSI! Sheet 8 and the lens sheet 4.
  • the surface of the sheet 8 facing these gaps 9 is formed with a ⁇ 41 force, which will be described later.
  • the light guide plate 1 can be hollow instead of being solid. In this case, the surface of the solid light guide plate 1 in contact with the matrix 2 and the output surface are each l-shaped, and the space between them is a rectangular parallelepiped cavity.
  • the light source 3 is a line or a light source and is housed in a lamp house 5.
  • the lamp nose 5 covers the back and sides of the light source 3 and functions as a reflecting surface that reflects light from the light source 3 toward the light sheet 8.
  • 100 indicates the entire surface light source
  • 200 indicates the entire display device.
  • 1 is obtained by forming microscopic irregularities (for example, sand texture, satin pattern, etc.) on the entire surface of the light diffusion sheet 8 at random, and the minute irregularities Wavelength Co., Ltd., having a surface roughness of 100 ⁇ m or less.
  • microscopic irregularities for example, sand texture, satin pattern, etc.
  • Wavelength Co., Ltd. having a surface roughness of 100 ⁇ m or less.
  • the light diffusion sheet 8 used in the present invention is formed from a body material.
  • the ttS material poly (meth) acrylic acid methyl (here, (meth) acrylic acid Means Acrylic IK means methacrylic acid.
  • (meth) acrylates such as poly (meth) acrylate, thermoplastics such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polystyrene, polymethylpentene, etc.
  • Fats and the like are used such as transparent ultraviolet ray or electrocurable resin cross-linked and cured by ultraviolet ray or electricity, transparent glass, transparent ceramics and the like.
  • Examples of the ultraviolet-curable or electro-curable resin include pre-polymers, oligomers, and z or z or ⁇ ⁇ ⁇ having a heavy ft unsaturated bond such as a (meth) acryloyl group, a (meth) acryloyloxy group, or an epoxy group therein. * ⁇ Products obtained by appropriately mixing monomers can be used. Throughout the present specification, (meth) acryloyl is used in the meaning of acryloyl or methacryloyl.
  • prepolymers and oligomers examples include acrylates such as urethane (meth) acrylate, polyester (meth) acrylate, and epoxy (meth) acrylate, and unsaturated polyesters.
  • Examples of the monomer include dipentaerythritol pentyl (meth) acrylate, trimethylolpropanetri (meth) acrylate, and the like.
  • the above 3 ⁇ 3 ⁇ 4 ⁇ material usually has a thickness of 5 to 200 // m3 ⁇ 4g.
  • the light diffusion sheet 8 when used for a direct-type surface light source, the light diffusion sheet 8 itself supports its own weight and external force.
  • the light emitting sheet 8 may have a single-layer configuration as shown in FIG. 1, a two-layer configuration as shown in FIG. 13, or a multilayer configuration having three layers and Lh.
  • the height of the surface of the above light sheet 8 is less than the wavelength of the light source light J3 ⁇ 4 ⁇ , 100 // m 41 formed by small irregularities can be directly formed on the surface of ⁇ fettS material by embossing by hot pressing, sand blasting, etc., or can be manufactured by It is also possible to form a material layer having a projection 41 on the surface.
  • the light 41 formed on the light diffusion sheet 8 not only diffuses the light conversion isotropically, but also between the light diffusion sheet 8 and the smooth flat surface 10 of the light guide plate 1 as shown in FIG.
  • the object is to form at least a gap 9 (dimension ⁇ ) of the wavelength of the light source light between the flat smooth surface 7 of the lens sheet 4 and the sheet 8. If the gap is full of light from the light source, the total reflection power of the light guide plate 1 on the flat surface 10 will not be sufficient, and the height of the unevenness due to 3 ⁇ 4 £ 4 1 will exceed 100 m. In this case, the uneven shape of the projection 41 becomes conspicuous, which is inconvenient.
  • 3 ⁇ 4g41 can be any unevenness, but it is most important in terms of obtaining a uniform brightness angle ft ⁇ within the desired diffusion angle and a uniform brightness distribution within the light 21®.
  • the surface of the light emitting sheet 8 is provided with random fine irregularities (for example, sand texture, satin pattern, etc.) on the entire surface, and the minute irregularities are generated at a wavelength of 100 m of the light source light.
  • the surface roughness is as follows.
  • the vertical distribution is the percentage of the height of the fine irregularities and the horizontal axis is the cumulative distribution curve of the height of the fine irregularities.
  • the cumulative number distribution curve force becomes a curve including a downwardly convex portion of the coordinates, and the average value of the heights of the minute irregularities becomes larger than the intermediate value. It was formed as follows.
  • the light L 1, L 2 S, etc. which is ⁇ ! ⁇ out of the light diffusion sheet 8, also act as the To spread,
  • the incident light has a uniform angular distribution, and a high quality and high brightness surface light source can be obtained without any noticeable halftone dot pattern.
  • the shape of the group 41 may be such that the concave portion becomes narrower toward the bottom of the valley as shown in FIGS. 22 and 24, or as shown in FIG. 18 and FIG. preferable.
  • the cross section of the Wei group 41 is a sinusoidal curve, a cycloid curve, etc., in which the periodic amplitude is randomly changed in each cycle, or a cross-sectional curve with a random and narrow valley by sandblasting, mill engraving, or the like. Then, minute irregularities are formed so that the depth and the distance between adjacent convex portions are equal to or more than the wavelength of the light source light and equal to or less than 100 m, and satisfy the above-mentioned cumulative frequency distribution condition.
  • Such a shape is represented by ⁇ F from the point of uniformity of the angular distribution of transmitted light, high transmittance, and the point of total reflection at the interface between the light guide plate surface and the light sheet. is there.
  • Japanese Patent Application Laid-Open No. 56-1577310 discloses a method of embossing a UV-curable thermoplastic resin film with a roll embossing plate, and then irradiating UV rays to cure the film
  • Japanese Patent Application Laid-Open No. 61-15663 / 73 discloses that a roller or a roller engraved with a lens shape is coated with an ultraviolet or electro-curable resin, filled into a concave portion, and then passed through the resin.
  • the roll ⁇ is coated with a transparent substrate film and irradiated with ultraviolet light from the back of the film, or the resin is cured by irradiating ultraviolet rays etc.
  • the lens sheet 4 used in the present invention is, for example, as shown in FIG. 4, in which unit lenses 42 of a prism body are arranged with the direction thereof being ⁇ ,
  • the cross-sectional shape of the unit lens 42 may be a continuous, smooth curve such as a circle, an ellipse, a cardioid, an egg shape of Rankin, a cycloid, or an involute curve, or a polygon such as a triangle, a square, or a hexagon. Part or all of the square is used.
  • These unit lenses may be convex lenses as shown in FIG. 6 or concave lenses as shown in FIG. Of these, preferred are ease of design, manufacture, low light characteristics (half-value angle, luminance peak generated in the sidelobe light direction), isotropic half-angle luminance, ⁇ 3 ⁇ 4 ⁇ direction. From the viewpoint of the brightness).
  • an elliptic cylinder having the long axis in the normal direction of the surface light source is preferable because of its high luminance.
  • lens sheets can be used in an lti composition, but in order to control the light diffusion angle in two directions ( ⁇ down, left and right) using a columnar lens, two lenses as shown in Fig. 8 are used.
  • the sheet may be 3 ⁇ 4S so that the, is S3 ⁇ 4.
  • the orientation of the lens is the same as shown in Fig. 8 and the two lenses are oriented in the same direction.
  • Transient or K is the best, but ⁇ ⁇
  • the lenses of each lens sheet face each other ( The lens may be sandwiched between two lens sheets.
  • the lens sheet 4 is formed from a 3 ⁇ 43 ⁇ 4S material.
  • the ⁇ : 3 ⁇ 4S material the same material as the light diffusion sheet 8 described above can be used.
  • a thermoplastic resin such as acrylic or polycarbonate, or a UV- or electrocurable (meth) acrylate acrylate is used.
  • the above ⁇ : 1 ⁇ 23 ⁇ 4 material is usually 20 ⁇ 1 OO And
  • ⁇ The higher the property required for the base material, the better, the most desirable is the opacity. However, when used as a lens sheet, depending on the application, it may be feS bright, bran translucent, or gloss translucent. .
  • the extinguishing transparency refers to a property that makes light substantially uniform in all directions within a semi-solid angle, and is used as a synonym for light isotropic diffusion.
  • the angular distribution of light 3 ⁇ 4 ⁇ I G . ⁇ ) is represented by the following c 0 s distribution,
  • either a flat plate made of a transparent material or a flat plate made of a transparent material having a body cavity can be used.
  • a plate of material In order to make the light source light evenly distributed throughout the light guide using the total internal reflection inside the light guide, and to support the light diffusion sheet 8 It is preferred to use a plate of material.
  • the present invention uses the light guide plate 1 (FIG. 1) made of a flat plate made of a transparent material.
  • the opposite surface 10 of the light guide plate 1 opposite to the light scattering reflector is a flat surface and has a surface roughness less than the wavelength of the light source light.
  • the surface roughness referred to in this specification is not the average value of the Wei group (unevenness) but is evaluated by the average value of the difference between the peak and the valley bottom of the 53 ⁇ 4g group.
  • JI SB-0601 or It is measured by the ten-point average roughness Rz of ISO standard.
  • the light from the light source is acceptable and its wavelength is 0.4 to 0.8; um, so the surface roughness should be 0.4 um or less.
  • the distance between the convex portions is evaluated by an average value such as the average interval Sm of irregularities of the IS0 standard.
  • a method to increase or decrease the roughness of the surface a method of ⁇ , for example, heat pressing on the master plate, injection using a mirror-like shape, (casting) swelling, lens precision, etc. Use polishing, etc., 0
  • the material of the light guide plate 1 is selected from the same ⁇ 3 ⁇ 4 materials as those of the above-mentioned lens sheet.
  • an acrylic resin having a thickness of 1 to 1 OmmSS is used such as a polycarbonate resin plate.
  • a linear light source such as a fluorescent lamp is preferable from the viewpoint of obtaining uniform luminance over the entire surface.
  • a light source such as an incandescent lamp can also be used.
  • the light source 3 is provided separately from the side end of the light guide plate 1 as shown in FIG. 1, and a through hole is provided at the side end of the light guide plate 1 or a part of the side end is provided. It is also possible to provide a notch so that part or all of the light source can be inserted into the light guide plate.
  • Another light source 3 ′ (not shown) can be provided at the other side end of the light guide plate 1 in order to improve the luminance and improve the distribution of the luminance in the plane.
  • the number of these light sources may be one as shown in FIG. 1 or two or more as shown in FIG.
  • the edge light type surface light source as shown in Fig. 1 may be used to place the light source on the side edge of 2m2U:
  • a known member for example, a member such as a parabolic column, a hyperbolic column, an elliptic column, or the like, or a metal thin film provided on a recessed inner surface of a plate or the like by vapor deposition or plating is used.
  • the above-mentioned light sheet 8 is laminated, and on the light sheet 8, the lens sheet 4 is coated.
  • the lens of the lens sheet 4 faces outward (opposite the plane 10), and the smooth surface 7 of the lens sheet 4 faces the ⁇ group 41 of the optical sheet 8.
  • ⁇ (wavelength; Ih, the entire surface of the light guide plate with a gap at h, XI 00% depends on the uniformity of the required in-plane distribution of brightness H ⁇ ⁇ , the light energy use efficiency, and the light guide plate dimension i ⁇
  • the determined force typically the ratio K will be 80% KUi, more preferably 90% Ri: force.
  • ⁇ must be 80-90% i :, and ⁇ in the previous section was derived.
  • the light reflection layer 2 used in the present invention is a layer having a performance of causing light to be emitted by ffcS, and can be configured as follows. 1 Light guide 3 ⁇ 4 On one side of the surface, a pigment with high concealment and high whiteness, such as titanium dioxide or aluminum, is dispersed to form a white powder by painting.
  • ⁇ ⁇ Attenuation of ⁇ B from the light source 3 may be corrected by forming a halftone dot-shaped white layer and decreasing the white portion as the distance from the light source increases.
  • the combination of the light sheet and the lens sheet according to the present invention can be used for the direct type surface light source as shown in FIG. Further, two optical sheets 8 according to the present invention can be used by laminating J3 ⁇ 4 ⁇ . Further, if the required light ⁇ tfcft (half-value angle or the like) may be wide enough, the surface light source may be constituted by only one light diffusion sheet 8 of the present invention or a multilayered light diffusion sheet 8. .
  • the working mechanism of the edge light type surface light source is that the light source 3 enters the light guide plate 1 by ⁇ ! Since the incident L 1 has a small ⁇ ⁇ angle (the angle between the normal to the surface 10) and the critical angle, it is emitted as light LIT, which is a fraction of the power of the incident fi. As a result, emitted light near the light 23 ⁇ 4S is formed.
  • L2 that directly ⁇ ! ⁇ relatively far from the light source 3 has a large ⁇ ! ⁇ angle and a critical angle J3 ⁇ 4 ⁇ , so it is not emitted to the outside and becomes totally reflected light L2R. The light is sent to a distant place and is reflected by the male (disturbed) reflected light L
  • FIG. 16 shows a state in which the smooth surface 7 of the lens sheet 4, which is a non-lens smooth surface, is laminated on the smooth surface 10 of the light guide plate 1 in a direction in contact with the surface 10. It is shown.
  • the refractive index of the active materials is about 1.5, and the difference between them is not large. Therefore, although there is a difference of 3 ⁇ 4Jg, the lens sheet 4 and the light guide plate 1 are almost optically as shown in FIG.
  • wei groups 41 are formed on the surface of the light diffusing sheet 8, whereby the light guide plate 1 has at least a partial area between the smooth plane 10 and the lens sheet 4. Then, a void 9 is formed.
  • the gap 9 is usually adjacent to the light guide plate 1 having a refractive index of 1.5 3 ⁇ 4, the air layer (or true) having a refractive index of 1.0 and the surface 10 as an interface, FIG. Total reflection of light occurs as in the case of. Therefore, as shown in FIG. 3, in the region near the light source 3, the emitted light is illuminated by the light beam LIT that is ⁇ ! After being totally reflected at the interface of the cavity 9, the emitted light is obtained by L 2 T of less than the critical angle in the irradiating with the expanded icR in the light-spreading IfcS emitting layer 2.
  • the height of the surface 41 (that is, the gap 9) is set to the wavelength of the light source light
  • the present invention light energy can be used efficiently, and a uniform and high-luminance surface light source can be obtained.
  • the optical sheet 8 of the present invention the characteristics of various kinds of ⁇ 41 obtained by changing the conditions of the roll ⁇ will be described in Examples 1 to 6 of H. Production examples, surface light sources using them, examples of display devices using the surface light sources, and examples of it will be described with reference to FIG.
  • the light diffusion sheet 8 having 53 ⁇ 4S41 must be peeled off from the roll, it is necessary to peel off the cured resin layer from the mold in order to remove the mold M from the mold M.
  • the shape can be expanded or undercut as shown in Figs. 18 and 19.
  • characteristic and the suitability of the light OT ⁇ 8 are as follows: in addition to the above-mentioned ⁇ concavity, there is no middle spread or undercut.
  • the distribution of the number of jobs on the surface roughness is also important. That is, with a surface roughness measuring device such as an electro-needle type or a light ⁇ ; The reverse relationship is obtained)
  • the statistics of the depth of the valley (concave) of the surface (the height of the peak of the ⁇ g portion of the S! Resin) are taken, and the surface roughness is plotted on the vertical axis as shown in Fig.
  • the cross section of the mold in the case of a function that forms a downwardly convex curve with a gentle rising slope like the curve f B (R) in Fig. 17 is schematically exaggerated.
  • the shape as shown in FIG. 19 is obtained, and the shape of the mold 41 having such characteristics is similar to that of the fB (R) mold with the cumulative distribution curve of the height.
  • a mold having characteristics represented by a function such as a curve f A (R) has, for example, a shape as shown in FIG.
  • the height of 3 ⁇ 4g41 that is, the measurement and data of the surface roughness of the light diffusion sheet 8
  • the analysis was performed using a surf coder SE-30K manufactured by Kosaka Laboratories Co., Ltd. as a measuring instrument, with a feed rate of 0.2 imnZ s and a measurement length of l mm.
  • the light diffusing sheet 8 shown in FIG. 13 was crimped by the following steps using the apparatus shown in FIG.
  • a take-up roll 11 of a 50-m thick femless biaxially stretched polyethylene terephthalate base film was prepared.
  • the above-mentioned material film 12 is unwound from the take-up roll 11 at a speed synchronized with the rotation of the roll ⁇ l 4, and the base film is rolled on the roll ⁇ ! With the fat interposed between the layers, the mercury lamp 23,
  • Ultraviolet rays were irradiated from the back side of the base film 12 using 23, and the resin was cross-linked and cured in the concave portion of the surface of the roll 14 and simultaneously adhered to the base film 12.
  • the base film 12 running using the peeling roll 18 was peeled off together with the hardened resin in the form of Group 41 adhered to the base film 12 to obtain a light sheet 8.
  • the light diffusion sheet 8 was wound up as it was, and then cut to a desired size according to and used.
  • the ultraviolet-curable resin used in this step is obtained by adding a polyfunctional polyester acrylate oligomer to ⁇ and adding a reaction initiator.
  • Example 2 The roll in Example 2 was made by sandblasting the surface with # 200 spherical sand, and the ⁇ 3S41 value obtained is as follows.
  • the cumulative 3 ⁇ 4 ⁇ cloth curve, as in Example 1 has a partially upwardly convex distribution curve, and satisfies the relationship of “average value ⁇ middle ⁇ J” of the uneven height.
  • the shape of 41 obtained was as shown in FIG. 24, and the resilience from the concave portion of the cured resin layer was almost good, and the light property was also good.
  • the surface of the roll ⁇ in Example 3 was lightly corroded with a salt solution, After that, sand blasting was performed with sand of # 200 and gloss chrome plating was applied to the surface.
  • the characteristic values of the obtained 3 ⁇ 4g 41 are as follows.
  • the cumulative frequency distribution curve has an average value of 52% of the maximum value, and the cumulative frequency distribution curve includes a downwardly convex portion and an upwardly convex portion. In this case, there was a little resistance, though sometimes. Therefore, it is determined that the above-mentioned number is a critical condition of about 3 degrees.
  • the measured value of 5 g 41 was as shown in FIG. 26, and as indicated by the characteristic values, the optical characteristics were good.
  • the mouth used at m 4 is a cylindrical surface cut into a ridge with a right-angled isosceles triangular cross-section, and the obtained ⁇ 41 is a Sil-like cumulative frequency distribution curve as shown in Fig. 27. showed that. This is also a force that corresponds to the critical condition between the curve f A (R) and the curve f B (R) in FIG. 17, the shape of 3 ⁇ 4g 41 is as shown in FIG. 28, and the ira property was a child .
  • the ⁇ -le used in Comparative Example 1 was made of chromium mat ( ⁇ Fushi) This was created by applying a plating layer, and the characteristic values of ⁇ 41 obtained are as follows.
  • the cumulative ⁇ S number distribution curve is convex up to 3 ⁇ 4
  • the cross section was as shown in FIG. 30, and the flexibility was poor.
  • Optical rat sheet 8 was produced under the same conditions as in Example 1 except that only the preparation conditions were changed.
  • Example 5 Used in Example 5 was prepared by molding from a polyethylene terephthalate film into which calcium carbonate having a particle size of 1 to 10 m was kneaded, and was prepared by an electrodeposition method. It is as follows.
  • Table 1 below shows the properties of the light diffusion sheet 8 obtained in Examples 1 to 5 of H1 ⁇ 2.
  • Example 1 Example 2
  • Example 3 Example 4
  • Example 5 Comparative Example 1 Example 1
  • JIS-Z-8741 11.3 11.2 12.5 55.3 15.0
  • a take-up roll 11 of a base film made of 100 m-thick and femless biaxially stretched polyethylene terephthalate was prepared.
  • the material film 12 is unwound from the take-up roll 11 at a speed synchronized with the rotation of the roll 14, and the light is used.
  • Lenticular lens sheet 4 was obtained.
  • the lens sheet 4 was wound up as it was, and then cut into desired dimensions according to ⁇ before use.
  • Example 8 Using the light sheet 8 produced in Example 1 and the lens sheet 4 produced in Example 6, an edge light type surface light source having a configuration as shown in FIG. 1 was produced. However, as shown in FIG. 8, the two lens sheets 4 were overlapped so that ⁇ was perpendicular to each other, and both lenses faced in the exit direction.
  • the light guide plate 1 and the light source 3 used had the following characteristics.
  • ⁇ a specular reflective film in which aluminum was vacuum-deposited on a polyethylene terephthalate film was placed.
  • Halftone dots were formed by silk-screen printing using a siri-powered street end dispersed in an acryl-based paste binder.
  • the dots were arranged vertically and horizontally at a repetition period of 5 mm.
  • the diameter of the halftone dot was 0.2 mm near the light source, increased in proportion to the distance from the light source, and 2.0 mm at the end opposite to the light source.
  • cold-cathode tube-type white fluorescent lamps (power consumption: 4 W, tube diameter: 3 mni) were placed at both ends of the light guide plate.
  • a metallic anti! ⁇ On the opposite side of the light guide plate was placed a metallic anti! ⁇ .
  • the performance of the surface light source according to the RJL configuration was as follows.
  • Example 7 lens sheet 4 was not used, and only optical sheet 8 created in Example 1 was used.
  • the performance of the surface light source having the configuration was as follows.
  • Fig. 34 shows the angular distribution of luminance.
  • Half angle (0h) 74 degrees (However, even outside the half value angle, there is no sudden attenuation and a certain amount of emitted light is distributed.)
  • Example 7 a surface light source without using the light sheet 8 was created.
  • the ten-point average roughness Rz of the lens sheet Sffi was Rz ⁇ 0.1 fim.
  • Sheet 8 is formed from a transparent material that does not contain any light diffusing agent particles, it was possible to improve the light source energy utilization rate and achieve high brightness without any light absorption loss due to light diffusion itself.
  • the halftone dots of the light spreading tfcS layer of the light guide plate 1 became inconspicuous, and it was possible to obtain a high-quality surface light source.
  • the edge light type surface light source of the present invention uses the light sheet 8 and the lens sheet 4, the emitted light can be uniformly distributed within a desired angle gffl, and the emitted light can be distributed. However, it was possible to obtain a uniform luminance distribution over the entire surface without concentrating only near the light source.
  • the optical fim sheet 8 of the present invention when the optical fim sheet 8 of the present invention is placed between the lens sheet 4 and the light guide plate 1 of the edge light type surface light source, the optical contact between the lens sheet 4 and the light guide plate 1 does not occur, and the Newton ring It was possible to prevent the occurrence of interference fringes having the same thickness.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Planar Illumination Modules (AREA)

Abstract

Source de lumière plane servant de rétroéclairage, comportant une plaque de guidage de la lumière (1), une source lumineuse (3), une couche de diffusion de la lumière (8), une couche optique (4) et un élément translucide de visualisation (6). La couche de diffusion de la lumière (8) renferme un matériau de base transparent, exempt de particules est constitué d'un agent de diffusion de lumière. Elle comporte de minuscules projections et évidements (41) disposés de manière aléatoire, donnant une surface dont la rugosité n'est pas inférieure à la longueur d'onde de la lumière en provenance de la source lumineuse mais n'excède pas 100 microns. La couche de diffusion de la lumière est conformée de telle sorte que, lorsque la courbe de distribution des fréquences cumulatives de la hauteur de ces minuscules projections et évidements (41) est établie en prenant un pourcentage de la distribution de fréquences cumulatives de leur hauteur sur un axe vertical et sur un axe horizontal, cette courbe comporte une partie en projection incurvée vers la partie inférieure des coordonnées, avec une valeur moyenne de hauteur des évidements et projections plus élevée que la valeur médiane. Avec une source d'éclairage plane ainsi réalisée, on obtient une lumière d'un éclat uniforme et intense, émise seulement sur la plage angulaire souhaitée, et une émission en surface ne présentant pas d'irrégularités d'éclat selon les différentes parties du plan.
PCT/JP1995/001608 1994-08-12 1995-08-11 Source de lumiere plane mettant en ×uvre une couche de diffusion de la lumiere WO1996005466A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
KR1019960701957A KR100215127B1 (ko) 1994-08-12 1995-08-11 광학산 시트를 이용한 면광원
US08/619,623 US5944405A (en) 1994-08-12 1995-08-11 Flat light source using light-diffusing sheet with projections thereon

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP6/210694 1994-08-12
JP6210694 1994-08-12

Publications (1)

Publication Number Publication Date
WO1996005466A1 true WO1996005466A1 (fr) 1996-02-22

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6445504B1 (en) * 1999-06-11 2002-09-03 Dai Nippon Printing Co., Ltd. Light diffusing film and use thereof
KR100422938B1 (ko) * 1999-03-24 2004-03-12 주식회사 엘지 백라이트 시스템

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01112202A (ja) * 1987-10-27 1989-04-28 Mitsubishi Rayon Co Ltd 光拡散装置
JPH05196940A (ja) * 1991-02-01 1993-08-06 Tosoh Corp パネル用バックライト

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01112202A (ja) * 1987-10-27 1989-04-28 Mitsubishi Rayon Co Ltd 光拡散装置
JPH05196940A (ja) * 1991-02-01 1993-08-06 Tosoh Corp パネル用バックライト

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100422938B1 (ko) * 1999-03-24 2004-03-12 주식회사 엘지 백라이트 시스템
US6445504B1 (en) * 1999-06-11 2002-09-03 Dai Nippon Printing Co., Ltd. Light diffusing film and use thereof

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