CN102770704A

CN102770704A - Light-guide plate and method for manufacturing a light-guide plate

Info

Publication number: CN102770704A
Application number: CN201080064776XA
Authority: CN
Inventors: 岩川隆一; 吉村修; 新治修; 园田丰英; 小野阳二
Original assignee: Kuraray Co Ltd
Current assignee: Kuraray Co Ltd
Priority date: 2010-02-26
Filing date: 2010-02-26
Publication date: 2012-11-07
Also published as: WO2011104765A1; JPWO2011104765A1; KR20120120935A; TW201129832A; TWI464462B; JP5436655B2

Abstract

Disclosed is a method for manufacturing a light-guide plate. Said method, which can easily and inexpensively form a fine pattern on a diffusion layer, is used to manufacture a light-guide plate (100) with a light source disposed on an end surface thereof, constituting a planar light-source device. The back and/or front surface of a light-guide plate base material (1) is coated with tiny droplets of a liquid coating (2) containing light-diffusing microparticles (21) and a light-transmitting binder (22), thereby forming a diffusion layer (3). Taking the light-diffusing microparticles (21) as an aggregate (210), the planar area of the coated surface(s) of the light-guide plate base material (1) covered by the aggregate (210) is between 0.1% and 70% of the area coated by the liquid coating (2).

Description

LGP and manufacturing method of light conducting board

Technical field

The present invention relates to from the back side illuminaton light of display panels or signboard etc. planar light source device, be the LGP and the manufacturing method of light conducting board of so-called backlight (back light) device usefulness, the LGP and the manufacturing method of light conducting board that particularly are formed with diffusion portion at the surface at least or the back side of LGP.

Background technology

About backlight apparatus from the back side illuminaton light of display panels or signboard etc., known have light source is configured to planar and is disposed at the LGP mode that is called as edge light (edge light) or sidelight (side light) of the end face of LGP through the directly-below type of formation faces such as diffusing panel uniformly light-emitting with line source.

In recent years, the more slim and light weight of expectation, energy-saving backlight apparatus.As such backlight apparatus, the LGP mode is attracted attention.Particularly as light source, replace in the past fluorescent lamp or cold-cathode tube, from high brightness and long-life, energy-conservation viewpoint, LED (Light Emitting Diode, light emitting diode) just receives publicity.

In the LGP that backlight apparatus is used, the diffusion member is disperseed, perhaps optical diffusion layer or diffusing pattern are set at least one side surperficial, the back side.This LGP makes light be injected in this LGP from cold-cathode tube or the led array light source that is arranged on end face, and light is penetrated and the formation planar light source device to emitting side.

As the backlight apparatus of the LGP mode that is used for such transmission-type liquid crystal display floater or signboard etc., the known technology (with reference to patent documentation 1) that has gradual change of being provided with (gradation) to distribute.This graded profile is the light diffusion ability that increases diffusing layer more away from light source more, so that the brightness of the outgoing plane of backlight apparatus becomes even.

As the method that graded profile is set through diffusing layer or diffusing pattern, the known method that has injection mo(u)lding or punch forming through having used metal pattern to come the transfer printing relief pattern.Be pre-formed the gradual change pattern of expectation at this metal pattern.In addition, also known have through silk screen (screen) print process the printing ink of diffuse is carried out a method of printing (with reference to patent documentation 2) etc.

The prior art document

Patent documentation

Patent documentation 1: japanese kokai publication sho 57-128383 communique;

Patent documentation 2: No. 3734547 communique of Japan Patent.

Summary of the invention

The problem that invention will solve

In the diffusing layer that is formed at the LGP base material, eye-catching and need be with each diffusion portion miniaturization, little spacingization for fear of the pattern of this diffusing layer.Yet in recent years, display unit is required slimming.But if make the LGP attenuation, then the pattern of this diffusing layer becomes eye-catching easily.Therefore, need the further miniaturization of the pattern of this diffusing layer, little spacingization.

Yet, the injection mo(u)lding of having used version or metal pattern, punch forming, and silk screen print method in, be difficult to make the abundant miniaturization of pattern of diffusing layer.In addition, in layout, exist under the situation of defective, design also will be made version at high price, metal pattern again, reach the silk screen version from needless to say again, causes cost to rise.

The object of the present invention is to provide a kind of LGP and manufacturing method of light conducting board that can form the fine pattern of diffusing layer simple and easy and at an easy rate.

Be used to solve the means of problem

Manufacturing method of light conducting board of the present invention is the manufacturing method of light conducting board that light source is disposed at end face in order to constitute planar light source device; At the back side of LGP base material or surface or two sides apply the coating liquid that comprises light diffusion particulate and light transmission adhesive (binder) with the fine droplets state; Be coated with diffusing layer thus; Said light diffusion particulate becomes agglomerate, and the ratio of the area of plane that the said agglomerate in the coated face of said LGP base material is shared and the surface covered of said coating liquid is more than 0.1% below 70%.Thus, even unlike such version or metal pattern made in the past, when applying liquid when being coated on the LGP base material, also can be simply and form the superior diffusing layer of light diffusion ability of fine pattern at an easy rate.

Preferably in coating during said diffusing layer, make the coating density step-down of said light diffusion particulate in the part that approaches said light source, from said light source part far away the coating density of said light diffusion particulate is uprised.Thus, even unlike such version or metal pattern made in the past, when applying liquid when being coated on the LGP base material, also can be simply and form the superior diffusing layer of light diffusion ability of fine pattern at an easy rate.

The spraying process of preferably utilization of said coating liquid being sprayed to this coating liquid from nozzle is coated in the back side or the surface or the two sides of said LGP base material.Because in spraying process, only make light weight and little nozzle in the enterprising line scanning of X-Y direction, so, achieve the goal with low cost equipment.That is, spraying process also is applied to large-scale LGP through low cost equipment.

Preferably dispose a plurality of nozzles side by side, make said a plurality of nozzle almost parallels ground scanning, make the coating density one dimension or two-dimentional the variation of said light diffusion particulate thus.

Being spaced apart below the above 300mm of 70mm of coated face preferably from said nozzle to said LGP base material.

Preferably in said spraying process; Said coating liquid is sprayed on one side from nozzle; On one side on the coated face of said LGP base material; To make in direction with the first limit almost parallel of said LGP base material scanning that said nozzle moves with the direction of the said first limit quadrature on carry out times without number with the pitch of feed of regulation, said coating liquid is coated on whole or a part of said coated face.

Preferably carry out following operation repeatedly through ground, coated face top at said LGP base material; Thereby the coating density one dimension ground of said light diffusion particulate is changed; In said operation, will make in direction with the first limit almost parallel of said LGP base material scanning that said nozzle moves with the direction of the said first limit quadrature on carry out times without number with the pitch of feed of regulation.

The pitch of feed of said nozzle is changed, apply said coating liquid, make the coating density one dimension ground variation of said light diffusion particulate thus whole of the coated face of said LGP base material or a part.

Preferably in each scanning of this nozzle, make the scan speed change of said nozzle, apply said coating liquid, make the coating density one dimension ground variation of said light diffusion particulate thus whole of the coated face of said LGP base material or a part.

Coating amount from the time per unit of the coating liquid of said nozzle is changed; Apply said coating liquid whole of the coated face of said LGP base material or a part, make the coating density one dimension ground variation of said light diffusion particulate thus.

LGP of the present invention is the LGP that light source is disposed at end face in order to constitute planar light source device; It is characterized in that; At the back side of LGP base material or surface or two sides apply the coating liquid that comprises light diffusion particulate and light transmission adhesive; Be coated with diffusing layer thus, said light diffusion particulate becomes agglomerate, and the ratio of the area of plane that the said agglomerate in the coated face of said LGP base material is shared and the surface covered of said coating liquid is more than 0.1% below 70%.Thus, even unlike such version or metal pattern made in the past, when applying liquid when being coated on the LGP base material, also can be simply and form the superior diffusing layer of light diffusion ability of fine pattern at an easy rate.

The number of the light diffusion particulate that preferably in 1 said agglomerate, comprises is more than 10 below 10000.

Preferably along with leaving from said light source, the spreading area ratio of the area of the coated face of the ratio of the area of plane that the said agglomerate in the coated face of said LGP base material is shared and the surface covered of said coating liquid or the surface covered of said coating liquid and said LGP base material uprises.

The invention effect

According to the present invention, a kind of LGP and manufacturing method of light conducting board that can form the fine pattern of diffusing layer simple and easy and at an easy rate can be provided.

Description of drawings

Fig. 1 is illustrated in the manufacturing method of light conducting board of the present invention the skeleton diagram that applies the situation of liquid in the coated face spraying of LGP base material.

Fig. 2 A is that expression will apply the side view that liquid is coated on the state of LGP base material with spraying process.

Fig. 2 B is that expression will apply the plane that liquid is coated on the state of LGP base material with spraying process.

Fig. 3 A is that expression will apply the side view that liquid is coated on the state of LGP base material with spraying process.

Fig. 3 B is that expression will apply the plane that liquid is coated on the state of LGP base material with spraying process.

Fig. 4 A is the side view of the state individually arranged of expression light diffusion particulate.

Fig. 4 B is the plane of the state individually arranged of expression light diffusion particulate.

Fig. 5 is the skeleton diagram of the situation of the expression Luminance Distribution of measuring planar light source device.

Fig. 6 is that expression changes pitch of feed and is coated with the figure of distribution of directions X of the relative brightness of the LGP that applies liquid equably.

Fig. 7 A is the figure that roughly is illustrated in the track of the nozzle when applying applying liquid with spraying process.

Fig. 7 B is the figure of distribution of directions X of the coating density of the light diffusion particulate after expression applies according to the track of the nozzle shown in Fig. 7 A.

Fig. 8 A has stipulated the scanning direction of the nozzle when applying applying liquid with spraying process and the figure of direction of feed.

Fig. 8 B is the figure that the condition of the rubbing method that is used for manufacturing method of light conducting board of the present invention at length is shown.

Fig. 9 A is expression according to the track of the nozzle of the rubbing method shown in Fig. 8 B, and the figure of the distribution of the directions X of the coating density of light diffusion particulate.

Fig. 9 B is expression according to the track of the nozzle of the rubbing method shown in Fig. 8 B, and the figure of the distribution of the directions X of the coating density of light diffusion particulate.

Fig. 9 C is expression according to the track of the nozzle of the rubbing method shown in Fig. 8 B, and the figure of the distribution of the directions X of the coating density of light diffusion particulate.

Fig. 9 D is expression according to the track of the nozzle of the rubbing method shown in Fig. 8 B, and the figure of the distribution of the directions X of the coating density of light diffusion particulate.

Fig. 9 E is expression according to the track of the nozzle of the rubbing method shown in Fig. 8 B, and the figure of the distribution of the directions X of the coating density of light diffusion particulate.

Fig. 9 F is expression according to the track of the nozzle of the rubbing method shown in Fig. 8 B, and the figure of the distribution of the directions X of the coating density of light diffusion particulate.

Figure 10 A is the figure that is illustrated in the distribution of the directions X of the coating density that applies the light diffusion particulate of liquid when being coated on the LGP base material equably.

Figure 10 B is the figure of distribution of directions X of left end and the brightness measured of the expression LGP base material that light source is arranged on Figure 10 A.

Figure 10 C is the figure of the distribution of the target of the expression light diffusion particulate directions X that applies density.

Figure 10 D is the figure of the distribution of the target of the different light diffusion particulate of the expression directions X that applies density.

Figure 11 schematically shows supposition is provided with the two-dimensional graded distribution of line source on 4 limits of LGP figure.

Figure 12 is that expression utilizes a plurality of nozzles to apply the skeleton diagram of the situation of liquid in the coated face spraying of LGP base material.

Figure 13 is the skeleton diagram of each process sequence of expression manufacturing method of light conducting board of the present invention.

Figure 14 A is a side view of roughly representing to be coated with the LGP that applies liquid with being globule shape.

Figure 14 B is a plane of roughly representing to be coated with the LGP that applies liquid with being globule shape.

Figure 15 A is the side view that the whole face that roughly is illustrated in coated face is coated with the LGP that applies liquid.

Figure 15 B is the plane that the whole face that roughly is illustrated in coated face is coated with the LGP that applies liquid.

Figure 16 A is the microphotograph of the coated face of LGP base material.

Figure 16 B is the microphotograph of the coated face of LGP base material.

The specific embodiment

At first, the process of finding out technological thought of the present invention is described, the details to each embodiment describes then.

Form in the technology of diffusing layer at the LGP base material, enumerate silk screen print method, hectograph (offset) print process etc.It all need be at the initial pattern that becomes mother matrix (master) of making galley or metal pattern etc.For example, in screen printing plate, describe or ink-jet printer is critically described by the pattern of optical design through laser.Then, to selecting sensitization and clean being coated with the pattern picture that forms on the silk of emulsion.Thus, form diffusing layer at this LGP.

In these operations, aspect miniaturization, there is the limit respectively.Must eliminate the problem of the restriction, the adhesion when cleaning etc. of the luminous sensitivity of line thickness that laser for example describes or emulsion.Promptly enable in addition to form this version, also can bring out the printing process such as performance of products change that the printing that is accompanied by miniaturization is defective, the transferring rate change causes, the problem of performance.Therefore, also need improve printing technology simultaneously.And then layout, produce the version underproof situation under, make again the high price mother matrix.For fear of these problems, do not need the diffusing layer formation method of mother matrix to be fit in itself.

On the other hand, from large-size light-conducting plate, desiring to make the even brightness viewpoint of light emergence face, in diffusing layer, form the gradual change pattern sometimes.That is, near light source, form the low pattern of light diffusion ability, along with form the high method of patterning of light diffusion ability away from light source.Method for the light diffusion ability that physically makes diffusing layer itself reduction of the method for carrying out with geometric composition of the spacing that reduces the light diffusion ability, for example enumerate to reduce pattern, area etc. and the concentration that reduces diffusion member or reflecting member etc.But the concentration change of diffusion member or reflecting member can reduce productivity significantly.Therefore, usually with area, density, the spacing of coating portion, highly adjust.Yet because above-mentioned reason, accurate composition printing becomes obstacle, makes the maximization of LGP become difficult.

Therefore, the present invention is in view of these problems, provides a kind of and need not make version, metal pattern and can form the LGP and the manufacturing method of light conducting board of the diffusing layer of fine pattern simple and easy and at an easy rate.

That is such structure and operation below, LGP of the present invention and manufacturing method of light conducting board adopt.

＜embodiment 1＞

Below embodiment 1 of the present invention is described.LGP of the present invention is a structural elements from the backlight apparatus of the back side illuminaton light of display panels, signboard etc.End face configuration light source at LGP.

This LGP shown in Fig. 1 and 2, through at the back side of LGP base material 1 or surface or apply the coating liquid 2 that comprises light diffusion particulate 21 and light transmission adhesive 22 with the fine droplets state on the two sides, thus coating diffusing layer 3.This light diffusion particulate 21 becomes agglomerate 210.

Particularly, at first prepare LGP base material 1.As LGP base material 1, preferably use general transparent resin substrates such as polymethyl methacrylate (PMMA) resin, polystyrene resin, polycarbonate resin.Particularly, as large-scale LGP substrate, more preferably transparent superior plexiglass substrate.The curvature of the warpage of preferred LGP base material 1 (curvature of the most crooked part) is ± 1.61 * 10 in addition ^-4(1/mm).

Then, at the back side of LGP base material 1 or surface or (still, in this embodiment, be merely the surface, be called coated face on the two sides.) apply the coating liquid 2 comprise light diffusion particulate 21 and light transmission adhesive 22.In addition, shown in Fig. 2 A, B, in the diffusing layer 3 of this embodiment, the mode that disposes randomly with coating portion and uncoated portion is coated with coating liquid 2.But in the illustrated example of Fig. 2 A, B, though dispose the coating portion of island randomly, shown in Fig. 3 A, B, the uncoated portion that disposes island randomly also can.

Here, the light that the LGP utilization of in planar light source device, using is injected with the angle below the critical angle the interface of gas phase and solid phase (below, have the situation that is called gas-solid interface.) carry out the situation that total reflection is advanced on one side repeatedly on one side in this LGP, light is propagated into away from the light source place.Thus, thus take out the total reflection at the interface of light and take out light through hindering desire.Therefore, need form the technology of diffusing layer certainly in the luminous part of desire, but the technology that also need the interface former state be kept in the luminous part of desire not.That is, need to form the technology of diffusing layer certainly, but also need the technology of retained gas liquid/solid interface wittingly.As diffusing layer formation method corresponding to this requirement, spraying (spray coat) method of preferably in the gas ejection, coating liquid being sprayed.

Usually, do not use the apparatus for coating of version to apply equably with whole face and be purpose.Therefore, be difficult to make wittingly uncoated portion.Though the style of calligraphy characterized by hollow strokes that coating liquid deficiency causes also can form uncoated portion, the control of this style of calligraphy characterized by hollow strokes is extremely unsettled.In addition sometimes, as the situation that is difficult to expect, the situation of the uncoated portion of existence generation aperture (pinhole) etc., but it just can not be controlled originally.On the other hand, spraying process is owing to spraying to the coating liquid of fine droplets state, so be surrounded by the superior characteristics of the coating portion and the uncoated portion of minimum unit in having in itself.

Therefore, in this embodiment, utilize spraying process will apply liquid 2 and be coated on LGP base material 1.That is,, preferably superior and do not have a device of the worry of spray nozzle clogging etc. aspect discharge stability as apparatus for coating.In addition, as apparatus for coating, preferably can spray, almost not apply the outer and high device of surface covered of plane domain that liquid 2 is splashed to LGP base material 1 to applying liquid 2 with uniform fine droplets state.Therefore, use sprayer 4 as apparatus for coating.But diffusing layer forms gimmick and is not limited to spraying process, in a word so long as can get final product with the spraying process that the fine droplets state is coated on LGP base material 1 applying liquid 2.

Sprayer 4 sprays gas force feed to nozzle 5.And sprayer 4 will together be sprayed to LGP base material 1 with the gas of this ejection from the coating liquid 2 that storage groove 6 utilizes the pump equipressure to deliver to nozzle 5.The gas of force feed to nozzle 5 is controlled by flow-control portion 7,8 respectively with the flow that applies liquid 2.

Nozzle 5 is the nozzle of spiral flow (spiral flow) type preferably.The spraying fluid of spiral flow nozzle is a swirl shape, and spreading of spray narrows down.Therefore, light diffusion particulate 21 condenses easily.In addition, the flow velocity of the normal direction when arriving LGP base materials 1 owing to light diffusion particulate 21 is low, makes it be attached to LGP base material 1 so can not destroy the cohesion of light diffusion particulate 21.

Nozzle 5 adopts the structure that can move in directions X and Y direction.Nozzle 5 adopts and can (but also can be a part to the plane of LGP base material 1 Zone Full with applying liquid 2.) structure of spraying.Nozzle 5 also adopts the structure that can move at above-below direction.Like this, preferred nozzle 5 adopts the structure of the interval variation that can make nozzle 5 and LGP base material 1.In addition, nozzle 5 limits at the driving mechanism of X/Y direction with in that the driving mechanism of above-below direction is not special.But, in this embodiment, adopted the structure that nozzle 5 is moved at X/Y direction and above-below direction, but the structure that also can adopt the workbench (omitting diagram) that can make supporting LGP base material 1 to move at X/Y direction and above-below direction.

As gas, for example can use dry air, dry nitrogen etc.Using under the situation of flammable solvent, catching fire, preferably using dry nitrogen for what prevent that static etc. from causing.Have again, as back narration,, also can the gas that become carrier (carrier) for example be heated to before spraying more than 30 ℃ below 120 ℃ in order to promote the cohesion of light diffusion particulate 21.

Applying liquid 2 is the mixture that comprises light diffusion particulate 21 and light transmission adhesive 22 as above-mentioned.Light diffusion particulate 21 is the members that make light transmission diffusion.As light diffusion particulate 21, can use organic based fine particles such as mineral-type particulates such as silica, calcium carbonate, barium sulfate, titanium oxide, aluminium oxide or silicone pearl (beads), PMMA pearl, MS pearl, styrene pearl.

Be coated under the situation on surface (light emergence face) of LGP base material 1 will applying liquid 2, as light diffusion particulate 21 preferred clear glass particulate, the transparent resin particulates that carry out the transmission scattering that use.Be coated under the situation at the back side (light reflection surface) of LGP base material 1 will applying liquid 2, as light diffusion particulate 21 preferred white particles, the pigment that carry out specular scattering that use.

The shape of light diffusion particulate 21 can be just spherical, spherical, flakey, indefinite shape etc., is not particularly limited.

The average grain diameter of light diffusion particulate 21 is preferably below the above 50 μ m of 1 μ m.If this average grain diameter is littler than above-mentioned lower limit, then exist to make light diffusing scarce capacity or the painted possibility of diffused light.If this average grain diameter is bigger than above-mentioned higher limit, then possibly when using nozzle, stop up easily, or the diffused light of these light diffusion particulate 21 generations in the little part of coating density become bright spot and eye-catching.Preferred especially this average grain diameter is below the above 20 μ m of 1 μ m.

, be preferably below the above 20wt% of 1wt% with respect to applying the shared ratio of liquid 2 as light diffusion particulate 21.If this ratio breaks away from from above-mentioned scope, then there is the situation of the agglomerate that is difficult to generate light diffusion particulate 21.If the above-mentioned lower limit of this ratio is low, then there is the situation that is difficult to obtain high asperratio, light diffusion scarce capacity.

Light transmission adhesive 22 is the members that light diffusion particulate 21 are adhered to LGP base material 1.As light transmission adhesive 22, can use for example solvent type adhesive, heat-curing resin, uv curing resin etc.In addition as light transmission adhesive 22, such like the back narration, use and in solvent dilutes, be not close to and after the solvent drying, manifest the resinous principle of being close to power, for example acrylic compounds sticker.But, non-reacted polymer is dissolved in solvent spray, on the LGP base material, make solvent dry, the light diffusion particulate is played a role as bonding agent, this also belongs to category of the present invention.

Length at the light conducting direction of LGP is under the situation below the 600mm, and the difference of the refractive index of preferred light transmission adhesive 22 and the refractive index of light diffusion particulate 21 is below-0.1 or more than 0.1.This is because the diffusion of light effect through the two performance of concavo-convex and refringence on surface, can be taken out light in the face direction with relatively shorter leaded light distance efficiently.Length at the light conducting direction of LGP is under the situation more than the 300mm, and the difference of the refractive index of preferred light transmission adhesive 22 and the refractive index of light diffusion particulate 21 is more than-0.1 below 0.1.The diffusion of light effect is main can gently take out light only through the concavo-convex performance on surface, is suitable for long leaded light distance.The main little light diffusion particulate 21 of refringence that uses is mainly using the big light diffusion particulate 21 of refringence also can away from the position of light source near light source.Can the diffusion of light effect more dynamically be changed at light conducting direction, can take into account the taking-up efficient of long leaded light distance and high light.

The viscosity of light transmission adhesive 22 is preferably below the above 100mPas of 1mPas.If the above-mentioned lower limit of this ratio of viscosities is little, at LGP base material 1 homogenizing (leveling) takes place then easily, the light diffusion ability reduces.If the above-mentioned higher limit of this ratio of viscosities is big, then be easy to generate apply inhomogeneous.Be preferably especially below the above 20mPas of 1mPas.

The difference of the refractive index of preferred light transmission adhesive 22 and the refractive index of LGP base material 1 is in ± 0.1.Owing to can not consider the refraction reflection on the interface of light transmission adhesive 22 and LGP base material 1, so optical design is simple.

, using sprayer only to apply under the situation of light transmission adhesive, the light transmission adhesive that on the LGP base material, applies produces the homogenizing phenomenon.Because it is that (following existence is called the situation of asperratio for sufficient concave-convex surface, the particularly concavo-convex average headway of concavo-convex height ÷ to hindering total reflection fully, promptly that this homogenizing phenomenon causes being difficult to form to causing that light diffusion is.), there is the possibility of planarization.In addition, if repeatedly repeat to apply the light transmission adhesive, then, still there is the possibility of planarization because its surface tension is close to the coating liquid of fine droplets state each other.

In order to improve these, consider to apply the method for full-bodied light transmission adhesive or light diffusion particulate interpolation (mixing) is formed concavo-convex method in the light transmission adhesive.But the high viscosityization of light transmission adhesive takes place to apply inhomogeneous when spraying easily.In addition, if the light diffusion particulate that applies big diameter adds the coating liquid in the light transmission adhesive to, then there are the spray nozzle clogging of sprayer or the possibility that sedimentation takes place the light diffusion particulate in the light transmission adhesive.

Therefore, in this embodiment, the light transmission adhesive is diluted to about 1.1～10 times with solvent.Add the light diffusion particulate of the small particle diameter below the 20 μ m more than the 1 μ m in the low viscous light transmission adhesive below for example being diluted to the above 20mPas of 1mPas; Make at light diffusion particulate 21 and condense once more, obtain the high diffusing layer of light diffusion ability 3 (with reference to Fig. 2 A, B and Fig. 3 A, B) thus from nozzle to the coating liquid 2 of spraying out the LGP base material.

That is the coating liquid 2 of, spraying out from nozzle 5 is the state that disperses at the amount of solvent for a long time.When solvent is dry, a light diffusion particulate 21 is condensed as core once more with surface tension.At this moment, light diffusion particulate 21 becomes botryose agglomerate 210.Agglomerate 210 is attached to LGP base material 1.In addition, a large amount of when residual when solvent, after adhering to, cause homogenizing, therefore undesirable.Therefore, also can use hot blast (hot air) to promote cohesion.

When the speed when arriving LGP base material 1 was fast, shown in Fig. 4 A, B, grape cluster was damaged by pressure, and light diffusion particulate 21 is individually arranged, and caused the light diffusion ability to reduce.These can be through adjusting and eliminate the interval T from nozzle 5 to LGP base material 1 (Fig. 1).For example, as interval T, be preferably below the above 300mm of 70mm from nozzle 5 to LGP base material 1.If this interval T is shorter than above-mentioned lower limit, then the drying of solvent becomes insufficient.Therefore, there be agglomerate, each light diffusion particulate 21 situation that sedimentation reduces the light diffusion ability significantly in light transmission adhesive 22 that is difficult to generate light diffusion particulate 21.In addition, since fast to the coating speed of the coated face of LGP base material 1, so agglomerate is destroyed easily.If this interval T is longer than above-mentioned higher limit, then apply liquid 2 before arriving the coated face of LGP base materials 1 during flow velocity step-down significantly.Therefore, it is uncoated in the coated face of this LGP base material 1 to apply liquid 2, but the quantitative change of splashing to foreign side is many.

As solvent, there is not the restriction of ketone, ethanol class, ester class etc.But about solvent, preferred boiling point is the solvent below 200 ℃ more than 60 ℃ in order to make the condensing stabilisation once more of light diffusion particulate 21.And then about solvent, from preventing the aspect of sedimentation, preferred specific gravity is the solvent below 1.3 more than 0.8.If this boiling point or proportion are higher than above-mentioned higher limit, then the drying of solvent becomes insufficient.Therefore, the situation that has the agglomerate be difficult to generate light diffusion particulate 21.If this boiling point or proportion are lower than above-mentioned lower limit, the material that then ratio of viscosities is lower is many.Therefore, there is the situation that the problems such as sedimentation of light diffusion particulate 21 take place easily that produces.Preferred this boiling point is more than 120 ℃ below 170 ℃.And then more preferably this boiling point is more than 130 ℃ below 160 ℃.

The amalgam of light diffusion particulate 21 and light transmission adhesive 22 is preferably below the above 50wt% of 2wt% with respect to the blending ratio of solvent.If this blending ratio is more than above-mentioned higher limit, then there are the situation of the agglomerate 210 be difficult to generate light diffusion particulate 21 or the situation of coating difference.Even this blending ratio lacks than above-mentioned lower limit, can not generate the agglomerate of light diffusion particulate 21 especially significantly yet, exist the use amount of solvent to increase the situation that the cost increase that causes becomes problem.This blending ratio is more preferably below the above 30wt% of 3wt%.

Then, in being coated with the LGP base material 1 that applies liquid 2, utilize natural air drying or hot blast etc. to make this solvent dry.Under the situation that light transmission adhesive 22 is processed by ultraviolet curable resin, after operation in irradiation ultraviolet radiation, this light transmission adhesive 22 is solidified.Consequently, shown in Fig. 2 A, B and Fig. 3 A, B, be core with a light diffusion particulate 21, a plurality of light diffusion particulates 21 become botryose agglomerate 210.This agglomerate 210 is attached to the coated face of LGP base material 1.This agglomerate 210 has high asperratio, and forms the diffusing layer 3 of fine pattern.Therefore, even unlike such version or metal pattern made in the past, when applying liquid 2 when being coated on LGP base material 1, also can be simply and form the superior diffusing layer 3 of light diffusion ability of fine pattern at an easy rate.And, repeating to be coated on LGP base material 1 even will apply liquid 2 through spraying process, light diffusion particulate 21 also can be close to state of aggregation, therefore is difficult to planarization.Therefore, can will apply liquid 2 through spraying process well and repeat to be coated on LGP base material 1.

Here, the ratio R of the shared area of plane of the agglomerate in the coated face of LGP base material 1 and the surface covered that applies liquid 2 is more than 0.1% below 70%.If this ratio R is lacked than above-mentioned lower limit, then there is the situation of the light diffusion scarce capacity of LGP 100.If this ratio R is bigger than above-mentioned higher limit, then the light diffusion ability of LGP 100 becomes excessive, under the long situation of leaded light length L (Fig. 5), has in the not enough situation of the quantity of light emission of the position of leaving from light source.

In the LGP of as above-mentioned, making 100, comprise the coating liquid 2 of light diffusion particulate 21 and light transmission adhesive 22 through surface applied, thereby be coated with diffusing layer 3 at LGP base material 1.Light diffusion particulate 21 becomes agglomerate 210.The ratio R of the shared area of plane of the agglomerate 210 in the coated face of LGP base material 1 and the surface covered that applies liquid 2 is more than 0.1% below 70%.This LGP 100 that kind for example as shown in Figure 5 constitutes planar light source device by the diffuse reflection film 10 of the line source 9 of the led array that is provided with end etc., side setting overleaf and at the diffuser 11 of face side setting.The agglomerate 210 of a plurality of light diffusion particulates 21 has high asperratio, and forms the diffusing layer 3 of fine pattern.Therefore, even unlike such version or metal pattern made in the past, when applying liquid 2 when being coated on LGP base material 1, also can be simply and form the superior diffusing layer 3 of light diffusion ability of fine pattern at an easy rate.In addition, between LGP base material 1 and diffusing layer 3, the light transmission adhesive that does not comprise light diffusion particulate 21 also can with the upper surface Zone Full that homogeneous thickness is coated in LGP base material 1.This light transmission adhesive is as chargedly preventing layer, being coated with (hard coat) layer firmly and waiting and play a role.

The spreading area ratio S of the area of the coated face of the surface covered of preferred coated liquid 2 (area of plane of diffusing layer) and LGP base material 1 is more than 5% below 95%.If this spreading area ratio S lacks than above-mentioned lower limit, then there is the situation of the light diffusion scarce capacity of LGP 100.If S is bigger than above-mentioned higher limit for this spreading area ratio, then can not ignore the absorption of the light that light transmission adhesive 22 causes, there is the situation of luminance shortage.

The number of the light diffusion particulate 21 that preferably in 1 agglomerate 210, comprises is more than 10 below 10000.If this number is lacked than above-mentioned lower limit, then there is the situation of the light diffusion scarce capacity of LGP 100.If this number is bigger than above-mentioned higher limit, then be easy to generate inhomogeneous or outward appearances such as harsh feeling, bright spot not good.

But, at the coated face of LGP base material 1, except the number of light diffusion particulate 21 is more than 10 the agglomerate below 10000, the agglomerate 210 that also can exist

light diffusion particulate

21 or 10 light diffusion particulates 21 of less than by single dispersion to constitute.In this case, the agglomerate 210 that preferably is made up of

light diffusion particulate

21 or 10 light diffusion particulates 21 of less than of single dispersion is 20% of the sum of not enough light diffusion particulate.

The number of the light diffusion particulate 21 that in agglomerate 210, comprises in addition, can be counted through the observation of light microscope about 300～1000 times or laser microscope etc.In addition, after extracting agglomerate 210 and having removed light transmission adhesive 22, can count through the observation of light microscope etc.

Under the situation of light diffusion scarce capacity, repeat to apply and also can with primary coating.Repeat to apply, though the agglomerate of light diffusion particulate 21 be close to each other/integrated, also keep the high asperratio of this agglomerate 210.Therefore, it is high and be difficult to the advantage that causes that outward appearance is not good to have a light diffusion ability.

The difference of the refractive index of preferred agglomerate and the refractive index of light transmission adhesive is more than 0.001 below 0.5.The micro concavo-convex on the volumetric concentration of the refringence of the light diffusion ability material that basis is different with the material transparent refractive index in fact, the volume of material, material, the shape of material (setting of positive ball etc./unsetting), surface etc. changes.If this refringence is littler than above-mentioned lower limit, it is few and be difficult to obtain the illumination uniformization effect then to reflect scattering property.If this refringence is bigger than above-mentioned higher limit, then the reflection of (gas-solid interface) becomes many at the interface, for example is difficult to obtain the illumination uniformization effect at 300mm under with the long situation of first-class leaded light length.

Preferably the arithmetic mean surface roughness of the micro concavo-convex in agglomerate 210 is more than the 0.01 μ m below the 10 μ m.If this arithmetic mean surface roughness is littler than above-mentioned lower limit, the few and easily deepening on the whole of then specular scattering property.If this arithmetic mean surface roughness is bigger than above-mentioned higher limit, then specular scattering key element becomes big physically, becomes clear partly near the light source etc., is difficult to obtain the illumination uniformization effect.

＜embodiment 2＞

Below embodiment 2 of the present invention is described.Though the LGP of LGP of this embodiment and manufacturing method of light conducting board and embodiment 1 and manufacturing method of light conducting board are roughly same; But, improve the ratio R of the shared area of plane of agglomerate the coated face of LGP base material and the surface covered that applies liquid along with leaving or apply the spreading area ratio S of area of coated face of surface covered and the LGP base material of liquid from light source for the brightness that makes LGP becomes roughly even.That is, improve the coating density of light diffusion particulate along with leaving from light source.

Be accompanied by the maximization of display unit in recent years, backlight also is asked to maximize.That is, need lengthening leaded light length L (Fig. 5).For the brightness uniformity of the light emergence face that makes LGP, near the light diffusion ability of the diffusing layer the light source in the LGP is diminished, in LGP, make the light diffusion ability big more away from light source more on the other hand.Therefore, need be in LGP make the light diffusion ability of diffusing layer become big significantly away from the position of light source.Under the inappropriate situation of the composition of diffusing layer; Even in addition having carried out design under the situation of printing precision difference, exist near the bright and central portion in the end only light source in the LGP secretly, promptly not satisfy or the problem of the brightness irregularities of light emergence face takes place as the problem of the performance of the essence of LGP.From these viewpoints, need the miniaturization and the formation correctly of the pattern of diffusing layer to make this diffusion portion approach light source pattern arrangement thin more, that become close more away from light source more more.Have again, " light source near " be meant effective light injection part of being arranged in LGP near the position of light source.That is, " light source near " is meant the end of the side that light source is set.The position of light source " away from " be meant in effective light injection part of LGP away from the position of light source.That is, the position of light source " away from " is meant and is provided with the end of an end side in opposite directions of a side of light source 9 under the situation of LGP shown in Figure 5.

In this embodiment, roughly likewise will apply liquid 2 with embodiment 1 and be coated on LGP base material 1 through spraying process.At this moment, as core, a plurality of light diffusion particulates 21 are condensed into thyrsiform with a light diffusion particulate 21.The agglomerate 210 of cohesion adopts more the pattern arrangement of the graded profile that becomes close more away from light source like this.

Here, on the PMMA substrate of thickness 5mm, leaded light length 600mm, attempt even coating with the scanning on the Y direction that fixing pitch of feed carries out nozzle repeatedly at directions X.And the left end that has applied the LGP 100 of liquid 2 changing pitch of feed with condition shown in Figure 6 is provided with led array light source 9.With the coated face of LGP base material 1 as the outgoing plane side.Be provided with diffuse reflection film 10 at the back side of coated face.Front surface at coated face is provided with diffuser 11.Make the side-light type backlight like this.As shown in Figure 5, use face luminance meter 12 to measure from the top of this side-light type backlight.In this case, the limit that is configured in the Y direction in LGP base material 1 is said first limit in the present invention.

The coating width at the single pass of Y direction of nozzle 5 is about 50mm.Become coating density at the light diffusion particulate 21 of central part high, along with advancing to foreign side distributing of that kind of step-down gradually with like Gauss (Gaussian) distributional class.The pitch of feed on the directions X for the situation that surpasses the such sparse spacing of 10mm under, in the coating density of light diffusion particulate 21, produce inhomogeneously, it is inhomogeneous that light and shade takes place in Luminance Distribution that kind as shown in Figure 6.Through pitch of feed is made as 10mm, thereby can realize not because the uneven coating that pitch of feed causes.

In addition, as shown in Figure 6, far away more from light source 9, relative brightness reduces more.The coating density of lip-deep light diffusion particulate 21 of light diffusion performance and LGP base material 1 of LGP 100 that has applied liquid 2 is proportional.Therefore, as long as with the coating density step-down that makes light diffusion particulate 21 in light source side, side makes its mode that uprises spray this coating liquid 2 in a light source distant place.Below narrate its method.

Fig. 7 A, B are the figure that the situation of following such graded profile is shown: the scanning that on directions X, with the pitch of feed of stipulating nozzle 5 is moved in the Y direction; Around the central portion of one dimension ground in the coated face of LGP base material 1 the coating density of light diffusion particulate 21 is uprised, make the coating density step-down of light diffusion particulate 21 in the both sides of this central portion (being end face A, B side).

Suppose that this LGP base material 1 is the LGP base material that the line source of led array etc. is set at both ends of the surface A, B.In the example of Fig. 7 A, B, the coating amount that applies liquid 2 is fixed, and nozzle 5 is scanned with fixed speed on the Y direction.From end face A side, inhomogeneous in order not have, the pitch of feed at directions X of nozzle 5 is begun from 10mm.Around the central portion of LGP base material 1 so that the mode that pitch of feed narrows down successively apply applying liquid 2.Thus, realize not having discontinuous perfect graded profile.

Aspect the realization graded profile, the free degree of spraying process is high.Fig. 8 A, B have put each parameter and the various rubbing method when coating liquid 2 is applied in order.Here, right ends face A, the B that considers to be manufactured on LGP base material 1 is provided with the situation of LGP of two ends light source type of the line source of led array etc.

Under the situation of two ends light source type, fix in order to make the Luminance Distribution in the face, improve relevant ratio R or spreading area ratio S along with leaving from light source.That is, make the coating density step-down of the light diffusion particulate 21 in the both ends of LGP base material 1, around central portion, the coating density of light diffusion particulate 21 is uprised.The mode that other condition becomes agglomerate 210 well with light diffusion particulate 21 and is attached to LGP base material 1 is set.Have again, in this embodiment, with directions X as the length direction of LGP base material 1, be light conducting direction, with the width dimensions direction of Y direction as LGP base material 1.

In the table of Fig. 8 B, as each parameter, the coating amount of the pitch of feed of the scanning direction of consideration nozzle 5, the sweep speed of nozzle 5, nozzle 5, the time per unit of coating liquid 2 etc.Wherein any one or more parameters of control are fixed other parameter.

Particularly, the rubbing method shown in Fig. 8 B (1) is to applying the method that liquid 2 applies like following mode.In this rubbing method (1), the limit that is configured in the Y direction of LGP base material 1 is said first limit in the present invention.

At first, whole parameters is fixed, coating liquid 2 is coated on equably the whole or part (Fig. 9 A) of transparent LGP base material 1.Then, around central portion, likewise repeatedly apply applying liquid 2 equably.That is, whole parameters is fixed, around central portion, apply the coating of liquid 2 repeatedly.

Thus, improve relevant ratio R or spreading area ratio S along with leaving from light source.That is, make the coating density step-down of the light diffusion particulate 21 in the both ends of approaching light source of LGP base material 1, the coating density of the light diffusion particulate 21 around light source central portion far away is uprised.Though this situation has been shown in Fig. 9 A, can not have avoided certainly leading to the situation of limited ladder difference on the border of repeating to apply.Therefore, the coating amount of preferred coated liquid 2 is the least possible, and the sweep speed of nozzle 5 is fast as far as possible.That is, preferred so that 1 time evenly the coating density of the light diffusion particulate 21 in the coating the least possible, make and repeat to apply number of times and become many modes and apply applying liquid 2.

Have again, repeat to apply for such multilayer, on one side change sweep speed, the nozzle 5 of the coating amount that applies liquid 2, nozzle 5 pitch of feed wait suitably and adjust, implement on one side to repeat to apply also can.

Rubbing method shown in Fig. 8 B (2) is pitch of feed at directions X is changed continuously and to make the fixing rubbing method of other parameter.In this rubbing method (2), the limit that is configured in the Y direction that also will be in LGP base material 1 is as said first limit in the present invention.

The coating density of the light diffusion particulate 21 that applies and the pitch of feed of nozzle 5 increase and decrease inversely proportionally.Therefore, for the inversely prroportional relationship of the graded profile function that becomes expectation and increase and decrease pitch of feed (Fig. 9 B) continuously.That is, the pitch of feed of nozzle 5 is broadened, around central portion, the pitch of feed of nozzle 5 is narrowed down at the both ends of LGP base material 1.

Thus, improve relevant ratio R or spreading area ratio S along with leaving from light source.That is, make the coating density step-down of the light diffusion particulate 21 in the both ends of approaching light source of LGP base material 1, the coating density of the light diffusion particulate 21 around light source central portion far away is uprised.In this rubbing method (2), though do not apply liquid 2 repeat apply, also obtain the graded profile expected, productivity is high.And owing to be the perfect graded profile that can not produce discontinuity point, so obtain not have the high-quality planar light source device of brightness irregularities.

Rubbing method shown in Fig. 8 B (3) is in each scanning of nozzle 5, only to make scan speed change and make the fixing rubbing method of other parameter.In this rubbing method (3), the limit that is configured in the Y direction that also will be in LGP base material 1 is as said first limit in the present invention.

The coating density of light diffusion particulate 21 and the sweep speed of nozzle 5 are inversely proportional.Therefore, shown in Fig. 9 C, for the inversely prroportional relationship of the graded profile that becomes expectation and the sweep speed of each scanning of nozzle 5 is changed continuously.That is, the sweep speed of nozzle 5 is accelerated, around central portion, make it slack-off at the both ends of LGP base material 1.

Thus, improve relevant ratio R or spreading area ratio S along with leaving from light source.That is, make the coating density step-down of the light diffusion particulate 21 in the both ends of approaching light source of LGP base material 1, the coating density of the light diffusion particulate 21 around light source central portion far away is uprised.Also this is preferred aspect two to this rubbing method (3) in productivity and brightness irregularities quality.

Rubbing method shown in Fig. 8 B (4) is in each scanning of nozzle 5, only to make the coating changes in flow rate that applies liquid 2 and make the fixing rubbing method of other parameter.In this rubbing method (4), the limit that is configured in the Y direction that also will be in LGP base material 1 is as said first limit in the present invention.

That is,, make the coating amount that applies liquid 2 tail off (Fig. 9 D) along be fed to the end face B side that light source is set from central portion along with the spacing of nozzle 5 with regulation is fed to central portion and makes the coating quantitative change that applies liquid 2 many from end face A side.

Thus, improve relevant ratio R or spreading area ratio S along with leaving from light source.That is, make the coating density step-down of the light diffusion particulate 21 in the both ends of approaching light source of LGP base material 1, the coating density of the light diffusion particulate 21 around light source central portion far away is uprised.In coating, can be rapidly, easily and in the spraying process the well coating amount that applies liquid 2 set of high accuracy and repeatability, also this is preferred aspect two to this rubbing method (4) in productivity and brightness irregularities quality.

But, make the coating amount that applies liquid 2 superfluous and make agglomerate 210 sedimentation in light transmission adhesive 22 of light diffusion particulate 21 in end face A side.Along with nozzle 5 is fed to central portion, the coating amount of this coating liquid 2 is made as in right amount.And then, make the coating amount that applies liquid 2 superfluous and make agglomerate 210 sedimentation in light transmission adhesive 22 of light diffusion particulate 21 once more along with nozzle 5 is fed to end face B side from central portion.Through being coated with like this, thereby can obtain same effect.

Rubbing method shown in Fig. 8 B (5) is the rubbing method that makes the scanning that nozzle 5 moves at directions X in the Y direction with the pitch of feed of regulation repeatedly.Particularly, in the scanning of nozzle 5, sweep speed is changed continuously, other parameter is fixed.In this rubbing method (5), the limit that is configured in directions X in LGP base material 1 is said first limit in the present invention.

Say that at length the inverse function relation for the graded profile function that becomes expectation changes the sweep speed at directions X of nozzle 5 continuously.That is, in the scanning at directions X of nozzle 5, the sweep speed of nozzle 5 is accelerated, around central portion, make its slack-off (Fig. 9 E) at the both ends of LGP base material 1.

Thus, improve relevant ratio R or spreading area ratio S along with leaving from light source.That is, make the coating density step-down of the light diffusion particulate 21 in the both ends of approaching light source of LGP base material 1, the coating density of the light diffusion particulate 21 around light source central portion far away is uprised.Also this is preferred aspect two to this rubbing method (5) in productivity and brightness irregularities quality.

Rubbing method shown in Fig. 8 B (6) also is the rubbing method that makes the scanning that nozzle 5 moves at directions X in the Y direction with the pitch of feed of regulation repeatedly.Particularly, the coating amount that applies liquid 2 is changed continuously, other parameter is fixed.In this rubbing method (6), the limit that is configured in directions X that also will be in LGP base material 1 is as said first limit in the present invention.

At length say, in the scanning at directions X of nozzle 5, make the coating amount that applies liquid 2 few at the both ends of LGP base material 1, and spray (Fig. 9 F) on every side morely at central portion.

Thus, improve relevant ratio R or spreading area ratio S along with leaving from light source.That is, make the coating density step-down of the light diffusion particulate 21 in the both ends of approaching light source of LGP base material 1, the coating density of the light diffusion particulate 21 around light source central portion far away is uprised.Also this is preferred aspect two to this rubbing method (6) in productivity and brightness irregularities quality.In addition, under the variable at high speed situation of the coating amount that can make coating liquid, utilize this rubbing method (6) can realize the graded profile of expecting easily.

But; Even make the sedimentation and be made as in right amount in light transmission adhesive 22 of the superfluous and agglomerate 210 that makes light diffusion particulate 21 of the coating amount that applies liquid 2 at the both ends of LGP base material 1, also can obtain same effect at the coating amount that central portion will apply liquid 2.

Describe with quantitative mode in more detail.At first, will comprise the coating liquid 2 that light diffusion particulate 21 also comprises solvent with light transmission adhesive 22, as required and coat LGP base material 1 equably with the pitch of feed that brightness irregularities does not take place, the pitch of feed of for example 10mm.Change applies the coating amount of liquid 2, the sweep speed of nozzle 5 waits LGP of making several (in illustrated example, being these 3 kinds of α to γ) even like this coatings.The coating density of the light diffusion particulate 21 of the LGP α to γ that Figure 10 A representes to produce.For each LGP α to γ, at left end the line source of led array etc. is set, when as Fig. 5, measuring Luminance Distribution, shown in Figure 10 B.Based on this, the coating density that the light diffusion particulate 21 of that kind of uniform luminance in the face is provided under the situation of the LGP of right ends light source shown in Figure 10 C.In addition, under the situation of the LGP of left end light source shown in Figure 10 D.

In order to realize the coating density of such light diffusion particulate 21, the 6 kinds of rubbing methods (1) shown in preferred respectively use Fig. 8 B are to (6).The coating amount that applies liquid 2 is made as F, and (X Y), is made as V with the sweep speed in the Y direction of nozzle 5 _Y(X), the sweep speed at directions X with nozzle 5 is made as V _X(X), the pitch of feed at directions X of nozzle 5 is made as Δ X (X), the pitch of feed in the Y direction of nozzle 5 is made as Δ Y (X).Rubbing method shown in Fig. 8 B (1) is coated with as following to (6) and gets final product.But, when Fig. 8 A is made as X at the X of left end coordinate ₀, will be made as F respectively at coating amount of the coating liquid 2 of left end etc. ₀, V _Y0, Δ X ₀, will apply density in the target of the light diffusion particulate 21 of left end and be made as C ₀The time, apply density C (X) about the target of the light diffusion particulate 21 of X among Figure 10 C or Figure 10 D in the position, get final product while as following, determine parameter to be coated with.At this moment, be set at above-mentioned 10mm in order to prevent to apply pitch of feed inhomogeneous and nozzle that need will be the longest under whole situation.

。

Have again, also can be as required and with rubbing method (1) to (6).

Use such rubbing method (1) to (6), comprise the coating liquid of light diffusion particulate and light transmission adhesive, be coated with diffusing layer thus in the surface applied of LGP base material 1.The light diffusion particulate becomes agglomerate.The ratio of the shared area of plane of the agglomerate in the coated face of LGP base material 1 and the surface covered that applies liquid is more than 0.1% below 70%.Therefore, in this embodiment, the agglomerate of a plurality of light diffusion particulates also has high asperratio, and forms the diffusing layer of fine pattern.Therefore, even unlike such version or metal pattern made in the past, when applying liquid when being coated on LGP base material 1, also can be simply and form the superior diffusing layer of light diffusion ability of fine pattern at an easy rate.

And spraying process can all have no problem ground to use on surface, the back side and then the two sides of LGP base material 1.For example, for the surface, utilize this rubbing method (1) to (6); Be implemented in the one dimension graded profile of directions X,, utilize this rubbing method (1) to (6) for the back side; Be implemented in the one dimension graded profile of Y direction, also can make the LGP of 3 marginal ray Source Types and 4 marginal ray Source Types.

Usually, in order to realize the graded profile of high-luminous-efficiency, need wide diffuse reflection limit of power, be the coating density range of light diffusion particulate 21.Usually be difficult to make the coating density of light diffusion particulate 21 to increase and decrease and realize 5 times to the light diffusion performance more than 10 times.Under these circumstances, spray the coating density of light diffusion particulate 21 overleaf equably,, and utilize this rubbing method (1) to (6) to realize graded profile for the light diffusion performance of part of covering the shortage on the surface.Thus, also there is the situation of making the even brightness gradual change LGP of high-luminous-efficiency easily.The present invention also can use under these circumstances effectively.

In addition, spraying process also can easily be applied to for example 50 inches large-scale LGPs that size is above.Injection mo(u)lding or punch forming, some printing etc. all need large-scale precision metallic mould or silk screen version, in addition also need large-scale equipment, and cost of investment is high.In addition, in ink jet printing method, also need huge investment in order to tackle large scale.If spraying process, then only make light weight and little nozzle in the enterprising line scanning of X-Y direction.Therefore, can achieve the goal with low cost equipment.That is, spraying process of the present invention is also used through low cost equipment for large-scale LGP.Be that LGP more than the 900mm is preferred to the leaded light length L especially.In this case, preferably near the illumination the light source be more than 0.8 below 1.2 away from the ratio of the illumination of the position of light source.

And then, if use the structure that self contains the diffusion member at the LGP base material, the whole decline of the coating density ground of the light diffusion particulate that is coated in the surface is applied.Therefore, according to circumstances be useful.For example be as above-mentioned, only to pass through surface coated and the not enough situation of light diffusion performance.In addition for example, under the situation of thick and short LGP, before fully not colliding with the diffuse reflection face, arrive opposite end face from the leaded light light of light source incident, existence can't be carried out the luminous situation of face fully.In this case, through a small amount of diffusion portion is disperseed in LGP, thereby can carry out luminous effectively.The present invention also is preferred for such purposes.

In addition, be more than 5% below 50% preferably near the spreading area ratio S1 the light source, be more than 20% below 95% away from the spreading area ratio S2 of the position of light source, S2＞S1.

In addition; At near (2 π/360) * 60rad gloss (gloss) value GS1 of the coated face of the LGP base material the light source is more than 40 below 90; Be more than 10 below 60 away from (2 π/360) * 60rad gloss number GS2 of the coated face of the LGP base material 1 of the position of light source, GS2＞GS1 also can.

And then, be more than 5% below 30% near mist degree (haze) the value H1 of the face direction the light source, be more than 10% below 40% away from the haze value H2 of the position of light source, H2＞H1 also can.

＜embodiment 3＞

Below embodiment 3 of the present invention is described.Though the LGP of LGP of this embodiment and manufacturing method of light conducting board and embodiment 2 and manufacturing method of light conducting board are roughly same, difference is, makes the light diffusion particulate become two-dimensional graded distribution.Therefore, only different portions is at length described.

In Figure 11, schematically show supposition is provided with line source on 4 limits of LGP 100 two-dimensional graded distribution.That is, the M among Figure 11 shows the coating density part about equally of light diffusion particulate with linking with line.N among Figure 11 shows the distribution of directions X of the coating density of light diffusion particulate.P among Figure 11 shows the distribution of Y direction of the coating density of light diffusion particulate.If with C (X Y) representes this graded profile as target, can through separately or and land used use rubbing method (1) to (6) to make.

As the application of rubbing method (1), implement successively to repeat to apply through the line of (a) in Figure 11, thereby can realize.Poor in order to prevent at the brightness irregularities or the brightness ladder on the border of repeating to apply, need much more fully to repeat to apply number of times.

As the application of rubbing method (3), through in the single pass of Y direction, sweep speed being changed continuously, thereby can realize at nozzle.That is, as long as the sweep speed in the Y direction of nozzle is scanned according to following numerical expression.

。

As the application of rubbing method (4), change continuously through in the single pass of Y direction, make the coating amount that applies liquid at nozzle, thereby can realize.That is, as long as the coating amount that applies liquid is sprayed according to following numerical expression at nozzle.

。

Make rubbing method (5) and (6) combination, also can realize two-dimensional graded distribution.That is, need only according to following numerical expression at the directions X scan nozzle.

。

In addition, through using rubbing method (2), and in the single pass of Y direction, changes the sweep speed of nozzle or the coating amount of coating liquid, thereby also can realize two-dimensional graded distribution at nozzle.

Here said two-dimensional graded distribution is not limited to the structure in 4 marginal ray sources, also can be quadrature 2 light sources or 3 marginal ray sources, is also contained in situation that the end face periphery finely tunes the coating density of light diffusion particulate etc.This also is same in above-mentioned one dimension graded profile.

In the manufacturing method of light conducting board of above-mentioned

embodiment

1,2, under the productive situation of consideration, only on the coated face of large-area LGP base material, be coated with and expend time in 1 nozzle.Therefore, may not be good method.In Figure 12, for example the Y direction, promptly with the scanning direction roughly the direction of quadrature equally spaced dispose a plurality of nozzles 5 side by side.This a plurality of nozzle 5 is scanned at directions X.But, also can be equally spaced to dispose a plurality of nozzles 5 side by side at directions X, and the structure that these a plurality of nozzles 5 are scanned in the Y direction.Through adopting multiinjector like this, thereby shortened the coating time significantly.Also consider

adjacent nozzles

5 and 5 interval need be when applying not mutually the abundant wide interval of mutual interference, perhaps according to circumstances adjacent nozzles is staggered and situation about being configured alternately at directions X.

These a plurality of nozzles 5 are by individually or control jointly, and will apply liquid and be sprayed at LGP base material 1.

Under the situation of one dimension graded profile, for example use the nozzle 5 that rubbing method (5) or (6) make configuration arranged side by side and carry out 1 scanning at directions X.At this moment, each nozzle 5 is same flow.Then, stagger about the abundant little Y direction pitch of feed that do not produce brightness irregularities, for example 10mm in the Y direction, and utilize rubbing method (5) or (6) to scan at directions X.Through making its scan nozzle amount at interval, thereby can apply equably at whole face.

Under the situation of two-dimensional graded distribution,, through in each scanning, controlling coating amount independently, thereby can realize from the coating liquid 2 of each nozzle 5 for corresponding with coating Density Distribution at the light diffusion particulate of Y direction.

Figure 13 be illustrated in use the light transmission adhesive as ultraviolet hardening, also and used the trial-production/manufacturing process under the situation that the coating liquid of the light diffusion particulate of solvent sprays.At first, will apply liquid 2 and be sprayed at LGP base material 1, and make solvent dry through Wen Feng etc. afterwards.Then, irradiation ultraviolet radiation solidifies the light transmission adhesive, makes the surface of light diffusion particulate permanent adhesive at the LGP base material.

The situation of the even brightness LGP that as a rule, obtains to expect with 1 graded profile design is less.But shown in figure 13 according to the present invention, evaluation of measuring Luminance Distribution at once under the situation of the uniformity that does not obtain expectation, applies fine setting and is coated with once more each parameter.If carry out this operation as required repeatedly, then can be at short notice and easily realize the graded profile of light diffusion particulate.

As above, according to the present invention, the one dimension graded profile of light diffusion particulate, two-dimensional graded distribution do not need metal pattern or galley etc., can implement trial-production/production at once from design.The light that particularly can make light source efficiently and also the graded profile of the best light diffusion particulate of the even brightness of that kind that forwards penetrates equably according to the size of LGP base material, shape, thickness of slab, light source position etc. and different fully, but method of the present invention is preferably applied in the production of so many kinds and multi-brand.

In above-mentioned embodiment 1, make the agglomerate 210 of light diffusion particulate 21 be attached to LGP base material 1 randomly.In above-mentioned embodiment 2, along with from light source 9 away from and improve the ratio R of the shared area of plane of agglomerate 210 the coated face of LGP base material 1 and the surface covered that applies liquid 2 or apply the spreading area ratio S of area of coated face of surface covered and the LGP base material 1 of liquid 2.But; If satisfying the ratio of the shared area of plane of agglomerate 210 in the coated face of LGP base material and the surface covered that applies liquid 2 is the necessary condition below 70% more than 0.1%, then makes the agglomerate 210 of light diffusion particulate 21 roughly be attached to LGP base material 1 equably and also can.That is, constitute near light source 9 spreading area ratio S1 be more than 80% below 120% away from the value of the ratio S2/S1 of the spreading area ratio S2 of the position of light source 9.

Though in above-mentioned embodiment 2, will be made as at the ratio of the shared area of plane of the agglomerate in the coated face of LGP base material 1 210 and the surface covered that applies liquid 2 more than 0.1% below 70%, be not limited thereto.In a word, need only the coating density step-down that makes the light diffusion particulate in the part that approaches light source, in part the coating density of light diffusion particulate is uprised and get final product away from light source.

Though in above-mentioned embodiment 1 to 3, make light diffusion particulate 21 become agglomerate, be not limited thereto.That is, light diffusion particulate 21 can not condense yet.At this moment, for the light diffusion performance that obtains to expect, the spraying condition at interval of control/selective light diffusive particles, light transmission adhesive, solvent, LGP base material and nozzle etc. suitably.At this moment, for example to apply liquid 2 be that globule shape ground applies also can (Figure 14).In addition, in order to increase the light diffusion performance, with apply liquid 2 cover whole face also can (Figure 15).In addition, Figure 16 A, B are that coating liquid with the light transmission adhesive of MS particulate and ultraviolet hardening and solvent is sprayed on the PMMA base material and makes the microphotograph of the state of its curing.In Figure 16 A, B, the part of performance is the light diffusion particulate as bubble.The light diffusion particulate that is attached to the coated face of LGP base material 1 becomes diffusion portion respectively, therefore can form fine diffusion portion simply.In addition, the light diffusion particulate must apply randomly, therefore can suppress the generation of ripple (moire).

Embodiment

＜embodiment 1＞

Go up the acrylic resin sheet material of placing length (length of light conducting direction) 1200mm, width 1000mm, thickness 8mm as the LGP base material at platform (workbench); From the top of this acrylic resin sheet material, utilize the nozzle of sprayer to spray to applying liquid.Apply liquid and be the resin particle (refractive index 1.56, average grain diameter 3 μ m φ) that is used as the light diffusion particulate, be the mixed solution after the mode of 5wt% is diluted with the solid constituent as the acrylic compounds ultraviolet curable resin of light transmission adhesive, as the ketones solvent of dilution solvent.Nitrogen and this coating liquid are together sprayed.

At this moment, be coated in whole in order to apply liquid, and make nozzle on one side at the in-plane (that is, X, Y direction) of LGP base material Yi Bian move and spray.At length say, coating amount changed according to the length direction (that is, directions X) of LGP base material, for the central portion at directions X applies at most, according to the position with the pitch of feed 10～40mm of nozzle carry out 1 time～8 times repeat apply.In addition, the distance of LGP base material 1 and nozzle 5 is made as 100～200mm, the coating amount that applies liquid 2 is made as 0.5～4.0gr/ branch, the sweep speed of nozzle 5 is made as 200～400mm/sec.

Consequently, the surface state of utilizing coating to obtain is gloss 85 near light source, is gloss 15 in the position of length direction 600mm.

Then, the light source that White LED is configured is set with being wire,, makes the side-light type backlight at the range upon range of light-diffusing film of the coated face that becomes face side at the range upon range of diffusive white reflective sheet of the rear side of this LGP base material in two ends of LGP base material.

When backlight, is uniform brightness at whole through visual this side-light type of observing in the position of having left 2m from the front, and the brightness irregularities of bright spot etc. is not eye-catching yet.

＜embodiment 2＞

Go up the transparent PMMA LGP base material of placing the size that equates with embodiment 1 at platform (workbench), as Fig. 7, utilize nozzle to apply applying liquid from the top.At this moment, utilize the rubbing method shown in Fig. 8 B (1), the scanning direction is made as the Y direction, the directions X pitch of feed is made as the 10mm spacing, at first implement evenly to apply.Apply liquid and be the crosslinked particle that is used as the MS resin of light diffusion particulate (average grain diameter 3 μ m, remove the solid constituent conversion concentration 10wt% of solvent), be the mixed solution after the mode of 20wt% is diluted with the solid constituent as the polyurethanes ultraviolet curable resin of light transmission adhesive, as the PGMAC (propylene glycol monomethyl ether) of dilution solvent.Nitrogen and this coating liquid are together sprayed.

The distance of LGP base material and nozzle is made as 150mm, and the coating amount that applies liquid is converted with solution is made as 1mL/min, and the sweep speed of nozzle is made as 150mm/min.In this case, application width is about 50mm.

Under this condition, will apply the whole surface that liquid is coated in the LGP base material in scanning one side of feeding nozzle at directions X at interval with 10mm on one side in the Y direction.But, be the empty scanning of 20mm beginning before the LGP substrate surface at first in the coating of an end face (the downside end face in the paper at Fig. 5) side of directions X configuration.In addition, finishing in the coating of another end face (the upside end face in the paper at Fig. 5) side of directions X configuration also is the place that scans above LGP base material 20mm.20mm before the LGP substrate surface is coated with in an end face (left end face in the paper at Fig. 5) side of Y direction configuration.In addition, another end face (its right end face in the paper at Fig. 5) side that disposes in the Y direction is coated with above LGP base material 20mm ground, implements with the inhomogeneous mode that enters into substrate body of the coating at changes direction end of avoiding nozzle.

In order to make the LGP of two ends light source type, as Fig. 9 A, carry out 8 grades the coating that repeats.As emitting side, likewise to make side-light type backlight with embodiment 1 with the coated face of this LGP.Though when the visual examination backlight of this side-light type and Luminance Distribution were measured, visible 8 grades brightness ladder was poor, having obtained can be by the uniform LGP of abundant acceptance.

＜embodiment 3＞

Though under the condition identical, begun coating, the method for in this rubbing method (3), having used the sweep speed that makes the Y direction semi-continuously to change according to the directions X pitch of feed with embodiment 2.Under the coating condition of embodiment 2, be that the coating of the light diffusion particulate on the LGP base material 1 of even coating of 10mm distributes and is made as C with the directions X pitch of feed ₀, the sweep speed 150mm/min in the Y direction of nozzle 5 is made as V _Y0, the pitch of feed Δ X=10mm at directions X of nozzle 5 is fixed, and as following, changes the n time scan velocity V on the LGP base material 1 successively _Y(X).Other variable all is made as regularly is coated with.

。

When the LGP after adopting the two ends light source to coating carried out visual examination and Luminance Distribution mensuration, complete invisible brightness irregularities or brightness ladder were poor, have obtained also extremely high, the high-quality LGP of the even precision of brightness.

Have again, the invention is not restricted to above-mentioned embodiment and embodiment, in the scope that does not break away from purport, can suitably change.

Utilizability on the industry

LGP of the present invention and manufacturing method of light conducting board can as from the planar light source device of the back side illuminaton light of display panels or signboard etc., be LGP and the manufacturing method of light conducting board that so-called backlight apparatus is used.

The explanation of Reference numeral:

1 LGP base material;

2 apply liquid;

3 diffusing layers;

4 sprayers;

5 nozzles;

6 storage grooves;

7 flow-control portions;

9 light sources;

10 diffuse reflection films;

11 diffusers;

12 luminance meters;

21 light diffusion particulates;

22 light transmission adhesives;

100 LGPs;

210 agglomerates.

Claims

1. manufacturing method of light conducting board, said LGP is disposed at end face in order to constitute planar light source device with light source, and said manufacturing method of light conducting board is characterised in that,

At the back side of LGP base material or surface or apply the coating liquid that comprises light diffusion particulate and light transmission adhesive with the fine droplets state on the two sides; Be coated with diffusing layer thus; Said light diffusion particulate becomes agglomerate, and the ratio of the area of plane that the said agglomerate in the coated face of said LGP base material is shared and the surface covered of said coating liquid is more than 0.1% below 70%.

2. manufacturing method of light conducting board according to claim 1; It is characterized in that; When the said diffusing layer of coating, in approaching the part of said light source, make the coating density step-down of said light diffusion particulate, in said light source part far away, the coating density of said light diffusion particulate is uprised.

3. manufacturing method of light conducting board according to claim 1 is characterized in that, the spraying process that the utilization of said coating liquid is sprayed to this coating liquid from nozzle is coated in the back side or the surface or the two sides of said LGP base material.

4. manufacturing method of light conducting board according to claim 3 is characterized in that, disposes a plurality of nozzles side by side, makes said a plurality of nozzle almost parallels ground scanning, makes the coating density one dimension or two-dimentional the variation of said light diffusion particulate thus.

5. according to claim 3 or 4 described manufacturing method of light conducting board, it is characterized in that being spaced apart below the above 300mm of 70mm of the coated face from said nozzle to said LGP base material.

6. according to claim 3 or 4 described manufacturing method of light conducting board; It is characterized in that; In said spraying process, Yi Bian said coating liquid is sprayed from nozzle, Yi Bian on the coated face of said LGP base material; To make in direction with the first limit almost parallel of said LGP base material scanning that said nozzle moves with the direction of the said first limit quadrature on carry out times without number with the pitch of feed of regulation, said coating liquid is coated on whole or a part of said coated face.

7. according to claim 3 or 4 described manufacturing method of light conducting board; It is characterized in that; Ground, coated face top through at said LGP base material carries out following operation repeatedly; Thereby the coating density one dimension ground of said light diffusion particulate is changed, in said operation, will make in direction with the first limit almost parallel of said LGP base material scanning that said nozzle moves with the direction of the said first limit quadrature on carry out times without number with the pitch of feed of regulation.

8. according to claim 3 or 4 described manufacturing method of light conducting board; It is characterized in that; The pitch of feed of said nozzle is changed, apply said coating liquid, make the coating density one dimension ground variation of said light diffusion particulate thus whole of the coated face of said LGP base material or a part.

9. according to claim 3 or 4 described manufacturing method of light conducting board; It is characterized in that; In each scanning of this nozzle, make the scan speed change of said nozzle; Apply said coating liquid whole of the coated face of said LGP base material or a part, make the coating density one dimension ground variation of said light diffusion particulate thus.

10. according to claim 3 or 4 described manufacturing method of light conducting board; It is characterized in that; Coating amount from the time per unit of the coating liquid of said nozzle is changed; Apply said coating liquid whole of the coated face of said LGP base material or a part, make the coating density one dimension ground variation of said light diffusion particulate thus.

11. a LGP is disposed at end face in order to constitute planar light source device with light source, said LGP is characterised in that,

At the back side of LGP base material or surface or apply the coating liquid that comprises light diffusion particulate and light transmission adhesive on the two sides, be coated with diffusing layer thus,

Said light diffusion particulate becomes agglomerate, and the ratio of the area of plane that the said agglomerate in the coated face of said LGP base material is shared and the surface covered of said coating liquid is more than 0.1% below 70%.

12. LGP according to claim 11 is characterized in that, the spraying process that the utilization of said coating liquid is sprayed to this coating liquid from nozzle is coated in the back side or the surface or the two sides of said LGP base material.

13., it is characterized in that the number of the light diffusion particulate that in 1 said agglomerate, comprises is more than 10 below 10000 according to claim 11 or 12 described LGPs.

14. according to claim 11 or 12 described LGPs; It is characterized in that; Along with leaving from said light source, the spreading area ratio of the area of the coated face of the ratio of the area of plane that the said agglomerate in the coated face of said LGP base material is shared and the surface covered of said coating liquid or the surface covered of said coating liquid and said LGP base material uprises.