JP2019008219A - Light diffusion member, manufacturing method of light diffusion member, and light integrator - Google Patents

Abstract

To provide a light diffusion member that reduces the manufacturing cost, has a high light transmission efficiency, and can adjust the light diffusion angle.SOLUTION: A light diffusion member 1 includes: an incident plane 2 for receiving incident light 3; and an outgoing plane 4 that faces the incident plane 2 and emits the incident light 3 as outgoing beams 6 and 7. The light diffusion member 1 includes a refraction index adjustment unit 5 having a refraction index different from that of the light diffusion member 1. The refraction index adjustment unit 5 has a substantially cylindrical shape or a substantially conical shape. A plurality of refraction index adjustment units are arranged so that the axial directions of them are substantially parallel. The refraction index adjustment unit 5 diffuses and emits, from the outgoing plane 4, the light of an angle of 7.2 degrees or less with respect to the normal line of the incident plane, and rectilinearly emits, from the outgoing plane 4, light of an angle of 7.2 degrees or more with respect to the normal line of the incident plane.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light diffusing member, a method for manufacturing the light diffusing member, and an optical integrator.

In a liquid crystal display and a projector using a liquid crystal, a surface light source using a light emitting diode, a fluorescent tube, or the like is often employed. In these applications, a surface light source with less in-plane unevenness is required.
As means for reducing the in-plane unevenness of the surface light source, it is common to make the light diffusive member uniform by reflecting or transmitting light. Examples of a method for developing light diffusibility include a method of refracting light traveling in various directions by containing particles having different refractive indexes in the member or roughening the surface of the member.

However, if the above method is used as a method of developing light diffusivity, the light spread angle may become wider than the desired range, and the light that has spread beyond the desired range is eventually wasted. Therefore, there is a problem that energy efficiency as a light source is lowered.
Accordingly, it is desired to develop an anisotropic light diffusing member having a diffusion function in which light in a predetermined incident angle range diffuses and light in an angle range other than the predetermined angle travels straight, that is, a spread angle is limited.

  As an anisotropic light diffusing member, there is a method in which ultraviolet curable resin is irradiated with ultraviolet rays with controlled parallelism, and portions having different refractive indexes are regularly formed in the light diffusing member (see, for example, Patent Document 1). ). This light diffusing member is generally manufactured by adjusting the diffusion angle range according to the application to be used, and as a method for adjusting the spread angle, the ultraviolet ray during curing is passed through a film having a predetermined haze. There is a method of adjusting the parallelism of ultraviolet rays (see, for example, Patent Document 2).

JP 2016-200841 A Japanese Patent Laid-Open No. 2006-194687

  The light diffusing member proposed in the cited references 1 and 2 requires the use of a plurality of jigs and tools such as a film having a predetermined haze and a fixture for fixing the film, resulting in an increase in manufacturing cost. is there.

  As a result of diligent research, the present inventors have found that it is possible to provide a part for adjusting the refractive index only by adjusting the manufacturing conditions without using a plurality of jigs and tools, and the diffusion angle at the part for adjusting the refractive index. It has been found that the above problem can be solved by adjusting the range.

  Accordingly, the present invention provides a light diffusing member, a light diffusing member manufacturing method, and an optical integrator that solve the above problems, reduce manufacturing costs, have good light transmission efficiency, and can adjust the light diffusing angle. is there.

The present invention relates to the following.
(1) A light diffusing member having an incident surface on which incident light is incident, and an exit surface that faces the incident surface and emits the incident light as outgoing light, the light diffusing member including the light diffusion member A refractive index adjustment unit having a refractive index different from that of the member is provided, and the refractive index adjustment unit has a substantially cylindrical shape or a substantially conical shape, and a plurality of the refractive index adjustment units are arranged so that the axial directions are substantially parallel to each other. The unit diffuses and emits light within 7.2 degrees from the exit surface normal to the incident surface normal, and travels light of 7.2 degrees or more from the exit surface straight from the exit surface. A light diffusing member to be emitted.
(2) The light diffusing member according to (1), wherein a diffusion plate is provided on the emission surface.
(3) A method for producing a light diffusing member according to (1) or (2), wherein a disposing step of disposing a photocurable resin composition on a support member, and collimating light on the photocurable resin composition The manufacturing method of the light-diffusion member including the exposure process which irradiates.
(4) The exposure step is a step of irradiating the photocurable tree composition with light from two directions, and after irradiating the collimated light from one side, irradiating scattered light from the other side (3) The manufacturing method of the light-diffusion member of description.
(5) The method for producing a light diffusing member according to (3) or (4), wherein the time for irradiating the collimated light is adjusted, and the length and density of the refractive index adjusting unit are adjusted.
(6) An optical integrator using the light diffusing member according to (1) or (2).

  According to the present invention, it is possible to provide a light diffusing member, a light diffusing member manufacturing method, and an optical integrator that can reduce the manufacturing cost, have good light transmission efficiency, and can adjust the light diffusing angle.

FIG. 1A is a top view of the light diffusing member according to the embodiment of the present invention, and FIG. 1B is a cross-sectional view of the light diffusing member according to the embodiment of the present invention. It is sectional drawing which shows the exposure method of the light-diffusion member which concerns on embodiment of this invention. It is an external view of the optical integrator using the light-diffusion member which concerns on embodiment of this invention. It is a graph which shows the cumulative brightness according to angle in Example 1 and Comparative Example 2. 6 is a graph showing a luminance distribution by angle in Example 1; It is a graph which shows the luminance distribution according to angle in the comparative example 2.

As shown in FIG. 1, the light diffusing member 1 according to the embodiment of the present invention faces the incident surface 2 on which the incident light 3 is incident and the incident surface 2, and emits the incident light 3 as the emitted lights 6 and 7. And an exit surface 4 to be used. The light diffusing member 1 includes a refractive index adjusting unit 5 having a refractive index different from that of the light diffusing member 1. The light diffusing member 1 has a basic function of transmitting light.
Hereinafter, each member and manufacturing method used in the present invention will be described in detail.

[Configuration of light diffusing member]
The light diffusing member 1 is made of a photocurable resin composition and has a property of transmitting incident light 3 incident from the incident surface 2 with a constant transmittance. Although the transmittance of the light diffusing member 1 is not particularly limited, it is preferably 30% or more and 99% or less from the viewpoint of increasing the energy efficiency of the light emitting surface in order to transmit light more efficiently as the transmittance increases. % To 99% is more preferable, and 50% to 99% is more preferable.
The light diffusing member 1 can be provided with the function of a wavelength filter by intentionally changing the transmittance of some wavelengths.

  The thickness of the light diffusing member 1 is not particularly limited, but is preferably 50 μm or more and 4,000 μm or less, more preferably 50 μm or more and 3,000 μm or less, and further preferably 50 μm or more and 2,500 μm or less. When the thickness of the light diffusing member 1 is in the above range, a long path for incident light can be secured, and the effect of diffusion can be exerted strongly.

  The light diffusing member 1 can also be provided with a functional layer having another property on one or both of the incident surface 2 and the exit surface 4. As a functional layer, a light diffusive layer is provided to increase the spread of the emitted light, a polarizing layer is provided to align the wavefront of light, or an adhesive layer is provided to facilitate assembly. Can be made easier.

  The exit surface 4 is preferably provided with a diffusion plate (not shown). The diffusing plate has a function of spreading out the light emitted from the emission surface 4 with a certain angular distribution and emitting it. By providing the diffusing plate, the light emitted from the emission surface 4 can be emitted without loss. The diffusion plate is not limited to a plate-like one, and a film-like diffusion film can be used.

[Refractive index adjuster]
It is preferable that the refractive index adjusting unit 5 has a cylindrical shape or a conical shape. Then, it is preferable that a plurality of columnar or conical refractive index adjusters 5 are arranged on the light diffusing member 1 such that the axial direction (length direction) is substantially parallel.
The refractive index adjusting unit 5 is formed on the wall surface of the refractive index adjusting unit 5 when light that is substantially parallel to the cylindrical or conical axial direction (light within 7.2 degrees with respect to the incident surface normal) is incident. By repeating reflection or refraction, the traveling direction of the light is changed, and the scattered component 7 of the emitted light is generated. As the light substantially parallel to the axial direction of the columnar shape or the conical shape, the incident angle θ ₁ with respect to the incident surface normal is preferably within a range from 2.3 degrees to 7.2 degrees, and preferably from 2.5 degrees to 7. It is more preferably within 0 degree, and further preferably within 2.7 to 6.8 degrees. Since the number of repetitions and angles of reflection or refraction at the wall surface of the refractive index adjusting unit 5 differ depending on the incident position of the light with respect to the refractive index adjusting unit 5, it looks macroscopically that light is diffused.
The refractive index adjusting unit 5 is not reflected on the wall surface and is refracted when light having an angle different from the cylindrical or conical axial direction (light of 7.2 degrees or more with respect to the incident surface normal) is incident. Is transmitted once or twice, the light traveling direction is not changed, and the straight traveling component 6 of the emitted light is generated. That is, macroscopically, the light seems to go straight. As the light having an angle different from the cylindrical or conical axial direction, the incident angle θ ₁ with respect to the incident surface normal is preferably 7.4 degrees or more, and more preferably 7.6 degrees or more, More preferably, it is 7.8 degrees or more.

The refractive index N1 of the refractive index adjusting unit 5 needs to be higher than the refractive index N2 of the surrounding light diffusing member 1, and the traveling direction of the light can be changed depending on the ratio of the refractive indexes. N1 / N2 is, for example, 1.0068 or more and 1.0083 from the viewpoint that the light diffusion angle can be adjusted when light of 7 degrees is incident on the incident surface normal (θ ₁ = 7.0). It is preferable that it is below 1, more preferably 1.0071 or more and 1.0079 or less, further preferably 1.0073 or more and 1.0077 or less.
What is necessary is just to select and use the light-diffusion member 1 and the refractive index adjustment part 5 so that the ratio of the refractive index of the light-diffusion member 1 and the refractive index adjustment part 5 may become the said range.

(Constituent material of photocurable resin composition)
The material used for the light diffusing member 1 including the refractive index adjusting unit 5 is a photocurable resin composition, and the photocurable resin composition mainly contains a compound having a photopolymerizable functional group and a photopolymerization initiator. .

  The compound having a photopolymerizable functional group is not particularly limited as long as it is photocurable, and ethylene curable with a photopolymerization initiator that generates radicals such as (meth) acryloyl group, vinyl group, and allyl group. A compound having a cyclic unsaturated bond; a compound containing a cyclic ether group curable with a photoacid generator that generates an acid such as an epoxy group and an oxetane group. The compound having a photopolymerizable functional group is preferably a compound containing an ethylenically unsaturated bond, and more preferably a compound containing a (meth) acryloyl group, from the viewpoints of curability, transparency and reliability. The component of the photopolymerizable functional group preferably contains photoradically polymerizable poly (meth) acrylate as a main component, but is not limited thereto. Among these, a compound having a plurality of (meth) acryloyl groups in one molecule is preferably used as the compound having a photopolymerizable functional group. Specifically, by using a compound having six (meth) acryloyl groups, functions of improving the rigidity, improving the heat resistance, improving the creep resistance and adjusting the refractive index of the cured product can be exhibited. Moreover, flexibility can be imparted to the cured product by using a compound having two (meth) acryloyl groups. It is preferable to combine a plurality of these (meth) acryloyl group-containing compounds because it becomes easy to adjust the viscosity, the elasticity of the cured product, and the refractive index.

  The photopolymerization initiator is not particularly limited as long as it generates radicals by irradiation with active energy rays such as ultraviolet rays, electron beams, α rays, β rays, and γ rays to accelerate the curing reaction of the resin composition. It is possible to use known materials such as benzophenone, anthraquinone and benzoyl, and known materials such as sulfonium salts, diazonium salts and onium salts. Examples of the photopolymerization initiator include benzophenone, N, N′-tetramethyl-4,4′-diaminobenzophenone (Michler ketone), N, N-tetraethyl-4,4′-diaminobenzophenone, 4-methoxy-4, 4′-dimethylaminobenzophenone, α-hydroxyisobutylphenone, 2-ethylanthraquinone, tert-butylanthraquinone, 1,4-dimethylanthraquinone, 1-chloroanthraquinone, 2,3-dichloroanthraquinone, 3-chloro-2-methylanthraquinone 1,2-benzoanthraquinone, 2-phenylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthraquinone, thioxanthone, 2-chlorothioxanthone, 2,2-dimethoxy-1,2-diphenylethane-1- ON, 2,2-die Aromatic ketone compounds such as xyacetophenone; benzoin compounds such as benzoin, methylbenzoin, and ethylbenzoin; benzoin ether compounds such as benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether, and benzoin phenyl ether; benzyls such as benzyl and benzyldimethyl ketal Compound; ester compound such as β- (acridin-9-yl) (meth) acrylic acid; acridine compound such as 9-phenylacridine, 9-pyridylacridine, 1,7-diacridinoheptane; 2- (o-chlorophenyl) ) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5-di (m-methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-diphenyl Imi Dazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer, 2,4-di (p -Methoxyphenyl) 5-phenylimidazole dimer, 2- (2,4-dimethoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methylmercaptophenyl) -4,5-diphenylimidazole dimer 2,4,5-triarylimidazole dimer such as 2-mer; 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone, 2-methyl-1- [4- (methylthio ) Phenyl] -2-morpholino-1-propane and other alkylphenone compounds; 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl -1-phenyl-propan-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- { 4- [4- (2-Hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one, oligo {2-hydroxy-2-methyl-1- [4- (1- Α-hydroxyalkylphenone compounds such as methyl vinyl) phenyl] propanone}; phenylglyoxylic acid methyl ester; bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (2,6-dimethoxybenzoyl) ) -2,4,4-trimethyl-pentylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl Examples thereof include phosphine oxide compounds such as phosphine oxide. Among these photopolymerization initiators, aromatic ketone compounds, phenylglyoxylic acid methyl esters and alkylphenone compounds are preferable from the viewpoint of curability and reactivity, and phosphine oxide compounds and alkylphenone compounds are particularly preferable. Compounds are more preferred.

  The photocurable resin composition may contain a solvent in order to facilitate application. The solvent is not particularly limited, and examples thereof include (mono) such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and dipropylene glycol dimethyl ether. Or poly) alkylene glycol (mono or poly) alkyl ethers and their acetates; diacetates such as propylene glycol diacetate and 1,3-butylene glycol diacetate; ethers such as tetrahydrofuran; methyl ethyl ketone, cyclohexanone, 2 -Ketones such as heptanone; methyl 2-hydroxypropionate, 3-hydroxypro Ethyl onate, ethyl acetate, n-butyl acetate, isobutyl acetate, isobutyl butyrate, n-butyl butyrate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, 3-methoxybutyl acetate, ethyl lactate, cyclohexanol acetate, etc. And aromatic hydrocarbons such as toluene and xylene. A solvent may be used individually by 1 type and may use 2 or more types together.

  Other additives can be further blended in the photocurable resin composition as long as the effects of the present invention are not impaired. Other additives include general adhesion improvers such as silane coupling agents, thermal polymerization initiators, moisture curing agents, antioxidants, thixotropic agents, chain transfer agents, stabilizers and photosensitizers. Additives can be included.

[Production Method of Light Diffusing Member]
A method for manufacturing the light diffusing member 1 will be described with reference to FIG.

<Arrangement process>
First, an arrangement step of arranging the photocurable resin composition 12 on the support member 11 is performed.
The method for disposing the photocurable resin composition 12 on the support member 11 is not particularly limited. For example, when the support member 11 has a flat surface such as a film and glass, a method of arranging the photocurable resin composition 12 on the support member 11 using a printing machine can be employed. Alternatively, in the case where the support member 11 is a cavity-shaped mold, a method of arranging the photocurable resin composition 12 by injecting the support member 11 into the support member 11 can be employed.
After the disposing step of disposing the photocurable resin composition 12 on the support member 11, a step of evaporating a solvent or the like and a step of covering the support member 11 with a lid 11a such as a film and glass can be added.

<Exposure process>
Next, an exposure step of irradiating the photocurable resin composition 12 with collimated light 9 is performed.
By irradiating the photocurable resin composition 12 with the collimated light 9, the photocurable resin composition 12 can be photopolymerized and cured.
The light diffusing member 1 can be produced by cutting the cured photocurable resin composition 12 into a predetermined size.
The exposure process will be described in detail below.

A method for irradiating the photocurable resin composition 12 with the collimated light 9 in the exposure step is not particularly limited. In the specification, there is a method of irradiating this with collimated light).
Examples of the active light source include a light source that emits ultraviolet rays, such as an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a mercury vapor arc lamp, a metal halide lamp, a xenon lamp, and a carbon arc lamp. In addition, examples of the active light source include a light source that effectively emits visible light, such as a photographic flood bulb and a solar lamp.

When the photocurable resin composition 12 is irradiated with the collimated light 9, the refractive index adjusting unit 5 is formed. The mechanism by which the refractive index adjusting unit 5 is formed is as follows.
When the photopolymerizable functional group in the photocurable resin composition 12 causes a polymerization reaction, the refractive index is locally increased to form a high refractive index part. When light is further irradiated in the vicinity of the high refractive index portion, the light propagates in one direction to the deep resin portion while being bent to the center of the high refractive index portion according to Snell's law, and the polymerization reaction proceeds. These reactions occur in various places in the resin, but if the irradiation light is collimated light, the traveling direction of each reaction becomes parallel, and as a result, columns or conical high refractive index portions arranged in parallel in the cured resin are formed. It is formed. In the present invention, this high refractive index portion is referred to as a refractive index adjusting portion 5.
The photocurable resin composition 12 can adjust the length and density of the refractive index adjusting unit 5 by adjusting the time for irradiating the collimated light 9 or by irradiating it in combination with scattered light. When the length of the refractive index adjusting unit 5 is short or the density is low, the light diffusion effect by the refractive index adjusting unit 5 becomes weak, and light with high directivity is output. On the other hand, when the length of the refractive index adjustment unit 5 is long or the density is high, the light diffusion effect by the refractive index adjustment unit 5 is high, and light with high diffusibility is output.

The exposure step is a step of irradiating light to the photocurable tree composition 12 from two directions, and after irradiating the collimated light 9 from one side, it is preferable to irradiate the scattered light 10 from the other side.
Specifically, after irradiating the collimated light 9 by the above method, the light curable tree composition 12 is irradiated with the scattered light 10 via the scattering layer 13. By irradiating the photocurable tree composition 12 with the scattered light 10, the portion that is not cured by the collimated light 9 is cured. Since the refractive index adjusting portion 5 is already cured, the resin structure does not change.

After the exposure step, a heating step for heating the photocurable resin composition 12 can be added as necessary.
The heating step is preferably performed within 10 minutes after the irradiation of the collimated light 9 in the exposure step, and within 7 minutes from the viewpoint of suppressing the deactivation of the active species generated by the irradiation of the collimated light 9. More preferably, it is more preferably performed within 5 minutes.
The concentration in the heating step is preferably 40 ° C. or higher and 160 ° C. or lower, more preferably 50 ° C. or higher and 150 ° C. or lower, and further preferably 60 ° C. or higher and 140 ° C. or lower.
In the heating step, the heating time is preferably from 30 seconds to 10 minutes, more preferably from 40 seconds to 9 minutes, and further preferably from 50 seconds to 8 minutes.

[Optical integrator using light diffusing member]
As shown in FIG. 3, the optical integrator 14 according to the embodiment of the present invention cuts the light diffusing member 1 into a rectangular parallelepiped and a cube, and enters the incident light 3 from the incident surface 2. Outgoing lights 6 and 7 having uniform in-plane luminance can be obtained from the opposing outgoing faces 4. The incident light 3 is refracted and diffused in the optical integrator 14, but if the light reaching the wall surface is equal to or greater than the critical angle, it is reflected from the inner surface and does not leak. By adjusting the spread angle of the light diffusing member 1 so that it does not fall below the critical angle, leakage light can be reduced and the optical integrator 14 having high light transmission efficiency can be obtained.

  The shape of the optical integrator 14 is not particularly limited. However, when the exit surface 3 is tapered so as to be larger than the entrance surface 2, it is possible to obtain exit light having a large amount of collimated light components. By making the shape of the optical integrator 14 a gentle arch and providing an angle difference between the entrance surface normal and the exit surface normal, a function of changing the direction of the outgoing light beam can be provided.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist.

<Production of light diffusion member>
<< Photo-curable resin composition (no particles) >>
As a compound having a photopolymerizable functional group, KAYARAD DPCA-20 (Nippon Kayaku Co., Ltd.) is 30% by mass, New Frontier PE-200 (Daiichi Kogyo Seiyaku Co., Ltd.) is 67% by mass, a photopolymerization initiator. IRGACURE 1173 (manufactured by BASF) was mixed with 2% by mass and Adeka Stub AO-80 (manufactured by ADEKA) was mixed with 1% by mass as an antioxidant, and the mixture was stirred for 3 hours with a mix rotor. This was designated as a photocurable resin composition (no particles).

<< Photocurable resin composition (with particles) >>
A predetermined proportion of polystyrene particle techpolymer SSX-302ABE (manufactured by Sekisui Plastics Co., Ltd.) is blended with the photocurable resin composition (without particles). After putting in an ultrasonic generation tank and irradiating with ultrasonic waves for 10 minutes, the mixture was stirred for 3 hours with a mix rotor. This was designated as a photocurable resin composition (with particles).

"exposure"
A blue plate glass plate, a silicone rubber sheet with a central portion cut into a 40 mm square, and a blue plate glass plate were stacked in order to obtain a molding die (support member).
The upper blue plate glass plate was shifted and the photocurable resin composition was poured, and the upper blue plate glass plate was put back again and sealed.
This was irradiated with collimated ultraviolet rays using a high pressure mercury lamp as a light source using EXM-1201-F02-02 (manufactured by Oak Manufacturing Co., Ltd.). Continuous irradiation was performed until the integrated exposure amount reached a predetermined amount.
Irradiation from one side was set as the first exposure, and after the first exposure, additional exposure (this was set as the second exposure) was performed from the other side as necessary.
In addition, when scattered ultraviolet rays were applied as necessary, a lens diffuser plate (manufactured by Optical Solutions Co., Ltd., half-value angle 20 degrees) as a scattering layer was placed between the mold for molding and the exposure light source and irradiated with ultraviolet rays.
After the exposure, it was removed from the mold and used as a light diffusing member.

《Cutting》
The obtained light diffusing member was cut with a dicer DAC552 (manufactured by DISCO Corporation). The light diffusing member was cut under the following conditions.
Dicing blade: particle size # 5000
Rotation speed: 30,000rpm
Cutting speed: 0.5mm / sec
Light diffusion member thickness: 2.0 mm
Light diffusing member width: 40 mm x 40 mm

<Evaluation of outgoing light spread angle>
Using an NA measurement device (manufactured by Synergy Opto Systems Co., Ltd.), the spread angle (0 to 30 degrees) of the emitted light and the luminance at each angle were measured. In addition, incident light used the red laser, and irradiated the 1st exposure surface within the range of 0 degree to 1 degree.
The direction with the highest luminance in the emitted light is defined as an emission angle of 0 degree, and the luminance from 0 degree to an arbitrary angle φ degree is integrated to define the light quantity S (φ) at φ degree.
The light quantity S (φ) at the maximum measurable angle is defined as the total light quantity, and φ where the light quantity S (φ) is 90% of the total light quantity is defined as the outgoing light spread angle φ (90).

<Evaluation of emitted light uniformity>
Similar to the step of evaluating the outgoing light spread angle, the outgoing light spread angle and the luminance at each angle were measured. 100 × (minimum luminance / maximum luminance) was defined as the emitted light uniformity (%) in the luminance from 0 degree to φ90.

Example 1
The photocurable resin composition (without particles) was exposed to collimated light having a first exposure amount of 120 (mJ / cm ² ) to produce a light diffusing member of Example 1. And the emitted light spreading angle in the light-diffusion member of Example 1 was measured, and the emitted light uniformity was calculated.
FIG. 4 shows the measured cumulative luminance by angle. From this measurement result, the outgoing light spread angle φ (90) was 7.2 degrees.
FIG. 5 shows the measured luminance distribution for each angle. From this measurement result, the maximum luminance value from 0 to 7.2 degrees was 2,834, the minimum luminance was 524, and the emitted light uniformity was 18.5 (%).

(Example 2)
A diffusion film (manufactured by Optical Solutions Co., Ltd., half-value angle: 20 degrees, product name: lens diffusion plate) was pasted on the emission surface of the light diffusing member produced in Example 1 to produce the light diffusing member of Example 2. And the outgoing light spreading angle and outgoing light uniformity in the light diffusion member of Example 2 were measured and calculated.
The outgoing light spread angle was 21.0 degrees, and the outgoing light uniformity was 11.5%.

Example 3
The photocurable resin composition to (no particles), and exposure processing by the scattered light of the collimated light of the first exposure 60 (mJ / cm ^2), the second exposure 61 (mJ / cm ^2), Example 3 A light diffusing member was prepared. And the outgoing light spreading angle and outgoing light uniformity in the light diffusion member of Example 3 were measured and calculated.
The outgoing light spread angle was 3.5 degrees, and the outgoing light uniformity was 8.5%.

(Example 4)
The photocurable resin composition (without particles) was exposed to light with a first exposure amount of 26 (mJ / cm ² ) collimated light and a second exposure amount of 90 (mJ / cm ² ) of scattered light. Example 4 A light diffusing member was prepared. And the emitted light spreading angle and emitted light uniformity in the light diffusing member of Example 4 were measured and calculated.
The outgoing light spread angle was 2.3 degrees, and the outgoing light uniformity was 7.9%.

(Comparative Example 1)
A light diffusing member of Comparative Example 1 was prepared in the same manner as in Example 1 except that the photocurable resin composition (containing particles) (particle concentration 0.01%) was used. And the emitted light spreading angle and emitted light uniformity in the light diffusing member of Comparative Example 1 were measured and calculated.
The outgoing light spread angle was 6.0 degrees, and the outgoing light uniformity was 4.4%.

(Comparative Example 2)
A light diffusing member of Comparative Example 2 was prepared in the same manner as in Example 2, except that the photocurable resin composition (containing particles) (particle concentration 0.15%) was used. And the emitted light spreading angle and emitted light uniformity in the light diffusing member of Comparative Example 2 were measured and calculated.
FIG. 6 shows the measured luminance distribution for each angle. The outgoing light spread angle was 20.7 degrees, and the outgoing light uniformity was 5.7%.

(Evaluation of Examples and Comparative Examples)
Table 1 shows the evaluation of the light diffusing member produced by various methods.
Example 1 has a larger divergence angle than that of Comparative Example 1, has a high diffusion effect, and high uniformity, so that light transmission efficiency is good, and light is more evenly diffused in a limited range of about 6 degrees. I understand that.
Example 2 has a larger divergence angle than Comparative Example 2, a high diffusion effect, and high uniformity, so that light transmission efficiency is good and light is more evenly diffused in a limited range of about 21 degrees. I understand that. Moreover, Example 2 can also be said to be an example showing that the diffusion angle of the light diffusing member of the present invention can be widely adjusted by combining conventional diffusing plates.
As in the third and fourth embodiments, the spread angle can be narrowed by reducing the exposure amount of parallel light and increasing the exposure amount of scattered light.
In all the examples, it was confirmed that the uniformity of the emitted light was high and evenly diffused with respect to any of the comparative examples.

  According to the light diffusing member, the optical integrator, and the manufacturing method thereof of the present invention, it is possible to easily provide a light diffusing member and an optical integrator that have good light transmission efficiency and can adjust the light diffusing angle.

DESCRIPTION OF SYMBOLS 1 ... Light diffusing member 2 ... Incident surface 3 ... Incident light 4 ... Outgoing surface 5 ... Refractive index adjustment part 6 ... Outgoing light (straight-ahead component)
7: Outgoing light (scattering component)
DESCRIPTION OF SYMBOLS 9 ... Collimated light 10 ... Scattered light 11 ... Support member 12 ... Photocurable resin 13 ... Scattering layer 14 ... Optical integrator

Claims (6)

A light diffusing member having an incident surface on which incident light is incident, and an exit surface that faces the incident surface and emits the incident light as emitted light,
The light diffusing member includes a refractive index adjusting unit having a refractive index different from that of the light diffusing member,
The refractive index adjuster is substantially cylindrical or conical, and a plurality of the refractive index adjusters are arranged so that the axial directions are substantially parallel.
The refractive index adjusting unit diffuses and emits light within 7.2 degrees from the exit surface with respect to the incident surface normal, and emits light of 7.2 degrees or more with respect to the entrance surface normal. Light diffusing member that emits straight from the light.   The light-diffusion member of Claim 1 provided with a diffusion plate in the said output surface. It is a manufacturing method of the light diffusing member according to claim 1 or 2,
An arrangement step of arranging the photocurable resin composition on the support member;
The manufacturing method of a light-diffusion member including the exposure process which irradiates collimated light to the said photocurable resin composition. The exposure step is a step of irradiating light to the photocurable tree composition from two directions,
The manufacturing method of the light-diffusion member of Claim 3 which irradiates scattered light from the other after irradiating the collimated light from one side.   The manufacturing method of the light-diffusion member of Claim 3 or 4 which adjusts the time which irradiates the said collimated light, and adjusts the length and density of the said refractive index adjustment part.   An optical integrator using the light diffusing member according to claim 1.