JP2022128167A - Light guide plate, surface light emitting device and manufacturing method for light guide plate - Google Patents

Abstract

To solve the problem that in order to exhibit an antibacterial effect with a light guide formed by arranging light diffusion dots in a pattern on the surface of a light-transmitting substrate, treatment with an antibacterial film or antibacterial agent changes an optical refractive index, which makes appearance worse.SOLUTION: A light guide plate is characterized in that a printing layer having a plurality of dots or holes comprises a binder resin, light diffusion material particles having a photocatalytic function with a higher optical refractive index than the binder resin, and as inorganic particles, hydrophobic fumed silica bound with a hydrophobic group, and a surface of the light guide plate is finely covered with a light emitting part made of the printing layer to exhibit an antibacterial effect on the surface of the light guide plate by a visible light responsive photocatalyst and a visible light LED light source.SELECTED DRAWING: Figure 3

Description

The present invention provides a light guide plate in which a light-emitting portion containing light-diffusing material particles that function as a photocatalyst is formed on the surface of a light-transmitting substrate by screen printing, a surface light-emitting device using the light guide plate, and the light guide plate. related to the manufacturing method of

2. Description of the Related Art Conventionally, various surface emitting devices have been used for display devices such as liquid crystal display devices that require planar illumination. In particular, a surface emitting device arranged on the back surface of a liquid crystal display panel of a mobile phone, a smart phone, a notebook computer, or a TV is well known as a backlight unit. In addition, a front light unit that emphasizes the translucency of the light guide plate itself, which illuminates the display from the front, lighting using light from both sides of the light guide plate, and information such as pictograms are displayed. A surface emitting device is also used for a double-sided emitting panel such as a pictogram.

FIG. 14 is a schematic cross-sectional view showing the configuration of a surface emitting device 1 used in a typical front light unit according to the prior art. A liquid crystal display element 2 and a reflection sheet 3 are arranged in the lower part of the surface emitting device 1, and it has a light guide plate 4 and an LED light source 5. The structure is such that the inside of the light guide plate 4 is irradiated from the portion 6 .

15 is a plan view of the surface light-emitting device 1 viewed from above, and a partially enlarged cross-sectional view of the light guide plate 4 of FIG.

As shown in FIGS. 15 and 16, on the upper surface of the light guide plate 4, dots 7 containing light diffusion material particles are patterned and formed, and the light incident end surface 6 facing the LED light source 5 is smoothly polished. A reflective tape 9 is attached to the remote end face portion 8 facing the light incident end face portion 6 and other end face portions.

Next, the state of light in the configuration of such a conventional surface emitting device 1 will be described.

When the light from the LED light source 5 enters the light guide plate 4 made of a translucent substrate such as acrylic resin as incident light from the light incident end surface 6, the light passes through the acrylic resin plate due to the difference in the optical refractive index between the acrylic resin and the air. The light that is totally reflected and reaches three end face parts including the separated end face part 8 of the side wall is reflected by the reflection tape 9 and is reflected inside the light guide plate 4 to return to the inside of the light guide plate 4 and try to be confined.

However, when the incident light hits the plurality of dots 7 containing the light diffusing material particles formed on the upper surface of the light guide plate 4, the light diffusing material particles contained in the dots 7 or the irregularities formed on the surface of the dots 7 , diffuses and diffuses reflection. As a result, the light that is diffused and irregularly reflected and strikes the lower surface of the light guide plate 4 at an angle close to the vertical is emitted from the lower surface, and the light that has passed through the dots 7 is emitted from the upper surface of the light guide plate 4 as emitted light. The emitted light emitted from the lower surface illuminates the liquid crystal display element 2, is reflected by the reflection sheet 3, passes through the liquid crystal display element 2 again, returns to the light guide plate 4, and joins the emitted light as light from the upper surface. Become.

When there are dots 7 containing light diffusion material particles thinly formed on the entire upper surface of the light guide plate 4, a relatively large amount of light is reflected on the surface of the light diffusion material particles and emitted downward from the lower surface, thereby improving the liquid crystal display. Since the element 2 is efficiently illuminated, it can serve as a front light.

The light guide plate 4 used in such a conventional surface emitting device 1 has dots 7 formed on the surface of the translucent substrate by a screen printing method. It is the mainstream to form a pattern arrangement so that the area ratio of the dots 7 is reduced and the area ratio of the dots 7 is gradually increased toward the remote end face portion 8 as the distance from the LED light source 5 is increased.

For such applications as front lights, there are an increasing number of lighting products that are used directly at the fingertips of people like tablets and smartphones, and are used in direct contact with the outside air. Such coronaviruses and Escherichia coli strains that cause mass food poisoning such as O-157 are causing a stir in the world. This is a big issue and an important need.

In addition, as antibacterial and antiviral products, there are antibacterial films with an adhesive layer whose surface is antibacterially treated, and spray type antibacterial agents. adheres to the surface, the refractive index of the light changes, and there is a problem that the emitted light is not uniform.

In order to solve the problem, in Patent Document 1, a lighting light emitting diode provided in the main body, an ultraviolet light emitting diode provided side by side in the main body, and a main body provided opposite to each of the diodes and a photocatalyst that is provided on the transparent body and transmits visible light.

Certainly, it is possible to save space if the illumination light-emitting diode and the ultraviolet light-emitting diode are provided side by side in the main body of the illumination device, and the illumination light-emitting diode emits continuous white visible light with a wavelength of 380 to 780 nm. Because it is a thing, the inside of the warehouse becomes bright. In addition, the ultraviolet light emitting diode emits near ultraviolet light with a wavelength of 360 to 380 nm, and the photocatalyst is effectively excited by the light, so that it can exhibit functions such as deodorization, sterilization, and antifouling. .

However, in the case of a configuration in which the photocatalyst provided on the translucent body is illuminated from behind, the effective area that can be used for lighting with a single light-emitting diode becomes very small, and the area that can be used as illumination is very small, considering the directivity of the light emitted from the light-emitting diode. In order to commercialize it as lighting, a large amount of light emitting diodes for lighting and ultraviolet light emitting diodes are required, so it is difficult to say that it saves space. In addition, since the photocatalyst is provided on the entire surface of the translucent body, the transparency is lost, and if the photocatalyst is mainly composed of titanium oxide, it emits near ultraviolet rays with a wavelength of 360 to 380 nm using an ultraviolet light emitting diode. However, it becomes less active. In addition, although it is possible to increase the emission intensity of near-ultraviolet light by adjusting the voltage, there are data indicating that irradiation from behind affects the human body, especially the eyes, and is problematic.

In addition, when the photocatalyst film or photocatalyst particles are used in close contact with the material, there is no problem on the inorganic substrate, but with the exception of some organic materials, the photocatalyst film or photocatalyst particles are generally supported on the organic substrate. When used as such, the surface portion of the organic substrate deteriorates due to the photocatalytic action, and various problems arise. Specifically, when the surface portion of the organic substrate deteriorates, the photocatalyst layer existing thereon loses its footing, and the photocatalyst particles fall off. In addition, as a result, the functions such as antifouling, antibacterial, and deodorizing properties, which are the purposes of photocatalysis, are lost. is also lost.

In Patent Document 2, an LED light source consisting of a near-ultraviolet LED that emits light with a peak wavelength of 350 to 390 nm and a white LED that emits visible white light, the LED light source is arranged at the side end, and the light from the light source It has a surface light emitter that emits light, and the light emission time of a near-ultraviolet LED that emits light with a peak wavelength of 350 to 390 nm is 1/100 to 99/100 per unit light emission time of a visible light or white light LED. A display that is controlled to be

In addition, an LED light source is disposed at the side end, and the surface light emitter is composed of a base material layer containing a light diffusing agent and a coating layer, and emits light by light from the LED light source. By controlling the thickness ratio of 1/300 to 1/7 and the ratio of the light scattering agent concentration of the coating layer to the light scattering agent concentration of the base layer to 100/1 to 2000/1, the LED A display body that uniforms luminance in the vicinity of the light source and in the remote surface is described.

Further, a display body is described in which the main surface of a surface light emitter is coated with a photocatalyst layer made of a photocatalyst composition containing a photocatalyst and a binder component. In the detailed description of the invention of Patent Document 2, TiO ₂ , ZnO, SrTiO ₃ , CdS, GaP, InP, GaAs, BaTiO ₃ , BaTiO ₄ , BaTi ₄ O ₉ can be used as photocatalysts. _{, K2NbO3 , Nb2O5 , Fe2O3 , Ta2O5} , _K3Ta3Si2O3 , _{WO3 , SnO2} , _{Bi2O3 , BiVO4 , NiO} , _Cu2O , Layered oxides containing at least one element selected from SiC, MoS ₂ , InPb, RuO ₂ , CeO ₂ , Ta ₃ N ₅ , Ti, Nb, Ta and V (JP-A-62-74452 Publications, JP-A-2-172535, JP-A-7-24329, JP-A-8-89799, JP-A-8-89800, JP-A-8-89804, JP-A-8-198061, JP-A-9-248465, JP-A-10-99694, JP-A-10-244165, etc.) and nitrogen-doped titanium oxide (JP-A-13-278625, JP-A-13-278627, Patent Visible light responsive type such as oxygen-deficient titanium oxide (see JP-A-13-335321, JP-A-14-029750, JP-A-13-207082, etc.) and oxygen-deficient titanium oxide (see JP-A-13-212457) A titanium oxide photocatalyst can also be suitably used, and oxynitride compounds such as TaON, LaTiO ₂ N, CaNbO ₂ N, LaTaON ₂ and CaTaO ₂ N, and oxysulfide compounds such as Sm ₂ Ti ₂ S ₂ O ₇ . has high photocatalytic activity with visible light, and many photocatalytic species are described as being suitable for use.

Furthermore, these photocatalyst materials are added or immobilized with metals such as Pt, Rh, Ru, Nb, Cu, Sn, Ni, Fe and/or their oxides, or coated with porous calcium phosphate or the like. It is described that a photocatalyst material (see JP-A-10-244166) or the like can also be used.

Further, the photocatalyst is preferably a modified photocatalyst modified with a modifier compound, and the modification of the photocatalyst means fixing one modifier compound on the surface of the photocatalyst particles. Immobilization of the modifier compound on the surface of the photocatalyst particles is believed to be due to Van der Waals force (physical adsorption), Coulomb force, or chemical bond. Modification using chemical bonding is particularly preferred because the modifier compound and the photocatalyst interact strongly, and the modifier compound is firmly immobilized on the surface of the photocatalyst particles.

In this display, by using a modified photocatalyst as the photocatalyst, when a photocatalyst layer containing a photocatalyst is formed on the surface emitter, the concentration of the photocatalyst in the photocatalyst layer changes from the side in contact with the surface emitter to the other side. It is preferable because it facilitates the formation of a structure that becomes higher toward the exposed surface of the photocatalyst layer, and the modified photocatalyst can be efficiently present on the surface (exposed surface) of the photocatalyst layer.

Moreover, it is said that it is preferable to use a photocatalyst sol instead of a photocatalyst powder as the photocatalyst for the following reasons. In general, powders consisting of fine particles form secondary particles in which single crystal particles (primary particles) are strongly agglomerated, so many surface properties are wasted. is difficult to On the other hand, in the case of photocatalyst sol, the photocatalyst particles do not dissolve and exist in a form close to primary particles, so the surface characteristics can be effectively used, and the modified photocatalyst generated from it has dispersion stability, film formation properties, etc. It is described that it can be preferably used because it not only excels in the ability to function, but also effectively exhibits various functions.

Further, in the photocatalyst composition, it is highly preferable to select a resin having a surface energy greater than that of the modified photocatalyst by 2 mN/m or more, preferably 5 mN/m or more, as the compound that can be used as the binder component, because the self-tilting property increases. Examples thereof include various monomers, synthetic resins, natural resins, and the like, and those which are cured by drying, heating, moisture absorption, light irradiation, etc. after formation of the film can also be mentioned. In addition, the form may be a solvent-free state or a form dissolved or dispersed in a solvent. Specifically, silicone resins, acrylic resins, methacrylic resins, fluororesins, alkyd resins, aminoalkyds. Resin, vinyl resin, polyester resin, styrene-butadiene resin, polyolefin resin, polystyrene resin, polyketone resin, polyamide resin, polycarbonate resin, polyacetal resin, polyether ether ketone resin, polyphenylene oxide resin, polysulfone resin, polyphenylene sulfone resin, poly Ether resins, polyvinyl chloride resins, polyvinylidene chloride resins, urea resins, phenol resins, melamine resins, epoxy resins, urethane resins, silicone-acrylic resins, etc., and natural polymers such as nitrocellulose. cellulose-based resins, isoprene-based resins such as natural rubber, protein-based resins such as casein, and starch. Phenyl group-containing silicone (BP) is the best because it has a higher surface energy than the modified photocatalyst and the siloxane bond (-O-Si-) that forms the skeleton does not undergo oxidative decomposition due to photocatalysis. ,a.

The content described in the above Patent Document 2 will be considered.

Certainly, if the light emission time of an LED that emits light with a peak wavelength of 350 to 390 nm is controlled to be short per unit light emission time of a visible light or white light LED, the surface of the organic substrate will be decomposed by photocatalysis. less problems.

However, controlling the irradiation time to a short time shortens the time during which the photocatalyst is activated at the same time, sacrificing the original deodorizing effect, decomposition of organic matter, and antibacterial effect, so it can be a good countermeasure. I didn't.

In addition, it is certainly a surface light emitter in which an LED light source is arranged at the side end, is composed of a base material layer containing a light diffusing agent and a coating layer, and emits light by light from the LED light source. If the ratio of the thickness of the coating layer to is made as small as possible and the ratio of the light scattering agent concentration in the coating layer to the light scattering agent concentration in the base material layer is controlled to increase, the luminance between the vicinity of the LED light source and the separated surface is It tends to be uniform.

In addition, it is possible to place an LED light source on the side edge and use it as a surface light emitter (light guide plate) that emits light from the light, and increase irregular reflection by controlling the concentration of the light diffusion material, and spread the low directivity of the LED light to the light guide plate. It is possible to illuminate even a large area, which is advantageous in terms of cost.

However, no matter how much the gradient technology is used to search for and apply materials that are compatible with each other, simply controlling the ratio of the base layer and the coating layer in the thickness direction of the light-emitting body will not change the thickness. Even if the density of the light diffusing substance is controlled with respect to the direction to make it easier for light to pass through depth, the amount of light diffusely reflected toward the depth from the vicinity of the LED light source attenuates and becomes darker toward the depth. Problems remained and could not be resolved.

Further, a display body in which the main surface of a surface light emitter is coated with a photocatalyst layer made of a _{photocatalyst} composition containing a photocatalyst and a binder component is described. In addition to Fe ₂ O ₃ , WO ₃ and the like, layered oxides containing at least one element selected from Ti, Nb, Ta and V, nitrogen-doped titanium oxides, and oxygen-deficient titanium oxides. Such visible light responsive titanium oxide photocatalysts can also be suitably used, and these photocatalyst materials include metals such as Pt, Rh, Ru, Nb, Cu, Sn, Ni and Fe, and/or oxides thereof. It is also possible to use photocatalyst materials that are added or immobilized with substances, or coated with porous calcium phosphate, etc., but after all, if they exhibit activity as photocatalysts when mixed with organic substances. It will degrade the organic matter.

In addition, by making this photocatalyst a modified photocatalyst that has been modified using a modifier compound, the interaction between the modifier compound and the photocatalyst is strong, and the modifier compound is firmly immobilized on the surface of the photocatalyst particles. By selecting a compound that is considered preferable and can be used in an appropriate amount for the binder component, grading is used to facilitate the formation of a structure in which the concentration of the photocatalyst increases from the side in contact with the surface emitter toward the other exposed surface. Even so, it could not be a solution for improving uniformity of light as a light guide plate.

In Patent Document 3, a lighting device including a light guide plate and an LED light source unit provided on a side surface of the light guide plate, wherein a photocatalyst is disposed at a position through which light rays emitted from the light guide plate pass, The LED light source unit emits a pair of white LED units provided on opposite sides of the light guide plate and a pair of ultraviolet light rays provided on the opposite sides of the light guide plate perpendicular to the white LED units. A lighting device is described in which a plurality of reflective dots are formed on a reflective sheet.

Certainly, the photocatalyst is arranged at the position where the light beam emitted from the light guide plate passes, and the LED light source unit irradiates light with a wavelength that can excite the photocatalyst, from the side wall at the position perpendicular to the white LED, Since it is configured by irradiating an LED light beam containing ultraviolet rays, the photocatalyst is excited and the lighting device can have an air cleaning function. In addition, by patterning the dots on the surface of the reflective sheet, it is possible to uniform the illuminance in the vicinity of the LED light source and in the depth. A planar lighting device having a cleaning function and suitable for indoor use can be obtained.

However, this lighting device requires a diffusion sheet formed with a catalyst, which is a separate part from the light guide plate. In addition, if the same light guide plate is used, and a white LED and an LED beam containing near-ultraviolet rays are emitted from the side wall at a position perpendicular to the white LED, dots in the same dot pattern are used, so white light is used. Even if the uniformity of the entire light guide plate is maintained, only the vicinity of the light guide plate in the vicinity of the LED light source receives strong ultraviolet light due to the large refractive index of the blue LED light including near-ultraviolet light, and the LED light source that emits ultraviolet light. As it moves away from , the intensity becomes extremely weak. That is, there is a problem that only the vicinity of the ultraviolet LEDs of the light guide plate has an air cleaning effect, and a sufficient cleaning effect cannot be produced.

The present invention provides a light guide plate, a surface light emitting device, and their manufacture that have new functions that enable the antibacterial and antiviral properties of the surface of the light guide plate to be effective by using a photocatalyst responsive to visible light as a light diffusing material. It was developed as a method.
In addition, the screen printing ink has a function to prevent stains such as finger marks and fingerprints, and the light guide plate has a function to prevent finger marks and fingerprints from sticking to the entire surface including the printed layer of the light guide plate and the base surface of the light-transmitting substrate. A surface light-emitting device and its manufacturing method were developed in Japanese Patent No. 4800813, and the present invention corresponds to this invention as a function added thereto.

JP-A-2006-12511 JP 2007-273309 A JP 2013-114875 A

As shown in Patent Documents 1 to 3 above, as a normal flat lighting fixture, a lighting fixture in which the surface of the light guide plate that emits surface light with emitted light such as a front light is on the surface that is exposed to the outside air, In addition to antifouling and deodorizing effects, it is expected to have antibacterial and antiviral effects. The use of antibacterial films and antibacterial sprays for optical sheets can be seen in many products, but lighting fixtures that use a light guide plate and emit light from an LED light source, etc. It is said that it is difficult to adopt it for products because it causes light disturbance when attached.

Therefore, methods using photocatalysts have been proposed, and in addition to Patent Documents 1 to 3, there are many methods of using photocatalysts as light diffusing agents. It can be said that it is very efficient because it uses the light of lighting equipment, but the entire light-emitting surface as a lighting equipment maintains uniform brightness, and visible light is safe for producing antibacterial and antiviral effects. The photocatalyst cannot be activated by light alone, making it difficult to put it to practical use.

In particular, the surface of the light guide plate, which has been used in the past, is patterned with diffusive dots on the light transmissive plate to uniformly emit light. presumed to be difficult.

Moreover, even if the photocatalyst is activated, decomposition of the organic matter, which is the ink component resin used as the binder, occurs, causing chalking on the surface and causing deterioration.

Furthermore, while the development of photocatalysts that respond to visible light is progressing, if the photocatalyst is mixed with a binder and printed, the photocatalyst will be buried in the binder resin, and the original function as a photocatalyst will not work, resulting in an antibacterial effect. Not appearing was also a big problem.

Therefore, in order to solve the above-mentioned conventional problems, the present invention prints dots or the like that finely cover the surface of the light guide plate within the range of the printed layer so that uniform light can be extracted from the surface of the light guide plate. , by improving the ink composition for screen printing, by improving and using a photocatalyst responsive to visible light, and by devising a manufacturing method, the effect as a photocatalyst is maintained even on the printing surface, and the photocatalyst It is a light guide plate that forms a printed layer that does not fall off due to deterioration (choking) of the binder due to In addition, a light guide plate with a pattern design of diffusion dots is a light guide plate that maintains an antibacterial effect while emitting uniform surface light even though there are many parts that are not printed surfaces. An object of the present invention is to provide a surface light source device and a method for manufacturing a light guide plate thereof.

In order to solve the above problems, a light guide plate according to a first aspect of the present invention includes a printed layer having a plurality of non-printed substantially circular holes on at least one main surface of a light-transmitting substrate having both main surfaces. Alternatively, a printing layer comprising a plurality of printed substantially circular dots is provided, and the printing layer comprises a translucent binder resin, photocatalyst material particles, and light having a higher optical refractive index than the binder resin. The light guide plate includes diffusing material particles and inorganic particles having a refractive index similar to that of the binder resin and having a hydrophobic group bonded thereto.

According to this configuration, the non-printed portion is a non-light-emitting portion that does not diffuse light, and the printed portion is a light-emitting portion, making it easy to control the brightness depending on the printed area. In addition, the light diffusion material particles, which have a higher optical refractive index than the binder resin contained in the printed layer, diffuse and diffusely reflect the light guided into the light guide plate to ensure the necessary brightness intensity, and the light diffusion material particles A predetermined content provides a light-emitting portion with stable luminance.

In addition, the photocatalyst material particles are activated by receiving diffused and irregularly reflected light, thereby inactivating bacteria and viruses adhering to the surface. The photocatalyst material particles do not have a specified optical refractive index, but even if they have the same optical refractive index as the binder resin, there are some that exhibit light diffusion depending on the state of the clusters that form the mass of the particles. Modifications such as doping metal ions, etc., or supporting metal particles in material particles change the light refractive index, so depending on the degree of brightness, the balance with light diffusion material particles should be considered. In this way, both the photocatalyst effect and the light diffusion effect are achieved.

Inorganic particles with a hydrophobic group bonded thereto have a refractive index similar to that of the binder resin and have little light diffusion effect. Since it prevents the sagging necessary for printing, it plays a role in making the printed layer thin.

In addition, as a role of the inorganic particles, by mixing a relatively large amount of inorganic particles, a part or the entire surface of the photocatalyst material particles is interposed to coat the photocatalyst material particles, so that the ink is transparent. It also plays a role of preventing chalking of the binder resin having lightness. If the photocatalyst material particles are in direct contact with the organic matter, the activity of the photocatalyst degrades the binder resin.

In the present invention, the term "light guide plate" is not limited to a "plate" in the usual sense, but also includes a smaller thickness such as "sheet" and "film", or a flexibly bendable object. Used as an inclusive. In addition, in the present invention, the term “light transmissive” is not limited to being colorless and transmitting light. However, it also widely includes those that retain the property of being permeable. Moreover, the "printing layer" indicates the entire printed area on at least one main surface, and includes both the "light-emitting portion" and the "non-light-emitting portion". The 'light-emitting portion' refers to a portion of the printed layer where the actual printed matter is formed, that is, the dot-forming portion covering the base surface portion of the main surface, or a portion other than the hole portion, and the 'non-light-emitting portion' refers to the dot It refers to the outer surface of the forming part or the base portion of the main surface on which the printed material is not formed on the inner surface of the hole.

A light guide plate according to a second aspect of the present invention includes a printed layer having a plurality of non-printed substantially circular holes on at least one main surface of a light-transmitting substrate having both main surfaces, or a plurality of printed holes. A printing layer made up of substantially circular dots is provided, and the printing layer has a binder resin having translucency and a higher optical refractive index than the binder resin, and is doped with metal ions or the like, or carries metal particles. a light diffusing material particle having a photocatalytic function; and inorganic particles having a light refractive index similar to that of the binder resin and having a hydrophobic group bonded thereto.

According to this configuration, as with the light guide plate according to the first aspect of the present invention, the non-printed portion is a non-light-emitting portion that does not diffuse light, and the printed portion is a light-emitting portion, making it easy to control the brightness by changing the printed area. becomes. In addition, the light diffusion material particles, which have a higher optical refractive index than the binder resin contained in the printed layer, diffuse and diffusely reflect the light guided into the light guide plate to ensure the necessary brightness intensity, and the light diffusion material particles It is intended to provide a planar light-emitting portion having a stable luminance with a predetermined content.

In addition, since the light diffusing material particles themselves have a photocatalytic effect, the photocatalytic function of the light diffusing material particles works and is activated by receiving diffused and irregularly reflected light, thereby eliminating bacteria and viruses adhering to the printing surface that is in contact with the outside air. It is revitalizing. In general, some photocatalyst particles have the same optical refractive index as the binder resin, but depending on the state of the clusters that form a mass of particles, there are some that exhibit light diffusion. In addition, since the optical refractive index changes due to modification such as carrying metal particles, depending on the results of luminance measurement by trial and error, pattern arrangement design with changed printing density of dots or holes, or light diffusion By considering the balance of the concentration of the substance particles, both the photocatalyst effect and the light diffusion effect are achieved.

As in the first aspect of the present invention, the hydrophobic group-bonded inorganic particles have a refractive index similar to that of the binder resin and have little light diffusion effect, but are included in the solution of the screen printing ink. When this is done, thixotropic properties are exhibited to prevent sagging, which is necessary for ink properties, so it plays a role in making the printing layer a thin film.

In addition, as the role of the inorganic particles, as described in the light guide plate related to the first aspect, by mixing a relatively large amount of inorganic particles, part or the entire surface of the photocatalyst material particles is coated. Therefore, it plays a role of preventing chalking of the binder resin having translucency as ink. If the photocatalyst material particles are in direct contact with the organic matter, the organic matter deteriorates.

In the light guide plate according to the third aspect of the present invention, within the range of the printed layer, the holes are independent one by one, and are formed in a pattern arrangement under predetermined conditions, and the inner surfaces of the plurality of holes 3. The light guide plate according to claim 1, wherein the base portion of the main surface of the transparent substrate is formed.

According to this configuration, since the holes in the printed layer are independent one by one, the inner surface of each hole becomes the main surface base portion of the translucent substrate and becomes a non-light-emitting portion, so that the light-emitting portion and the non-light-emitting portion can be distinguished. becomes clear. It is convenient because it is easy to calculate the area ratio of the non-light-emitting portion in the printed layer to form a pattern arrangement from the light incident end surface to the distant end surface. That is, since there is a proportional relationship between the area ratio of the light-emitting portion with respect to the printed layer area in each portion of the main surface and the luminance intensity of the light, the total area of the inner surface of the hole of the main surface base portion, which is the non-light-emitting portion, and the actual area of the light-emitting portion It is possible to calculate and logically change the ratio, and it is possible to design a pattern arrangement with predetermined conditions by summing the number of holes and the area of each hole on the surface of the transparent substrate, and the brightness of the light guide plate surface can be easily achieved. and uniformity can be controlled.

In the light guide plate according to the fourth aspect of the present invention, within the range of the printing layer, the dots are independent one by one and are formed in a pattern arrangement under predetermined conditions, and the plurality of dots are formed. The outer surface serves as the base portion of the main surface of the translucent substrate.

According to this configuration, the dots of the printed layer are independent one by one, the dots are the light-emitting portion, and the dot forming outer surface portion is the main surface base of the translucent substrate and is the non-light-emitting portion, and the light-emitting portion and the non-light-emitting portion This is convenient because the area ratio of the non-light-emitting portion can be easily obtained by calculation of the pattern arrangement from the light-incident end face to the remote end face. That is, by calculating the total area of the dots that are the light-emitting portion and the actual area of the dot-formed outer surface portion of the non-light-emitting portion and logically changing the ratio, it is possible to design the pattern arrangement under predetermined conditions, and the light guide plate can be easily designed. Surface brightness and uniformity can be controlled.

In the light guide plate according to the fifth aspect of the present invention, within the range of the printed layer, the main surface base portion other than the printed dots or the main surface base portion of the hole not printed has a thickness of 2 mm or more. It is the size of the adjacent dots or the size of the hole that cannot draw a virtual circle with a diameter dimension.

Normally, photocatalyst material particles or light diffusing material particles having photocatalytic function are not interposed in the main surface base portion other than the printed dots, or in the main surface base portion of the holes that are not printed, so it is expected to have a photocatalytic effect. No antibacterial or antiviral effect is observed, and such bacteria adhering to the main surface substrate cannot be inactivated. However, as in this configuration, if the distance is about 1 mm from the printed dot part, a part of the antibacterial agent doped with metal ions is eluted, and the growth inhibition zone (halo) of bacteria is formed. By generating, the antibacterial effect of the entire printed layer is maintained.

Single-component photocatalysts such as titanium oxide, which have been used in the past, did not form growth-inhibitory zones even when activated by exposure to light. is doped, and as listed in paragraph (0031), the growth inhibition zone of bacteria appears due to the elution of those metal ions, and the growth inhibition zone of 1 mm or more is generally present. .

In the light guide plate according to the sixth aspect of the present invention, the hydrophobic fumed silica, which is one of synthetic amorphous silica, is used as the inorganic particles to which the hydrophobic groups are bonded.

According to this configuration, the hydrophobic fumed silica, which is one type of synthetic amorphous silica and has a hydrophobic group bonded to it, has almost the same optical refractive index as the light guide plate material and the acrylic resin used as the binder resin. Translucency is maintained without interfering with transmission. In addition, since it is a commercially available general-purpose inorganic particle, it is relatively inexpensive, and since it is a solid, there is no adverse effect on the surface that changes the optical refractive index such as a blade phenomenon like a liquid additive. do not have.

In addition, hydrophobic fumed silica exhibits thixotropic properties when contained in the solution of screen printing ink, prevents sagging necessary for ink properties, and makes it possible to add a large amount of solvent components, so after screen printing It is possible to finish the printing thickness thinly.

In addition, hydrophobic fumed silica has a strong cohesive force, and is coated so as to be adsorbed on the surface of the photocatalytic substance particles and light diffusing substance particles by mixing with the photocatalytic substance particles and light diffusing substance particles in advance. be. Therefore, when the photocatalyst is activated by light, it acts as a cushioning material between the binder resin in the printed layer and organic substances are less likely to be decomposed and deteriorated.

In the light guide plate according to the seventh aspect of the present invention, when the total weight of the binder resin, the photocatalytic substance particles, the light diffusing substance particles, and the hydrophobic fumed silica is taken as the printing layer weight, the The hydrophobic fumed silica is included in an amount of 5 wt % or more and 35 wt % or less with respect to the printed layer weight.

With this configuration, deterioration due to choking of the binder resin of the printed layer by the photocatalyst, which is the subject of the present invention, can be suppressed. That is, when the amount of hydrophobic fumed silica mixed is 5 wt% or more relative to the weight of the printing layer such as the binder resin, the effect of suppressing deterioration of the binder resin begins to appear, and when it is 5 wt% or less, sufficient suppression of deterioration of the binder resin cannot be exhibited. . Further, if the amount of hydrophobic fumed silica mixed is 35 wt % or more relative to the weight of the printing layer such as the binder resin, the printed matter becomes brittle and the ink properties do not allow screen printing.

In the present invention, the "print layer weight" is the amount of ink residue after drying after volatilization of volatile substances, and is the weight of the screen printing ink components excluding the amount of solvent. That is, it represents the amount of binder resin, photocatalyst material particles, light diffusing material particles, inorganic particles, and other small amounts of additives.

In the light guide plate according to the eighth aspect of the present invention, the binder resin contains an acrylic resin as a main component.

With this configuration, the acrylic resin has the same optical refractive index as that of the light-transmitting substrate, and the interface between the main surface of the light-transmitting substrate and the printed layer does not refract the light, and diffusely reflects the light. Also, since there is no adhesiveness, the translucency can be maintained, and the adhesiveness is also good.

A surface light-emitting device according to a ninth aspect of the present invention comprises a light guide plate according to any one of claims 1 to 8, light sources disposed on end surfaces in contact with both main surfaces of the translucent substrate, and the guide plate. A fixing jig comprising a housing body for supporting the one end surface of the light plate and the light source is provided.

According to this configuration, a light-transmitting substrate having both main surfaces, and a printed layer having light-emitting portions and non-light-emitting portions with a plurality of dots or holes are provided over at least one of the main surfaces of the light-transmitting substrate. The light guide plate surface has the effect that the light emitting portion receives light from the light source, activates the photocatalyst material particles, and inactivates bacteria and viruses attached to the surface.

A surface light-emitting device according to a tenth aspect of the present invention comprises the light guide plate according to any one of claims 1 to 8, visible light and a white LED light source; and a first fixing jig supporting the one end surface of the light guide plate and the visible light and white LED light sources; A second fixing jig that supports a UV-LED light source that emits near-ultraviolet light with a peak wavelength of 350 to 390 nm is provided on one end surface of the UV light guide plate, and the A reflecting sheet is provided on the opposite surface of the UV light guide plate.

According to this configuration, as in the ninth aspect, the light-transmitting substrate having both main surfaces, and the light-emitting portion and the non-light-emitting portion formed of a plurality of dots or holes are formed on at least one of the main surfaces of the light-transmitting substrate. The light guide plate surface provided with the printed layer has the effect that the light emitting part receives light from the light source and activates the photocatalyst material particles to inactivate bacteria and viruses attached to the surface.

Furthermore, the surface emission of the light from the UV light source by the UV light guide plate further activates the photocatalyst material particles in the printed layer, thereby further enhancing the antibacterial effect of the printed surface of the light guide plate. . In addition, since the light from the UV light source has a different refractive index from the light from the visible light LED, if a light guide plate with the same pattern arrangement is used for the UV light source, the UV intensity will be strong only near the light source, and the light will not reach deep inside. The antibacterial effect in the part is weakened. Therefore, uniform UV intensity can be obtained by using a light guide plate dedicated to the UV light source. A light guide plate exclusively for UV is a light guide plate in which a dot pattern with a relatively low print density is arranged using screen printing ink containing a few percent of a diffusing agent such as titanium oxide.

A method for manufacturing a light guide plate according to an eleventh aspect of the present invention includes a first step of mixing inorganic particles having thixotropic properties to which hydrophobic groups are bonded and a solvent to prepare a solution composition (S); a second step of preparing a light diffusing material paste (P) by mixing the solution composition (S) with the light diffusing material particles doped with metal ions or supported with metal particles and also serving as a photocatalyst; , a third step of mixing the clear ink for screen printing (C) mainly containing the binder resin and the light diffusion substance paste (P) to prepare a composite ink (G); A fourth step of printing and applying G) onto at least one main surface of a translucent substrate having both main surfaces by a screen printing method, and volatilizing a volatile substance such as a solvent of the composite ink (G). and a fifth step of solidifying to form a light guide plate having a printed layer made up of a plurality of dots or a printed layer made up of a plurality of holes on the surface of the translucent substrate, and synthesize the inorganic particles having thixotropic properties. It is one of amorphous silica, and the light diffusing substance particles which also serve as the photocatalyst substance particles coated with hydrophobic fumed silica to which hydrophobic groups are bound are distributed on the surface of the printing layer.

According to this configuration, by mixing a solvent composition containing a large amount of hydrophobic fumed silica for screen printing, it is possible to mix a large amount of solvent with respect to the weight of the printing layer, and in the state of the printing layer film after drying, Light diffusing material particles having photocatalytic function are distributed on the surface of the light emitting part of the printed layer, and not only are they effective as photocatalysts, but the inorganic particles of hydrophobic fumed silica are coated with the light diffusing material. Therefore, the binder resin, which is an organic matter, is prevented from deteriorating the photocatalyst.

In addition, by selecting hydrophobic fumed silica, which is one of the synthetic amorphous silicas that improve viscosity and thixotropic properties, as inorganic particles, composite ink for printing uses a large amount of monomer components and solvents in the binder resin. Even if it is contained in the resin, it has a thickening property and retains thixotropic properties, so it does not deteriorate printability.

That is, a diffusion ink for screen printing containing light diffusing substance particles having a photocatalytic function with a light refractive index greater than that of a binder resin, and a solution composition obtained by mixing a solvent and inorganic particles having thixotropic properties to adjust the viscosity are individually mixed. By blending in, it is possible to mix the amount of hydrophobic fumed silica that could not be conventionally with respect to the printed layer weight after volatilizing the solvent by drying. This makes it possible to reduce the thickness of the printed layer, and a relatively large number of light-diffusing substance particles having photocatalytic function are formed on the surface of the light-emitting portion, so that the photocatalytic function can be effectively utilized. It is possible to reliably exert antibacterial and antiviral effects. Moreover, the interposition of the inorganic particles around the light diffusing substance particles having photocatalytic function also suppresses deterioration of the binder resin, which is an organic substance.

As described above, according to the present invention, the surface of the light guide plate is finely covered with a printed layer having light-emitting portions and non-light-emitting portions, so that the light guide plate has an appropriate luminance intensity and a uniform and stable light-emitting surface. The light guide plate can improve the sanitary environment of the living space by exhibiting an antibacterial effect against dirt and germs adhering to the surface. In addition, a surface light-emitting device using it is inexpensive because it does not require a light diffusion sheet or a protective cover. Furthermore, it is possible to easily manufacture a light guide plate having appropriate luminance intensity and uniformity and antibacterial effect by a normal screen printing method.

1 is a schematic cross-sectional configuration diagram showing an example of a surface emitting device using a light guide plate according to a first embodiment of the present invention as a front light unit; FIG. FIG. 3 is a vertical cross-sectional view of a light guide plate portion according to the first embodiment of the present invention; FIG. 3 is a plan view showing an example of a light-emitting portion made of a printed layer in which a plurality of holes are formed in a pattern arrangement of the light guide plate according to the first embodiment of the present invention; FIG. 4 is an enlarged plan view showing a part of a plurality of holes of the light guide plate according to the first embodiment of the present invention; FIG. 4 is an enlarged cross-sectional view showing part of a plurality of holes of the light guide plate according to the first embodiment of the present invention; FIG. 3 is a schematic cross-sectional configuration diagram showing an example of a surface light-emitting device capable of emitting light from both sides, in which the light guide plate according to the second embodiment of the present invention is used as a pictogram; FIG. 5 is a vertical cross-sectional view of part of a light guide plate according to a second embodiment of the present invention; FIG. 10 is a plan view showing an example of a light-emitting portion made up of a printed layer formed by a pattern arrangement of a plurality of dots according to the second embodiment of the present invention; FIG. 8 is an enlarged plan view showing a part of a plurality of dot portions according to the second embodiment of the invention; FIG. 8 is an enlarged cross-sectional view showing a part of a plurality of dot portions according to the second embodiment of the present invention; FIG. 10 is a schematic cross-sectional configuration diagram showing an example of a surface emitting device to which a near-ultraviolet UV-LED light source and a UV light guide plate are added according to a third embodiment of the present invention; FIG. 4 is an enlarged cross-sectional view showing the state of the composite ink of the present invention applied to a translucent substrate surface by screen printing. FIG. 4 is an enlarged cross-sectional view showing the state of the ink solid content of the light-emitting portion that has been screen-printed using the composite ink of the present invention and dried. It is a schematic diagram showing the configuration of a typical surface emitting device according to the prior art. FIG. 2 is a vertical cross-sectional view of a light guide plate on which typical light diffusion dots are formed according to the prior art; FIG. 4 is a plan view of a light guide plate formed with typical light diffusion dots according to the prior art; It is a photograph showing the results of evaluating the antibacterial effect of the present invention using a stamp-type medium.

A first embodiment of the present invention will be described below with reference to FIGS. 1 to 5. FIG.

FIG. 1 is a schematic cross-sectional configuration diagram showing an example of a surface emitting device using a light guide plate according to the first embodiment of the present invention as a front light unit, and FIG. 3 is a plan view showing an example of a light-emitting portion made of a printed layer in which a plurality of holes are formed in a pattern arrangement in the light guide plate according to the first embodiment of the present invention; FIG. FIG. 5 is an enlarged plan view showing a part of a plurality of holes of the light guide plate according to the first embodiment, and FIG. 5 is an enlarged AA sectional view showing a part of the plurality of holes of the light guide plate according to the first embodiment of the present invention; is.

A surface light-emitting device 31 of the first embodiment illustrated in FIG. It is composed of a fixing jig 34 consisting of a body. The light emitting device 33 has a light guide plate 35 and an LED light source 36 . The inside of the light guide plate 35 is irradiated from the light incident end face portion 37 of the light guide plate 35 . The light guide plate 35 includes a light-transmitting substrate 38 made of, for example, a light-transmitting acrylic resin, and a lower surface 39 opposite to the non-light-transmitting display object 32 among both main surfaces of the light-transmitting substrate 38 . A printed layer 41 is formed on the upper surface 40 by a screen printing method to form a main surface base portion 53 that is a non-light-emitting portion and a light-emitting portion 42 .

It should be noted that since the light-transmitting substrate 38 is the main body of the light guide plate 35, the two are sometimes described without distinguishing between them. In the following description, as an example, the translucent substrate 38 is assumed to be a translucent acrylic resin plate.

The fixing jig 34, which is a housing body, integrally fixes the light guide plate 35 and the light emitting device 33, which is composed of the LED light source 36, and also has the role of protecting the end surfaces of the LED light source 36 and the light guide plate 35. There is no protective cover in the front opening 43 of the fixing jig 34, and the light guide plate 35 is attached so that the upper surface of the light guide plate 35 can be directly exposed to the outside air. 47. When it is desired to replace the opaque display object 32 inside the fixing jig 34 consisting of the housing body, the clasp 47 can be removed and the back plate 46 can be opened and replaced.

Since the light guide plate 35 itself decomposes dirt with a photocatalyst and has an antibacterial effect, the front opening 43 on the upper surface of the light guide plate 35 does not require a protective cover and is exposed to the outside air. becomes.

The LED light source 36 is connected by a power cord 48 to an ON-OFF switch 49 , a transformer 50 and an outlet 51 .

In the light guide plate 35 of the first embodiment, the entire upper surface 40 of the translucent substrate 38 is screen-printed with a printing layer 41 having a plurality of holes 52 having a main surface base portion 53 serving as a non-light-emitting portion and a light-emitting portion 42 . It is formed by The light-emitting portion 42 includes a translucent binder resin such as an acrylic resin, photocatalyst material particles, light diffusion material particles having a higher optical refractive index than the binder resin, and inorganic particles having a hydrophobic group bonded thereto. It is formed by printing using composite ink (G) for screen printing containing a large amount of solvent, and volatilizing the solvent by drying after printing.

Here, the photocatalyst material particles are light having energy greater than the energy gap between the conduction band and the valence band of the material, that is, when irradiated with excitation light with a shorter wavelength, valence electrons are generated by light energy. Electrons in the band are excited, producing electrons in the conduction band and holes in the valence band. Various chemical reactions are carried out by the reducing power of electrons and/or the oxidizing power of holes, and the above substances can be used like catalysts under excitation light irradiation, so they are called photocatalysts. . Titanium oxide is known as the most representative example.

In addition to titanium oxide, layered oxides containing at least one element selected from titanium, niobium, tantalum, and vanadium, as well as zinc oxide, iron oxide, tungsten oxide, etc., which can be used as photocatalysts. Visible light responsive titanium oxide photocatalysts such as nitrogen-doped titanium oxide and oxygen-deficient titanium oxide can also be suitably used. Metals such as tin, nickel, iron, and silver and/or oxides thereof added or immobilized, or photocatalyst materials coated with porous calcium phosphate or the like can also be used.

As shown in FIGS. 2 and 3, the entire upper surface 40 of the light guide plate 35 is screen-printed to form a plurality of holes 52 of the main surface base portion 53, which serve as non-light-emitting portions, and light-emitting portions 42 around them. A printed layer 41 is formed. The light incident end surface 37 facing the LED light source 36 is mirror-finished, and a reflective tape 55 is attached to the other two side wall end surfaces and the remote end surface 54 .

Further, the holes 52 in the printed layer 41 are formed independently one by one, and the main surface base portion 53, which is the non-light-emitting portion on the inner surface of the plurality of holes 52, is formed by exposing the main surface base of the translucent substrate 38. is.

In addition, although the entire upper surface 40 of the main surface of the light-transmitting substrate 38 is generally the printed layer 41, the area ratio of the main surface base portion 53, which is the non-light-emitting portion of the inner surfaces of the plurality of holes 52, to the printed layer 41 is different from that of the LED light source 36. A plurality of holes 52 are arranged in a fine pattern over the entire upper surface 40 of the translucent substrate 38 under the condition that the number of holes gradually decreases from the facing light incident end face portion 37 toward the opposing remote end face portion 54 .

Here, the inner surfaces of the plurality of holes 52 in the printed layer 41 form non-light-emitting portions that become the main surface base portions 53 of the translucent substrate 38, but the amount of light-diffusing substance particles in the screen ink may be adjusted. By forming dots of the same size as the plurality of holes 52 at the positions of the plurality of holes 52 and reversing the light incident end face portion 37 and the separated end face portion 53, substantially the same effect can be obtained. In this embodiment, the pattern design of a plurality of holes 52 is taken as an example, but there is no problem even in the pattern design of a plurality of dots as long as the entire main surface is finely covered, and it is not limited to the plurality of holes 52. do not have

4 is an enlarged plan view showing a part of the plurality of holes 52 of the light guide plate according to the first embodiment of the present invention, showing an enlarged enclosing portion (M) shown in FIG. . FIG. 5 is an enlarged sectional view showing a part of the plurality of holes 52 of the light guide plate according to the first embodiment of the present invention, and (M) shows the AA cross section of the enclosure.

The diameter (W) of the imaginary circle 56 drawn on the main surface base portion 53 serving as the non-light-emitting portion of the inner surfaces of the plurality of holes 52 formed in the printed layer 41 was set to 2 mm or less. In general, antibacterial agents containing metal ions, etc., have a bacterial growth inhibition zone called halo, and a visible light responsive photocatalyst doped with silver ions has a growth inhibition zone of 1 mm or more and is non-luminous. In order to spread the antibacterial effect to the main surface base portion 53 which becomes a part, the diameter of the imaginary circle 56 is set to 2 mm or less, and the distance from the end face of the light emitting portion 42 on both sides is set to 1 mm.

Titanium oxide particles were used as the light diffusion material particles having a higher optical refractive index than the binder resin. The optical refractive index of titanium oxide is about 2.7, which is nearly twice as large as the optical refractive index of about 1.47 for acrylic resins used as light guide plate materials and binder resins. However, the light is refracted and reflected at the boundaries, and light is emitted efficiently at the interfaces of the titanium oxide particles.

In addition, hydrophobic fumed silica, which is one of synthetic amorphous silica, was selected as the inorganic particles having a refractive index similar to that of the binder resin and having a hydrophobic group bonded thereto. Synthetic amorphous silica includes dry process silica and wet process silica. Both dry-process silica and wet-process silica have a primary particle size of several nanometers, but wet-process silica has a strong cohesive force and exists as secondary particles with a particle size of several micrometers. It is used as a reinforcing material, a filler such as matte, and a desiccant using its moisture adsorption power.

On the other hand, dry-process silica, also known as fumed silica, is loosely cohesive and has excellent dispersibility in liquids. A three-dimensional network structure is formed to increase the viscosity of the composition liquid, impart thixotropic properties, and is used to suppress sedimentation and prevent dripping of the liquid.

Hydrophilic silanol groups (Si--OH) and hydrophobic siloxane (Si--O--Si) exist on the surface of fumed silica. easily soluble in liquids. However, since the screen printing ink used for the light guide plate is generally solvent type, it is used after being modified with hydrophobic fumed silica. Hydrophobic fumed silica is obtained by reacting silanol groups with silane compounds such as chlorosilanes to bind hydrophobic groups represented by (Chemical Formula 1) to (Chemical Formula 3). Commercially available hydrophobic fumed silica to which a hydrophobic group is bound includes R972, R974, R809, R812, R202 manufactured by Nippon Aerosil Co., Ltd., and the like.

Silane compounds such as chlorosilanes are selected from dimethylsilyl, trimethylsilyl, dimethylpolysiloxane, dimethylsiloxane, aminoalkylsilyl, alkylsilyl, methacrylsilyl, and the like.

In general, regardless of whether it is hydrophilic or hydrophobic, fumed silica is used to adjust the viscosity of liquid compositions of paints and inks and as an anti-sagging agent in anticipation of its thixotropic effect. Therefore, when the total weight of the binder resin, the photocatalytic substance particles, the light diffusing substance particles and the hydrophobic fumed silica is defined as the printing layer weight, the mixing amount was 1 wt % or less with respect to the printing layer weight. However, there is no known example as a coating agent for photocatalytic substance particles. In the present invention, the cohesive force of the hydrophobic fumed silica in the solution is further exerted, and screen printing is performed with the ink property of excessive solvent to thin the printing layer 41, and the photocatalytic substance particle coating treatment agent is used. In order to obtain the effect, the mixed amount of the hydrophobic fumed silica was adjusted so as to be 5 wt % or more and 35 wt % or less with respect to the printed layer weight.

Next, the movement of light in the surface light emitting device 31 having such a front light unit structure and the functional action as the light guide plate 35 will be described.

First, when the outlet 51 is connected to the commercial power supply and the ON-OFF switch 49 is turned ON, the voltage changed to DC 12 V by the DC transformer 50 is applied to the LED light source 36 connected to the power cord 48 to light it.

Incident light entering the light guide plate 35 from the light incident end face portion 37 facing the LED light source 36 repeats total reflection within the light guide plate 35 due to the relationship between the refractive indices of the acrylic resin and the air, and is reflected by the remote end face. The light reaching the portion 53 and the side wall end face portion is reflected by the reflective tape 55 and bounced back inside the light guide plate 35 , and is usually confined inside the light guide plate 35 made of acrylic resin.

However, the photocatalyst material particles contained in the light-emitting portion 42 of the printed layer 41 having a plurality of holes 52 formed on the entire upper surface 40 of the light guide plate 35 opposite to the surface facing the opaque display object 32, When the light hits the particles of the light diffusing material, the light is diffused and diffusely reflected, dispersed above and below the light guide plate 35, and part of the light comes out as emitted light.

The light emitted to the lower surface 39 hits the opaque display target 32, brightly illuminates the surface of the display target 32, and is reflected upward. The reflected light passes through the light guide plate 35 at an acute angle, and the thickness of the printed layer 41 of the light emitting portion 42 is as thin as about 1 μm to 7 μm. Even if it is about 10%, the particle diameter is as small as 2 μm or less, so most of the light passes through without being greatly attenuated. It is viewed as a clean image.

However, in the case of diffused light, when light collides with one light-diffusing substance particle in the light-emitting portion 42, the light spreads greatly due to diffusion and irregular reflection, so that the surface of the light guide plate 35 is illuminated widely. In addition, since the light that does not collide with the light diffusing substance particles in the light-emitting portion 42 is totally reflected at the interface between the binder resin and the air, the plurality of main surface base portions 53 serving as non-light-emitting portions without the light-emitting portion 42 , toward the spaced end face 54 in the same manner as the face of the hole 52 of .

However, the light reflected by the display object 32 is incident on the light guide plate 35 of the main surface base portion 53, which is a non-light-emitting portion, at an acute angle, and is emitted. Since the print area ratio to the main surface is about 10%, even if the LED light source 36 is turned off, the print surface hardly interferes with visibility and the function as a front light is maintained.

That is, the particle size of the light diffusing material particles is small and the content is as small as 10% or less, and the printed light emitting portion 42 is thin and has almost no unevenness on the surface, so that the light emitting portion 42 occupies the entire surface of the light guide plate 35 . However, the light that does not collide with the light diffusing substance particles is totally reflected, so that the function of transmitting the light to the back remains, and a uniform and stable surface light emitter can be obtained.

In addition, the light directly directed upward is not the direct light from the LED light source 36, but the light diffused and diffusely reflected by the titanium oxide particles, which are the light diffusion material particles, and the image of the display object 32 as backlight. has little adverse effect on visibility. Therefore, the light transmittance is good both when it is lit and when it is extinguished, and it fully plays the role of the surface light emitting device 31 as a front light unit.

In addition, by using titanium oxide, which has a high light refractive index, as the light diffusing material particles contained in the light emitting portion 42 of the print layer 41, the effect of reflecting and diffusing light is obtained even if the particles are embedded in the binder resin. That is, the optical refractive index of titanium oxide is about 2.7, which is nearly twice as large as the optical refractive index of about 1.47 for acrylic resins used as light guide plate materials and binder resins. Even if it is, the light is diffused and diffusely reflected at the interface, so that the interface of the titanium oxide particles efficiently emits light in all directions. As other light diffusing substance particles with a high optical refractive index, iron oxide, copper oxide, zinc oxide, carbon, etc. can be considered, but titanium oxide is the most excellent in safety, color and translucency, but is limited. is not.

However, in the case of the present invention, about 10% of photocatalyst material particles and light diffusion material particles are contained, and a relatively large amount of inorganic material particles of hydrophobic fumed silica with high thixotropic properties are added, and the screen is used as an ink material with a large amount of solvent. Since printing is performed, the film thickness of the printed layer is about 2 μm after drying, and the photocatalyst material particles can be exposed without being buried in the resin, and the antibacterial effect of the photocatalyst can be maintained.

Also, the thickness (t) of the light-emitting portion 42 made of the printed layer 41 is set to 1 μm or more and 7 μm or less. If the thickness of the light-emitting portion is 1 μm or more, the height is almost equal to or greater than the diameter of the light-diffusing substance particles, and the photocatalyst substance particles tend to form clusters of single particles, and many of them are several microns in size. The photocatalytic function is also fully exhibited.

In addition, the size (W) of the diameter (W) of the virtual circle 56 drawn on the main surface base portion 53, which is the non-light-emitting portion on the inner surface of the plurality of holes 52 formed in the printed layer 41, is set to 2 mm or less. Due to the effect of the growth inhibition zone of 1 mm or more possessed by the photocatalyst responsive to visible light doped with , an antibacterial effect appears even in the main surface base portion 53 which is a non-light-emitting portion. That is, by forming many virtual circles 56 in the printed layer 41, the light transmittance as a front light is maintained, and the antibacterial property is also maintained by the halo effect of the photocatalyst.

Furthermore, when hydrophobic fumed silica, which is one type of synthetic amorphous silica, is used as the inorganic particles to which hydrophobic groups are bonded, in a state where it is solidified as the light emitting portion 42 of the printed layer 41 after drying, it is possible to transmit light. During the drying process, the photocatalyst material particles are coated with cohesive force without losing their properties, so that deterioration of the binder resin can be prevented.

In addition, hydrophobic fumed silica, which is one of the synthetic amorphous silicas, dissolves well in binder resin components and solvents, has a thickening effect in the state of ink for screen printing, and controls fluidity as a thixotropic agent. Since it prevents sagging, it is an inorganic particle that is convenient for use as an ink composition for screen printing with an excessive amount of solvent.

In addition, since it is a commercially available inorganic particle, it has high versatility and is relatively inexpensive, and since it is a solid, there is no adverse effect on the surface that inhibits the optical refractive index such as a blade phenomenon like a liquid additive. .

Conventionally, the mixing amount of fumed silica, which exerts a thixotropic effect as a viscosity adjustment and anti-sagging agent for liquid compositions of paints and inks, was 1 wt% or less of the printing layer weight such as the amount of binder resin. . However, the object of the present invention is to prevent deterioration of the binder resin by coating the surface of the photocatalytic substance particles and to form an ink layer with a low film thickness after drying. The printed layer 41 is formed so as to be 5 wt % or more with respect to the printed layer weight. As mentioned above, if the amount of hydrophobic fumed silica mixed is 5 wt% or less with respect to the weight of the binder resin, etc., the amount is not sufficient to wrap the photocatalytic substance particles, and if it is 35 wt% or more, the printed matter becomes fragile. As a result, the ink properties did not allow screen printing.

Inorganic particles of a light-transmitting material whose optical refractive index is similar to that of the binder resin include inorganic materials such as natural silicon oxide and glass beads, organic materials such as polystyrene and polycarbonate, or gel synthesis made by a wet method. Amorphous silica can be considered, but in order to maintain compatibility with a solvent and cohesive force, it is necessary to make it into nano-order fine powder, which increases the production cost.

In addition, expected functions such as thickening, thixotropy, and antifouling properties are insufficient unless hydrophobic fumed silica, which is one of the synthetic amorphous silicas, is used. Therefore, it is advisable to use hydrophobic fumed silica, which is one of the inexpensive and highly functional synthetic amorphous silicas already commercialized by Nippon Aerosil Co., Ltd., to which a hydrophobic group is bonded.

In addition, the main surface base portions 53, which are the non-light-emitting portions of the inner surfaces of the plurality of holes 52, are independent one by one and reach the main surface base of the translucent substrate 38, so that the light-emitting portions 42 and the non-light-emitting portions The main surface base portion 53 that becomes the part is clear, and it is convenient to calculate the pattern arrangement of the area ratio of the light emitting part 42 from the light incident end face to the distant end face. That is, since the area ratio of the light emitting portion 42 with respect to the area of the printed layer 41 and the luminance intensity of light have a proportional relationship, the actual area of the light emitting portion can be obtained by calculation based on the area ratio of the plurality of holes 52 and the logical ratio can be changed. The number of holes on the surface of the light-transmitting substrate 38 and the sum of the area of each hole makes it possible to easily design a pattern arrangement under predetermined conditions, and to control the brightness and uniformity of the surface of the light guide plate 35. can be done.

In the first embodiment of the present invention, the light-emitting portion 42 made of the printed layer 41 having a plurality of holes 52 is formed over the entire main surface of the upper surface 40 of the translucent substrate 38. 3. If the light-emitting portion 42 is formed on the lower surface 39, the backlit light is dazzling and the display object 32 becomes difficult to see, so only the upper surface 40 is processed. However, it is not limited to being one-sided.

Next, with reference to FIGS. 6 and 10, a surface emitting device 61 capable of emitting light from both sides used for pictograms will be described as a second embodiment of the present invention. The same parts and functions as those of the first embodiment are given the same numbers and the description thereof is omitted.

FIG. 6 is a schematic cross-sectional configuration diagram showing an example of a surface light-emitting device capable of emitting light from both sides using a light guide plate according to the second embodiment of the present invention as a pictogram, and FIG. 7 shows the light guide plate according to the second embodiment of the present invention. FIG. 8 is a plan view showing an example of a light-emitting portion composed of a printed layer formed by a pattern arrangement of a plurality of dots according to the second embodiment of the present invention, and FIG. 9 is a second embodiment of the present invention. FIG. 10 is an enlarged plan view showing the surrounding portion (M) of the plurality of dot portions according to the embodiment, and FIG. 10 is an enlarged cross-sectional view showing the BB section of the plurality of dot portions according to the second embodiment of the present invention.

A surface emitting device 61 illustrated in FIG. 6 has a light guide plate 62, an LED light source 63, and an upper opening portion 64 and a lower opening portion 65 which are opened at the top and bottom. The light guide plate 62 and the LED light source 63 are fixed. It is composed of a fixing jig 67 consisting of a housing body 66 which

The light guide plate 62 has a main surface base portion 77 serving as a non-light emitting portion and a light emitting portion 73 over both main surfaces of the upper surface 69 and the lower surface 70 of the translucent substrate 68. The main surface base portion 77 serving as a non-light emitting portion Alternatively, the printed layer 71 is provided with a printed layer 71 in which the light-emitting portions 73 are pattern-arranged under predetermined conditions, and the printed layer 71 is made up of a plurality of dots 72 as the light-emitting portions 73 . As in the first embodiment, the light emitting portion 73 has a binder resin having translucency such as an acrylic resin and a higher optical refractive index than the binder resin, and is doped with metal ions or supported by metal particles. and a light diffusing material particle having a photocatalytic function, and a hydrophobic inorganic particle having a light refractive index similar to that of the binder resin and having a hydrophobic group bonded thereto. The light-emitting portion 73 is formed by volatilizing the solvent.

A light-emitting portion 73 composed of a plurality of dots 72 is formed on the entire printed layer 71 by screen printing on both the main surfaces of the upper surface 69 and the lower surface 70 of the light-transmitting substrate 68 serving as the light guide plate 62 . A light incident end face portion 74 facing the LED light source 63 is mirror-finished, and a reflective tape 76 is attached to the separated end face portion 75 and the two side wall end faces.

In addition, the plurality of dots 72 of the light-emitting portion 73 formed on the printed layer 71 are independent one by one, and the main surface base portion 77 serving as the non-light-emitting portion of the outer surface of the plurality of dots 72 is the main portion of the light-transmitting substrate 68. This is the surface where the surface base material is exposed.

In addition, both the upper surface 69 and the lower surface 70 of the light-transmitting substrate 68 generally form a printed layer 71, and the area ratio of the plurality of dots 72 to the printed layer 71 varies from the light incident end surface portion 74 facing the LED light source 63 to A plurality of dots 72 are arranged in a fine pattern over both the main surfaces of the upper surface 69 and the lower surface 70 of the translucent substrate 68 under the condition that the number of dots gradually increases toward the opposing separated end surface portion 75 .

9 is an enlarged view of the enclosing portion (M) shown in FIG. 8, and FIG. 10 is a BB cross section of the enclosing portion (M). The print layer 71 is composed of a light-emitting layer 73 and a main surface base portion 77 serving as a non-light-emitting portion. The distance between the adjacent dots is such that a virtual circle having a diameter of .

Further, as the light diffusing substance particles having a photocatalytic function having a photorefractive index larger than that of the binder resin, particles of a photocatalytic apatite composition in which a metal oxide and silver ions are doped in the apatite crystal structure are used. was selected and used. The mixing ratio of the light diffusing material particles having a photocatalytic function is such that both the upper surface 69 and the lower surface 70 of the translucent substrate 68 are printed layers 71 to form the light emitting portion 73 having a plurality of dots 72 . , and the content thereof was adjusted to about 10% with respect to the amount of the binder resin.

In addition, as the inorganic particles in which hydrophobic groups having a similar optical refractive index to the binder resin are combined, hydrophobic fumed silica, which is one of synthetic amorphous silica, is selected as in the first embodiment. It was prepared by mixing 5 wt % to 35 wt % with respect to the weight of the printed layer.

The upper opening 64 and the lower opening 65 of the housing 66 are open without a protective sheet or a back plate, so that the light guide plate is directly exposed to the outside air. Other members are the same as those of the first embodiment, and description thereof is omitted.

Next, the movement of light in the surface light-emitting device 61 having a structure in which both surfaces emit light, which can be used for such a pictogram, and the functional characteristics of the light guide plate 62 will be described. Although not shown, when used as a pictogram, the upper surface 68 or the lower surface 69 may be a translucent plate or film on which information is drawn, a liquid crystal panel, or a separate guide with a pattern applied with diffusion ink. It is necessary to install a light plate panel.

When the LED light source 63 of the surface emitting device 61 is turned on, the light is irradiated and enters the light guide plate 62 from the light incident end face portion 74 as incident light. The incident light is totally reflected repeatedly due to the relationship between the refractive index of the acrylic resin and the air. As a result, the light is confined inside the light guide plate 62 made of acrylic resin.

However, if there is a printed layer 71 having light-emitting portions 73 of a plurality of dots 72 formed on both the main surfaces of the upper surface 69 and the lower surface 70 , the light-diffusing material particles having photocatalytic function existing in the light-emitting portions 73 will emit light. Upon hitting the particles, the light is diffused and diffusely reflected on the particle surface, dispersed above and below the light guide plate 62 , and part of the light is emitted from the surface of the light guide plate 62 through the upper surface 69 and the lower surface 70 .

In the second embodiment, a printed layer 71 having light emitting portions 73 of a plurality of dots 72 is finely formed on both the upper surface 69 and the lower surface 70 of the light guide plate 62 so as to cover both the main surfaces. Therefore, the incident light is diffused and diffusely reflected by each of the light diffusing substance particles having photocatalytic function. The light is totally reflected at the interface between the resin and the air, and advances toward the remote end surface portion 75 in the same manner as the main surface base portion 77 which is a non-light-emitting portion where the dots 72 do not exist.

However, although the primary particle diameter of the light diffusing substance particles having photocatalytic function is several nanometers, when it comes to particles of a photocatalytic apatite composition in which metal oxides and silver ions are doped in the apatite crystal structure, many The primary particles are aggregated into a cluster state and have a size of several μm. In addition, the optical refractive index of calcium phosphate, which is a component of apatite, is close to that of the binder resin at around 1.5. It can be used as a substance particle. Therefore, the printed light-emitting portion 73 emits light by diffusing and irregularly reflecting the light, and if a dot pattern arrangement is performed, even if the light-emitting portion 73 occupies the entire both main surfaces of the light guide plate 35, the light diffusion material can be used. Light that does not collide with particles is totally reflected, so it has the function of sending light deeper and deeper, making it a uniform and stable surface light emitter. In addition, since the light diffusing substance particles have a photocatalytic function, they are activated on the surface of the light-emitting portion of the printed layer, exhibiting an antibacterial effect.

Although the second embodiment of the present invention has been described with reference to pictograms, products that utilize light emission from both sides include light-transmissive partition lighting fixtures and the like. In pictograms, the surface of the light guide plate can be protected by attaching a separate light-transmitting information film to the surface, but it is usually used as an open partition that allows light to pass through, and when individual security is required. A product that becomes invisible when lit as a lighting fixture is also conceivable. Such light-transmissive partition lighting fixtures are often directly touched by people, and conventional light guide plates require a protective sheet. Therefore, a protective sheet is not necessary, and the lighting fixture improves the sanitary environment of the living space.

Next, with reference to FIG. 11, a surface light emitting device 101 which is provided with a UV light source as a third embodiment of the present invention and which can further enhance the antibacterial effect will be described. The same parts and functions as those of the first embodiment are given the same numbers and the description thereof is omitted.

FIG. 11 is a schematic cross-sectional configuration diagram showing an example of a surface emitting device to which a near-ultraviolet UV-LED light source and a UV light guide plate are added according to the third embodiment of the present invention. A surface light-emitting device 101 illustrated in FIG. 11 includes a first light-emitting device 105 and a second light-emitting device 109 stacked in a housing case 110 . The first light emitting device 105 is composed of a first light guide plate 102 , a visible light LED light source 103 , and a first fixing jig 104 for fixing the first light guide plate 102 and the visible light LED light source 103 . The second light-emitting device 109 includes a second light guide plate 106, a UV-LED light source 107 that emits near-ultraviolet rays, and a second fixing jig 108 that fixes the second light guide plate 106 and the UV-LED light source 107. It consists of

A housing case 110 on the upper surface of the first light emitting device 105 has an opening 111 that exposes the entire upper surface of the first light guide plate 102, and a reflective sheet 112 is installed on the lower surface side of the second light emitting device 109. A rear plate 113 is attached to the rear opening of the housing case 110 with a clasp 114 .

A printed layer 115 having a plurality of dots arranged in a pattern under predetermined conditions as a light emitting portion is formed on the entire upper surface of the first light guide plate 102 facing the opening 111 . As in the embodiment, a light-transmitting binder resin such as an acrylic resin, and a light diffusing light having a photocatalytic function, which has a higher optical refractive index than the binder resin, is doped with metal ions, or supports metal particles. It contains material particles and hydrophobic inorganic particles having an optical refractive index similar to that of the binder resin and having hydrophobic groups bonded thereto, and is formed by applying ink by screen printing and then drying to evaporate the solvent. ing.

In addition, on the upper surface of the second light guide plate 106, a predetermined pattern arrangement is designed using screen printing ink mixed with ordinary titanium oxide as a light diffusing agent, which diffuses the light from the near-ultraviolet UV-LED light source 107. A diffusion layer 116 having dots printed on the entire surface is formed.

In addition, in the surface emitting device 101 shown as the third embodiment, visible light LED light sources 103 are attached to both sides of the first light guide plate 102, and near-ultraviolet UV-LED light sources 107 are attached to both sides of the second light guide plate 106. As with the first and second embodiments, the end faces of each light guide plate facing the LED light sources are polished. Other members such as an outlet are the same as those in the first embodiment, and descriptions thereof are omitted.

Next, the movement of light in the surface light emitting device 101 to which the UV-LED light source 107 of near-ultraviolet rays is added, and the functional characteristics of the first light guide plate 102 and the second light guide plate 106 will be described.

When the visible light LED light source 103 of the surface light emitting device 101 is turned on, the light is irradiated and enters the first light guide plate 102 from the light incident end surface portion as incident light. Incident light penetrates into the first light guide plate 102 by repeating total reflection due to the relationship between the refractive indices of acrylic resin and air. The light from the visible light LED light source 103 is reflected by the reflective tape on the side wall, and bounces back into the first light guide plate 102 to be confined inside the transparent acrylic resin plate.

However, the entire top surface of the first light guide plate 102 facing the opening 111 is formed with a printed layer having a plurality of dots arrayed in a predetermined pattern as a light-emitting portion, and there is a printed layer having the light-emitting portion. Then, the light hits the light diffusing substance particles having photocatalytic function existing in the light emitting part, the light is diffused and irregularly reflected on the particle surface, and is also dispersed above and below the first light guide plate 102, and a part of the light reaches the first light guide plate 102. As the emitted light from the surface, it will jump out from the upper surface and the lower surface.

Also, when the near-ultraviolet UV-LED light source 107 of the surface emitting device 101 is turned on, near-ultraviolet light of 350 to 390 nm is emitted and enters the second light guide plate 106 as incident light from the light incident end surface. Similar to visible light, the near-ultraviolet light penetrates into the second light guide plate 106 by repeating total reflection due to the relationship between the refractive index of the acrylic resin and the air. The light that reaches 1 is reflected by the light from the other near-ultraviolet UV-LED light source 107 and the reflective tape 112 on the side wall, bounces back into the second light guide plate 106, and is confined inside the transparent acrylic resin plate.

However, on the upper surface of the second light guide plate 106, screen printing ink mixed with rutile-type titanium oxide as a light diffusing agent, which diffuses the light from the near-ultraviolet UV-LED light source 107, is applied to a predetermined pattern arrangement design. dots are printed on the entire surface. There are no particular restrictions on the dot diameter or dot spacing, and the pattern arrangement was designed with an emphasis on luminance and uniformity, and screen printing was performed. When there is a printed layer having a light-emitting portion, near-ultraviolet light hits the light-diffusing substance particles of titanium oxide present in the light-emitting portion, and the near-ultraviolet light is diffused and diffusely reflected on the surface of the light-diffusing substance particles, and the second light guide plate 106 The light is also dispersed vertically, and is emitted from the upper surface and the lower surface as emitted light from the surface of the second light guide plate 106 .

Of the light emitted from the first light guide plate 102 and the second light guide plate 106, the light emitted to the lower surface side hits the reflection sheet 112 and is reflected and added as emitted light from the upper surface. A printed layer 115 is formed on the upper surface of the first light guide plate. The printed layer 115 includes a binder resin having translucency such as an acrylic resin, and a light refractive index larger than that of the binder resin. A screen comprising light diffusing material particles having a photocatalytic function, which are doped or metal particles are supported, and hydrophobic inorganic particles having a light refractive index similar to that of the binder resin and having a hydrophobic group bonded thereto. It is formed by drying after applying ink in printing to volatilize the solvent.

Therefore, the mixed light of visible light and near-ultraviolet light emitted from the first light guide plate 102 and the second light guide plate 106 is irradiated to the light diffusing material particles having a photocatalytic function, thereby exerting the photocatalytic function and exposing the light to the outside air. It decomposes dirt and germs adhering to the outer surface of the first light guide plate 102 and has an antibacterial effect.

Also, as in the second embodiment, the adjacent dot spacing is such that a virtual circle having a diameter of 2 mm or more cannot be drawn on the main surface base portion other than the printed dots. Since the metal ions doped into the light diffusing substance particles form a bacterium growth inhibition zone of 1 mm or more, the main surface substrate also has an antibacterial effect.

Further, as in the second embodiment, the printed layer 115 contains 5 wt % or more of hydrophobic fumed silica as inorganic particles to which hydrophobic groups are bonded, relative to the weight of the printed layer 115. Since it is interposed so as to enclose the light diffusing substance particles having photocatalytic function, even if the photocatalytic function works, the binder resin is not directly decomposed and deteriorated.

As in conventional Patent Documents 2 and 3, when a UV-LED light source that emits near-ultraviolet light is combined with a visible light LED light source on the same light guide plate and irradiated from the end face, the refractive index of near-ultraviolet light is Due to the large size, it was difficult to emit surface light with a uniform near-ultraviolet intensity. However, by using a light guide plate different from the visible light LED light source dedicated to the near ultraviolet UV-LED light source as in the present invention, the antibacterial effect can be achieved over the entire surface.

<Method for manufacturing light guide plate>
Next, a method for manufacturing the light guide plates 35 and 62 according to the embodiment of the present invention will be described with reference to FIGS. 11 and 12. FIG. FIG. 11 is an enlarged cross-sectional view showing the ink state in which the printed layers 41 and 71 of the translucent substrates 38 and 68 are coated by the screen printing method using the composite ink (G) 80 of the present invention, and FIG. FIG. 4 is an enlarged cross-sectional view showing a state in which the composite ink (G) 80 of the present invention is screen-printed to form printed layers 41 and 71 composed of ink solids formed by drying and concentrating the composite ink (G) 80. be.

First, a composite ink (G) 80 for screen-printing the light-emitting portions 42, 73 to be formed on the printed layers 41, 71 on the entire main surfaces of the translucent substrates 38, 68 is prepared.

The composite ink (G) 80 includes a binder resin 81 having translucency, light diffusing substance particles 82 having a photocatalyst function having a higher optical refractive index than the binder resin 81, and optical refractive index similar to that of the binder resin. , inorganic particles 83 to which hydrophobic groups having thixotropic properties are bonded, and a solvent (not shown because it is included in the binder resin component) that dissolves the binder resin 81 .

First, as the binder resin 81 having translucency, an acrylic resin is often used. Particles of the composition that are clustered to a particle size of 1 to 5 μm are used. Isophorone solvent is mainly used as a solvent for dissolving the binder resin 81. As the inorganic particles 83 having a light refractive index similar to that of the binder resin and having a thixotropic hydrophobic group bonded thereto, one type of synthetic amorphous silica is used. A hydrophobic fumed silica was used.

As the inorganic particles 83 having thixotropic properties, fumed silica produced by a dry method of synthetic amorphous silica is well known. When it exists in water or a solvent, it exhibits thixotropic properties due to the loose cohesive force that tries to form secondary particles from the primary particles.

Hydrophilic fumed silica is commonly used in water-based paints and inks, and hydrophobic fumed silica is commonly used in solvent-based paints and inks. Even if the amount of fumed silica mixed is 1 wt % or less based on the weight of the paint or ink, the thixotropic properties work effectively and the anti-sagging effect is exhibited.

Fumed silica, which is synthetic amorphous silica made by dry method, has an average primary particle size of 4 to 40 nm and a specific surface area of 4 to 40 nm, unlike synthetic amorphous silica and crystalline mineral silica made by wet method. It is in an ultrafine powder state with a particle size of 50 to 380 square m / g, and hydrophilic silanol groups and hydrophobic siloxane are present on the surface. It exhibits thickening properties when mixed.

Among fumed silica, hydrophobic fumed silica is obtained by reacting silanol groups with silane compounds such as chlorosilanes to bond the hydrophobic groups represented by (Chemical Formula 1) to (Chemical Formula 3) to increase hydrophobicity. is.

Next, particles of a photocatalytic apatite composition in which a metal oxide and silver ions are doped in the apatite crystal structure selected as the light diffusing substance particles 82 having a photocatalytic function will be described.

This photocatalytic apatite composition is one of the light diffusing material particles 82 having a photocatalyst, and the diameter of the primary particles is several nanometers. When it comes to particles of matter, in the manufacturing process by the sol-gel method, many primary particles are aggregated into a cluster state and have a size of several μm. The optical refractive index of calcium phosphate, which is a component of apatite, is close to that of the binder resin at around 1.5. As a result, it has a higher optical refractive index than the binder resin, and can be used as the light diffusing substance particles 82 . Therefore, if the printed light-emitting portion 73 emits light by diffusing and diffusely reflecting light, and a pattern of dots is arranged, even if the light-emitting portion 73 occupies the entire both main surfaces of the light guide plate 35, the printing area ratio is If is small, the light that does not collide with the light diffusing substance particles 82 is totally reflected, so that the function of transmitting the light further and further remains, resulting in a uniform and stable surface light emitter.

Next, a method for producing a composite ink (G) that can be used for screen printing using the selected light diffusing substance particles 82 having photocatalytic function will be described.

First, a binder resin 81 having translucency is mixed with additives such as a thickener, antifoaming agent, and antiseptic that do not impede translucency, and then a solvent is added to adjust the viscosity to allow screen printing. A clear ink (C) for screen printing was prepared.

Next, in the first step, the inorganic particles 83 having thixotropic properties and having hydrophobic groups bonded thereto are used as hydrophobic fumed silica and mixed with the isophorone solvent so as to be about 10 wt % to about 30 wt % with respect to the isophorone solvent. Then, the viscosity was adjusted to the same level as that of the clear ink for screen printing (C) to prepare a solution composition (S). This solution composition (S) requires sufficient kneading because the hydrophobic fumed silica has loose cohesiveness. A step of kneading for several passes to loosen agglomerated particles is required.

Next, as a second step, a light diffusing substance paste (P) is prepared by mixing the light diffusing substance particles 82 with the solution composition (S). A light diffusing substance paste (P) is prepared by mixing 20 parts of the light diffusing substance particles 82 with 100 parts of the solution composition (S). As a method for mixing, for example, a well-known stirring method such as mixing the mixture with a rod-shaped member can be used. requires a step of passing the light diffusing substance paste (P) through a three-roll mill several times under predetermined conditions to knead it to loosen agglomerated particles.

Next, in the third step, a composite ink (G) was prepared by mixing an appropriate amount of the previously prepared light diffusion material paste (P) with the screen printing clear ink (C). The appropriate amount of the light diffusing substance paste (P) is obtained by mixing 50 parts of the light diffusing substance paste (P) and 20 parts of a solvent with 100 parts of the clear ink for screen printing (C). The light diffusing substance particles 82 are calculated and mixed so as to be about 10 wt % with respect to the weight of the ink solid content excluding the solvent content.

As the clear ink for screen printing (C), commercially available ink may be used. For example, SR930 medium ink manufactured by Mino Group Co., Ltd. can already be used as a clear ink (C) for screen printing because it maintains its properties. An appropriate amount of the light diffusing material paste (P) using photocatalytic apatite may be added and used as a composite ink (G).

In addition, the predetermined conditions in the kneading operation by the three-roll mill are set such that each roll has a rotation ratio of about 1:3:8, the rotation speed of the front roll is about 120 rpm, and the roll interval is about 200 μm. It is preferable to adjust the viscosity to 4,000 to 8,000 pa's by passing through a three-roll mill three to five times.

Due to the properties of hydrophobic fumed silica, which has thixotropic properties, if 10 wt% to 30 wt% is mixed with an isophorone solution, it will become a putty state. .

Next, as the fourth step, the case of using the substantially rectangular translucent acrylic resin substrates 38 and 67 will be described as an example.

Using the composite ink (G) 80 obtained as described above, a plurality of non-light-emitting holes 52 are formed on one surface of the substantially rectangular acrylic resin translucent substrates 38 and 67 by silk screen printing. The printing layer 41 having the main surface base portion 53 and the light emitting portion 42 which are to be the portion is printed in a predetermined pattern arrangement.

In screen printing, by appropriately changing the opening ratio of the screen mesh (gauze) and the thickness of the emulsion, the thickness (t) of the light-emitting portion 42 that becomes the printing layer 41 having the desired plurality of holes 52, the plurality of holes A plate arranged in a pattern is obtained in consideration of the diameter (W) of the holes and the distance between the holes. Normally, the thickness of the printed layer printed by the screen printing method is thinner when solvent type ink is used than when UV irradiation type ink is used. ) 80, the film thickness becomes thinner upon drying. As a result, part of the light diffusing substance particles 82 having a photocatalytic function protrude from the printed layer, thereby maintaining the photoactivation force, which is convenient.

As the screen mesh, a known material that has been used as a mesh material for screen printing plates can be used. Examples thereof include metal meshes such as stainless steel, aluminum, iron, copper, and alloys containing these metals (metal meshes), and resin meshes such as polyester (eg, Tetoron (registered trademark)). As the screen mesh, for example, a Tetoron (registered trademark) mesh sheet with a mesh number of 270 is used to adjust the thickness of the emulsion to 50 μm, thereby forming a plurality of holes 52 having a thickness (t) of 4 μm or more and 6 μm or less. and a Tetoron (registered trademark) mesh sheet having a mesh number of 420 is used to obtain a plurality of holes 52 having a thickness of 2 μm or more and 3 μm or less. can be obtained.

Next, as a drying step of the fifth step, the translucent substrates 38 and 67 having one surface coated with the composite ink (G) 80 by screen printing are placed in a drying oven at 80° C. for 20 minutes, and the composite ink (G) 80 is applied. Volatilize and volatilize the solvent inside and solidify. In this drying process, the light guide plates 35 and 62 provided with the light emitting portions 42 as the printed layer 41 having the plurality of holes 52 are obtained. In the case of a light guide plate 62 attached to a surface light emitting device 61 capable of emitting light from both sides, after one surface is treated and dried, the light emitting portion 42 is formed as a printed layer 41 having a plurality of holes 52 in the same manner on the other surface. do.

In this way, by using hydrophobic fumed silica, which is one of synthetic amorphous silica, the composite ink 80 to which a large amount of solvent is added can be screen-printed while maintaining its viscosity, so that the solvent can be removed in the drying process after coating. Volatilization results in a relatively thin printed layer. That is, even if the coating film thickness of the composite ink 80 containing a large amount of solvent in the screen printing process is 10 to 20 μm, it is possible to form a thin film of 1 μm or more and 7 μm or less by volatilizing the solvent in the drying process. Become.

In addition, even in the process of volatilizing the solvent in the drying process, the thixotropic effect of the hydrophobic fumed silica forms a layer of inorganic particles on the surface of the light diffusing material particles having photocatalytic function, so the binder resin and the photocatalyst is less likely to intervene directly, and the deterioration of the binder resin due to the photocatalyst can be suppressed.

Furthermore, the hydrophobic fumed silica contained in the composite ink (G) 80 is concentrated by volatilizing the solvent in the drying process. Assuming that the composite ink (G) 80 originally contains a 10 wt % concentration of hydrophobic fumed silica, this concentration causes the hydrophobic The concentration of fumed silica will increase to concentrations of about 20 wt % or higher. As a result, the amount of the hydrophobic fumed silica interposed around the light diffusing substance particles having photocatalytic function increases, so that the effect of preventing deterioration of the binder resin becomes more pronounced.

As described above, hydrophobic fumed silica, which is one of the synthetic amorphous silicas, dissolves in binder resin components and solvents, and in the state of ink for screen printing, it acts as a thickener and a thixotropic agent to improve fluidity. It has a function to prevent sagging by blocking it. This provides a diffusion ink for screen printing that contains a large amount of solvent, so after drying, the solvent component volatilizes, resulting in an extremely thin printed layer, and the light diffusion ink that has a photocatalytic function contained in a cluster state. A part of the material particles are formed so as to protrude from the surface, so that the photocatalytic function can be exhibited, and deterioration of the resin due to less contact with the binder resin can be suppressed.

In an embodiment of the present invention, the amount of hydrophobic fumed silica to which hydrophobic groups are bound is 5 wt % to 35 wt % based on the weight of the printing layer. Compared to conventional additives such as thickeners, antifoaming agents, and antifouling agents, which were about 1% by weight, the mixing amount is very large.

Normally, it is difficult to mix fumed silica having a thixotropic effect with respect to the printing layer weight at a high concentration. ), the solution composition (S), and the light diffusion substance paste (P) are separately prepared to the same viscosity, and then blended and mixed to obtain a composite ink 80 for screen printing. is.

In particular, as a second step, the light diffusing substance particles 82 are mixed in advance with the solution composition (S) to prepare a light diffusing substance paste (P), in which the light diffusing substance particles 82 are added to the solution composition. Since the hydrophobic fumed silica of the inorganic particles in (S) is in contact with the surface of the light diffusing material particles having photocatalytic function, a layer of inorganic particles is formed, so that the binder resin and the photocatalyst are less likely to be directly interposed. , the suppression of deterioration of the binder resin by the photocatalyst is strengthened.

That is, the composite ink 80 shown in FIG. 11 contains several times more hydrophobic fumed silica and solvent than the conventional one, and by volatilizing the solvent in the drying process, the thickness of the printed layer is reduced as shown in FIG. becomes thinner, the hydrophobic fumed silica contained in large amounts is concentrated on the surface of the light emitting part, and the hydrophobic fumed silica is coated around the light diffusing material particles, and even if it exhibits the photocatalytic function Deterioration of the double nnD fur resin is suppressed.

The reason why the binder resin liquid 81 is greatly reduced by drying is that the content of the solvent is large, and although it is usually about 20%, the composite ink of the present invention contains 50% or more of the solvent. As a result, the light diffusing substance particles 82 having a photocatalytic function come out from the printing surface of the binder resin by evaporating the solvent, so that the photocatalytic effect can be maintained and the antibacterial effect can be maintained.

As the light diffusing material having a photocatalytic function used in the embodiment of the present invention, a photocatalyst apatite doped with silver ions manufactured by Taihei Kagaku Sangyo Co., Ltd. was used. Visible light responsive photocatalysts such as doped Photopaque MPT-623 and copper ion doped titanium oxide Lumiresh CT-2 are commercially available.

In-house production is also possible. Anatase titanium oxide ST01, known as a photocatalyst manufactured by Ishihara Sangyo Co., Ltd., is mixed with a very small amount of cupric chloride in an isophorone solvent, and fumed silica is added to increase the viscosity. A light diffusing substance paste (P) can also be made by adjustment.

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to the following examples.

First, as the binder resin 81 having translucency, the same acrylic resin as that of the translucent substrate is used, and additives such as a thickening agent, an antifoaming agent, and an antiseptic that do not impede translucency are mixed, and isophorone solvent is added as a solvent. Thus, a clear ink (C) for screen printing was prepared by adjusting the viscosity to 4,000 to 8,000 pa's enabling screen printing. In addition, SR930 medium ink manufactured by Mino Group Co., Ltd., which is commercially available, may be used.

Next, hydrophobic fumed silica as the inorganic particles 83 having thixotropic properties is put into the isophorone solvent and mixed with the isophorone solution so as to be about 20% by weight. A solution composition (S) having an adjusted viscosity was prepared. This solution composition (S) requires sufficient kneading because the hydrophobic fumed silica has loose cohesiveness. As a ratio, each condition was set such that the number of revolutions of the front roll was about 120 rpm and the gap between the rolls was about 200 μm.

In addition, the hydrophobic fumed silica used this time, which has thixotropic properties, has an optical refractive index similar to that of the binder resin, and is the inorganic particles 83 in which a hydrophobic group is bonded, was performed using R202 manufactured by Nippon Aerosil Co., Ltd. .

Next, a light diffusing substance paste (P) is prepared by mixing the light diffusing substance particles 82 into the solution composition (S). A light diffusion substance paste (P) is prepared by mixing 20 parts of the light diffusion substance particles 82 with 100 parts of the solution composition. As a method for mixing, the mixture was stirred for 15 minutes using a universal vibration stirrer AD-MIX. Furthermore, in order to break the clusters grown by the cohesive force of the light diffusing substance particles 82, each roll was set to a rotation ratio of about 1:3:8 in a three-roll mill, the rotation speed of the front roll was about 120 rpm, and the roll interval was 200 μm. The viscosity was adjusted to 4,000 to 8,000 pa's by setting each condition to about 3 times.

Photocatalytic apatite doped with silver ions manufactured by Taihei Kagaku Sangyo Co., Ltd. was used as the light diffusing material particles having photocatalytic function used this time.

Next, as a clear ink for screen printing (C), 100 parts of SR930 medium ink manufactured by Mino Group Co., Ltd., 50 parts of the previously prepared light diffusion substance paste (P) and 20 parts of isophorone solvent were mixed to form a composite. An ink (G) was prepared. The amount of the light diffusing substance particles 82 is calculated and mixed so as to be about 10 wt % with respect to the weight of the ink solid content excluding the solvent content. In order to crush the clusters of the light diffusing substance particles that were more agglomerated, the mixture was kneaded with the three-roll mill under the above conditions to adjust the viscosity to 4,000 to 8,000 pa's.

Next, using the composite ink (G) 80 obtained as described above, a 160 μm diameter ink is applied to one surface of the substantially rectangular acrylic resin translucent substrates 38 and 67 by silk screen printing. , a printing layer 71 having light-emitting portions 73 of a plurality of dots 72 with a dot interval of 600 μm was printed.

As the screen mesh, by using a mesh sheet made of Tetoron (registered trademark) with a mesh number of 420, it is possible to obtain the light emitting portion 42 of the printed layer 41 having a plurality of dots and holes 52 with a thickness of 2 μm or more and 3 μm or less. However, in the case of printing with a dot diameter of 160 μm and a dot pitch of 600 μm on the entire surface to form a square pattern arrangement, the dot thickness was about 2 μm.

Next, as a drying step of the fifth step, the translucent substrates 38 and 67 with composite ink (G) 80 applied on one side by screen printing are placed in a drying oven at 80° C. for 20 minutes, and the solvent in the composite ink 80 is removed. volatilized and volatilized and solidified. In this drying step, the light guide plates 35 and 62 provided with the light emitting portions 42 as printed layers having a plurality of dots are obtained.
(Evaluation test)

Next, after assembling as a surface light emitting device and confirming that the illuminance of the entire light guide plate surface was uniform and appropriate illuminance was obtained, the antibacterial property was evaluated. The antibacterial evaluation method and results will be explained.

First, preparation of the standard test solution will be described. As a method for collecting various germs from a real living space, the kitchen was selected, the entire sink was wiped clean, the cloth was rinsed with a sterile liquid, 20 ml of milk was added to 2 L of the rinsing liquid, stirred, and cultured at room temperature of 20 ° C for 24 hours. What was left was prepared as a stock solution.

Next, one end surface of the prepared light guide plate was irradiated with a visible light LED light source to cause the light guide plate to emit surface light of about 7500 lux. 5 drops (approximately 0.2 ml) of the test solution obtained by diluting the stock solution 1000 times were dropped on the printed surface with an illuminance of .

Next, a polyethylene film having a thickness of 20 μm and a size of 40 mm square was placed on the dropping liquid, and a visible light LED light source provided on the end surface of the light guide plate was turned on to irradiate the liquid for a predetermined time.

After irradiation for a predetermined time, the film was peeled off, and a commercially available stamp medium (food stamp standard agar medium for general bacteria manufactured by Nissui) was pressed to collect the bacteria. After that, the cells were cultured at 35°C for 24 hours, and the number of bacteria was comparatively evaluated.

FIG. 17 shows the state of the number of bacteria on the printed surface irradiated with a visible light white LED at 7500 lux. After 3 hours of irradiation without photocatalyst, an increase in the number of bacteria was observed, whereas in the presence of photocatalyst, all the bacteria disappeared.

Furthermore, in the case of near-ultraviolet UV-LED irradiation, the antibacterial effect was observed in a shorter period of time even when near-ultraviolet rays having a wavelength of 365 nm with an intensity of 50 μW/cm 2 were added.

The embodiments and examples described above merely show typical forms of the present invention, and the present invention is not limited to the embodiments and examples. That is, those skilled in the art can carry out various modifications according to conventionally known knowledge without departing from the gist of the present invention. As long as the light guide plate and surface light emitting device of the present invention are provided even with such modifications, they are of course included in the scope of the present invention.

The light guide plates 35 and 62 according to the present embodiment are used, for example, in lighting panels of game machines, vending machines, and the like, and do not require a protective sheet, so that they can enhance the performance effect and also improve the design. can be excellent. In addition, since it glows even in water, for example, by using the light guide plates 35 and 62 of the present embodiment in a part of the water tank of an aquarium, it is possible to produce an antibacterial effect in the water tank, and it is also commercialized as a water purification device. can. Furthermore, the light guide plates 35 and 62 can also be used as surface light emitters (backlights and frontlights) for electronic device displays and lighting devices.

31, 61, 101... surface light-emitting device, 32... opaque display object, 33... light-emitting device, 34, 67... fixing jig, 35, 62... light guide plate, 36, 63 ... LED light source, 37, 74 ... light incident end surface, 38, 68 ... translucent substrate, 39, 70 ... lower surface, 40, 69 ... upper surface, 41, 71, 115... printed layer, 42, 73... light-emitting portion, 43... front opening, 44... protective cover, 45... back opening, 46, 113... back plate, 47, 114... Clasp, 48... Power cord, 49... ON-OFF switch, 50... Transformer, 51... Socket, 52... Plural holes, 53, 77... Principal surface base portions serving as non-light-emitting portions 54, 75 Separate end surface portions 55, 76 Reflective tapes 56, 78 Virtual circles 64 Upper openings 65 Lower opening 66 Housing body 72 Plural dots 80 Composite ink 81 Binder resin liquid 82 Light diffusing substance particles 83 Hydrophobic group 102 First light guide plate 103 Visible LED light source 104 First fixture 105 First light emitting device 106 Second Light guide plate 107 Near-ultraviolet UV-LED 108 Second fixing jig 109 Second light-emitting device 110 Housing case 111 Opening 112 Reflective sheet, 116...Diffusion layer

Claims (11)

A printed layer having a plurality of unprinted substantially circular holes or a printed layer consisting of a plurality of printed substantially circular dots on at least one principal surface of a light-transmitting substrate having both principal surfaces, The printing layer includes a binder resin having translucency, photocatalyst material particles, light diffusing material particles having a higher optical refractive index than the binder resin, and an optical refractive index similar to that of the binder resin. and inorganic particles. A printed layer having a plurality of unprinted substantially circular holes or a printed layer consisting of a plurality of printed substantially circular dots on at least one principal surface of a light-transmitting substrate having both principal surfaces, The printed layer includes a binder resin having translucency, a light diffusing material particle having a photocatalytic function, which has a higher optical refractive index than the binder resin and is doped with metal ions or supported by metal particles, and the binder resin. and inorganic particles having a similar optical refractive index and having a hydrophobic group bonded thereto. Within the range of the printed layer, the holes are independent one by one and are formed in a pattern arrangement under predetermined conditions, and the inner surface of the plurality of holes becomes the main surface base portion of the translucent substrate. 3. The light guide plate according to claim 1, wherein: Within the range of the printing layer, the dots are independent one by one, and are formed in a pattern arrangement under predetermined conditions, and the outer surface of the plurality of dot forming portions is the base portion of the main surface of the translucent substrate. 3. The light guide plate according to claim 1, characterized in that: Within the range of the printed layer, a virtual circle with a diameter of 2 mm or more cannot be drawn on the main surface base portion other than the printed dots or on the main surface base portion of the hole that is not printed. 5. The light guide plate according to any one of claims 1 to 4, wherein the dot spacing or the size of the holes are set to be equal to each other. 6. The light guide plate according to any one of claims 1 to 5, wherein the inorganic particles to which the hydrophobic groups are bonded are hydrophobic fumed silica, which is one of synthetic amorphous silica. When the total weight of the binder resin, the photocatalytic substance particles, the light diffusion substance particles, and the hydrophobic fumed silica is defined as the printing layer weight, the hydrophobic fumed silica is 7. The light guide plate according to claim 6, wherein the contains an amount of 5 wt % or more and 35 wt % or less. 8. The light guide plate according to claim 1, wherein the binder resin contains acrylic resin as a main component. Supporting the light guide plate according to any one of claims 1 to 8, LED light sources disposed on end surfaces in contact with both main surfaces of the light-transmitting substrate, and the one end surface of the light guide plate and the LED light sources A surface light emitting device comprising a fixing jig comprising a housing body. The light guide plate according to any one of claims 1 to 8, an LED light source disposed on at least one end surface in contact with both main surfaces of the light-transmitting substrate, and the one end surface of the light guide plate and the LED light source A UV light guide plate separate from the light guide plate is arranged on one main surface of the light guide plate, and at least one end surface of the UV light guide plate has a peak wavelength of 350 to 390 nm. 1. A surface emitting device comprising: a second fixed jig for supporting a near-ultraviolet UV light source that emits a wavelength; A first step of mixing inorganic particles having thixotropic properties with hydrophobic groups bonded thereto and a solvent to prepare a solution composition (S), and doping the solution composition (S) with metal ions, or A second step of preparing a light diffusing substance paste (P) by mixing the light diffusing substance particles having a photocatalytic function on which metal particles are supported, and a screen printing clear ink (C) mainly containing the binder resin. and the light diffusion substance paste (P) to prepare a composite ink (G); and at least one of a translucent substrate having both main surfaces using the composite ink (G). and a fifth step of volatilizing and solidifying a volatile matter such as a solvent of the composite ink (G) on the surface of the translucent substrate. Forming a light guide plate having a printed layer made up of a plurality of dots or a printed layer made up of a plurality of holes, and synthesizing inorganic particles having the thixotropic property with one of the amorphous silicas to form a hydrophobic hydrophobic group. 10. The method of manufacturing a light guide plate according to any one of claims 1 to 9, wherein the light diffusing material particles having a photocatalytic function coated with fumed silica are distributed on the surface of the printed layer.

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