JP4359967B2 - Glass fiber sheet for light diffusion and lighting device using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light diffusing glass fiber sheet that uniformly diffuses light from an illumination light source, and an illuminating device using the same.
[0002]
[Prior art]
In lighting devices such as surface lighting devices and internally illuminated signboards, it is generally required that the light emitting surface has sufficiently high luminance and that the luminance distribution is sufficiently uniform over the entire light emitting surface. As such a light emitting surface, a light diffusion sheet that diffuses light from a light source is used.
[0003]
As a material used for the light diffusion sheet, for example, a resin sheet such as an acrylic resin sheet, or frosted glass is generally used. Further, glass fiber sheets using a glass fiber fabric as a base fabric are also being used for such light diffusion sheets. References relating to the glass fiber sheet for light diffusion include, for example, JP-A-8-195114, JP-A-8-259637, JP-A-8-290528, and JP-A-8-306215.
[0004]
[Problems to be solved by the invention]
In recent years, there has been an increasing demand for a large-sized, large-area, and light-weight illuminating device that achieves uniform light irradiation with a light diffusion sheet. For example, in an illuminating device used in an exhibition room or the like for exhibiting paintings or the like, it is necessary to uniformly shine light on each exhibit. In this case, it is preferable that the light is uniformly irradiated from a wide range of the ceiling surface. Therefore, a lighting device having sufficient illumination uniformity and a large area is desired. When such an illuminating device is used, the illumination light is emitted from the entire light emitting surface made of the light diffusing sheet without visually recognizing the shape and position of the light source such as a fluorescent lamp, so that the illumination is soft, and various facilities and applications are used. Therefore, an illumination device having a large area with the above-described uniform illumination is desired.
[0005]
In response to such demands, in any light diffusing sheet made of a resin sheet or frosted glass, it is necessary to achieve both a large area and a thinning necessary for weight reduction, such as the strength of the sheet and the production process thereof. It is difficult from the aspect. Further, when a resin sheet is used, it is a flammable material, so that it cannot be used for a ceiling surface with a sufficiently large area due to legal restrictions due to fire prevention problems.
[0006]
In contrast, light diffusion sheets made of glass fiber sheets have high light diffusivity, and at the same time, it is possible to achieve both large area and light weight / thinning due to the characteristics of materials such as flexibility and durability. is there. In addition, it is described in the above-mentioned document that a light diffusing sheet having excellent incombustibility and antifouling properties can be obtained by forming a glass fiber sheet having a non-combustible translucent resin coated on the surface of a glass fiber base fabric. .
[0007]
However, the conventional light diffusing glass fiber sheet has a problem that the lighting performance required in the lighting device is not sufficiently obtained. That is, the high brightness and the uniformity of the brightness distribution required in the lighting device correspond to the light transmittance and light diffusibility of the light diffusion glass fiber sheet, respectively. With respect to these two light transmission characteristics, in order to obtain high light diffusibility and ensure the uniformity of illumination, there is a problem that the other light transmission property is not set and secured sufficiently high.
[0008]
For example, in the light source light diffusion translucent material disclosed in Japanese Patent Application Laid-Open No. 8-195114, the transmissivity is set to be less than 50%, and the light diffusibility is not specifically studied. Also in the glass fiber sheets described in JP-A-8-259637 and JP-A-8-290528, the total light transmittance is about 38 to 45%. Further, the glass fiber sheet described in JP-A-8-306215 improves the mechanical properties and the like, and no specific study has been made on light transmittance and light diffusibility.
[0009]
In other words, the conventional light diffusion glass fiber sheet has been improved in terms of structure, mechanical properties, nonflammability and antifouling properties, etc., but with a uniform luminance distribution in terms of light transmission properties and lighting properties. However, under the condition that it has sufficient light diffusibility to make it light, the examination and development of a configuration for simultaneously optimizing, improving and improving the light transmittance have not been sufficient.
[0010]
The present invention has been made in view of the above-described problems, and has a high light diffusibility and at the same time an improved light transmission and can realize uniform and bright illumination. And an illumination device using the same.
[0011]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above object, the inventor of the present application uses total light transmittance as a light transmittance index and parallel light transmittance as a light diffusivity index. It has been found that it is possible to reliably evaluate and control these characteristics to optimize the light transmission characteristics, and in particular, their respective transmittances depend on the configuration of the glass fiber fabric used as the base fabric for the glass fiber sheet. The knowledge that it changes greatly while correlating to Furthermore, as a result of experiments and examinations on the change and correlation of both transmittances due to the configuration of the glass fiber fabric, it is possible to construct a glass fiber sheet that simultaneously improves the light transmittance in a configuration with sufficiently high light diffusivity. The present inventors have found that it is possible to create and realize a glass fiber fabric that can be used.
[0012]
  That is, the glass fiber sheet for light diffusion according to the present invention is a glass fiber sheet configured with a glass fiber fabric as a base fabric, and transmits and diffuses incident light with a predetermined light transmission property,The glass fiber fabric is made of plain weave with glass fibers made of a plurality of glass filaments, and its mass is 80 g / m. ² 110 g / m ² In addition to the following, the air permeability is 20 cm ³ / Cm ² / S or less, and the glass fiber count of the warp and weft used for the glass fiber fabric is 10 tex to 70 tex, and a resin coating layer made of a fluororesin or a silicone resin is formed on at least one surface side of the glass fiber fabric. AndThe light transmission characteristic is characterized in that the total light transmittance is 50% or more and the parallel light transmittance is 5% or less.
[0013]
Here, the total light transmittance and the parallel light transmittance are determined by a test / calculation method defined in JISK7105. Among these, the total light transmittance indicates the ratio of the amount of light transmitted to the opposite side of the sample in the incident light. This becomes an index of light transmittance in the light diffusion sheet, and the larger this value, the higher the light transmittance. The parallel light transmittance corresponds to the difference between the total light transmittance and the diffuse transmittance, and indicates the ratio of the amount of incident light that is transmitted in a direction parallel to the incident light without being diffused by the sample. This becomes an index of light diffusibility in the light diffusion sheet, and the smaller this value, the higher the light diffusibility.
[0014]
In particular, for the light diffusibility index, the diffuse transmittance is an amount that matches the total light transmittance depending on the configuration of the individual glass fiber sheet when all of the transmitted light is diffused. Will differ depending on the sheet. On the other hand, the parallel light transmittance is an amount of 0% when all the transmitted light is diffused. Therefore, it is possible to realize suitable light diffusibility for any glass fiber sheet by using the value as an index of light diffusibility, and particularly setting the upper limit value.
[0015]
For these, the inventor of the present application optimizes the configuration of the glass fiber sheet, particularly the configuration of the glass fiber fabric as the base fabric, under the condition that the parallel light transmittance of the glass fiber sheet is 5% or less and maintains high light diffusibility. Thus, it has been found that a glass fiber sheet for light diffusion having a high light transmittance of 50% or more can be prepared. That is, with the glass fiber sheet for light diffusion having the above-described configuration, the glass fiber sheet has high light diffusibility and at the same time has improved light transmission that has not been sufficient in the past, and can achieve uniform and bright illumination. A light diffusion sheet is realized.
[0016]
The structure of the glass fiber sheet for light diffusion according to the present invention that satisfies the above-described condition is that the glass fiber fabric as the base fabric has a mass of 150 g / m.²In addition to the following, the air permeability is 20 cm^Three/ Cm²/ S or less.
[0017]
The above-mentioned two constituent conditions for total light transmittance and parallel light transmittance are, for example, 1 m of glass fiber fabric.²This can be achieved by setting and optimizing the hit mass and air permeability. Here, 1m about glass fiber fabric²The hit mass, air permeability, and thickness described later are based on the test / calculation method defined in JIS R3420.
[0018]
1m of glass fiber fabric²Since the weight per unit corresponds to the amount of glass material per unit area, it is closely related to the total light transmittance among the light transmission characteristics.²By reducing the hit mass, the total light transmission is increased. The air permeability of the glass fiber fabric indicates the amount of air that passes when a predetermined pressure is applied, and is an amount determined by the shape of the gap between the glass fibers and the area ratio thereof. Closely related to the parallel light transmission, reducing this air permeability reduces the parallel light transmission.
[0019]
About these components, 1m²The upper limit of mass per hit is 150 g / m²By setting to, light transmittance with a total light transmittance of 50% or more can be obtained. At the same time, the upper limit of air permeability is 20cm^Three/ Cm²By setting to / s, a light diffusibility in which the parallel light transmittance is 5% or less is obtained, and a glass fiber sheet having both improved light transmittance and light diffusibility is realized.
[0020]
Alternatively, the structure of the light diffusing glass fiber sheet is such that the glass fiber woven fabric as the base fabric has a thickness of 95 μm or less and an air permeability of 20 cm.^Three/ Cm²/ S or less.
[0021]
The above-mentioned two constituent conditions for the total light transmittance and the parallel light transmittance can also be achieved by setting and optimizing the thickness and air permeability of the glass fiber fabric.
[0022]
The thickness of glass fiber fabric is 1m²Since it corresponds to the amount of glass per unit area as well as the mass per unit, it is closely related to the total light transmittance among the light transmission characteristics, and the total light transmittance increases by reducing this thickness. . Further, the air permeability is as described above.
[0023]
With respect to these constituent conditions, by setting the upper limit value of the thickness to 95 μm, light transmittance with a total light transmittance of 50% or more can be obtained. At the same time, the upper limit of air permeability is 20cm^Three/ Cm²By setting to / s, a light diffusibility with a parallel light transmittance of 5% or less is obtained, and 1 m²Similar to the case where the structure of the glass fiber fabric is defined by the hit mass and the air permeability, a glass fiber sheet with improved light transmission and light diffusibility is realized.
[0024]
For the above numerical range, 1 m²The weight per hit is 80 g / m²110 g / m²More preferably, it is as follows. The thickness is more preferably 80 μm or more and 90 μm or less. The air permeability is 15cm.^Three/ Cm²/ S or less is more preferable.
[0025]
Further, the glass fiber fabric may be characterized by being subjected to a fiber opening process. The fiber opening process is generally a process of opening (breaking) the fibers. For example, when the glass fibers composed of a plurality of glass filaments are spread to separate the filaments, the volume or area occupied by the glass fibers is increased to reduce the thickness and reduce the total light While improving the transmittance, it is possible to further reduce the parallel light transmittance by reducing the air permeability.
[0026]
In addition, a resin coating layer may be further formed on at least one surface side of the glass fiber fabric. By providing a resin coating layer on the surface of the glass fiber fabric, it is possible to further control and adjust the light transmittance and light diffusibility by the glass fiber sheet.
[0027]
In particular, the resin coating layer is preferably formed from a fluororesin or a silicone resin. According to the resin coating layer using these resins, it is possible to control the light transmittance and light diffusibility of the glass fiber sheet, and at the same time improve its nonflammability and antifouling properties.
[0028]
Moreover, the illumination device according to the present invention is an illumination device using the above-described light diffusion glass fiber sheet, and fixes the light source used for illumination and the light diffusion glass fiber sheet to a predetermined support frame. And a light diffusion cover installed so as to cover the light source, and the light from the light source is transmitted and diffused by the light diffusion glass fiber sheet of the light diffusion cover and emitted. And
[0029]
Using the above glass fiber sheet having excellent light transmission characteristics of light transmission and light diffusion as a light diffusion sheet, it is fixed to a support frame according to the shape of the lighting device and the like to form a light diffusion sheet surface and a light emitting surface By configuring the light diffusing cover, it is possible to realize an illuminating device that transmits and diffuses illumination light so that the light source is not visually recognized, is bright and bright, and has a uniform luminance distribution on the light emitting surface.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a light diffusion glass fiber sheet and a lighting device using the same according to the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the dimensional ratios in the drawings do not necessarily match those described.
[0031]
FIG. 1 is an enlarged perspective view schematically showing a configuration of an embodiment of a glass fiber sheet for light diffusion according to the present invention, with a part thereof cut out. The light diffusing glass fiber sheet 10 includes a glass fiber fabric 20 and a fluororesin layer 30 that is a resin coating layer.
[0032]
The glass fiber fabric 20 used in the glass fiber sheet 10 according to the present embodiment is created by a plain weaving method, and is configured by weaving warp yarns 21 and weft yarns 22 that are glass fibers together as shown in the figure. Has been. Moreover, in this embodiment, in order to improve the nonflammability, antifouling property, etc. of the glass fiber sheet 10, the fluororesin layer 30 is formed on one surface (the lower surface in FIG. 1) side of the glass fiber fabric 20. ing.
[0033]
By configuring the light transmission characteristics of the glass fiber sheet 10 such that the total light transmittance is 50% or more and the parallel light transmittance is 5% or less, both light transmittance and light diffusibility are improved and compatible. A glass fiber sheet for light diffusion that can be applied as the light diffusion sheet thus obtained is obtained. These characteristic values can be realized by adjusting the configuration of the glass fiber fabric 20 as the base fabric and selecting suitable conditions, as will be described below.
[0034]
The value of the total light transmittance mainly varies depending on conditions such as the amount of glass material existing per unit area when viewed from the light source when the lighting device is configured. For example, 1 m of the glass fiber woven fabric 20 can be used as a constituent condition for realizing high light transmission with the value of 50% or more.²The weight per hit is 150 g / m²It is preferable to make it below, especially 80 g / m²110 g / m²The following is more preferable from the relationship with other characteristics. Alternatively, the thickness is preferably 95 μm or less, and more preferably 80 μm or more and 90 μm or less. 1m²The hit mass or thickness corresponds to the glass amount described above, and high light transmittance of 50% or more can be obtained by adopting a configuration that satisfies the numerical condition described above for any of them.
[0035]
On the other hand, the value of the parallel light transmittance varies mainly depending on conditions such as the ratio of the gap between the glass fibers per unit area as viewed from the light source. For example, the air permeability of the glass fiber fabric 20 is 20 cm as a constituent condition for realizing high light diffusibility with the value being 5% or less as described above.^Three/ Cm²/ S or less, particularly 15 cm^Three/ Cm²/ S or less is more preferable.
[0036]
Here, the correlation between the air permeability of the glass fiber fabric 20 and the parallel light transmittance / light diffusibility will be described.
[0037]
The air permeability of the glass fiber fabric is the amount of air that passes when a predetermined pressure is applied (see JIS R3420), and is related to the shape of the gap between the glass fibers, the area ratio, and the like. For example, in FIG. 1, the passage A from above the glass fiber fabric 20 passes through the gap between the glass fibers of the warp 21 and the weft 22, so that air can pass through the passage A. On the other hand, since one of the warps 21 exists in the passage B, air cannot pass through the passage B.
[0038]
On the other hand, when the light having the path A as the optical path is considered, the light passes through the gap between the warp 21 and the weft 22, so that the light is not diffused by the glass fiber but remains parallel to the incident light and is opposite to the glass fiber fabric 20. The light is emitted from the light and contributes to an increase in the parallel light transmittance. On the other hand, considering the light having the path B as the optical path, the light passes through one of the warp yarns 21, so that the light is emitted while being diffused by the glass fiber, which contributes to an increase in the diffuse transmittance. .
[0039]
That is, the region where air passes does not correspond to the region where light is not diffused, and the region where air cannot pass substantially corresponds to the region where light is diffused. Therefore, the air permeability of the glass fiber fabric 20 is preferably set. By reducing, parallel light transmittance can be reduced.
[0040]
The above-described conditions for reducing the mass or thickness and the conditions for reducing the air permeability are adjusted and set by selecting the yarn types of the warp yarn 21 and the weft yarn 22 used in the glass fiber fabric 20, the weaving interval, the density, and the like. For example, it is preferable to use a glass fiber having a count of 10 tex to 70 tex, and more preferably 10 tex to 35 tex. In addition, the count of glass fiber is equivalent to the gram number per 1000 m.
[0041]
In addition, it is preferable to process with a sizing agent when weaving into a glass fiber fabric, but in this case, the sizing agent may be removed by performing a deoiling process such as heat cleaning. For example, when the glass fiber sheet is used in an atmosphere of high humidity, it is preferable to perform a process such as heat cleaning.
[0042]
Moreover, it is more preferable that the fiberglass fabric 20 is subjected to a fiber opening process. Increase the volume and area range in which the glass fibers of the warp yarn 21 and the weft yarn 22 are closed, for example, the glass filaments constituting the glass fiber are separated by the fiber opening treatment, and the cross-sectional shape of the glass fiber is flattened. It can be deformed. At this time, since the area seen from the light source side of the gap portion between the glass fibers is reduced, the air permeability can be reduced by the above processing, and the parallel light transmittance can be reduced. At this time, the thickness of the glass fiber fabric 20 is also generally reduced.
[0043]
Various methods such as a method using a high-pressure water jet, a method using a vibro washer, and a method using ultrasonic vibration can be used as a specific method for the fiber opening treatment.
[0044]
In the present embodiment, the fluororesin layer 30 is formed as described above to improve nonflammability and antifouling properties. However, the resin used for the resin coating layer is not limited to the fluororesin. For example, even if a silicone resin is used, improvement of nonflammability and antifouling property can be achieved similarly.
[0045]
Moreover, it is also possible to improve or adjust the light transmittance and light diffusibility of the glass fiber sheet by providing a resin coating layer. In such a case, in addition to the above-described fluororesin and silicone resin, any material that is flexible and can be applied to a glass fiber fabric is applicable. For example, natural rubber, synthetic rubber, Various types of resins such as vinyl chloride resin, ethylene vinyl acetate copolymer resin, acrylic resin, polyurethane resin, polyester resin, polyethylene resin, and polypropylene resin can be used.
[0046]
As a method of forming a resin coating layer on a glass fiber fabric, there are various methods such as a method of impregnating a glass fiber fabric with a resin varnish, a coating method, a spraying method, and a method of processing and sealing a resin sheet on a glass fiber fabric. The method can be used. In particular, in order to improve the workability of the resin coating layer forming step and improve the uniformity of the coating layer, it is preferable to use a method of processing and sealing the resin sheet.
[0047]
The thickness of the resin coating layer and the amount of resin are 5 g / m in order to sufficiently ensure antifouling properties and durability.²In order to prevent a decrease in light transmittance, 500 g / m is preferable.²The following is preferable. A particularly suitable range is 50 g / m.²300 g / m²More preferably, it is as follows. Moreover, in the case of a resin sheet, it is preferable that the thickness shall be 50 micrometers or more and 200 micrometers or less from points, such as ensuring antifouling property and durability, and workability | operativity of a coating process. In addition, when forming a resin film layer by the method of impregnating, the method of apply | coating, etc., the resin film layer is formed in the state which osmose | permeated the inside of the glass fiber fabric and was partially integrated.
[0048]
The glass fiber fabric 20 is preferably impregnated with an adhesive substance in advance for the purpose of improving the durability of the glass fiber sheet 10. As an adhesive substance, well-known adhesives, such as a silane coupling agent normally used as a glass fiber processing agent, can be used, for example. This adhesive substance can satisfactorily bond the glass fiber fabric and the resin coating layer. However, since the adhesive substance adheres to the surface of each glass fiber, it hardly affects the light transmission characteristics and air permeability of the glass fiber fabric.
[0049]
The glass fiber sheet according to the present invention is not limited to the above-described embodiment, and various modifications and changes in configuration are possible. The composition of the glass fiber used for the glass fiber fabric 20 is not particularly limited, and glasses having various compositions may be used. Further, the cross-sectional shape of the glass filament constituting the glass fiber is not limited to a normal circular shape, and a non-circular shape such as a flat or elliptical shape may be used. When glass fibers made of glass filaments having a non-circular cross-sectional shape are used, the light diffusibility can be further increased, and also from the design aspect that is one of the important elements when applied to a lighting device. It is possible to obtain an excellent glass fiber sheet for light diffusion.
[0050]
Further, the glass fiber woven method is not limited to the plain weave described above, and various woven methods such as twill weave and satin weave can be used. A plain-woven glass fiber fabric can be made into a glass fiber sheet having high weaving efficiency and excellent mechanical strength. Moreover, when a twill weave or satin weave is used, a glass fiber sheet excellent in design can be obtained.
[0051]
Moreover, in resin film layers, such as the fluororesin layer 30, a light-diffusion material can further be added during a resin composition, and the light-diffusion property of the glass fiber sheet 10 can further be improved. As the light diffusing material, for example, glass beads, hollow glass beads, glass fiber powder, flat glass fiber powder and the like can be used. Furthermore, the resin coating layer is not necessarily provided, or may be formed on both surfaces of the glass fiber fabric 20.
[0052]
FIG. 2 is a perspective view showing a partially broken configuration of an embodiment of an illuminating device using the light diffusion glass fiber sheet 10 shown in FIG. In the illuminating device of the present embodiment, the light diffusion glass fiber sheet 10 is fixed so as to cover the entire opening on the lower surface side of the support frame 12, so that the light source 4 such as a fluorescent lamp disposed inside the support frame 12 is provided. The covering light diffusion cover 1 is configured. At this time, the light diffusing glass fiber sheet 10 constitutes the light emitting surface 1 a of the light diffusing cover 1 located below the light source 4, and the side surface 1 b is constituted by the support frame 12. The illuminating device having a light emitting surface 1a having a rectangular shape as shown in the figure is installed and used in a predetermined embedding hole or the like on the ceiling surface, for example.
[0053]
Here, the light diffusion glass fiber sheet 10 is configured so that the total light transmittance is 50% or more and the parallel light transmittance is 5% or less as described above. The light from the light source 4 is transmitted with a high light transmittance to obtain high brightness, and the entire surface is soft with a uniform brightness distribution so that the position, shape, etc. of the light source 4 cannot be visually recognized by being diffused with a high light diffusion degree. A shining lighting device is realized.
[0054]
When the resin coating layer is formed only on one surface of the glass fiber sheet 10 as in the embodiment shown in FIG. 1, the resin coating such as the fluororesin layer 30 is used from the viewpoint of antifouling property. It is preferable to form and install the light diffusion cover 1 so that the layer is on the surface opposite to the light source 4. Further, in the lighting device shown in FIG. 2, the specific structure of the support frame 12 actually composed of a plurality of members / parts, that is, the fixing structure to the ceiling, the fixing of the glass fiber sheet 10 and the light source 4, The support structure and the like are not shown.
[0055]
In addition to the above-described embodiment, the above-described light diffusion glass fiber sheet can be applied to lighting devices having various shapes and light source arrangements. For example, the above-mentioned glass fiber sheet can be used as a material having excellent light transmission, light diffusibility, and high design even in a normal lighting device that is not particularly required to have a large area and light weight.
[0056]
【Example】
The glass fiber sheet for light diffusion according to the present invention will be described with reference to more specific examples. In addition, about each Example and comparative example shown below, the structure and performance are put together in the list shown in FIG.
[0057]
Further, in this table, in addition to the numerical values related to each configuration and performance described below, determination results by visual tests are also shown. In this visual determination, four 40W daylight fluorescent lamps are used as light sources, a light diffusing glass fiber sheet is disposed at a distance of 5 cm to 25 cm from the light sources, and light transmittance is determined by luminance viewed from the opposite side of the light sources. Further, the light diffusibility was visually judged according to the degree of visual recognition of the light source, and the evaluation was performed by ranking in four stages. Here, it shows that it is excellent as a light-diffusion sheet, so that a number is small, and it is practically preferable that it is rank 1 or 2.
[0058]
Example 1
(1) Creation of glass fiber fabric
We used ECE225 1/0 (count 22.5 tex) made by Nittobo for both the warp and weft as glass fibers, and weaved in plain weave with a warp weaving density of 59 yarns / 25 mm and a weft yarn weaving density of 45 yarns / 25 mm. A fiberglass fabric was prepared by opening treatment with a vibro washer.
[0059]
At this time, the obtained glass fiber fabric was 1 m.²The mass per hit is 93.6 g / m², Thickness is 85μm, air permeability is 18cm^Three/ Cm²/ S.
[0060]
(2) Creation of glass fiber sheet
(A) Treatment of glass fiber with adhesive substance
A soft fluororesin (Sefran Soft G-180Y manufactured by Central Glass Co., Ltd.) is dissolved in N, N-dimethylformamide so as to have a solid content of 18% by weight, and a crosslinking agent isocyanate (Coronate manufactured by Dainippon Ink & Chemicals, Inc.). HX) was added in an amount of 0.5 part by weight based on 100 parts by weight of the soft fluororesin to obtain a treatment liquid. The glass fiber woven fabric prepared in (1) was impregnated with this treatment solution and dried by heating to treat the glass fiber woven fabric.
[0061]
(B) Creation of glass fiber sheet
100 parts by weight of a soft fluororesin (Seflan Soft G-180Y manufactured by Central Glass Co., Ltd.), 5 parts by weight of vinylidene fluoride resin, 0.2 parts by weight of polytetrafluoroethylene, 0.3 parts by weight of wax, 0. A film having a thickness of 0.1 mm containing 2 parts by weight and 1.0 part by weight of hollow glass beads (HSC-100C manufactured by Toshiba Barotini Co., Ltd.) is bonded to the treated glass fiber fabric obtained in (a) and light. A glass fiber sheet for diffusion was prepared.
[0062]
At this time, the obtained glass fiber sheet had a total light transmittance of 59.4% and a parallel light transmittance of 4.3%.
[0063]
In the following examples and comparative examples, the method for producing the glass fiber sheet (2) is the same as that in Example 1 described above, and therefore only the production of the glass fiber fabric is shown.
[0064]
Example 2
Nittobo's ECE225 1/0 (count 22.5 tex) is used for the warp as glass fiber, ECD450 1/0 (count 11.2 tex) is used for the weft, the weave density of the warp is 70/25 mm, and the weft density of the weft Were woven in plain weaving in three ways: (1) 65 pieces / 25 mm, (2) 68 pieces / 25 mm, and (3) 70 pieces / 25 mm, and a glass fiber fabric was prepared without performing the fiber opening treatment.
[0065]
At this time, the obtained glass fiber fabric was 1 m.²The weight per hit is (1) 94.3 g / m², (2) 95.6 g / m², (3) 96.5 g / m², Thickness is (1) 81μm, (2) 82μm, (3) 83μm, air permeability is (1) 12cm^Three/ Cm²/ S, (1) 11cm^Three/ Cm²/ S, ▲ 1 ▼ 9cm^Three/ Cm²/ S. The obtained glass fiber sheet had total light transmittance of (1) 60.4%, (2) 59.7%, (3) 58.2%, and parallel light transmittance of (1) 4.7. %, (2) 4.6%, and (3) 4.6%.
[0066]
Example 3
We used ECE225 1/0 (count 22.5 tex) made by Nittobo for both warp and weft as glass fibers, weaved with plain weave with a warp weaving density of 59 yarns / 25 mm and a weft yarn density of 58 yarns / 25 mm. A fiberglass fabric was prepared by opening treatment with a vibro washer.
[0067]
At this time, the obtained glass fiber fabric was 1 m.²The weight per hit is 105.0 g / m², Thickness is 86μm, air permeability is 14cm^Three/ Cm²/ S. The obtained glass fiber sheet had a total light transmittance of 55.4% and a parallel light transmittance of 4.0%.
[0068]
Comparative Example 1
Nittobo's ECE225 1/0 (count 22.5 tex) is used for both the warp and weft as the glass fiber, and the weave density of the warp is 59 yarns / 25 mm and the weave density of the weft yarns is 45 yarns / 25 mm. A glass fiber fabric was prepared without performing the fiber opening treatment.
[0069]
At this time, the obtained glass fiber fabric was 1 m.²The mass per hit is 93.6 g / m², Thickness is 98μm, air permeability is 117cm^Three/ Cm²/ S. Moreover, the obtained glass fiber sheet had a total light transmittance of 61.3% and a parallel light transmittance of 5.6%.
[0070]
Comparative Example 2
We used ECG75 1/0 (count 67.5 tex) made by Nittobo for both the warp and weft as glass fibers, weaved in plain weave with a weft density of 44/25 mm and a weft density of 33/25 mm. A glass fiber fabric was prepared without performing the fiber opening treatment.
[0071]
At this time, the obtained glass fiber fabric was 1 m.²Mass per hit is 207.9 g / m², Thickness is 175μm, air permeability is 5cm^Three/ Cm²/ S. Moreover, the obtained glass fiber sheet had a total light transmittance of 45.1% and a parallel light transmittance of 3.1%.
[0072]
Comparative Example 3
We used ECE225 1/0 (count 22.5 tex) made by Nittobo for both the warp and weft as glass fibers, weaved with plain weave with a weft density of 59/25 mm and a weft density of 58/25 mm. A glass fiber fabric was prepared without performing the fiber opening treatment.
[0073]
At this time, the obtained glass fiber fabric was 1 m.²The weight per hit is 105.0 g / m², Thickness is 105μm, air permeability is 82cm^Three/ Cm²/ S. The obtained glass fiber sheet had a total light transmittance of 57.0% and a parallel light transmittance of 5.8%.
[0074]
Comparison between Example and Comparative Example
Example 1 uses a glass fiber with a count of 22.5 tex and is subjected to a fiber opening treatment.²Both the hit weight and air permeability, or the thickness and air permeability satisfy the preferable constitutional conditions of the glass fiber fabric, and thereby, a glass fiber sheet having both high light transmission and light diffusibility is obtained. . In this embodiment, a resin coating layer is provided on one surface of the glass fiber fabric, but the effect of increasing the light diffusibility by this is small compared to the effect of the glass fiber fabric, and the light transmittance Is only about 2% lower. That is, in this configuration, even when the glass fiber sheet is formed only from the glass fiber fabric, the conditions of the total light transmittance of 50% or more and the parallel light transmittance of 5% or less are satisfied (the same applies to other examples).
[0075]
In Example 2, a thin 11.5 tex glass fiber is used as the weft, and the weave density is changed in three ways to create a sheet. In this example, the fiber-opening treatment is not performed, but the preferred glass fiber fabric configuration conditions and the light transmission characteristics of the glass fiber sheet are obtained by the glass fiber and the weave density.
[0076]
Further, Example 3 is obtained by increasing the weaving density of the wefts compared to Example 1, and 1 m²Although the total light transmittance is slightly reduced due to the increase in the hit weight, the condition of 50% or more is sufficiently satisfied, and the air permeability and the parallel light transmittance are further higher than those in Example 1. Has been reduced.
[0077]
On the other hand, Comparative Example 1 was not subjected to the fiber opening treatment with the same configuration as Example 1, and the air permeability was very large. Therefore, the parallel light transmittance increased to 5% or more, which is sufficient. Light diffusivity is not obtained.
[0078]
Moreover, the comparative example 2 uses 67.5 tex and a slightly thick glass fiber, and has not performed the fiber-spreading process.²The hit mass and thickness are large, and the total light transmittance is reduced to 50% or less, so that sufficient light transmittance is not obtained.
[0079]
Further, Comparative Example 3 was not subjected to the fiber opening treatment in the same configuration as Example 3, and although the thickness was slightly increased, the air permeability was increased particularly and the parallel light transmittance was 5% or more. However, sufficient light diffusivity is not obtained.
[0080]
As described above, all of the glass fiber sheets of Examples 1 to 3 have both improved light transmittance and light diffusibility, and have excellent properties as a light diffusion sheet. On the other hand, the glass fiber sheets of Comparative Examples 1 to 3 do not have suitable characteristics for one of light transmittance and light diffusibility.
[0081]
【The invention's effect】
As described in detail above, the glass fiber sheet for light diffusion according to the present invention has the following effects. That is, in the glass fiber sheet for light diffusion using a glass fiber fabric as a base fabric, the configuration of the glass fiber sheet, particularly the configuration of the glass fiber base fabric, is adjusted and optimized, and the total light transmittance is 50% for the light transmission characteristics. As described above, by configuring the parallel light transmittance to be 5% or less, it is possible to realize a light diffusion sheet that realizes sufficient light transmittance at the same time under the condition of high light diffusibility. As a constituent condition of the glass fiber fabric, for example, 1 m²Suitable conditions can be set and controlled by the hit mass, thickness, air permeability, and the like.
[0082]
By applying such a light diffusing glass fiber sheet to a lighting device as a light diffusing sheet, light is transmitted and diffused from the light emitting surface with sufficiently high luminance and a uniform luminance distribution without the light source being visually recognized. Thus, an illumination device capable of performing illumination with soft light can be obtained. In addition, it is possible to provide a lighting device that is superior in design as compared with the case where a resin sheet or frosted glass is used.
[Brief description of the drawings]
FIG. 1 is an enlarged perspective view schematically showing a configuration of an embodiment of a glass fiber sheet for light diffusion according to the present invention.
FIG. 2 is a partially cutaway perspective view showing a configuration of an embodiment of an illumination device using the light diffusion glass fiber sheet shown in FIG.
FIG. 3 is a table showing the configuration and performance of a glass fiber sheet for light diffusion with respect to examples and comparative examples.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Light diffusion cover, 1a ... Light emission surface, 1b ... Side surface, 10 ... Light diffusion glass fiber sheet, 12 ... Support frame, 20 ... Glass fiber fabric, 21 ... Warp, 22 ... Weft, 30 ... Fluorine resin layer, 4 ... Light source.

Claims (4)

A glass fiber sheet configured with a glass fiber woven fabric as a base fabric that transmits and diffuses incident light with a predetermined light transmission property,
The glass fiber woven fabric is made by plain weaving with glass fibers composed of a plurality of glass filaments, and has a mass of 80 g / m ² or more and 110 g / m ² or less and an air permeability of 20 cm ³ / cm ² / s or less. And
The glass fiber count of the warp and weft used for the glass fiber fabric is 10 tex to 70 tex,
A resin film layer made of a fluororesin or a silicone resin is formed on at least one surface side of the glass fiber fabric,
The light diffusing glass fiber sheet is characterized in that the total light transmittance is 50% or more and the parallel light transmittance is 5% or less. The resin coating layer has a resin amount of 50 g / m. ² 300 g / m ² The glass fiber sheet for light diffusion according to claim 1, wherein: The glass fiber fabric for light diffusion according to claim 1 or 2 , wherein the glass fiber fabric is subjected to fiber opening treatment. It is an illuminating device using the glass fiber sheet for light diffusion as described in any one of Claims 1-3 ,
A light source that generates light used for illumination;
A light diffusion cover, which is formed by fixing the light diffusion glass fiber sheet to a predetermined support frame, and is installed so as to cover the light source,
The light from the light source is transmitted and diffused by the light diffusion glass fiber sheet of the light diffusion cover and emitted.

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