Fabric for screen

Abstract

To provide a fabric for a screen which improves ventilation without impairing light-shielding property.SOLUTION: In a fabric for a screen so that warps 20 cross each other, skipping a plurality of wefts 10, the wefts 10 and the warps 20 each have a circular cross section, and in a region where the plurality of wefts 10 are aligned vertically, a ratio Ph / φh of a diameter φh of the weft 10 to a pitch Ph of the weft 10 is set to 1.66≤Ph / Φh<4.81, and a diameter Φv of the warp 20 and a pitch Pv of the warp 20 are set so that an opening rate O is 35.00%≤O≤60.00%.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a screen fabric. [Background technology]

[0002] As a screen fabric that takes into consideration light blocking properties, there is a type of fabric that uses a woven fabric woven so that multiple weft threads are skipped and warp threads cross each other, such as satin weave (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-21272 Summary of the Invention [Problem to be solved by the invention]

[0004] This type of screen fabric, designed with light blocking properties in mind, is set to a light blocking rate of over 99.975%, for example. Therefore, as shown in the area enclosed by the two-dot chain line in Figure 5, the opening rate is extremely low, and when the screen fabric is placed over an opening in a building, it is difficult to ensure ventilation even when the shoji screen is open. Incidentally, while screen netting can ensure sufficient ventilation, as shown in the area enclosed by the dashed line in Figure 5, it cannot be expected to function as a light blocker.

[0005] In view of the above circumstances, an object of the present invention is to provide a screen fabric that can improve ventilation without impairing light-blocking properties. [Means for solving the problem]

[0006] In order to achieve the above object, the screen fabric of the present invention is a screen fabric woven so that warp threads cross each other with a plurality of weft threads skipped, and is characterized in that the weft threads and the warp threads each have a circular cross section, and in the area where the plurality of weft threads are aligned vertically, the ratio Ph / φh of the diameter dimension φh of the weft thread to the pitch Ph of the weft thread is set to be 1.66≦Ph / Φh<4.81, and the diameter dimension Φv of the warp thread and the pitch Pv of the warp thread are set so that the opening rate O is 35.00%≦O≦60.00%.

[0007] Furthermore, the screen fabric according to the present invention is a screen fabric woven so that warp threads cross each other with a plurality of weft threads skipped, wherein the weft threads have a polygonal cross section that contacts each vertex of the circumscribed square, and the warp threads have a circular cross section, and in the region where the plurality of weft threads are aligned vertically, the ratio Ph / Dh of the side length Dh of the circumscribed square to the pitch Ph of the weft threads is set to 1.65≦Ph / Dh<5.70, and the diameter dimension Φv of the warp threads and the pitch Pv of the warp threads are set so that the opening rate O is 35.00%≦O≦60.00%. [Effects of the Invention]

[0008] According to the present invention, by setting the ratio Ph / φh of the weft diameter φh to the weft pitch Ph so that it satisfies 1.66≦Ph / Φh<4.81, the solar altitude that can be blocked by the upper and lower wefts can be set within the range of 53.0°≦θ<78.0°. This prevents direct sunlight from being felt indoors in the summer. Therefore, if the warp diameter Φv and the warp pitch Pv are set so that the opening ratio satisfies this condition and satisfies 35.00%≦θ≦60.00%, it is possible to ensure ventilation without compromising light-blocking properties.

[0009] According to the present invention, by setting the ratio Ph / Dh of the weft side length Dh to the weft pitch Ph so that it satisfies 1.65≦Ph / Dh<5.70, the solar altitude that can be blocked by the upper and lower wefts can be set within the range of 33.0°≦θ<78.0°. This prevents direct sunlight from being felt indoors in the summer. Therefore, if the warp diameter Φv and the warp pitch Pv are set so that the opening ratio satisfies this condition and satisfies 35.00%≦θ≦60.00%, it is possible to ensure ventilation without compromising light-blocking properties. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is an enlarged conceptual diagram of a screen fabric according to a first embodiment of the present invention, viewed from the front side. [Figure 2] 2A and 2B show the main part of the screen fabric shown in FIG. 1, where (a) is a cross-sectional view of the weft yarn and (b) is a cross-sectional view of the screen fabric. [Figure 3] 1 is a graph showing the relationship between the solar shading height and the ratio of the pitch to the diameter of the weft yarn. [Figure 4] This shows the solar shading height of the screen fabric shown in Figure 1, where (a) is a conceptual diagram showing the state of sunlight passing through the screen fabric, and (b) is a conceptual diagram showing the relationship between the pitch and diameter of the weft yarn for calculating the solar shading height θ. [Figure 5] 1 is a graph showing the relationship between the opening rate and the air permeability of a screen fabric. [Figure 6] This is a table showing reference examples and adjustment examples of screen fabrics in which the solar shading level and aperture ratio are set by the diameter and pitch of the weft threads and the diameter and pitch of the warp threads. [Figure 7] 1 is a table showing examples and comparative examples of screen fabrics in which the solar shading level and aperture ratio are set by the diameter and pitch of the weft yarns and the diameter and pitch of the warp yarns. [Figure 8] 10A and 10B are enlarged conceptual views of a screen fabric according to a second embodiment of the present invention, where (a) is a cross-sectional view of a weft yarn and (b) is a cross-sectional view of the screen fabric. [Figure 9] FIG. 9 is a conceptual diagram showing the relationship between the pitch of weft yarns and the side length for calculating the solar shading height θ of the screen fabric shown in FIG. 8. [Figure 10] This is a table showing reference examples and adjustment examples of screen fabrics in which the solar shading level and aperture ratio are set by the side length and pitch of the weft threads and the diameter and pitch of the warp threads. [Figure 11] 1 is a table showing examples and comparative examples of screen fabrics in which the solar shading level and aperture ratio are set by the side length and pitch of the weft threads and the diameter and pitch of the warp threads. [Figure 12] 10A and 10B are enlarged conceptual views of a modified screen fabric, where (a) is a cross-sectional view of a weft yarn and (b) is a cross-sectional view of the screen fabric. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the screen fabric according to the present invention will be described in detail below with reference to the accompanying drawings.

[0012] (Embodiment 1) 1 and 2 conceptually show the front side of a screen fabric according to a first embodiment of the present invention. The screen fabric exemplified here is a woven fabric woven so that warp threads 20 cross each other, skipping multiple weft threads 10, as in satin weave. More specifically, a satin (5x2; 5-ply satin with 2 skips) weave fabric is exemplified.

[0013] The weft threads 10 and warp threads 20 each have a substantially circular cross section and are provided with light-blocking properties by pigments or dyes. More specifically, the weft threads 10 have a diameter φh of 0.10 to 1.00 mm (7 tex to 1000 tex for polyester), and the warp threads 20 have a diameter φv of 0.02 to 0.80 mm (0.5 tex to 700 tex for polyester). It is preferable that the diameter φh of the weft threads 10 is larger than the diameter φv of the warp threads 20, with the ratio φv / φh being 0.20 to 0.80. If the ratio φv / φh exceeds 0.80 and the warp threads 20 become thicker, the positions of the weft threads 10 on the surface side become uneven in the thickness direction at the points where the weft threads 10 sink (the circled area indicated by A in FIG. 1). If φv / φh falls below 0.20 and the warp threads 20 become thin, there is a concern that the fabric may break if it is not able to support the weight of the weft threads 10 during long-term outdoor use.

[0014] In the region where multiple weft threads 10 are aligned vertically (e.g., the region indicated by B in Figure 1), the ratio Ph / φh of the diameter φh of the weft threads 10 to the pitch Ph of the weft threads 10 is set to 1.66 ≦ Ph / φh < 4.81. As a result, the solar shading altitude θ can be set to 53.0° ≦ θ < 78.0°, as shown by the solid line in Figure 3. The solar shading altitude θ is the altitude of the sun when the shadow of an upper weft thread 10 overlaps with the lower weft thread 10, as shown in Figure 4. The solar shading altitude θ can be geometrically determined by the diameter φh of the weft threads 10 and the pitch Ph of the weft threads 10. That is, the solar shading altitude θ can be calculated from θ = arccos(φh / Ph) [rad]. The upper limit of the solar shading altitude θ, 78.0°, is the altitude at noon on the summer solstice in Tokyo. The lower limit of the solar shading altitude θ, 55°, is the angle set so that sunlight casts a shadow for five hours around noon on the summer solstice in Tokyo.

[0015] Next, the diameter φv of the warp yarns 20 and the pitch Pv of the warp yarns 20 are set to ensure the desired breathability while satisfying the above-mentioned conditions, and a screen fabric is produced. The air permeability condition is set as the opening rate (= ((Oh × Ov) / (Ph × Pv)) × 100) within the range enclosed by the solid line in Figure 5. In other words, conventionally commonly used shading fabrics have opening rates of less than 35.00%. With this type of shading fabric, it is difficult to achieve a sense of ventilation in light breezes (2 m / s). On the other hand, with opening rates exceeding 60.00%, such as with screen door netting, paper placed near a window can be blown away by gentle breezes (4 m / s). For this reason, the opening ratio is set in the range of 35.00% to 60.00%, and the air permeability measured by the Frazier method is set to 450 to 1100 (cm3 / (cm2 / s). This makes it possible to obtain a screen fabric that ensures the desired light blocking and ventilation properties.

[0016] As shown in Reference Examples 1 to 4 in Fig. 6, even when the diameter φh of the weft yarn 10 and the pitch Ph of the weft yarn 10 satisfy the above-mentioned conditions, when the diameter φv of the warp yarn 20 is 0.15 mm and the pitch Pv of the warp yarn 20 is 0.60 mm, the opening ratio is less than 30.00%. If the diameter of the warp yarn 20 is reduced as in Adjustment Example 1 compared to Reference Example 1, the pitch Pv of the warp yarn 20 is increased, and the opening ratio can be set to 35.00% or more. Similarly, if the pitch Pv of the warp yarn 20 is increased as in Adjustment Examples 2 to 4 for Reference Examples 2 to 4, respectively, the opening ratio can be set to 35.00% or more. Incidentally, if the diameter φh of the weft thread 10 and the pitch Ph of the weft thread 10 do not satisfy the above-mentioned conditions, the solar shading altitude θ will be 78.0° or more, as in Reference Examples 5 and 6, and the shading rate will be less than 80% when the solar altitude θ1 = 70°, which is undesirable. The pitch Pv of the warp threads 20 is preferably set in the range of 0.20 to 2.30 mm so that the ratio to the diameter of the warp threads 20, Pv / φv, is 2.20 to 17.50. However, in order to prevent the entry of insects such as mosquitoes and foreign objects, it is preferable that the length and width dimensions Oh and Ov of the opening are both set to not exceed 1.50 mm.

[0017] Fig. 7 shows examples of structures of Examples 1 to 8 of screen fabrics that satisfy the above-mentioned conditions, and Comparative Examples 1 to 8 of screen fabrics that correspond to Examples 1 to 8, respectively. Below, the characteristic parts of the screen fabric according to the present embodiment 1 will be described with reference to Fig. 7.

[0018] Example 1 The diameter of the weft yarn 10 was set to φh = 0.20 mm (300 denier, 333 dtex), the pitch of the weft yarn 10 to Ph = 0.40 mm, the diameter of the warp yarn 20 to φv = 0.15 mm (160 denier, 178 dtex), and the pitch of the warp yarn 20 to Pv = 0.50 mm. A screen fabric was woven with a solar shading altitude θ of 60.00° and an opening rate of 35.00%. This screen fabric achieved a shading rate of 91% when the solar altitude θ = 70°, ensuring the desired shading performance. Furthermore, a slight draft was felt in light breezes, and the paper near the window did not fly up even in gentle breezes.

[0019] (Comparative Example 1) A screen fabric was woven by reducing the pitch Pv of the warp yarns 20 to 0.47 mm compared to Example 1. With this screen fabric, the shading rate was 91% when the solar altitude θ1 was 70°, as in Example 1, but the opening rate was reduced to 34.04%, so no ventilation was felt in light breezes.

[0020] Example 2 A screen fabric was woven using weft yarns 10 and warp yarns 20 with the same diameter dimensions as in Example 1, with the pitch Ph of the weft yarns 10 reduced to 0.38 mm and the pitch Pv of the warp yarns 20 increased to 0.58 mm. This screen fabric had a solar shading height θ of 58.24° and an opening rate of 35.12%, confirming that it had the desired light-blocking properties and breathability.

[0021] (Comparative Example 2) A screen fabric was woven by reducing the pitch Pv of the warp yarns 20 to 0.54 mm compared to Example 2. With this screen fabric, the solar shading height θ was 58.24°, as with Example 2, but the opening rate was reduced to 34.21%, so ventilation was not felt in light breezes.

[0022] Example 3 A screen fabric was woven using weft yarns 10 and warp yarns 20 with the same diameter dimensions as in Example 1, with the pitch Ph of the weft yarns 10 increased to 0.89 mm and the pitch Pv of the warp yarns 20 increased to 0.52 mm. This screen fabric had a solar shading height θ of 77.01° and an opening rate of 58.77%, confirming that it had the desired light-blocking properties and breathability.

[0023] (Comparative Example 3) A screen fabric was woven by increasing the pitch Ph of the weft yarns 10 to 0.97 mm compared to Example 3. In this screen fabric, the ratio Ph / φh of the diameter dimension φh of the weft yarns 10 to the pitch Ph of the weft yarns 10 was 4.85 mm, the solar shading altitude θ was 78.10°, and the opening rate was 60.18%. As a result, even in gentle breezes, gusts of wind strong enough to blow up paper near the window entered the fabric. Furthermore, when the solar altitude θ1 was 70°, the shading rate was undesirably 77%.

[0024] Example 4 A screen fabric was woven with the weft yarn 10 diameter φh = 0.50 mm (1800 denier, 1998 dtex), the weft yarn 10 pitch Ph = 0.90 mm, the warp yarn 20 diameter φv = 0.30 mm (650 denier, 722 dtex), and the warp yarn 20 pitch Pv = 1.50 mm. This screen fabric had a solar shading height θ of 56.25° and an opening rate of 35.56%, confirming that it had the desired light-blocking properties and breathability.

[0025] Comparative Example 4 A screen fabric was woven by reducing the pitch Ph of the weft yarn 10 to 0.85 mm compared to Example 4. With this screen fabric, the opening rate was reduced to 32.94%, so that ventilation could not be felt in light breezes.

[0026] Example 5 A screen fabric was woven using weft yarns 10 and warp yarns 20 with the same diameter dimensions as in Example 4, and the pitch Ph of the weft yarns 10 was increased to 2.00 mm. This screen fabric had a solar shading altitude θ of 75.52° and an opening rate of 60.00%, confirming that it had the desired light-blocking properties and breathability.

[0027] (Comparative Example 5) A screen fabric was woven by increasing the pitch Ph of the weft yarn 10 to 2.10 mm compared to Example 5. With this screen fabric, the solar shading height θ was 76.23°, so there was no problem with the shading performance, but the opening rate was 60.95%, and in gentle breezes, gusts of wind strong enough to blow up paper near the window could enter.

[0028] Example 6 A screen fabric was woven by setting the diameter of the weft yarn 10 φh = 0.70 mm (3500 denier, 3885 decitex), the pitch of the weft yarn 10 Ph = 1.30 mm, the diameter of the warp yarn 20 φv = 0.30 mm, and the pitch of the warp yarn 20 Pv = 1.50 mm. With this screen fabric, the solar shading height θ was 57.42° and the opening rate was 36.92%, confirming that it had the desired light-blocking properties and breathability.

[0029] (Comparative Example 6) A screen fabric was woven by reducing the pitch Ph of the weft yarn 10 to 1.20 mm compared to Example 6. With this screen fabric, the solar shading height θ was 54.31°, which was sufficient for shading, but the opening rate was 33.33%, and ventilation was not felt in light breezes.

[0030] Example 7 A screen fabric was woven with the weft yarn 10 diameter φh = 0.70 mm, the weft yarn 10 pitch Ph = 2.10 mm, the warp yarn 20 diameter φv = 0.50 mm (1800 denier, 1998 decitex), and the warp yarn 20 pitch Pv = 1.90 mm. This screen fabric had a solar shading height θ of 70.53° and an opening rate of 49.12%, confirming that it had the desired light-blocking properties and breathability.

[0031] (Comparative Example 7) A screen fabric was woven by increasing the pitch Ph of the weft yarn 10 to 1.50 mm compared to Example 7. This screen fabric has a solar shading height θ of 71.45° and an opening rate of 51.14%, which are not problematic, but the vertical and horizontal dimensions Oh and Ov of the openings both exceed 1.50 mm. This is therefore undesirable because there is a concern that insects (mosquitoes) may pass through the openings.

[0032] Example 8 A screen fabric was woven by reducing the pitch Pv of the warp yarns 20 to 1.10 mm compared to Example 7. Although the opening rate of this screen fabric was reduced to 36.36% compared to Example 7, it was confirmed that the desired light-blocking properties and breathability were maintained.

[0033] (Comparative Example 8) A screen fabric was woven by reducing the pitch Pv of the warp yarns 20 to 1.00 mm in comparison with Example 8. With this screen fabric, the opening rate was reduced to 33.33% compared to Example 7, and so ventilation was not felt in light winds.

[0034] (Embodiment 2) In the above-described first embodiment, we have exemplified weft yarns 10 having a circular cross section, but the cross section of the weft yarn is not necessarily limited to a circular one, and may be a square cross section as shown in the second embodiment of Figure 8. Below, we will explain a screen fabric in which weft yarns 11 having a square cross section are used. Although not explicitly shown in the figures, the second embodiment also exemplified a woven fabric in which warp yarns 20 cross each other with a plurality of weft yarns 11 skipped, as in a satin weave.

[0035] The weft thread 11 has a square cross section, while the warp thread 20 has a substantially circular cross section, as in the first embodiment. The weft thread 11 and the warp thread 20 are each provided with light-blocking properties by pigments or dyes. In a more specific example, the weft thread 11 has a side length Dh of 0.10 to 1.00 mm (7 tex to 1000 tex in the case of polyester), and the warp thread 20 has a diameter φv of 0.02 to 0.80 mm (0.5 tex to 700 tex in the case of polyester). However, it is preferable that the side length Dh of the weft thread 11 is greater than the diameter φv of the warp thread 20, such that φv / Dh = 0.20 to 0.80.

[0036] The ratio Ph / Dh of the side length Dh of the weft thread 11 to the pitch Ph of the weft thread 11 is set to 1.65≦Ph / Dh<5.70. This allows the solar shading altitude θ to be set to 33.0°≦θ<78.0°, as shown by the dashed line in Figure 3. The solar shading altitude θ is the altitude of the sun when the shadow of the upper weft thread 11 overlaps the lower weft thread 11, as shown in Figure 9. It is geometrically determined by the side length Dh of the weft thread 11 and the pitch Ph of the weft thread 11. That is, the solar shading altitude θ can be calculated from θ = arctan((Ph-Dh) / Dh) [rad]. The upper limit of the solar shading altitude θ, 78.0°, is a value set based on the meridian altitude in Tokyo. The lower limit of the solar shading altitude θ, 33.0°, is an angle set so that sunlight on the summer solstice casts a shadow for nine hours before and after meridian in Tokyo.

[0037] Next, the diameter φv of the warp yarns 20 and the pitch Pv of the warp yarns 20 are set to ensure the desired breathability while satisfying the above conditions, to produce a screen fabric. As with the first embodiment, the breathability conditions are set such that the opening ratio is in the range of 35.00% to 60.00%, and the air permeability measured by the Frazier method is 450 to 1100 (cm3 / (cm2 / s)). This makes it possible to obtain a screen fabric that ensures the desired light-blocking properties and breathability.

[0038] As shown in Reference Examples 1 to 5 in Fig. 10, even when the side length Dh of the weft yarn 11 and the pitch Ph of the weft yarn 11 satisfy the above-mentioned conditions, the opening ratio is less than 30.00% when the diameter φv of the warp yarn 20 is 0.15 mm and the pitch Pv of the warp yarn 20 is 0.60 mm. By reducing the diameter of the warp yarn 20 or increasing the pitch Pv of the warp yarn 20 as in Adjustment Example 1 for Reference Example 1, the opening ratio can be set to 35.00% or more. Similarly, by increasing the pitch Pv of the warp yarn 20 as in Adjustment Examples 2 to 5 for Reference Examples 2 to 5, respectively, the opening ratio can be set to 35.00% or more. If the side length Dh of the weft threads 11 and the pitch Ph of the weft threads 11 do not satisfy the above-mentioned conditions, the solar shading altitude θ will be 78.0° or more, as in Reference Examples 6 and 7, and the shading rate will be less than 80% when the solar altitude θ1 is 70°, which is undesirable. Furthermore, the aperture rate will exceed 60.00%, which may cause the paper near the window to fly up. It is preferable that the pitch Pv of the warp threads 20 be set in the range of 0.20 to 2.30 mm, and that the ratio of the pitch Pv to the diameter of the warp threads 20 be Pv / φv = 2.20 to 17.50. To prevent the entry of insects such as mosquitoes and other foreign objects, it is preferable that both the length and width of the apertures be set to no more than 1.50 mm.

[0039] Fig. 11 shows examples of the structure of Examples 1 to 4 of screen fabrics that satisfy the above-mentioned conditions, and Comparative Examples 1 to 4 of screen fabrics that correspond to Examples 1 to 4, respectively. Below, the characteristic parts of the screen fabric according to the present invention will be described with reference to Fig. 11.

[0040] Example 1 The weft yarn 11 side length Dh = 0.20 mm (300 denier, 333 dtex), the weft yarn 11 pitch Ph = 0.40 mm, the warp yarn 20 diameter φv = 0.15 mm (160 denier, 178 dtex), and the warp yarn 20 pitch Pv = 0.50 mm were set to create a screen fabric with an opening rate of 35.00% at a solar shading altitude θ of 45.00°. This screen fabric achieved a shading rate of 91% when the solar altitude θ1 = 70°, ensuring the desired shading performance. Furthermore, a slight draft was felt in light breezes, and the paper near the window did not fly up even in gentle breezes.

[0041] (Comparative Example 1) A screen fabric was woven by reducing the pitch Ph of the weft yarn 11 to 0.39 mm compared to Example 1. With this screen fabric, the solar shading height θ was 43.53°, but the opening rate was reduced to 34.10%, so ventilation could not be felt in light breezes.

[0042] Example 2 In Example 1, the pitch Ph of the weft yarns 11 was reduced to 0.33 mm, while the pitch Pv of the warp yarns 20 was increased to 1.35 mm to create a screen fabric. This screen fabric had an opening rate of 35.02% at a solar shading altitude θ of 33.02°, confirming that it had the desired shading and breathability. The shading rate was 94% when the solar altitude θ1 was 70°.

[0043] (Comparative Example 2) A screen fabric was woven by reducing the pitch Pv of the warp yarns 20 to 1.10 mm compared to Example 2. With this screen fabric, the solar shading height θ was 33.02°, as with Example 2, but the opening rate was reduced to 34.02%, so ventilation was not felt in light breezes.

[0044] Example 3 A screen fabric was woven by increasing the pitch Ph of the weft yarns 11 to 0.80 mm and the pitch Pv of the warp yarns 20 to 0.75 mm compared to Example 1. This screen fabric had a solar shading altitude θ of 71.57° and an opening rate of 60.00%, confirming that it had the desired light-blocking properties and breathability.

[0045] (Comparative Example 3) A screen fabric was woven by increasing the pitch Ph of the weft yarn 11 to 0.90 mm compared to Example 3. With this screen fabric, the solar shading height θ was 74.05°, which was not a problem, but the opening rate was 62.22%, and in gentle breezes, gusts of wind strong enough to blow up paper near the window could enter.

[0046] Example 4 The screen fabric was woven with the following settings: side length Dh of the weft yarn 11 = 0.70 mm, pitch Ph of the weft yarn 11 = 2.10 mm, diameter φv of the warp yarn 20 = 0.50 mm, and pitch Pv of the warp yarn 20 = 1.89 mm. This screen fabric had a solar shading height θ of 63.43° and an opening rate of 49.03%, confirming that it had the desired light-blocking properties and breathability.

[0047] Comparative Example 4 In Example 4, the pitch Ph of the weft yarns 11 was increased to 2.20 mm, and the pitch Pv of the warp yarns 20 was increased to 2.10 mm to create a screen fabric. This screen fabric had a solar shading height θ of 64.98° and an opening rate of 51.95%, which were acceptable, but both the length and width of the openings exceeded 1.50 mm. This is undesirable because there is a concern that insects (mosquitoes) could pass through the openings.

[0048] In the above-mentioned second embodiment, the weft thread 11 has been exemplified as having a square cross section, but it is also possible to weave the screen fabric under the same conditions as in the second embodiment even if the weft thread 12 has a polygonal cross section (a four-pointed star shape in the illustrated example) that touches each vertex of the circumscribing square 12a, as shown in the modified example of Figure 12.

[0049] In addition, in the above-described embodiment, the weft threads 10, 11, 12 and the warp thread 20 are exemplified as threads that have been given light-blocking properties using pigments or dyes, but it is also possible to apply a light-blocking resin treatment to the weft threads or the entire fabric, provided that the openings in the fabric are not blocked.

[0050] As described above, the screen fabric according to the present invention is a screen fabric woven so that warp threads cross each other with a plurality of weft threads skipped, and is characterized in that the weft threads and the warp threads each have a circular cross section, and in the region where the plurality of weft threads are aligned vertically, the ratio Ph / φh of the diameter φh of the weft thread to the pitch Ph of the weft thread is set to be 1.66≦Ph / Φh<4.81, and the diameter Φv of the warp thread and the pitch Pv of the warp thread are set so that the opening rate O is 35.00%≦O≦60.00%. According to this invention, by setting the ratio Ph / φh of the weft diameter φh to the weft pitch Ph so that it satisfies 1.66≦Ph / Φh<4.81, the solar altitude that can be blocked by the upper and lower wefts can be set within the range of 53.0°≦θ<78.0°. This prevents direct sunlight from being felt indoors in the summer. Therefore, if the warp diameter Φv and the warp pitch Pv are set so that the opening ratio satisfies this condition and satisfies 35.00%≦θ≦60.00%, it is possible to ensure ventilation without compromising light-blocking properties.

[0051] Furthermore, the present invention is characterized in that in the above-mentioned screen fabric, the diameter φh of the weft yarns is set to be larger than the diameter φv of the warp yarns. According to this invention, it is possible to prevent the position of the weft yarn from becoming uneven in the thickness direction at the point where the weft yarn sinks on the surface side.

[0052] Furthermore, the present invention is characterized in that, in the above-mentioned screen fabric, the diameter dimension φh of the weft yarn is set in the range of 0.10 mm < φh < 1.00 mm, and the ratio φv / φh of the diameter dimension φv of the warp yarn to the diameter dimension φh of the weft yarn is set to 0.20 ≦ φv / φh ≦ 0.80. According to the present invention, there is no concern of fabric breakage even when used outdoors for a long time.

[0053] Moreover, the fabric for a screen according to the present invention is a fabric for a screen woven such that warp threads cross while skipping a plurality of weft threads, wherein the weft threads have a polygonal cross-section that contacts each vertex of an externally tangent square, the warp threads have a circular cross-section, and in a region where the plurality of weft threads are aligned vertically, the ratio Ph / Dh of the side length Dh of the externally tangent square to the pitch Ph of the weft threads is set to 1.65 ≦ Ph / Dh < 5.70, and the diameter dimension Φv of the warp threads and the pitch Pv of the warp threads are set such that the aperture ratio O is 35.00% ≦ O ≦ 60.00%. According to the present invention, by setting the ratio Ph / Dh of the side length Dh of the weft thread to the pitch Ph of the weft thread to 1.65 ≦ Ph / Dh < 5.70, it is possible to set the altitude of the sun that can be shielded by the upper weft thread and the lower weft thread to the range of 33.0° ≦ θ < 78.0°. Thereby, it becomes possible to avoid direct sunlight indoors in summer. Therefore, if the diameter dimension Φv of the warp threads and the pitch Pv of the warp threads are set such that the aperture ratio O is 35.00% ≦ O ≦ 60.00% under conditions that satisfy this, it becomes possible to ensure ventilation without impairing the light-shielding property.

[0054] Moreover, the present invention is characterized in that, in the fabric for a screen described above, the side length Dh of the externally tangent square is set to be larger than the diameter dimension φv of the warp threads. According to the present invention, it is possible to suppress a situation where the position of the weft thread becomes uneven in the thickness direction at a point where the weft thread sinks on the surface side.

[0055] Moreover, the present invention is characterized in that, in the fabric for a screen described above, the side length Dh of the externally tangent square is set in the range of 0.10 mm < Dh < 1.00 mm, and the ratio φv / Dh of the diameter dimension φv of the warp threads to the side length Dh of the externally tangent square is set to 0.20 ≦ φv / Dh ≦ 0.80. According to this invention, there is no risk of the fabric breaking even when used outdoors for a long period of time.

[0056] Furthermore, the present invention is characterized in that in the above-mentioned screen fabric, the mutual intervals of the weft threads and the mutual intervals of the warp threads are each set to be less than 1.50 mm. According to this invention, it is possible to prevent insects such as mosquitoes and foreign objects from entering the room.

[0057] Furthermore, the present invention is characterized in that in the above-mentioned screen fabric, the ratio Pv / φv of the diameter dimension φv of the warp yarn to the pitch Pv of the warp yarn is set to 2.20≦Pv / Φv<17.50. According to this invention, a high-strength screen fabric can be woven. [Explanation of symbols]

[0058] 10,11,12 weft threads, 12a circumscribed square, 20 warp threads

Claims

1. A screen fabric woven so that warp threads cross each other with a plurality of weft threads skipped, The weft yarns and the warp yarns each have a circular cross section, In the region where the plurality of wefts are aligned vertically, a ratio Ph / φh of a diameter dimension φh of the weft yarn to a pitch Ph of the weft yarn is set to be 1.66≦Ph / φh<4.81; and wherein the diameter Φv of the warp threads and the pitch Pv of the warp threads are set so that the opening ratio O is 35.00%≦O≦60.00%.

2. 2. The screen fabric according to claim 1, wherein the diameter φh of the weft yarns is set to be larger than the diameter φv of the warp yarns.

3. The screen fabric according to claim 1, characterized in that the diameter dimension φh of the weft yarn is set in the range of 0.10 mm < φh < 1.00 mm, and the ratio φv / φh of the diameter dimension φv of the warp yarn to the diameter dimension φh of the weft yarn is set to 0.20 ≦ φv / φh ≦ 0.

80.

4. A screen fabric woven so that warp threads cross each other with a plurality of weft threads skipped, The weft yarn has a polygonal cross section that contacts each vertex of the circumscribed square, The warp yarns have a circular cross section, In the region where the plurality of wefts are aligned vertically, a ratio Ph / Dh of a side length Dh of the circumscribed square to a pitch Ph of the weft yarn is set to be 1.65≦Ph / Dh<5.70; and wherein the diameter Φv of the warp threads and the pitch Pv of the warp threads are set so that the opening ratio O is 35.00%≦O≦60.00%.

5. 5. The screen fabric according to claim 4, wherein the side length Dh of the circumscribing square is set to be greater than the diameter φv of the warp yarns.

6. The screen fabric according to claim 4, characterized in that the side length Dh of the circumscribed square is set in the range of 0.10 mm < Dh < 1.00 mm, and the ratio φv / Dh of the diameter dimension φv of the warp thread to the side length Dh of the circumscribed square is set to 0.20≦φv / Dh≦0.

80.

7. 5. The screen fabric according to claim 1, wherein the spacing between the weft threads and the spacing between the warp threads are each set to be less than 1.50 mm.

8. 5. The screen fabric according to claim 1, wherein the ratio Pv / φv of the diameter dimension φv of the warp yarns to the pitch Pv of the warp yarns is set to 2.20≦Pv / φv<17.50.

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