Heat-ray-reflecting substrate and window glass

Abstract

A heat-ray-reflecting substrate (10) is provided with a dielectric substrate (11) and a heat-ray-reflecting film (13) provided on at least one main surface of the dielectric substrate (11), the heat-ray-reflecting substrate (10) having a radio-wave-transmissive region (A) on at least a portion of the at least one main surface in plan view, the radio-wave-transmissive region (A) including a first repeating pattern (15) formed from slits (14) in which the heat-ray-reflecting film is not present, and the heat-ray-reflecting film (13) is provided on the at least one main surface of the dielectric substrate (11). The first repeating pattern (15) includes at least two first unit patterns (151a, 151b) extending in the first axial direction, and each of the first unit patterns (151a, 151b) includes a first line portion (154a, 154b) extending in the first axial direction, and a first connection portion (155a, 155b) having a predetermined structure.

Description

Technical Field

[0001] The present invention relates to a heat-reflecting substrate and a window glass. Background Art

[0002] In recent years, in order to prevent global warming, it is generally necessary to reduce power consumption by controlling cooling by air conditioning, etc. In response, attempts have been made to suppress the absorption of heat from sunlight into the vehicle or house by making the windows of vehicles and buildings reflect heat (infrared rays).

[0003] As a method for imparting a heat reflective function to a window or the like, for example, there is a method of forming a thin film (heat reflective film) containing a metal having a heat reflective function such as silver on a substrate such as glass.

[0004] When a substrate having a heat-reflecting function is applied to window glass, for example, high transmittance to radio waves of a predetermined frequency is required. For example, as a method for transmitting radio waves in a frequency band of hundreds of MHz to tens of GHz or more used in the fourth-generation mobile communication system (4G) and the fifth-generation mobile communication system (5G) in recent years, there is a method of partially removing a heat-reflecting film coated on the substrate by a method such as laser etching.

[0005] Among them, as a method of maintaining the heat reflective function and appropriately transmitting radio waves having a specified frequency, a method of forming a periodic pattern composed of multiple lines in the portion where the heat reflective film does not exist, for example, a method of removing the heat reflective film in a manner of forming parallel lines or a grid.

[0006] In the case of removing the heat reflective film by laser etching, the size of the area that can be laser processed in one process is generally limited. For example, although Patent Document 1 describes a method that can laser process a relatively wide area relatively quickly in one process, there is a case where the size of the area that can be laser processed in one process is still insufficient relative to the size of the entire area to be processed. Therefore, in the case of laser processing an area that is larger than the area that can be processed in one process, a pattern of a specified size that can be processed in one process is formed multiple times and continuously configured. As a result, a continuous pattern can be formed in the entire desired area, as in a so-called jigsaw workpiece.

[0007] At this time, in order not to damage the radio wave transmittance and aesthetics, it is ideal that the pattern is not interrupted or offset at the joints of multiple patterns formed in different processes. However, it is difficult to completely control the pattern formation position, and it is necessary to consider a slight error in the pattern formation position during laser processing. In particular, if the pattern is interrupted, it is easy to damage the radio wave transmittance, so in order to suppress this situation, the patterns need to be connected to each other as reliably as possible.

[0008] In contrast, for example, in the case of forming a lattice pattern, by arranging a plurality of lattice patterns formed in different processes so as to partially overlap each other, it is possible to suppress the interruption of the pattern that damages the radio wave transmittance. Patent document 2 describes that a first lattice plane is connected to a closed comb structure of a second lattice plane via an open comb structure, thereby preventing the situation where a double line in the overlapping area is offset and the coated area is not removed.

[0009] Patent Document 1: U.S. Patent Application Publication No. 2013 / 0295300

[0010] Patent Document 2: Japanese Patent Application Publication No. 2017-186251

[0011] However, in the technology described in Patent Document 2, for example, when forming parallel linear patterns, it is difficult to suppress interruptions between a plurality of patterns formed in different steps, and the degree of freedom of selectable patterns is limited. Summary of the invention

[0012] Therefore, an object of the present invention is to provide a heat reflective substrate having high freedom of choice of a pattern that can be formed in a portion where no heat reflective film exists in a radio wave transparent region and excellent reliability by suppressing interruption of the pattern, and a window glass including the heat reflective substrate.

[0013] As a result of intensive studies, the inventors of the present invention have found that the above-mentioned problems can be solved by setting the shape of the pattern formed in the radio wave transparent region in the portion where the heat ray reflecting film does not exist to a predetermined structure, and have completed the present invention.

[0014] That is, the present invention relates to the following 1 to 19.

[0015] 1. A heat reflective substrate, comprising:

[0016] a dielectric substrate; and

[0017] a heat-reflecting film provided on at least one main surface of the dielectric substrate;

[0018] At least one portion of the at least one main surface in a plan view has a radio wave transparent region,

[0019] The radio wave transparent area includes a first repeated pattern formed by slit portions without a heat-reflecting film,

[0020] The first repeating pattern includes at least two first unit patterns extending along a first axial direction,

[0021] The first unit patterns respectively include:

[0022] a first line portion extending along the first axial direction; and

[0023] a first connection portion, which is located at at least one end of the first line portion and is connected to another first unit pattern of the at least two first unit patterns;

[0024] The first connection portion includes a portion extending in a second axial direction different from the first axial direction, and at least a portion of the portion is connected to the first line portion.

[0025] 2. The heat-reflecting substrate according to item 1 above, wherein:

[0026] An angle θ (°) formed by the first axial direction and the second axial direction is 10°≤θ≤120°.

[0027] 3. The heat-reflecting substrate according to 1 or 2 above, wherein:

[0028] The first connection portion is located at both ends of the first line portion.

[0029] 4. The heat reflective substrate according to any one of 1 to 3 above, wherein:

[0030] The radio wave transparent area includes a plurality of the first repeating patterns arranged in parallel.

[0031] 5. The heat-reflecting substrate according to 4 above, wherein:

[0032] The intervals between the first repeating patterns are 100 μm to 10 mm.

[0033] 6. The heat-reflecting substrate according to 4 or 5 above, wherein:

[0034] The first connection portion is not connected to other adjacent first repeating patterns.

[0035] 7. The heat-reflecting substrate according to any one of 4 to 6 above, wherein:

[0036] The length of the components of the first connecting portion perpendicular to the first axial direction is 10% to 80% of the interval between the first repeating patterns.

[0037] 8. The heat-reflecting substrate according to any one of 1 to 7 above, wherein

[0038] The first unit pattern is axially symmetric or rotationally symmetric.

[0039] 9. The heat-reflecting substrate according to any one of 1 to 8 above, wherein:

[0040] The radio wave transparent area further includes a second repeated pattern formed by slit portions,

[0041] The second repeating pattern includes at least two second unit patterns along a third axial direction different from the first axial direction,

[0042] The second unit patterns respectively include:

[0043] a second line portion extending along the third axial direction; and

[0044] a second connecting portion, which is located at at least one end of the second line portion and is connected to another second unit pattern of the at least two second unit patterns,

[0045] The second connection portion includes a portion extending in a fourth axial direction different from the third axial direction, and at least a portion is connected to the second line portion.

[0046] 10. The heat-reflecting substrate according to 9 above, wherein:

[0047] An angle θ (°) formed by the third axial direction and the fourth axial direction is 10°≤θ≤120°.

[0048] 11. The heat-reflecting substrate according to 9 or 10 above, wherein:

[0049] The second connection portion is located at both ends of the second line portion.

[0050] 12. The heat-reflecting substrate according to any one of 9 to 11 above, wherein:

[0051] The radio wave transparent area includes a plurality of the second repeating patterns arranged in parallel.

[0052] 13. The heat-reflecting substrate according to 12 above, wherein:

[0053] The intervals between the second repeating patterns are 100 μm to 10 mm.

[0054] 14. The heat-reflecting substrate according to 12 or 13 above, wherein:

[0055] The second connection portion is not connected to other adjacent second repeating patterns.

[0056] 15. The heat-reflecting substrate according to any one of 12 to 14 above, wherein

[0057] The length of the components of the second connecting portion perpendicular to the third axial direction is 10% to 80% of the interval between the second repeating patterns.

[0058] 16. The heat-reflecting substrate according to any one of 9 to 15 above, wherein

[0059] The second unit pattern is axially symmetric or rotationally symmetric.

[0060] 17. The heat reflective substrate according to any one of 9 to 16 above, wherein

[0061] The radio wave transparent area includes a quadrilateral pattern, which is formed by two of the first repeating patterns arranged in parallel and adjacent to each other, and two of the second repeating patterns arranged in parallel and adjacent to each other, and at least one of the first connecting portion and the second connecting portion is located at the midpoint of at least one side of the quadrilateral.

[0062] 18. The heat-reflecting substrate according to any one of 1 to 17 above, wherein:

[0063] In the radio wave transparent region, the radio wave transmission loss for radio waves having a frequency of 28 GHz is 3 dB or less.

[0064] 19. A window glass comprising the heat-reflecting substrate according to any one of 1 to 18 above.

[0065] According to the present invention, for various patterns that can be formed in a portion where no heat-reflective film is present, a plurality of patterns that can be formed in different processes can be connected more reliably to each other. Thus, it is possible to provide a heat-reflective substrate having a high degree of freedom in selecting patterns that can be formed in a radio wave transparent region and having excellent reliability by suppressing interruption of the pattern, and a window glass having the heat-reflective substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 This is a diagram illustrating one embodiment of the heat reflecting substrate.

[0067] Figure 2 This is a diagram illustrating one embodiment of the heat reflecting substrate.

[0068] Figure 3 This is a diagram schematically illustrating a method of forming a continuous pattern.

[0069] Figure 4 It is a diagram schematically illustrating the conditions of the simulation.

[0070] Figure 5 It is a figure which shows the simulation result of pattern 1.

[0071] Figure 6 It is a figure which shows the simulation result of pattern 2.

[0072] Figure 7It is a diagram showing the simulation results of Pattern 3.

[0073] Figure 8 is a diagram illustrating an embodiment of a first repeating pattern.

[0074] Fig. 9 This is a diagram illustrating a grid pattern.

[0075] Fig.10 The figure schematically illustrates a pattern that matches the size of a unit processing area. DETAILED DESCRIPTION

[0076] Hereinafter, the present invention will be described in detail, but the present invention is not limited to the following embodiments, and can be arbitrarily deformed and implemented within the scope of the gist of the present invention. In addition, the " to " indicating a numerical range is used with the meaning of the numerical values ​​recorded before and after it as the lower limit and upper limit. In the following drawings, the same reference numerals are sometimes marked to illustrate the parts and parts that play the same role, and the repeated description is sometimes omitted or simplified. In addition, in order to clearly illustrate the present invention, the embodiments recorded in the drawings are schematically illustrated, and the size and proportion of the actual product are not necessarily accurately represented. In this specification, the terms such as "vertical" and "parallel" are not intended to strictly meet their definitions, and there may be some errors within the scope of the effect of the present invention. For example, when it is mentioned that a certain straight line A is perpendicular or parallel to other straight lines B, it can also have an inclination within ± 20 ° compared with the situation that the straight line A is strictly perpendicular or parallel to the straight line B.

[0077] The heat-reflecting substrate of the present embodiment (hereinafter also referred to as "the present heat-reflecting substrate") comprises: a dielectric substrate; and a heat-reflecting film, which is arranged on at least one main surface of the dielectric substrate, and at least a portion of the at least one main surface in a plan view has a radio wave transparent area, the radio wave transparent area includes a first repeating pattern formed by a slit portion where the heat-reflecting film does not exist, the first repeating pattern includes at least two first unit patterns extending along a first axial direction, the first unit patterns respectively include: a first line portion, which extends along the first axial direction; and a first connecting portion, which is located at at least one end of the first line portion and is connected to another first unit pattern of the at least two first unit patterns, the first connecting portion includes a portion extending in a second axial direction different from the first axial direction, and at least a portion is connected to the first line portion.

[0078] Figure 1 and Figure 2 This is a diagram illustrating one embodiment of the heat reflecting substrate. Figure 1(A) is a top view of the heat reflective substrate, (B) is an enlarged view of the cross section of (A) at XX line, and (C) is an enlarged view of region Y1 in (A).

[0079] Figure 1 The illustrated heat-reflecting substrate 10 includes: a dielectric substrate 11, and a heat-reflecting film 13 provided on at least one main surface of the dielectric substrate 11. Moreover, at least a portion of the at least one main surface in a plan view has a radio wave transparent region A. The radio wave transparent region A includes a slit portion 14 where the heat-reflecting film 13 does not exist. Here, the radio wave transparent region refers to a region having radio wave transparency due to a predetermined pattern formed by the slit portion. Figure 1 In the example of , a substantially parallel linear pattern formed by the slits 14 is formed on the entire surface of the main surface having the heat-ray reflecting film. Figure 1 In the example of , the entire area on the main surface having the heat radiation reflection film 13 in a plan view is the radio wave transparent area A. On the other hand, Figure 2 As illustrated, a portion of the main surface on which the heat-ray reflecting film 13 is formed may be made into the radio wave transparent region A.

[0080] Here, in Figure 1 , Figure 2 and the following Figure 3 In the embodiment, the slit portion 14 is formed into a substantially parallel linear pattern in which a plurality of first repeating patterns described later are arranged in parallel. Figure 1 (A) and (B), Figure 2 as well as Figure 3 In FIG. 1 , the specific shape of each first repeating pattern is omitted and is represented only as parallel lines.

[0081] As described above, when the slit portion is formed by laser etching, for example, the size of the area that can be laser processed in one process is often limited. Therefore, a pattern matching the size of a unit processing area that can be processed in one process (hereinafter, also referred to as a "unit processing area") is formed and continuously arranged multiple times to form a continuous pattern. Figure 3 1 is a diagram schematically illustrating the method. In a heat-reflecting substrate 10a having a heat-reflecting film 13 on at least one main surface of a dielectric substrate, for example, if patterns (slit portions 14) are formed in different processes in unit processing areas Za, Zb, and Zc, respectively, and each unit processing area is adjacently and continuously arranged in a partially overlapping manner, a continuous pattern can be formed in these three areas. Moreover, for areas other than Za, Zb, and Zc, patterns are repeatedly formed in unit processing areas and continuously arranged, so that a continuous pattern can be formed in a desired area.

[0082] As mentioned above, in Figure 3 In the method illustrated, it is difficult to completely control the pattern forming position, that is, the position of the configuration unit processing area. Therefore, it is necessary to consider the situation that a slight offset occurs in the pattern forming position during processing. In contrast, the inventors of the present invention have conducted in-depth research and found that by setting the shape of the pattern formed by the slit portion to a structure including a prescribed repeated pattern, multiple patterns formed in different processes can be more reliably connected to each other, and the present invention has been completed. According to this heat ray reflecting substrate, the interruption of the pattern in the radio wave transparent area is suppressed, so the reliability is excellent. Here, the pattern interruption refers to the interruption of the physical continuity of the slit portion. In addition, the excellent reliability means that the undesirable interruption of the pattern caused by the offset of the pattern forming position is suppressed, so that the radio wave transmittance of the radio wave transparent area is not easily damaged. According to the present heat ray reflecting substrate, the effect of improving reliability can be obtained for relatively diverse pattern shapes, thereby increasing the freedom of selection of patterns corresponding to desired characteristics. Below, such a heat ray reflecting substrate is described in more detail.

[0083] (First repeating pattern)

[0084] As mentioned earlier, Figure 1 and Figure 2 The heat-reflective substrate 10 shown as an example includes a dielectric substrate 11 and a heat-reflective film 13 provided on at least one main surface of the dielectric substrate 11. In addition, at least a portion of the at least one main surface in a plan view has a radio wave transparent region A. The radio wave transparent region A includes a first repeating pattern 15 formed by slit portions 14 where the heat-reflective film 13 does not exist.

[0085] The slit portion is a portion where at least the heat-reflecting film does not exist when the heat-reflecting substrate is viewed from above, and is divided by the heat-reflecting film. In other words, the slit portion is not covered by the heat-reflecting film, and may be in a form where the dielectric substrate is exposed. Alternatively, the slit portion may be in a form where a film (other film) other than the heat-reflecting film described later is provided on the dielectric substrate. The width of the slit portion can be appropriately adjusted according to the desired radio wave transmittance, the device for forming the slit portion, etc., but is preferably 20 μm or more, more preferably 30 μm or more, due to, for example, constraints of the processing technology. On the other hand, from the viewpoint of visibility and heat insulation, the width of the slit portion is preferably 200 μm or less, more preferably 100 μm or less, and further preferably 60 μm or less.

[0086] Figure 1(C) is an enlarged view of the area Y1 in (A), and is a view illustrating the structure of the first repeating pattern. The first repeating pattern 15 includes at least two first unit patterns 151a and 151b extending along the first axial direction. The above-mentioned first unit patterns respectively include: first line portions 154a and 154b, which extend along the above-mentioned first axial direction; and first connecting portions 155a and 155b, which are located at at least one end of the above-mentioned first line portions and are connected to another first unit pattern of the above-mentioned at least two first unit patterns. In other words, the first connecting portion connects the first unit patterns to each other, the first connecting portion 155a is connected to another first unit pattern 151b, and the first connecting portion 155b is connected to another first unit pattern 151a. The first connecting portions 155a and 155b respectively include portions extending in a second axial direction different from the above-mentioned first axial direction, at least a portion of the first connecting portion 155a is connected to the first line portion 154a, and at least a portion of the first connecting portion 155b is connected to the first line portion 154b. This means that the first line portion and the first connection portion are formed without interruption in one first unit pattern.

[0087] The present heat-reflecting substrate includes a first repeating pattern of a radio wave transparent region, thereby becoming a substrate with excellent reliability while suppressing the interruption of the pattern. If a first repeating pattern is taken as an example of an ideally continuous pattern, it can be equivalent to a line extending along the first axial direction. In the case where a line extending along the first axial direction is formed separately in multiple processes, it is ideal to consider making a plurality of short lines extending along the first axial direction continuous along the first axial direction. However, if the offset of the pattern forming position is taken into account, it is difficult to form an ideal line without interruption. Even if it is assumed that the pattern forming positions are intentionally overlapped, if a position offset greater than the width of the slit portion occurs in a direction perpendicular to the first axial direction, the line is easily interrupted. In contrast, in the above-mentioned first repeating pattern, the first unit pattern is respectively provided with a first connecting portion, the first connecting portion includes a first line portion extending along the first axial direction, and a portion at least partially connected to the first line portion and extending along a second axial direction different from the first axial direction. The first connecting portion includes a portion extending along the second axial direction, so that even if the pattern forming position is offset in various directions, it is easy to absorb the offset, thereby obtaining a heat-reflecting substrate with suppressed pattern interruption.

[0088] In addition, the first repeating pattern is a structure connected to the first unit pattern via the first connecting portion along the first axial direction, so it is impossible to form an ideal line itself. However, in this embodiment, by properly connecting the patterns, good radio wave transparency can be ensured in the radio wave transparency area. This situation is explained by the following simulation results.

[0089] Assuming that the following patterns 1 to 3 are infinitely repeated in the X-axis direction and the Y-axis direction respectively, a simulation was performed under the following conditions, in the radio wave transparent region by the slit portion.

[0090] (condition)

[0091] Figure 4 is a diagram schematically illustrating the conditions of the simulation. Figure 4 , a cross-sectional view in the thickness direction of a heat-reflecting substrate 10 having a heat-reflecting film 13 and a slit portion 14 on one main surface of a dielectric substrate 11 is shown as an example. On the heat-reflecting substrate 10, a plane wave of a linearly polarized wave having an electric field in the XZ plane is simulated to be reflected at an angle θ in the XZ plane. in The passing characteristics (radio wave transmission characteristics) of radio waves (TM waves) incident on the dielectric substrate. At this time, the thickness of the heat reflection film is assumed to be 9 nm, the interval between the parallel adjacent slits is assumed to be 1 mm, and the width of the slit is assumed to be 50 μm. The software "HFSS" manufactured by ANSYS was used in the simulation.

[0092] (Pattern 1)

[0093] A lattice-like pattern is formed by overlapping a parallel line pattern including a plurality of straight lines extending in the X-axis direction and a pattern including one straight line extending in the Y-axis direction orthogonal thereto.

[0094] (Pattern 2)

[0095] A lattice pattern is formed by overlapping a pattern of ideally continuous parallel lines including a plurality of straight lines extending in the X-axis direction and a pattern including straight lines extending in the Y-axis direction orthogonal thereto. In pattern 2, since the lattice pattern is offset by 50 μm in the X-axis direction, a straight line extending in the Y-axis direction is interrupted and divided into two lines at a point near the midpoint.

[0096] (Pattern 3)

[0097] An ideally continuous parallel line pattern including a plurality of straight lines extending in the X-axis direction and a first repeating pattern extending in the Y-axis direction orthogonal thereto are formed.

[0098] Figure 5 1 and 2 are diagrams showing simulation results of Pattern 1 , wherein (A) is a diagram showing the structure of Pattern 1 , and (B) is a diagram showing the radio wave transmission characteristics of Pattern 1 . Figure 6 1 and 10 are diagrams showing simulation results of Pattern 2 , wherein (A) is a diagram showing the structure of Pattern 2 , and (B) is a diagram showing the radio wave transmission characteristics of Pattern 2 . Figure 71 and 2 are diagrams showing simulation results of Pattern 3 , wherein (A) is a diagram showing the structure of Pattern 3 , and (B) is a diagram showing the radio wave transmission characteristics of Pattern 3 . Figure 5 (B) Figure 6 (B), and Figure 7 (B) represents the polarization wave in the X-axis direction, based on θ in The value of radio wave transmission at each frequency. In each figure, the smaller the value of radio wave transmission (dB) indicated by the negative value, that is, the larger the absolute value of the negative value, the greater the radio wave transmission loss under this condition, and the worse the radio wave transmission characteristics. Table 1 shows each pattern and each incident angle θ in The radio wave transmission at 28GHz.

[0099]

Table 1

[0100] Table 1

[0101] <![CDATA[Angle of incidence θ in > Pattern 1 Pattern 2 Pattern 3 0° -2.7dB -4.1dB -2.7dB 15° -3.0dB -4.0dB -3.0dB 30° -4.0dB -4.4dB -4.1dB 45° -6.2dB -6.5dB -6.2dB 60° -7.8dB -8.6dB -7.9dB

[0102] according to Figure 5 , in pattern 1 which is an ideally continuous parallel line pattern, at 28 GHz, at θ in =0°, the pass characteristic is -2.7dB, at θ in =15°, the pass characteristic is -3.0 dB. Moreover, the pass characteristic of pattern 2, in which the straight line extending in the Y-axis direction is discontinued in the middle due to the deviation in the X-axis direction, is as follows Figure 6 As shown, it becomes at 28GHz and at θ in =0°, the degradation is -4.1dB, at θ in =15°, the degradation is -4.0 dB. In contrast, in the pattern 3 formed so that the pattern is not interrupted even when the pattern is offset in the X-axis direction due to the presence of the connection portion, as shown in FIG. Figure 7 As shown, at θ in =0°, the pass characteristic is -2.7dB, at θ in =15°, the pass characteristic is -3.0 dB. This is the same performance as the case of an ideally continuous parallel line pattern. That is, in the pattern 2 where there is a break in the pattern formed along the Y-axis direction, although the radio wave transmittance is reduced due to easy reflection of radio waves, in the pattern 3 where the pattern formed along the Y-axis direction is appropriately connected, the pattern 1 formed along the Y-axis direction can have good radio wave transmittance as well.

[0103] Hereinafter, a more preferred embodiment of the first repeating pattern will be described in detail.

[0104] The first repeating pattern includes at least two first unit patterns extending along the first axial direction. The first axial direction may be, for example, any straight line direction on the surface on which the pattern is formed. The first axial direction may also be adjusted according to the desired radio wave to be transmitted, for example, it is preferably a direction orthogonal to the polarization wave plane of the desired radio wave. As a more specific example, if the heat-reflecting substrate is vertically erected relative to the ground and the first axial direction is horizontal relative to the ground, it is easy to obtain a higher radio wave transmittance for vertically polarized radio waves. The first axial direction may also be a direction along any curve within the range that does not hinder the effect of the present invention. The first repeating pattern may be composed only of first unit patterns of the same shape, or it may be composed of a plurality of first unit patterns of different shapes.

[0105] The length of each first unit pattern along the first axial direction is not particularly limited, but may be, for example, equal to or less than the maximum length of the unit processing region along the first axial direction.

[0106] The first unit pattern includes a first line portion extending along the first axial direction. The first line portion is a portion of the first repeating pattern that mainly constitutes a line along the first axial direction. Therefore, the ratio of the length of the first line portion along the first axial direction to the length of the first unit pattern is preferably 90% or more, more preferably 95% or more. The ratio of the length of the first line portion to the length of the first unit pattern is 100% or less.

[0107] The first unit pattern is located at the end of at least one side of the first line portion, and includes a first connection portion connected to another first unit pattern of the at least two first unit patterns. The first connection portion includes a portion extending along a second axial direction different from the first axial direction, at least a portion of which is connected to the first line portion. As long as the second axial direction is in a direction different from the first axial direction, it can also be the direction of any straight line or any curve on the surface where the pattern is formed, just like the first axial direction. In addition, when the first connection portion is located at both ends of the first line portion and when the first repeating pattern contains a plurality of first unit patterns of different shapes, the "second axial direction" of each of the first connection portions does not need to be in the same direction. That is, in a first unit pattern and a first repeating pattern, a plurality of first connection portions with different directions corresponding to the second axial direction may also be mixed.

[0108] Figure 8 1 and 2 are diagrams illustrating an embodiment of a first repeating pattern, and (A) to (D) are diagrams illustrating an embodiment of a first unit pattern, respectively. Figure 8 (E) to (H) are diagrams illustrating how the plurality of first unit patterns illustrated in (A) to (D) are connected via first connecting portions. Figure 8In (A) to (D), the first unit patterns 51a, 51b, 51c and 51d include first line portions 54a, 54b, 54c and 54d, and first connecting portions 55a, 55b, 55c and 55d, respectively. The first unit patterns 51a, 51b and 51d include first connecting portions 55a, 55b and 55d at both ends of the first line portions 54a, 54b and 54d, respectively. The first unit pattern 51c includes a first connecting portion 55c at one end of the first line portion.

[0109] The angle θ (°) formed by the first axial direction and the second axial direction is preferably 10°≤θ≤120°. In this specification, the angle formed by the first axial direction and the second axial direction refers to the smaller angle between the imaginary straight line extending the first line portion toward the first axial direction and the first connecting portion in the second axial direction, that is, the angle greater than 0° and less than 180°. For example, Figure 8 (A) is a diagram illustrating the case where θ is 90°, and (B) is a diagram illustrating the case where θ is 45°. In addition, it is more preferably in the range of 10°≤θ≤90°, further preferably 10°≤θ≤80°, particularly preferably 15°≤θ≤60°, and further particularly preferably 15°≤θ≤45°. When θ is in the above range, the portion of the first connecting portion extending along the second axial direction tends to have a component parallel to the first axial direction and a component parallel to the direction perpendicular thereto with a good balance. Thus, it is easier to absorb the deviation of the pattern forming position in various directions. Alternatively, if θ is less than 90°, it is easy to suppress the situation where the slit portion is mixedly formed in the connection area between the first connecting portion and other first unit patterns connected thereto, and the aesthetics of the radio wave transparent area can be improved.

[0110] In addition, when the first line portion has connecting portions at both ends, the angles formed by the connecting portions may be the same or different, but as described later, the first unit pattern is preferably set to be axially symmetric or rotationally symmetric. That is, the angles θ are preferably set to be the same.

[0111] Preferably, the first connecting portion is located at both ends of the first line portion. Figure 8 In (A), (B) and (D), the first connection portion is located at both ends of the first line portion. Figure 8 As shown in (E), (F) and (H) of FIG. 1 , if the first unit patterns having first connecting portions at both ends of the first line portion are connected to each other, there are two first connecting portions in their connection area that are easy to absorb the deviation of the pattern forming position. As a result, it is easier to absorb the deviation of the pattern forming position in various directions.

[0112] Preferably, the radio wave transparent region includes a plurality of first repeating patterns arranged in parallel. As described above, if an ideally continuous pattern is used as an example, one first repeating pattern can be equivalent to a line extending along the first axis. The radio wave transparent region includes a plurality of first repeating patterns arranged in parallel, thereby forming a plurality of lines arranged in parallel, that is, a pattern equivalent to a parallel linear shape. For example, in Figure 1 In (C), a plurality of first repeating patterns 15 are arranged in parallel. The plurality of first repeating patterns arranged in parallel may be composed only of first repeating patterns of the same shape, or may be composed of a plurality of first repeating patterns having different shapes from each other.

[0113] In the case where the radio wave transparent area includes a plurality of first repeating patterns arranged in parallel, the intervals between the first repeating patterns are preferably 100μm to 10mm. In the case where the radio wave transparent area includes a periodic pattern based on a slit portion, by adjusting its period, radio waves having a desired frequency, etc. can be selectively transmitted. Therefore, the intervals between the first repeating patterns can be appropriately adjusted according to the characteristics of the radio waves to be transmitted. As an example, in the case of wanting to transmit a high frequency band of hundreds of MHz to 100GHz, the intervals between the first repeating patterns are preferably 100μm or more, more preferably 200μm or more, and further preferably 300μm or more. On the other hand, from the same point of view, the interval is preferably less than 10mm, more preferably less than 4000μm, further preferably less than 2000μm, and particularly preferably less than 1000μm. In addition, the intervals between the first repeating patterns refer to the average value of the distances between the first line portions in each first repeating pattern in a direction orthogonal to the first axial direction.

[0114] In the case where the radio wave transparent area includes a plurality of first repeating patterns arranged in parallel, it is preferred that the first connecting portion is not connected to other adjacent first repeating patterns. Thus, the length of the first repeating pattern in a direction perpendicular to the first axial direction is suppressed, so that the shape of the first repeating pattern can be closer to an ideal continuous line.

[0115] It is preferred that the length of the component of the first connecting portion perpendicular to the first axial direction is 10% to 80% relative to the spacing between the first repeating patterns. By making the length of the component perpendicular to the first axial direction greater than 10% relative to the spacing between the first repeating patterns, it is easy to make the size of the connecting portion sufficient and to more easily absorb the deviation of the pattern forming position. The ratio of the length is more preferably greater than 20%, and further preferably greater than 25%. On the other hand, by making the ratio less than 80%, the shape of the first repeating pattern can be closer to an ideal continuous line. In addition, since the size of the first connecting portion can be set to less than a certain level, the coating amount of the heat radiation reflective film in the radio wave transparent area can be relatively increased. This helps to improve the heat radiation reflectivity of the heat radiation reflective substrate and improve the efficiency of forming the slit portion. The ratio is more preferably less than 50%, more preferably less than 45%, and particularly preferably less than 40%. The length of the component of the first connecting portion perpendicular to the first axial direction refers to, for example, Figure 8 The length is shown as H in (B).

[0116] In addition, the above ratio is further described by assuming the following pattern. That is, assuming that in the top view of the heat reflective substrate, by repeating the left and right directions of the paper surface Figure 8 The multiple first repeating patterns of the first unit pattern 51b in (B) are repeated at a prescribed interval in the vertical direction of the paper so as to be arranged in parallel. If one of the first repeating patterns is set as a reference pattern, the reference pattern may have one other adjacent first repeating pattern on its upper and lower sides. As viewed from the first line portion 54b, the first connecting portion 55b of the first unit pattern 51b included in the reference pattern has a component perpendicular to the first axial direction on the upper side, but does not have the component on the lower side. In this case, the ratio of the length of the component perpendicular to the first axial direction to the interval of the first repeating pattern adjacent to the upper side is expressed by H / (interval of the first repeating pattern adjacent to the upper side). On the other hand, with respect to the first repeating pattern adjacent to the lower side, the ratio is 0. In this way, in the case where the component perpendicular to the first axial direction of the first connecting portion is only on one side of the direction perpendicular to the first axial direction (up and down direction) as viewed from the first line portion, the ratio of the component perpendicular to the first axial direction to the interval of the first repeating pattern adjacent to the single side is preferably within the above range. On the other hand, assuming that Figure 8 When the first unit pattern 51d of (D) is arranged in the same repeated manner, the components of the first connecting portion 55d perpendicular to the first axial direction can be said to be located on both sides of the direction perpendicular to the first axial direction (up and down direction) when viewed from the first line portion 54d. In this case, the ratio of the length of the component perpendicular to the first axial direction of the first connecting portion 55d as a whole to the interval between the first repeated pattern adjacent to the upper side and the sum of the first repeated pattern adjacent to the lower side is preferably within the above range.

[0117] Although the length of the component perpendicular to the first axial direction of the first connecting portion depends on the specific size of the interval between the first repeating patterns, it is preferably 100 μm to 1000 μm, for example, from the same viewpoint as the above ratio. That is, the length of the component perpendicular to the first axial direction is preferably 100 μm or more, and more preferably 200 μm or more. In addition, the length of the component perpendicular to the first axial direction of the first connecting portion is preferably 1000 μm or less, more preferably 700 μm or less, and more preferably 400 μm or less.

[0118] The first unit pattern is preferably axially symmetrical or rotationally symmetrical. The first unit pattern is axially symmetrical, which means that when the first unit pattern is reversed with a straight line as the axis, the graphics before and after the reversal remain unchanged. The first unit pattern is rotationally symmetrical, which means that when the first unit pattern is rotated 180° with a symmetry point as the symmetry center, the graphics before and after the rotation remain unchanged. Figure 8 The first unit patterns shown in (B) and (D) are both axisymmetric. Figure 8 The first unit patterns shown in (A) and (D) are rotationally symmetrical. By making the first unit pattern have such symmetry, it is easy to connect the first unit pattern even if the device and the heat-reflecting substrate are rotated when forming the first repeating pattern. Figure 8 As shown in (E), (F) and (H), when the axially symmetrical or rotationally symmetrical first unit patterns are connected to each other, the shapes of these connection areas are also likely to become symmetrical shapes, which can improve the aesthetics of the radio wave transparent area.

[0119] (Second repeating pattern)

[0120] In the present heat-reflecting substrate, it is preferred that the radio wave transparent region further includes a second repeating pattern formed by slit portions according to a desired pattern shape. Here, the second repeating pattern includes at least two second unit patterns along a third axial direction different from the first axial direction, and the second unit patterns respectively include: a second line portion extending along the third axial direction; and a second connecting portion located at at least one end of the second line portion and connected to another second unit pattern of the at least two second unit patterns, and the second connecting portion includes a portion extending to a fourth axial direction different from the third axial direction, and at least a portion of which is connected to the second line portion.

[0121] The second repeating pattern is the same as the first repeating pattern except that the repeating direction is along a third axial direction different from the first axial direction. The third axial direction is also defined in the same way as the first axial direction except that it is a direction different from the first axial direction.

[0122] Therefore, the preferred method of the second repeating pattern is the same as the case where the first repeating pattern is replaced as follows. That is, for the first repeating pattern, the first unit pattern, the first line portion, and the first connecting portion, "first" can be replaced with "second", the first axial direction can be replaced with the third axial direction, and the second axial direction can be replaced with the fourth axial direction. The preferred method of the second repeating pattern is also exemplified below.

[0123] The angle θ (°) formed by the third axial direction and the fourth axial direction is preferably 10°≤θ≤120°, more preferably 10°≤θ≤90°, further preferably 10°≤θ≤80°, particularly preferably 15°≤θ≤60°, and particularly further preferably 15°≤θ≤45°. When θ is in the above range, the portion of the second connecting portion extending along the fourth axial direction tends to have a component parallel to the third axial direction and a component parallel to the direction perpendicular thereto in a good balance. Thus, it is easier to absorb the deviation of the pattern forming position in various directions. Alternatively, if θ is less than 90°, it is easy to suppress the mixed formation of the slit portion in the connecting area between the second connecting portion and other second unit patterns connected thereto, which can improve the aesthetics of the radio wave transparent area.

[0124] When the radio wave transparent region includes the first and second repeating patterns, at least one of the angle θ(°) between the first and second axial directions and the angle θ(°) between the third and fourth axial directions is preferably within the above range.

[0125] The second connecting portion is preferably located at both ends of the second line portion, thereby making it easier to absorb the deviation of the pattern forming position in various directions.

[0126] When the radio wave transparent region includes the first repeating pattern and the second repeating pattern, it is preferable that the first connecting portion or the second connecting portion exists at both ends of at least one of the first line portion and the second line portion.

[0127] Preferably, the radio wave transparent region includes a plurality of second repeating patterns arranged in parallel. Thus, a plurality of lines arranged in parallel by the second repeating pattern, that is, a pattern equivalent to parallel lines, can be formed.

[0128] When the radio wave transparent region includes the first repeating pattern and the second repeating pattern, the radio wave transparent region preferably includes at least one of a plurality of first repeating patterns arranged in parallel and a plurality of second repeating patterns arranged in parallel.

[0129] In the case where the radio wave permeability region includes a plurality of second repeating patterns arranged in parallel, the intervals between the second repeating patterns can be appropriately adjusted according to the characteristics of the radio waves to be transmitted, but for example, it is preferably 100 μm to 10 mm. The intervals between the first repeating patterns are preferably 100 μm or more, more preferably 200 μm or more, and further preferably 300 μm or more. On the other hand, from the same point of view, the interval is preferably 10 mm or less, more preferably 4000 μm or less, further preferably 2000 μm or less, and particularly preferably 1000 μm or less.

[0130] When the radio wave transparent region includes a plurality of first repeating patterns arranged in parallel and a plurality of second repeating patterns arranged in parallel, at least one of the intervals between the first repeating patterns and the intervals between the second repeating patterns is preferably within the above range.

[0131] Preferably, the second connection portion is not connected to other adjacent second repeating patterns. Thus, the length of the second repeating pattern in the direction perpendicular to the third axial direction is reduced, and the shape of the second repeating pattern can be made closer to an ideal continuous line.

[0132] It is preferred that the length of the component of the second connecting portion perpendicular to the third axial direction is 10% to 80% relative to the spacing between the second repeating patterns. By making the ratio of 10% or more, it is easy to make the size of the connecting portion sufficient and it is easier to absorb the deviation of the pattern forming position. The ratio of the length is more preferably 20% or more, and further preferably 25% or more. On the other hand, by making the ratio less than 80%, the shape of the second repeating pattern can be closer to an ideal continuous line. In addition, since the size of the second connecting portion can be set to less than a certain level, the coating amount of the heat radiation reflective film in the radio wave transparent area can be relatively large. This helps to improve the heat radiation reflectivity of the heat radiation reflective substrate and improve the efficiency of forming the slit portion. The ratio of is more preferably less than 50%, more preferably less than 45%, and particularly preferably less than 40%.

[0133] In the case where the radio wave transparent region includes a plurality of first repeating patterns arranged in parallel and a plurality of second repeating patterns arranged in parallel, it is preferred that, on at least one of them, the length of a component of the first connecting portion perpendicular to the first axial direction relative to the spacing between the first repeating patterns, or the length of a component of the second connecting portion perpendicular to the third axial direction relative to the spacing between the second repeating patterns, is within the above-mentioned range.

[0134] The second unit pattern is preferably axially symmetrical or rotationally symmetrical. The second unit pattern has such symmetry that when forming the second repeating pattern, even if the device or the heat-ray reflecting substrate is rotated, the second unit pattern can be easily connected. In addition, when the axially symmetrical or rotationally symmetrical second unit patterns are connected to each other, the shapes of these connection areas are also likely to have symmetry, which can improve the aesthetics of the radio wave transparent area.

[0135] When the radio wave transparent region includes the first repeating pattern and the second repeating pattern, it is preferable that at least one of the first unit pattern and the second unit pattern is axially symmetric or rotationally symmetric.

[0136] The radio wave transparent area includes a plurality of first repeating patterns (first repeating pattern group) arranged in parallel, and a plurality of second repeating patterns (second repeating pattern group) arranged in parallel, and when the first repeating pattern group and the second repeating pattern group are formed overlapping each other, the pattern in the overlapping area can be a so-called grid-like shape. For example, when the first axial direction intersects the third axial direction perpendicularly, the pattern can be a grid-like shape in which squares or rectangles are periodically arranged. In addition, when the first axial direction is not perpendicular to the third axial direction, the pattern can be a grid-like shape in which parallelograms are periodically arranged. Fig. 9 (A) is a diagram illustrating a lattice pattern that can be formed on the radio wave transparent region when the first axial direction and the third axial direction intersect perpendicularly. Fig. 9 In (A), a first repeating pattern group 50 including a plurality of first repeating patterns 5 arranged in parallel and a second repeating pattern group 60 including a plurality of second repeating patterns 6 arranged in parallel are arranged to overlap each other.

[0137] When the radio wave transparent area includes a first repeating pattern and a second repeating pattern intersecting the first repeating pattern, it is preferred that the first connecting portion does not connect to the second repeating pattern, and it is preferred that the second connecting portion does not connect to the first repeating pattern. Thus, it is possible to prevent the slits from being mixedly formed in a part of the area, and to improve the aesthetics of the radio wave transparent area.

[0138] In the case where the radio wave transparent area includes a quadrilateral pattern formed by two first repeating patterns arranged in parallel and adjacent to each other and two second repeating patterns arranged in parallel and adjacent to each other, it is preferred that the first connecting portion does not touch the second repeating pattern, and it is preferred that the second connecting portion does not touch the first repeating pattern, for the same reason as above. In addition, in this case, it is more preferred that at least one of the first connecting portion and the second connecting portion is located at the midpoint of at least one side of the quadrilateral. Fig. 9 (B) is an enlarged view of region Y2 of (A). Fig. 9In (B), the first repeating pattern 5a and the first repeating pattern 5b arranged parallel to and adjacent to it, and the second repeating pattern 6a and the second repeating pattern 6b arranged parallel to and adjacent to it form a quadrilateral pattern S. Moreover, the second connecting portion 65 is located at the midpoint P1 of the side E1 of the formed quadrilateral, and the first connecting portion 55 is located at the midpoint P2 of the side E2. The opposite sides of each side E1 and side E2 are also the same. That is, in Fig. 9 In the quadrilateral pattern S illustrated in (B), the first connection portion or the second connection portion is located at the midpoint of all four sides thereof. At least one of the first connection portion and the second connection portion is located at the midpoint of at least one side forming the quadrilateral, so that the quadrilateral has symmetry, thereby improving the aesthetics of the radio wave transparent area. Here, the first connection portion being located at the midpoint of the side means that a straight line perpendicular to the side and passing through the midpoint of the side is connected to or intersected with the first connection portion included in the first unit pattern constituting the side. The same is true for the second connection portion.

[0139] In the case where the radio wave transparent area includes the first repeating pattern and the second repeating pattern at the same time, the shapes of the repeating patterns may be the same or different from each other. In addition, in the case where the radio wave transparent area includes the first repeating pattern group and the second repeating pattern group at the same time, for example, the intervals between the first repeating patterns and the intervals between the second repeating patterns may be the same or different from each other. These can be appropriately adjusted according to the desired radio wave transmission performance, other characteristics, etc. In addition, the radio wave transparent area may also include slit portions other than the first repeating pattern and the second repeating pattern within the range that does not hinder the effect of the present invention. For example, a third repeating pattern may also be included, which includes at least two third unit patterns extending along a fifth axial direction that is different from any one of the first axis and the third axial direction. In addition, the third repeating pattern may be defined in the same way as the first repeating pattern and the second repeating pattern, except that the repetition direction is different.

[0140] According to the present embodiment, by making various changes to the configuration of the first repeating pattern and the second repeating pattern formed as needed, various patterns can be formed on the radio wave transparent area. For example, the parallel line, grid, circular and other patterns exemplified above can be formed. In addition, by further having the above-mentioned third repeating pattern, etc., it is also possible to form a pattern in which triangles are periodically arranged, and other various patterns. Moreover, in the present embodiment, these repetition periods, grid shapes, etc. can be appropriately changed. According to the present embodiment, in this way, a heat-ray reflecting substrate with excellent freedom of pattern selection and excellent reliability in which interruptions of the pattern are suppressed in each pattern can be obtained.

[0141] Next, other structures of the heat reflecting substrate will be described.

[0142] (Dielectric Substrate)

[0143] The dielectric substrate in this embodiment is not particularly limited as long as it is a substrate composed of a dielectric, but for example, a glass substrate such as soda-lime glass, alkali-free glass, or quartz glass can be used. The glass substrate can also be subjected to physical strengthening treatment or chemical strengthening treatment. In addition, the glass substrate can be composed of a single piece of glass or a plurality of glasses sandwiching a resin film (resin film) or the like in a stacked manner.

[0144] In addition, the dielectric substrate in the present embodiment is not limited to a glass substrate, and may be, for example, a substrate made of resin (resin substrate), a composite substrate formed by laminating a resin substrate and a glass substrate, etc. As the resin substrate, for example, substrates composed of acrylic resins such as polymethyl methacrylate, aromatic polycarbonate resins such as polyphenylene carbonate, aromatic polyester resins such as polyethylene terephthalate (PET), etc. may be cited.

[0145] The physical properties of the dielectric substrate in this embodiment, such as radio wave transmittance and heat reflectivity, are not particularly limited as long as the effects of the present invention are achieved, and may be appropriately adjusted according to the physical properties required for the finally obtained heat reflective substrate.

[0146] When a glass substrate is used as the dielectric substrate in this embodiment, the following structure is preferred, for example. The specific gravity of the glass substrate is preferably 2.4 or more and 3.0 or less. In addition, the Young's modulus of the glass substrate is preferably 60 GPa or more and 100 GPa or less. In addition, the average thermal expansion coefficient of the glass substrate at 50°C to 350°C is preferably 50×10 －7 / ℃ or above, 120×10 －7 / °C or less. If the glass substrate satisfies these physical property requirements, it can be suitably used as a window material.

[0147] The shape of the dielectric substrate in this embodiment is not particularly limited, and may be flat or curved. In addition, the thickness of the dielectric substrate in this embodiment is not particularly limited, and may be appropriately adjusted according to desired strength, lightness, etc.

[0148] (Heat reflective film)

[0149] The heat-reflecting film is not particularly limited as long as it can impart a function of reflecting heat rays to the heat-reflecting substrate. As a film that can impart a function of reflecting heat rays, a conductive film can be typically mentioned.

[0150] In this specification, "conductive film" refers to, for example, a film having a resistivity of 10° [Ω·cm] or less at 20°C. The composition of the conductive film is not particularly limited, but for example, silver, aluminum, indium tin oxide (ITO), tin oxide doped with at least one of fluorine and antimony (SnO 2 :F, Sb), titanium nitride, niobium nitride, chromium nitride, zirconium nitride and hafnium nitride (hereinafter also referred to as "conductive film component group A") and other metals as the main components. In addition, in this specification, the main component refers to a content of 50 atomic % or more relative to all the constituent components. That is, the conductive film of this embodiment contains at least one selected from the group consisting of the conductive film component group A, and the content of the conductive film component group A in the conductive film of this embodiment is preferably 50 atomic % or more in total.

[0151] In order to achieve excellent heat-ray reflectivity in the radio wave transparent region, the conductive film preferably contains at least one of silver and aluminum as a main component, and the conductive film more preferably contains silver as a main component (i.e. contains more than 50 atomic %), and further preferably contains more than 95 atomic % of silver.

[0152] In addition, the conductive film with silver as the main component may also contain one or more additive elements such as gold, palladium, copper, bismuth, neodymium, platinum, etc. By making the conductive film with silver as the main component contain such additive elements, the diffusion of silver can be suppressed and the moisture resistance can be improved. In addition, the additive elements are not limited to the elements exemplified above, and any elements can be added as long as the effect of the present invention is achieved.

[0153] In addition, the thickness of the heat-reflective film (conductive film) of the present embodiment is not particularly limited, and can be appropriately adjusted according to the radio wave transmittance of the specified frequency required in the final heat-reflective substrate, heat-reflectivity, visible light transmittance, appearance, etc. The thickness of the heat-reflective film is usually 1 nm or more, preferably 3 nm or more, more preferably 5 nm or more, and further preferably 6 nm or more. In addition, the thickness is preferably 100 nm or less, more preferably 50 nm or less, and further preferably 20 nm or less. In addition, the heat-reflective film can be only one layer (single layer), or it can be two layers, three layers, or other multiple layers. In the case of multiple layers, they can be adjacent to each other in the thickness direction of the heat-reflective film, or they can be separated by sandwiching other layers between the layers. In addition, in the case where the heat-reflective film is a multilayer, the total thickness can be within the above range.

[0154] The heat reflective substrate may include a film (another film) different from the heat reflective film within a range in which the effects of the present invention are exhibited.

[0155] The present heat-reflecting substrate may include, for example, a metal oxide layer and a metal nitride layer, and preferably includes at least one of the metal oxide layer and the metal nitride layer. In particular, from the aspect of durability, it is preferred that the heat-reflecting film has a layer structure in which a conductive film is sandwiched by the other layers mentioned above, such as a metal oxide layer and a metal nitride layer. As the metal oxide layer, there can be mentioned layers of metal oxides whose main components are aluminum oxide, zinc oxide, indium oxide, titanium oxide, niobium oxide, tin oxide, bismuth oxide, tantalum oxide, tungsten oxide, zirconium oxide, silicon oxide, etc. Among them, from the aspect of good compatibility with silver, which is a preferred component of the conductive film, and improving the durability of the conductive film, it is preferred that the metal oxide layer has zinc oxide as the main component. As the metal nitride layer, there can be mentioned layers whose main components are silicon nitride (Si 3 N 4 ), aluminum nitride (AlN) and the like as the main component. In addition, in the radio wave transparent region of the heat ray reflecting substrate, the slit portion at least does not have a heat ray reflecting film, but the slit portion may also have other films within the scope of achieving the effect of the present invention. For example, when other films are further formed on the heat ray reflecting substrate on which the slit portion is formed in advance, the slit portion does not have a heat ray reflecting film, but may be in a form with other films.

[0156] (characteristic)

[0157] The heat reflecting substrate preferably has the following characteristics.

[0158] In the present heat-ray reflecting substrate, the radio wave permeability region preferably has excellent permeability to radio waves of frequencies of about hundreds of MHz to hundreds of GHz, for example, 300MHz to 300GHz, more preferably about 3GHz to 100GHz, and further preferably about 6GHz to 40GHz. Specifically, by appropriately changing the pattern formed by the slit portion in the radio wave permeability region, the radio wave permeability region can, for example, have excellent permeability to radio waves of various frequency bands such as 25 to 45GHz, 3 to 6GHz, 6 to 15GHz, 50 to 350GHz, or 50 to 100GHz. In more detail, the heat-ray reflecting substrate of the present embodiment is difficult to hinder the transmission of radio waves of a specified frequency in the radio wave permeability region. Thus, it is easy to obtain a heat-ray reflecting substrate having radio wave permeability required for applications such as window glass.

[0159] In the heat-reflecting substrate of the present embodiment, for example, the radio wave transmission loss for the radio wave of frequency 28 GHz in the radio wave transmission area is preferably 3 dB or less, more preferably 2 dB or less, and further preferably 1 dB or less. In addition, the radio wave transmission loss for the radio wave of frequency 79 GHz is also preferably 3 dB or less, more preferably 2 dB or less, and further preferably 1 dB or less.

[0160] In addition, the radio wave transmission loss for radio waves with a frequency of 28 GHz (79 GHz) in the radio wave transmission region is a value obtained by subtracting the radio wave transmission loss of the dielectric substrate for radio waves with a frequency of 28 GHz (79 GHz) from the radio wave transmission loss of the heat-reflecting substrate as a whole in the radio wave transmission region. The radio wave transmission loss refers to a value measured by a free space method, for example.

[0161] Thus, the radio wave transmission loss for radio waves with frequencies of 28 GHz and 79 GHz is described as an example, but it is not limited to the 28 GHz band and the 79 GHz band. It is preferable to obtain the same radio wave transmission loss as described above in the frequency band of about several hundred MHz to 100 GHz.

[0162] In addition, the heat reflective substrate preferably has excellent heat reflectivity. Heat reflectivity can be evaluated, for example, by the solar reflectivity specified in JIS R3106 (1998). The solar reflectivity in the radio wave transmittance region of the heat reflective substrate is preferably 30% or more, more preferably 35% or more, and further preferably 40% or more.

[0163] (use)

[0164] The present heat ray reflecting substrate is suitable for applications requiring heat ray reflectivity and radio wave transmittance. Examples of applications include window glass for construction or vehicle applications. Among them, the present heat ray reflecting substrate is suitable for window glass in which the area of ​​the radio wave transmittance region and the length of the maximum side are relatively easy to increase and it is difficult to form a pattern on the radio wave transmittance region in a single process, and is more suitable for window glass for construction purposes. That is, in the present heat ray reflecting substrate or the window glass having the present heat ray reflecting substrate, the length of the maximum side of the radio wave transmittance region on the main surface is, for example, preferably 300 mm or more, more preferably 500 mm or more. In addition, the area of ​​the radio wave transmittance region on the main surface is, for example, preferably 900 cm 2 More preferably 2500cm 2 The above. In the present heat-reflecting substrate or the window glass having the heat-reflecting substrate, when the area of ​​the radio wave transparent area on the main surface and the length of the maximum side are within the above range, it is easier to effectively obtain the effect of the present invention. However, within the range that can obtain the effect of the present invention, the area of ​​the radio wave transparent area and the length of the maximum side can be appropriately selected according to the application, etc., and therefore can be outside the above range. In addition, the maximum side of the radio wave transparent area refers to its long side when the shape of the area is a rectangle, and refers to the long side of the quadrilateral circumscribed with the shape in other shapes.

[0165] The window glass having the heat-reflecting substrate suppresses the interruption of the pattern in the radio wave transparent region, and thus has excellent reliability. In addition, in the window glass having the heat-reflecting substrate, the shape of the pattern formed in the radio wave transparent region can be selected with a relatively high degree of freedom according to the desired characteristics, while ensuring the above reliability.

[0166] (Method for manufacturing heat-reflecting substrate)

[0167] The present heat-reflecting substrate can be manufactured, for example, by the following method, which includes: preparing a heat-reflecting substrate having a heat-reflecting film formed on at least one main surface of a dielectric substrate; and forming a slit portion without the heat-reflecting film on at least a portion of the at least one main surface in a plan view, and forming a radio wave transparent region. In these methods, the slit portion is formed in such a way that the obtained radio wave transparent region includes at least a first repeated pattern formed by the slit portion.

[0168] The method for preparing the heat ray reflective substrate having the heat ray reflective film formed on at least one main surface of the dielectric substrate is not particularly limited, and may be a method of using a commercially available product or a method of forming the heat ray reflective film on at least one main surface of the dielectric substrate.

[0169] The method for forming the heat-ray reflective film on at least one main surface of the dielectric substrate is not particularly limited, and for example, physical vapor deposition (vacuum vapor deposition, ion vapor deposition, magnetron sputtering, etc.), chemical vapor deposition (thermal CVD, plasma CVD, optical CVD, etc.), ion beam sputtering, etc. can be used. When the film forming area is large, it is easy to control the uniformity of the thickness and the productivity is excellent, so DC magnetron sputtering, DC pulse magnetron sputtering or AC dual magnetron sputtering is preferred.

[0170] The heat reflective film in this embodiment may be formed directly on the dielectric substrate or indirectly. The method of indirectly forming the heat reflective film on the dielectric substrate is not particularly limited, but a method of attaching a resin film having the heat reflective film formed thereon to the dielectric substrate may be mentioned.

[0171] In addition, Figure 1 and Figure 2 In the illustrated embodiment, the heat-ray reflecting film 13 (including the radio-wave transparent region A) is formed on the entirety of one main surface of the dielectric substrate 11 , but may be formed on only a portion.

[0172] The method of forming the slit portion and forming the radio wave transparent region is also not particularly limited. For example, a method of forming a continuous (entire surface) heat-reflecting film in a predetermined region on a dielectric substrate and then partially removing the heat-reflecting film to form the slit portion, and a method of obtaining the radio wave transparent region by forming a heat-reflecting film only in a predetermined portion on a dielectric substrate can be cited. Among them, from the viewpoint of cost and ease of production, a method of forming a slit portion by partially removing the heat-reflecting film after forming the heat-reflecting film is preferred. As a method of partially removing the heat-reflecting film, for example, laser etching, photolithography, etc. can be cited. From the viewpoint of cost and practicality, a method based on laser etching is preferred.

[0173] As described above, in order to form the pattern of the slit portion in the radio wave transparent region in the above manner, the heat ray reflective film is partially removed, for example, by the following method: that is, patterns matching the size of the unit processing region are formed multiple times in the region where the radio wave transparent region is to be formed, and they are continuously arranged to form a continuous pattern. Fig.10 Schematically illustrates a pattern that matches the size of a unit processing area. Fig.10 (A) is a diagram illustrating "patterns matching the size of the unit processing area" when it is desired to form parallel linear patterns in the radio wave transparent area. These patterns are preferably first unit pattern groups 510 in which multiple first unit patterns 51 are arranged in parallel in the unit processing area ZA. Fig.10 (B) is a diagram illustrating a "pattern matching the size of the unit processing area" when a grid-like pattern is formed in the radio wave transparent area. These patterns are preferably a composite unit pattern group formed by overlapping the above-mentioned first unit pattern group 510 with a second unit pattern group 610 in which a plurality of second unit patterns 61 are arranged in parallel. Although it is related to the desired pattern shape, by forming a predetermined unit pattern group in the unit processing area through a single process, and performing the process multiple times, the unit pattern group is continuously arranged, so that the above-mentioned parallel linear pattern, grid-like pattern and other desired patterns can be formed. The specific mode of each unit pattern included in the unit pattern group, their intervals, etc. are preferably the same as the preferred mode in the first or second repeating pattern. In addition, the unit pattern group is more preferably axially symmetrical or rotationally symmetrical. By making the unit pattern group axially symmetrical or rotationally symmetrical, even when the unit pattern groups are continuously arranged with each other, accompanied by the rotation of the substrate or the change of direction, it is not necessary to further rotate the unit pattern group correspondingly, or the number of rotations can be reduced, so that a continuous pattern is easily formed.

[0174] When a plurality of unit pattern groups are arranged continuously, it is preferred that a connection end portion of a unit pattern group having a first connection portion or a second connection portion is arranged so as to overlap a connection end portion of another unit pattern group arranged adjacently. Fig.10 In (A), L1 and L2 respectively represent the connection ends of the first unit pattern group 510. Fig.10 (C) is a diagram illustrating a case where two first unit pattern groups 510 are arranged continuously. Fig.10 In (C), the connection end L1 of the first unit pattern group 510 on one side is arranged to overlap the connection end L2 of the first unit pattern group 510 on the other side arranged adjacently. At this time, from the viewpoint of suppressing the interruption of the pattern, the overlapping width W is preferably 50μm or more, more preferably 100μm or more, and further preferably 200μm or more. On the other hand, W is preferably 2000μm or less, more preferably 1000μm or less, and further preferably 500μm or less. In other words, it is preferred that the width of the overlap between the ends of two consecutive (interconnected) first unit patterns in the first repeating pattern is the same as the overlapping width W mentioned above. The same is true for the width of the overlap between the ends of two consecutive second unit patterns in the second repeating pattern.

[0175] By forming the slit portion without the heat-reflecting film and forming the radio wave transparent region, the heat-reflecting substrate is obtained. In addition, the unit pattern group exemplified as the "pattern matching the size of the unit processing area" includes a plurality of first unit patterns and second unit patterns, but the "pattern matching the size of the unit processing area" may be a variety of patterns such as only one first unit pattern according to the characteristics of the processing device and the desired pattern.

[0176] The method of manufacturing the heat reflective substrate is not limited to the above-described method, and can be appropriately changed within the scope of achieving the effects of the present invention.

[0177] Various embodiments have been described above, but it goes without saying that the present invention is not limited to these examples. Obviously, if a person skilled in the art can think of various variations or modifications within the scope described in the claims, and understand that they certainly belong to the technical scope of the present invention. In addition, the various constituent elements in the above embodiments may also be combined arbitrarily without departing from the scope of the gist of the invention.

[0178] In addition, the present application is based on the Japanese patent application (Japanese Patent Application No. 2022-087165) filed on May 27, 2022, the contents of which are incorporated herein by reference.

[0179] Description of Reference Numerals

[0180] 10, 10a…heat-ray reflecting substrate; 11…dielectric substrate; 13…heat-ray reflecting film; 14…slit portion; 5, 5a, 5b, 15…first repeating pattern; 50…first repeating pattern group; 151a, 151b, 51, 51a, 51b, 51c, 51d…first unit pattern; 154a, 154b, 54a, 54b, 54c, 54d…first line portion; 155a, 155b, 55, 55a, 55b, 55c, 55d…first connecting portion; 510…first unit pattern group; 6, 6a, 6b…second repeating pattern; 60…second repeating pattern group; 65…second connecting portion; 610…second unit pattern group; A…radio wave transparent area; Za, Zb, Zc, ZA, ZB…unit processing area.

Claims

1. A heat-reflecting substrate, characterized in that: have: Dielectric substrate; and a heat-reflecting film provided on at least one main surface of the dielectric substrate; At least one portion of the at least one main surface in a plan view has a radio wave transparent region, The radio wave transparent area includes a first repeated pattern formed by slit portions without a heat-reflecting film, The first repeating pattern includes at least two first unit patterns extending along a first axial direction, The first unit patterns respectively include: a first line portion extending along the first axial direction; as well as a first connection portion, which is located at at least one end of the first line portion and is connected to another first unit pattern of the at least two first unit patterns; The first connection portion includes a portion extending in a second axial direction different from the first axial direction, and at least a portion of the portion is connected to the first line portion.

2. The heat-reflecting substrate according to claim 1, characterized in that: An angle θ (°) formed by the first axial direction and the second axial direction is 10°≤θ≤120°.

3. The heat-reflecting substrate according to claim 1, characterized in that: The first connection portion is located at both ends of the first line portion.

4. The heat-reflecting substrate according to claim 1, characterized in that: The radio wave transparent area includes a plurality of the first repeating patterns arranged in parallel.

5. The heat-reflecting substrate according to claim 4, characterized in that: The intervals between the first repeating patterns are 100 μm to 10 mm.

6. The heat-reflecting substrate according to claim 4, characterized in that: The first connection portion is not connected to other adjacent first repeating patterns.

7. The heat-reflecting substrate according to claim 4, characterized in that: The length of the components of the first connecting portion perpendicular to the first axial direction is 10% to 80% of the interval between the first repeating patterns.

8. The heat-reflecting substrate according to claim 1, characterized in that: The first unit pattern is axially symmetric or rotationally symmetric.

9. The heat-reflecting substrate according to claim 1, characterized in that: The radio wave transparent area further includes a second repeated pattern formed by slit portions, The second repeating pattern includes at least two second unit patterns along a third axial direction different from the first axial direction, The second unit patterns respectively include: a second line portion extending along the third axial direction; and a second connecting portion, which is located at at least one end of the second line portion and is connected to another second unit pattern of the at least two second unit patterns, The second connection portion includes a portion extending in a fourth axial direction different from the third axial direction, and at least a portion is connected to the second line portion.

10. The heat-reflecting substrate according to claim 9, characterized in that: An angle θ (°) formed by the third axial direction and the fourth axial direction is 10°≤θ≤120°.

11. The heat-reflecting substrate according to claim 9, characterized in that: The second connection portion is located at both ends of the second line portion.

12. The heat-reflecting substrate according to claim 9, characterized in that: The radio wave transparent area includes a plurality of the second repeating patterns arranged in parallel.

13. The heat-reflecting substrate according to claim 12, characterized in that: The intervals between the second repeating patterns are 100 μm to 10 mm.

14. The heat-reflecting substrate according to claim 12, characterized in that: The second connection portion is not connected to other adjacent second repeating patterns.

15. The heat-reflecting substrate according to claim 12, characterized in that: The length of the components of the second connecting portion perpendicular to the third axial direction is 10% to 80% of the interval between the second repeating patterns.

16. The heat-reflecting substrate according to claim 9, characterized in that: The second unit pattern is axially symmetric or rotationally symmetric.

17. The heat-reflecting substrate according to claim 9, characterized in that: The radio wave transparent area includes a quadrilateral pattern, which is formed by two of the first repeating patterns arranged in parallel and adjacent to each other, and two of the second repeating patterns arranged in parallel and adjacent to each other, and at least one of the first connecting portion and the second connecting portion is located at the midpoint of at least one side of the quadrilateral.

18. The heat-reflecting substrate according to claim 1, characterized in that: In the radio wave transparent region, the radio wave transmission loss for radio waves having a frequency of 28 GHz is 3 dB or less.

19. A window glass, characterized in that: A heat-reflecting substrate according to any one of claims 1 to 18.

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