JP7756589B2 - Vehicle exterior part, vehicle illumination unit, and method for manufacturing vehicle exterior part - Google Patents

Description

The present invention relates to vehicle exterior parts, vehicle illumination units, and methods for manufacturing vehicle exterior parts.

For example, Patent Document 1 discloses an illumination grill equipped with a light source. In such an illumination grill, the illumination grill is illuminated by light emitted from the light source.

JP 2019-75283 A

In recent years, passenger cars have also been equipped with vehicle illumination units that can illuminate vehicles at night and other times. For example, such vehicle illumination units can be configured to include a light source that emits light and a vehicle exterior component that is positioned beyond the light source and transmits only a portion of the light from the light source. Vehicle exterior components that are visible from outside the vehicle often require three-dimensional decoration. To achieve such three-dimensional decoration, a recess can be formed in part of the back surface of the transparent component, and a thin metal layer can be formed on the inner wall surface of the recess. However, it is preferable to prevent the light source from being visible from outside the vehicle exterior component during the day. For this reason, a colored translucent layer can be formed on the back surface of the transparent component, in the area outside the recess where no metal layer is provided.

When manufacturing a vehicle exterior part that includes a metal layer provided in a recess in such a transparent member and a colored light-transmitting layer provided outside the recess, one approach is to insert a mask into the recess to form the colored light-transmitting layer, and then remove the mask to form the metal layer. However, when inserting a mask into the recess to form the colored light-transmitting layer, tiny gaps form between the inner wall surface of the recess and the mask, making it difficult to prevent the colored light-transmitting layer from seeping into the inner wall surface of the recess. If the colored light-transmitting layer seeps into the inner wall surface of the recess, the edges of the colored light-transmitting layer will appear to be blurred from the outside, detracting from the appearance.

Furthermore, when a light-blocking layer that blocks light from the light source is provided in a way that avoids the recess, it is possible to similarly form the light-blocking layer by inserting a mask into the recess. However, in such cases, tiny gaps are created between the inner wall surface of the recess and the mask, making it difficult to prevent the light-blocking layer from infiltrating into the inner wall surface of the recess. If the light-blocking layer infiltrates into the inner wall surface of the recess, light cannot pass through the edge of the recess, resulting in a poor appearance.

The present invention was made in consideration of the above-mentioned problems, and aims to prevent a decline in the appearance of vehicle exterior components and illumination units that have a recess on the back surface of a transparent member and that can be illuminated by transmitting part of the light from a light source.

The present invention employs the following configuration as a means to solve the above problems.

A first aspect of the present invention is a vehicle exterior part comprising a transparent member having a recess formed in part of its back surface; a metal layer formed on the inner wall surface of the recess; a colored light-transmitting layer covering the metal layer from the side opposite the transparent member and covering the entire interior of the recess, and also on the back surface of the transparent member, including the area where the metal layer is not formed; and a light-blocking member connected to the transparent member with the colored light-transmitting layer sandwiched therebetween, and having an opening.

A second aspect of the present invention is the first aspect, wherein the colored light-transmitting layer covers the entire back surface of the transparent member.

A third aspect of the present invention is the first or second aspect, wherein the light-shielding member includes a main body portion that covers the recess and a recess-filling portion that fills the recess.

A fourth aspect of the present invention is a vehicle illumination unit that includes a vehicle exterior part according to any one of the first to third aspects described above, and a light source unit that emits light toward the vehicle exterior part.

A fifth aspect of the present invention is a method for manufacturing a vehicle exterior part, comprising the following steps: a transparent member forming step of forming a transparent member having a recessed portion on a portion of its back surface; a mask placing step of placing a mask that covers the back surface except for the recessed portion; a metal layer forming step of adhering a metal layer to the back surface of the transparent member via the mask; a mask removing step of removing the mask; a colored light-transmitting layer forming step of forming a colored light-transmitting layer that covers the entire interior of the recessed portion from the side opposite the transparent member, including the portion where the metal layer is not provided, on the back surface of the transparent member; and a light-shielding member connecting step of connecting a light-shielding member that is formed separately from the transparent member and has an opening to the transparent member via the colored light-transmitting layer.

A sixth aspect of the present invention is the fifth aspect, wherein in the colored light-transmitting layer forming step, the colored light-transmitting layer is formed so as to cover the entire back surface of the transparent member.

A seventh aspect of the present invention is the fifth or sixth aspect, wherein the light-shielding member connected to the transparent member in the light-shielding member connecting step includes a buried portion that fills the recess.

According to the present invention, a metal layer is provided on the inner wall surface of the recess. The colored light-transmitting layer is provided on the back surface of the transparent member, covering the entire interior of the recess, including the area where the metal layer is not provided, and is also provided on the back surface of the transparent member, including the area where the metal layer is not provided. Therefore, when providing the metal layer and colored light-transmitting layer, there is no need to insert a mask into the recess. Furthermore, because the colored light-transmitting layer is provided so as to cover the back surface of the metal layer, the colored light-transmitting layer is not visible inside the recess from the outside of the transparent member. Therefore, according to the present invention, the colored light-transmitting layer is prevented from appearing to bleed around the edge of the recess, preventing a deterioration in the external appearance. Furthermore, according to the present invention, a light-shielding member separate from the transparent member is connected to the transparent member. Therefore, the light-shielding member can be formed separately from the transparent member, and when providing a light-shielding member with an opening aligned with the recess, there is no need to insert a mask into the recess. Therefore, according to the present invention, it is possible to prevent part of the light-shielding member from entering the interior of the recess located at the opening, preventing a deterioration in the external appearance.

1 is a schematic diagram showing a general configuration of a vehicle illumination unit according to a first embodiment of the present invention; 3A to 3C are schematic process diagrams illustrating a method for manufacturing a vehicle exterior part provided in the vehicle illumination unit according to the first embodiment of the present invention. 3A to 3C are schematic process diagrams illustrating a method for manufacturing a vehicle exterior part provided in the vehicle illumination unit according to the first embodiment of the present invention. FIG. 4 is a schematic diagram showing a general configuration of a vehicle exterior part according to a second embodiment of the present invention.

Hereinafter, with reference to the drawings, an embodiment of a vehicle exterior part, a vehicle illumination unit, and a method for manufacturing a vehicle exterior part according to the present invention will be described.

(First embodiment)
1 is a schematic diagram showing the general configuration of a vehicle illumination unit 100 according to this embodiment. As shown in this figure, the vehicle illumination unit 100 according to this embodiment is mounted on a vehicle and includes a vehicle exterior component 10 and a light source unit 20.

The vehicle exterior part 10 is located outside the vehicle relative to the light source unit 20 and is a part that is directly visible from outside the vehicle. This vehicle exterior part 10 includes a transparent member 1, a metal layer 2, a colored light-transmitting layer 3, and a light-blocking member 4.

The transparent member 1 is positioned at the outermost part of the vehicle exterior part 10. The transparent member 1 is formed, for example, by injection molding using a mold. For example, the transparent member 1 is formed from a transparent synthetic resin such as transparent PC (polycarbonate) or PMMA (polymethyl methacrylate resin).

In this embodiment, the transparent member 1 is formed in a plate shape. One surface of the transparent member 1 is the design surface 1a, which is positioned toward the outside of the vehicle. Note that the design surface referred to here is not limited to a surface on which patterns, letters, etc. are directly formed, but may be any surface that is visible to those outside the vehicle. In other words, the design surface 1a is the outer wall surface of the transparent member 1. If necessary, the design surface 1a of such a transparent member 1 may be treated with a hard coat or a clear coat of urethane paint to prevent scratches. Note that if the transparent member 1 is made of a scratch-resistant transparent synthetic resin, these scratch-resistant treatments are not necessary.

The surface of the transparent member 1 opposite the design surface 1a is the back surface 1b. As shown in Figure 1, a recess 1c is provided in a portion of the back surface 1b of the transparent member 1. In this embodiment, two recesses 1c are provided in the back surface 1b of the transparent member 1. The number of recesses 1c can be changed. These recesses 1c are formed so as to recess from the back surface 1b of the transparent member 1 toward the design surface 1a. The portion of the back surface 1b of the transparent member 1 that does not have a recess 1c is referred to as a shelf portion 1d. As shown in Figure 1, this shelf portion 1d is a flat portion.

The metal layer 2 is provided on the inner wall surface of the recess 1c of the transparent member 1. The metal layer 2 is formed from a metal material and has a thickness that allows a portion of the light emitted from the light source unit 20 to pass through. For example, the metal layer 2 can be formed from indium (In) or aluminum (Al). For example, forming the metal layer 2 by sputtering or vacuum deposition using indium (In) allows the metal layer 2 to transmit radio waves.

In this embodiment, this metal layer 2 is provided so as to cover the entire inner wall surface of the recess 1c. When this metal layer 2 is viewed from the outside (the side of the design surface 1a), an outsider can see the metal layer 2 as a three-dimensional metal.

The colored light-transmitting layer 3 is capable of transmitting a portion of the light emitted from the light source unit 20. The colored light-transmitting layer 3 is also colored. Therefore, the light emitted from the light source unit 20, transmitted through the colored light-transmitting layer 3, and emitted from the design surface 1a is perceived as having the color tone of the colored light-transmitting layer 3. Therefore, when light is emitted from the light source unit 20, an outsider will see the area where the light from the light source unit 20 is emitted to the outside through the colored light-transmitting layer 3 as if it is glowing.

The colored light-transmitting layer 3 also reflects a portion of light. Therefore, when external light incident from the design surface 1a is reflected by the colored light-transmitting layer 3, the reflected light appears to have the color tone of the colored light-transmitting layer 3. Therefore, in areas where the colored light-transmitting layer 3 is visible from the design surface 1a side, outsiders are prevented from seeing the back side of the colored light-transmitting layer 3.

The color tone of the colored light-transmitting layer 3 is not particularly limited. For example, the color tone of the colored light-transmitting layer 3 can be black. By making the color tone of the colored light-transmitting layer 3 black, the colored light-transmitting layer 3 functions like a smoke film.

The light-blocking member 4 is a member that blocks light and is provided separately from the transparent member 1. For example, this transparent member 1 has enough strength to maintain its shape even when not connected to the light-blocking member 4. Such a light-blocking member 4 is connected to the transparent member 1 by, for example, adhesive bonding or welding. Alternatively, the light-blocking member 4 and transparent member 1 may be connected to the transparent member 1 by engaging or fastening them together.

As shown in FIG. 1, the light-blocking member 4 has openings 4a in some parts. In this embodiment, as shown in FIG. 1, the light-blocking member 4 has three openings 4a. Each opening 4a penetrates from the light source unit 20 side to the design surface 1a side, and allows light emitted from the light source unit 20 to pass through.

As shown in FIG. 1, in this embodiment, one of the openings 4a is positioned to overlap one of the recesses 1c when viewed from the design surface 1a side. In this area where the openings 4a and recesses 1c overlap when viewed from the design surface 1a side, when no light is emitted from the light source unit 20, the metal layer 2 appears to have a natural metallic luster when viewed from the outside due to external light. Furthermore, in this area where the openings 4a and recesses 1c overlap when viewed from the design surface 1a side, when light is emitted from the light source unit 20, the light emitted from the light source unit 20 passes through the thin metal layer 2, causing the metal layer 2 to appear to glow brightly.

Furthermore, as shown in Figure 1, in the area where the opening 4a and shelf 1d overlap when viewed from the design surface 1a, when light is not being emitted from the light source 20, the colored light-transmitting layer 3 appears colored due to external light when viewed from the outside. Furthermore, when light is not being emitted from the light source 20, the shelf 1d appears colored due to the colored light-transmitting layer 3 when viewed from the outside, regardless of whether the opening 4a is present or not.

As shown in Figure 1, one of the recesses 1c is positioned so as not to overlap with the opening 4a when viewed from the design surface 1a side. In this way, in areas where the opening 4a and recess 1c do not overlap when viewed from the design surface 1a side, the metal layer 2 does not appear to be shining brightly, even when light is emitted from the light source unit 20. Even in areas where the opening 4a and recess 1c do not overlap when viewed from the design surface 1a side, the metal layer 2 appears to have a natural metallic luster when exposed to external light.

The light source unit 20 is positioned further inside the vehicle than the vehicle exterior part 10 and is capable of emitting light toward the vehicle exterior part 10. For example, the light source unit 20 emits light in response to a driver's instruction or at a preset time.

Next, a method for manufacturing the vehicle exterior part 10 of this embodiment will be described with reference to Figures 2 and 3. Figures 2 and 3 are schematic diagrams showing the manufacturing process for the vehicle exterior part 10 of this embodiment.

First, as shown in Figure 2(a), a transparent member 1 is formed with a recess 1c in part of the back surface 1b. The process shown in Figure 2(a) is the transparent member formation process. In the transparent member formation process, the transparent member 1 is formed, for example, by injection molding. By providing a protrusion that forms the recess 1c on the mold used for injection molding, the transparent member 1 can be formed in a single injection molding process.

Next, as shown in Figure 2(b), a mask M is placed to cover the back surface 1b of the transparent member 1 except for the recessed portion 1c. Here, the mask M, which has an opening M1 aligned with the recessed portion 1c, is superimposed on the back surface 1b of the transparent member 1. Also, as shown in Figure 2(b), a metal layer 2 is formed and adhered to the back surface 1b of the transparent member 1 via the mask M. Here, material X for forming the metal layer 2 is formed on the back surface 1b of the transparent member 1 by sputtering or vacuum deposition. Note that the process shown in Figure 2(b) is a combination of the mask placement process and the metal layer formation process.

The mask M shown in Figure 2(b) does not have any protrusions, but only has openings M1. In other words, the mask M is not placed inside the recess 1c. Therefore, there is no chance of an unintentional tiny gap being created between the mask M and the inner wall surface of the recess 1c.

Next, as shown in FIG. 2(c), the mask M is removed. The process shown in FIG. 2(c) is the mask removal process. As shown in FIG. 2(c), by removing the mask M, the metal layer 2 remains only on the inner wall surface of the recess 1c.

Next, as shown in Figure 3(d), the colored light-transmitting layer 3 is formed. Here, the colored light-transmitting layer 3 is provided over the entire interior of the recess 1c, covering the metal layer 2 from the side opposite the transparent member 1. The colored light-transmitting layer 3 is also provided on the back surface 1b of the transparent member 1, including the area where the metal layer 2 is not provided (the shelf portion 1d). In this embodiment, the colored light-transmitting layer 3 is formed to cover the entire back surface 1b, including the area where the metal layer 2 is formed (the inner wall surface of the recess 1c). The process shown in Figure 3(d) is the colored light-transmitting layer formation process.

Next, as shown in Figure 3(e), the light-blocking member 4 is prepared separately from the transparent member 1. The light-blocking member 4 is formed, for example, by injection molding, and has an opening 4a. Such a light-blocking member 4 can be formed in parallel with the processes shown in Figures 2(a) to 2(c) and 3(d).

Next, as shown in Figure 3(f), the light-blocking member 4 is connected to the transparent member 1. Here, the light-blocking member 4, which is formed separately from the transparent member 1 and has an opening, is connected to the transparent member 1 with the colored light-transmitting layer 3 sandwiched between them. This process shown in Figure 3(f) is the light-blocking member connection process.

The vehicle exterior part 10 of this embodiment as described above comprises a transparent member 1, a metal layer 2, a colored light-transmitting layer 3, and a light-blocking member 4. The transparent member 1 has a recess 1c formed in part of its back surface 1b. The metal layer 2 is provided on the inner wall surface of the recess 1c. The colored light-transmitting layer 3 covers the metal layer 2 from the side opposite the transparent member 1 and is provided throughout the interior of the recess 1c. The colored light-transmitting layer 3 is also provided on the back surface 1b of the transparent member 1, including a portion (shelf portion 1d) where the metal layer 2 is not provided. The light-blocking member 4 is connected to the transparent member 1 with the colored light-transmitting layer 3 sandwiched therebetween, and has an opening 4a.

In the vehicle exterior part 10 of this embodiment, the metal layer 2 is provided on the inner wall surface of the recess 1c. The colored light-transmitting layer 3 covers the metal layer 2 from the side opposite the transparent member 1 and is provided throughout the interior of the recess 1c, as well as on the back surface 1b of the transparent member 1, including areas where the metal layer 2 is not provided. Therefore, when providing the metal layer 2 and the colored light-transmitting layer 3, it is not necessary to insert a mask M into the recess 1c. Furthermore, because the colored light-transmitting layer 3 is provided so as to cover the back surface 1b side of the metal layer 2, the colored light-transmitting layer 3 cannot be seen inside the recess 1c from the outside of the transparent member 1. Therefore, the vehicle exterior part 10 of this embodiment prevents the colored light-transmitting layer 3 from appearing to bleed around the edge of the recess 1c, preventing a poor appearance.

Furthermore, with the vehicle exterior part 10 of this embodiment, a light-blocking member 4 that is separate from the transparent member 1 is connected to the transparent member 1. This allows the light-blocking member 4 to be formed separately from the transparent member 1, and when providing a light-blocking member 4 with an opening 4a that matches the recess 1c, there is no need to insert a mask M into the recess 1c. Therefore, with the vehicle exterior part 10 of this embodiment, it is possible to prevent part of the light-blocking member 4 from entering the interior of the recess 1c located at the opening 4a in a way that is visible from the outside, preventing a deterioration in the appearance.

Furthermore, in the vehicle exterior part 10 of this embodiment, the colored light-transmitting layer 3 covers the entire back surface 1b of the transparent member 1. This prevents the light source unit 20 from being visible through the transparent member 1 at any point.

The vehicle illumination unit 100 of this embodiment also includes the vehicle exterior part 10 described above and a light source unit 20 that emits light toward the vehicle exterior part 10. Therefore, the vehicle illumination unit 100 of this embodiment can prevent the appearance of the vehicle exterior part 10 from being impaired.

The manufacturing method for the vehicle exterior part 10 of this embodiment also includes a transparent member forming process, a mask placement process, a metal layer forming process, a mask removal process, a colored light-transmitting layer forming process, and a light-shielding member connecting process. The transparent member forming process forms a transparent member 1 having a recess 1c formed in a portion of the back surface 1b. The mask placement process places a mask M that covers the back surface 1b except for the recess 1c. The metal layer forming process adheres a metal layer 2 to the back surface 1b of the transparent member 1 via the mask M. The mask removal process removes the mask M. The colored light-transmitting layer forming process forms a colored light-transmitting layer 3 that covers the entire interior of the recess 1c from the side opposite the transparent member 1 and is also formed on the back surface 1b of the transparent member 1, including the portion where the metal layer 2 is not formed. The light-shielding member connecting process connects a light-shielding member 4 formed separately from the transparent member 1 and having an opening 4a to the transparent member 1 via the colored light-transmitting layer 3.

According to the manufacturing method for the vehicle exterior part 10 of this embodiment, the metal layer 2 is provided on the inner wall surface of the recess 1c. The colored light-transmitting layer 3 is provided on the entire interior of the recess 1c, covering the metal layer 2 from the side opposite the transparent member 1, and is also provided on the back surface 1b of the transparent member 1, including the area where the metal layer 2 is not provided. Therefore, when providing the metal layer 2 and the colored light-transmitting layer 3, it is not necessary to insert a mask M into the recess 1c. Furthermore, because the colored light-transmitting layer 3 is provided so as to cover the back surface 1b side of the metal layer 2, the colored light-transmitting layer 3 is not visible inside the recess 1c from the outside of the transparent member 1. Therefore, according to the manufacturing method for the vehicle exterior part 10 of this embodiment, the colored light-transmitting layer 3 is prevented from being visible as if it is bleeding around the edge of the recess 1c, preventing a deterioration in the appearance.

Furthermore, according to the manufacturing method for vehicle exterior part 10 of this embodiment, a light-blocking member 4 that is separate from transparent member 1 is connected to transparent member 1. This allows light-blocking member 4 to be formed separately from transparent member 1, and when providing a light-blocking member 4 having an opening 4a that matches recess 1c, there is no need to insert a mask M into recess 1c. Therefore, according to the manufacturing method for vehicle exterior part 10 of this embodiment, it is possible to prevent part of the light-blocking member 4 from entering the interior of recess 1c located at opening 4a in a way that is visible from the outside, preventing a deterioration in the appearance.

Furthermore, in the manufacturing method for the vehicle exterior part 10 of this embodiment, the colored light-transmitting layer 3 is formed in the colored light-transmitting layer formation process so as to cover the entire back surface 1b of the transparent member 1. This prevents the light source unit 20 from being visible through the transparent member 1 at any point.

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to Fig. 4. In the description of this embodiment, the description of the same parts as those in the first embodiment will be omitted or simplified.

Figure 4 is a schematic diagram showing the overall configuration of the vehicle exterior part 10A of this embodiment. As shown in Figure 4, in the vehicle exterior part 10A of this embodiment, the light-blocking member 4 includes a main body portion 40 and an embedded portion 41.

The main body 40 has the same flat plate shape as the light-blocking member 4 in the first embodiment. The embedded portion 41 protrudes from the main body 40 toward the transparent member 1. This embedded portion 41 is inserted into one of the recesses 1c to fill the interior of the recess 1c.

In this embodiment, the entire inner wall surface of the recess 1c is covered with the metal layer 2, so the embedded portion 41 housed inside the recess 1c is not visible from the outside. With the vehicle exterior part 10A of this embodiment, the interior of the recess 1c is embedded, eliminating the need for an air gap inside the recess 1c. This allows radio waves to pass through the recess 1c. This makes the vehicle exterior part 10A of this embodiment suitable for use as a radar cover.

Furthermore, according to the manufacturing method for vehicle exterior part 10A of this embodiment, by accommodating embedded portion 41 in recess 1c during the light-blocking member connecting step, the light-blocking member 4 can be easily and accurately positioned relative to transparent member 1. Therefore, according to the manufacturing method for vehicle exterior part 10A of this embodiment, it is possible to accurately connect light-blocking member 4 to transparent member 1.

The above describes a preferred embodiment of the present invention with reference to the accompanying drawings, but it goes without saying that the present invention is not limited to the above embodiment. The shapes and combinations of the components shown in the above embodiment are merely examples, and various modifications can be made based on design requirements, etc., without departing from the spirit of the present invention.

For example, in the above embodiment, a configuration has been described in which the colored light-transmitting layer 3 covers the entire back surface 1b of the transparent member 1. However, the present invention is not limited to this. An opening may be partially provided in the colored light-transmitting layer 3.

Furthermore, in the second embodiment described above, a configuration was described in which the embedded portion 41 was part of the light-shielding member 4. However, the present invention is not limited to this. For example, an embedded portion separate from the light-shielding member 4 may be embedded in the recess 1c.

1...Transparent member, 1a...Design surface, 1b...Back surface, 1c...Recess, 1d...Shelf portion, 2...Metal layer, 3...Colored light-transmitting layer, 4...Light-shielding member, 4a...Opening, 10...Vehicle exterior part, 10A...Vehicle exterior part, 20...Light source portion, 40...Main body portion, 41...Embedded portion, 100...Vehicle illumination unit, M...Mask, M1...Opening

Claims (5)

a transparent member having a recess in a part of its back surface;
a metal layer provided on an inner wall surface of the recess;
a colored light-transmitting layer that covers the metal layer from the side opposite to the transparent member and is provided throughout the interior of the recess, and is provided on the back surface of the transparent member including a portion where the metal layer is not provided;
a light-shielding member connected to the transparent member with the colored light-transmitting layer sandwiched therebetween, the light-shielding member having an opening ,
The light blocking member integrally includes a main body portion that covers the recessed portion and a filling portion that fills the recessed portion without any gaps.
An exterior part for a vehicle. The vehicle exterior part according to claim 1, characterized in that the colored translucent layer covers the entire back surface of the transparent member. The vehicle exterior part according to claim 1 or 2 ,
a light source unit that emits light toward the vehicle exterior part. a transparent member forming step of forming a transparent member having a recessed portion in a part of its rear surface;
a mask placement step of placing a mask that covers the back surface except for the recess;
a metal layer forming step of depositing a metal layer on the back surface of the transparent member through the mask;
a mask removal step of removing the mask;
a colored light-transmitting layer forming step of forming a colored light-transmitting layer that covers the metal layer from the side opposite to the transparent member, and is provided throughout the interior of the recess, and is provided on the back surface of the transparent member including a portion where the metal layer is not provided;
a light-shielding member connecting step of connecting a light-shielding member formed by injection molding separately from the transparent member and having an opening to the transparent member with the colored light-transmitting layer sandwiched therebetween,
The light-shielding member connected to the transparent member in the light-shielding member connecting step integrally includes a main body portion that covers the recess and an embedding portion that embeds the recess without any gaps.
A method for manufacturing an exterior part for a vehicle, comprising: 5. The method for manufacturing a vehicle exterior part according to claim 4 , wherein in the colored light-transmitting layer forming step, the colored light-transmitting layer is formed so as to cover the entire back surface of the transparent member.