JP7084614B2 - Lighting equipment and its manufacturing method - Google Patents

Description

The present invention relates to a lighting device including a design plate and a light irradiation means. The present invention also relates to a method for manufacturing the lighting device.

Conventionally, lighting devices have been used mainly for the purpose of brightening indoors and the like, but in recent years, they have also been used as decorative items such as vehicles and buildings.

Patent Document 1 describes an automobile interior lighting device including a light diffusing plate having a decorative design layer on the surface installed in an automobile interior and a light source installed on the back surface side of the light diffusing plate. Has been done. This lighting device for automobile interiors has a metallic appearance when it is turned off (daytime), but when it is turned on (nighttime), the light is dimly floated by the action of the light diffuser. be. By using this lighting device, it is said that different effects can be achieved between daytime and nighttime.

In recent years, with the diversification of consumer needs, there is a demand for a lighting device having a high degree of design both when it is turned off and when it is turned on. However, it cannot be said that the lighting device described in Patent Document 1 sufficiently satisfies such a requirement.

Japanese Unexamined Patent Publication No. 2009-18747

The present invention has been made to solve the above problems, and to provide a lighting device having a black and flat appearance when turned off and capable of expressing a three-dimensional design when turned on, and a method for manufacturing the same. Is the purpose.

The above issues are
It is a lighting device provided with a design plate in which a front plate and a back plate are laminated and a light irradiation means;
Both sides of the front plate are flat,
One surface of the back plate has a plurality of irregularities, and the other surface is flat.
The unevenness is arranged on the surface of the design plate, and the unevenness is arranged.
The unevenness is arranged so as to face the light irradiation means.
The total light transmittance (X) of the resin constituting the front plate is 20 to 95% / 2 mm, and the total light transmittance (Y) of the resin constituting the back plate is 0.01 to 40% / 2 mm. It is solved by providing a lighting device characterized in that there is, and the difference (XY) between the total light transmittance (X) and the total light transmittance (Y) is 10% or more.

At this time, the thickness of the front surface plate is 1 to 10 mm, the thickness of the concave portion (A) in the back surface plate is 0.1 to 5 mm, and the thickness (A) of the concave portion and the convex portion of the back surface plate. The thickness (B) ratio (A / B) is preferably 0.1 to 0.95. Further, it is preferable that the pitch of the unevenness is 1 to 20 mm.

Further, it is preferable that at least one of the front plate and the back plate is made of at least one selected from the group consisting of polycarbonate resin, ABS resin, and acrylic resin.

It is preferable that the light irradiation means irradiates diffused light. It is also preferable that the light irradiation means has a light diffusing plate and a light source.

Further, it is preferable to further have a light-shielding means for blocking a part of the light emitted from the light-irradiating means between the light-irradiating means and the design plate. It is also preferable to further have a color filter for coloring the light emitted from the light irradiation means between the light irradiation means and the design plate.

An automobile interior component made of the above lighting device is a preferred embodiment of the present invention.

The above-mentioned problem is a manufacturing method of the above-mentioned lighting apparatus;
Step 1 of injecting resin into the back plate cavity formed between the common mold and the first exchange mold and filling the cavity to form the back plate.
Step 2 of exchanging the first exchange type with the second exchange type,
Step 3 of injecting resin into the front plate cavity formed between the back plate and the second exchange mold and filling the cavity to form the front plate.
Step 4 of cooling the common mold and the second exchange mold and taking out the design plate from the common mold and the second exchange mold.
It is also solved by providing a method for manufacturing a lighting device having the step 5 of arranging the design plate in a direction in which the unevenness faces the light irradiation means.

Further, the above-mentioned problem is a method for manufacturing the above-mentioned lighting device;
Step 1 of injecting resin into the front plate cavity formed between the common mold and the first exchange mold and filling the cavity to form the front plate.
Step 2 of exchanging the first exchange type with the second exchange type,
Step 3 of injecting resin into the back plate cavity formed between the front plate and the second exchange mold and filling the cavity to form the back plate.
Step 4 of cooling the common mold and the second exchange mold and taking out the design plate from the common mold and the second exchange mold.
It is also solved by providing a method for manufacturing a lighting device having the step 5 of arranging the design plate in a direction in which the unevenness faces the light irradiation means.

The lighting device of the present invention has a black and flat appearance when it is turned off, and can express a design having a three-dimensional effect when it is turned on. Therefore, it has high designability both when it is turned off and when it is turned on. Further, according to the manufacturing method of the present invention, such a lighting device can be easily manufactured.

It is a figure which showed the shape of the design board produced in an Example and a comparative example. FIG. 1 is an enlarged view of a circled portion indicated by A in FIG. 1. FIG. 2 is a cross-sectional view taken along the line BB of FIG. It is an appearance photograph of the LED lighting used in an Example and a comparative example. It is an external photograph when the lighting is turned on in Example 1. It is an external photograph when the lighting is turned on in Example 2. It is an external photograph when the lighting is turned on in Example 3. It is sectional drawing of the design plate used in the comparative example 1. FIG. It is an appearance photograph when the lighting is turned on in the comparative example 1. It is an external photograph when the lighting is turned on in the comparative example 2. It is an appearance photograph when the lighting is turned on in the comparative example 3.

The present invention relates to a lighting device including a design plate and a light irradiation means. The design plate used in the present invention is formed by laminating a front plate and a back plate. Hereinafter, the design plate used in the present invention will be described first with reference to the drawings.

FIG. 1 is a diagram showing an example of a design plate 1 used in the present invention. FIG. 1A is a view of the design plate 1 viewed from the back plate surface 3 side, and FIG. 1B is a view of the design plate 1 viewed from the side surface. FIG. 2 is an enlarged view of the circled portion indicated by A in FIG. 1, and FIG. 3 is a sectional view taken along line BB of FIG.

As shown in FIG. 3, the design plate 1 is formed by laminating a front plate 2 and a back plate 3. Both sides of the front plate 2 are flat. One surface of the back plate 3 has a plurality of irregularities, and the other surface is flat. Then, the plurality of irregularities are arranged on the surface of the design plate 1. Although the details will be described later, in the lighting device of the present invention, the unevenness is arranged so as to face the light irradiating means. Therefore, the outer surface of the design plate 1 (the flat surface of the front plate 2) is the surface arranged on the user side. By having such a configuration of the design plate, it is possible to obtain a lighting device having a flat appearance when the design plate is turned off. In the present invention, the fact that the outer surface of the design plate is flat does not mean that the outer surface must be a perfect flat surface. Therefore, even if the design plate is curved with a large curvature, it is considered to be flat if the surface is not uneven.

In the present invention, when a design plate consisting of only the back plate is used without combining the front plate, it is inevitable that a wavy pattern derived from the unevenness on the opposite side is generated on the flat surface, and the appearance is deteriorated. This wavy pattern is caused by the fact that there is a large difference between the thickness of the convex portion and the thickness of the concave portion of the back plate, so that the amount of shrinkage of the convex portion is larger than that of the concave portion during cooling after melt molding. Is. In order to hide such a wavy pattern, it is preferable to combine the back plate and the front plate. The thickness of the front plate is preferably 1 to 10 mm. If the thickness of the front plate is less than 1 mm, the wavy pattern cannot be sufficiently hidden and the strength of the design plate may decrease. The thicker the front plate, the flatter the outer surface of the design plate and the better the appearance. Therefore, the thickness of the front plate is more preferably 1.5 mm or more, and further preferably 2 mm or more. On the other hand, if the thickness of the front plate exceeds 10 mm, the weight of the lighting device and the manufacturing cost may increase. It is more preferable that the thickness of the front plate is 8 mm or less.

The thickness (A) of the recess in the back plate is preferably 0.1 to 5 mm. Here, the thickness (A) of the recess means the thickness from the flat surface of the back surface plate to the bottom of the recess. If the thickness (A) of the recess is out of the above range, it may be difficult to mold the back plate, and the three-dimensional appearance of the design expressed at the time of lighting may be insufficient. The thickness (A) of the recess is more preferably 0.2 mm or more, and further preferably 0.3 mm or more. On the other hand, the thickness (A) of the recess is more preferably 3 mm or less, and further preferably 2 mm or less.

The ratio (A / B) of the thickness (A) of the concave portion to the thickness (B) of the convex portion in the back plate is preferably 0.1 to 0.95. Here, the thickness (B) of the convex portion means the thickness from the flat surface of the back surface plate to the top of the convex portion. If the ratio (A / B) is out of the above range, the three-dimensional effect of the design expressed at the time of lighting may be insufficient. The ratio (A / B) is more preferably 0.15 or more, and further preferably 0.2 or more. On the other hand, the ratio (A / B) is more preferably 0.8 or less, and further preferably 0.6 or less.

The pitch of the unevenness is preferably 1 to 20 mm. Here, the pitch of the unevenness means the distance from the concave portion to the adjacent concave portion, or the distance from the convex portion to the adjacent convex portion. If the pitch of the unevenness deviates from the above range, the three-dimensional effect of the design expressed at the time of lighting may be insufficient. It is more preferable that the pitch of the unevenness is 2 mm or more. On the other hand, the pitch of the unevenness is more preferably 10 mm or less.

The shape of the unevenness is not limited to the pyramid as shown in FIGS. 1 to 3, and may be a cylinder, a prism, a cone, or the like, or may be a shape composed of a curved surface. Further, unevenness having different shapes may be formed on the same surface of the back surface plate.

In the present invention, it is important that the total light transmittance (X) of the resin constituting the front plate is 20 to 95% / 2 mm. Here, the total light transmittance (X) is the total light transmittance of a 2 mm thick plate made of the resin. When the total light transmittance (X) is less than 20% / 2 mm, the light from the light irradiating means may not sufficiently transmit through the design plate and may not function sufficiently as a lighting device. The total light transmittance (X) is preferably 25% / 2 mm or more, and more preferably 30% / 2 mm or more. On the other hand, when the total light transmittance (X) exceeds 95% / 2 mm, the appearance may not be black when the light is turned off. The total light transmittance (X) is preferably 90% / 2 mm or less.

At this time, by setting the total light transmittance (X) to 80% / 2 mm or less, the appearance when the light is turned off becomes a deep black color. From this point of view, the total light transmittance (X) is more preferably 70% / 2 mm or less, and further preferably 60% / 2 mm or less. The total light transmittance (X) is a value measured according to JIS K7361-1 (1997), and is a value including a decrease due to surface reflection (the same applies to the following total light transmittance (Y)).

In the present invention, it is also important that the total light transmittance (Y) of the resin constituting the back surface plate is 0.01 to 40% / 2 mm. Here, the total light transmittance (Y) is the total light transmittance of a 2 mm thick plate made of the resin. When the total light transmittance (Y) is less than 0.01% / 2 mm, the light from the light irradiating means may not sufficiently transmit through the design plate and may not function sufficiently as a lighting device. The total light transmittance (Y) is preferably 0.02% / 2 mm or more, and more preferably 0.05% / 2 mm or more. On the other hand, when the total light transmittance (Y) exceeds 40% / 2 mm, the appearance may not be black when the light is turned off. The total light transmittance (Y) is preferably 20% / 2 mm or less, and more preferably 10% / 2 mm or less.

It is also important that the difference (XY) between the total light transmittance (X) and the total light transmittance (Y) is 10% or more. If the difference (XY) is less than 10%, the appearance may not turn black when the light is turned off. The difference (XY) is preferably 20% or more. On the other hand, the difference (XY) is usually 95% or less.

The total light transmittance (X) and (Y) can be adjusted by adding a colorant such as a pigment or a dye to the resin serving as the front plate and the back plate. At this time, the color of the colorant is not particularly limited, and various colorants can be used. For example, when the resin constituting the back plate contains a black pigment, a texture and a deep black appearance can be obtained when the light is turned off.

It is preferable that at least one of the front plate and the back plate is made of at least one selected from the group consisting of polycarbonate resin (hereinafter, may be abbreviated as PC resin), ABS resin and acrylic resin. From the viewpoint of impact resistance, it is preferable that at least one of the front plate and the back plate is made of PC resin. From the viewpoint of moldability, it is preferable that at least one of the front plate and the back plate is made of ABS resin. From the viewpoint of transparency, it is preferable that at least one of the front plate and the back plate is made of acrylic resin.

The polycarbonate resin, ABS resin, and acrylic resin may contain additives and the like as long as the effects of the present invention are not impaired. Further, either the resin constituting the front plate or the resin constituting the back plate may be a polymer blend. Preferred polymer blends include polymer blends in which a polycarbonate resin and an ABS resin are blended.

The front plate is preferably made of a resin having a pencil hardness of HB or more according to ASTM D3333, and more preferably made of a resin having a pencil hardness of F or more. Since the front plate constituting the outer surface of the design plate is made of the resin having the above-mentioned pencil hardness, the outer surface is not easily scratched even if the user touches it.

From the viewpoint of excellent scratch resistance while maintaining heat resistance and impact resistance, the front plate is a polycarbonate resin containing a structural unit derived from isosorbide, an alloy of bisphenol A type polycarbonate resin and bisphenol C type polycarbonate resin. Alternatively, it is preferably made of a polycarbonate resin containing a structural unit derived from bisphenol A and bisphenol C.

A polycarbonate resin containing a structural unit derived from isosorbide can be produced by transesterifying isosorbide with a carbonic acid diester. Isosorbide can be obtained by dehydration condensation of sorbitol produced from starch. Examples of the carbonic acid diester include diphenyl carbonate, ditril carbonate, dimethyl carbonate, diethyl carbonate and di-t-butyl carbonate. The number of moles of the structural unit derived from isosorbide is not particularly limited with respect to the number of moles of the monomer unit constituting the polycarbonate, and is usually 20 mol% or more, preferably 40 mol% or more. The polycarbonate resin containing a structural unit derived from isosorbide is sold by, for example, Mitsubishi Chemical Corporation under the trade name “DURABIO”, and a commercially available product can be easily obtained.

The alloy of bisphenol A type polycarbonate resin and bisphenol C type polycarbonate resin is a polymer blend in which bisphenol A type polycarbonate resin and bisphenol C type polycarbonate resin are blended. Additives and the like may be further contained in this polymer blend.

The mass ratio of the bisphenol A type polycarbonate resin (PC-A) and the bisphenol C type polycarbonate resin (PC-C) in the alloy of the bisphenol A type polycarbonate resin and the bisphenol C type polycarbonate resin [(PC-A) / (PC). -C)] is not particularly limited, but is usually 90/10 to 10/90. The content of the components other than the bisphenol A type polycarbonate resin and the bisphenol C type polycarbonate resin in the alloy is not particularly limited, but is usually 20% by mass or less, preferably 10% by mass or less, and more preferably. Is 5% by mass or less. The bisphenol A-type polycarbonate resin and the bisphenol C-type polycarbonate resin are usually obtained by known methods such as a method of interfacial polycondensing bisphenol and phosgen in the presence of an alkali catalyst, and a method of melt polycondensing bisphenol and diphenyl carbonate. Can be done. The alloy of the bisphenol A type polycarbonate resin and the bisphenol C type polycarbonate resin is sold by, for example, Mitsubishi Engineering Plastics Co., Ltd. under the name of "Iupilon", and a commercially available product can be easily obtained.

Further, from the viewpoint of excellent scratch resistance while maintaining heat resistance and impact resistance, it is also preferable that the front plate is made of a polycarbonate resin containing structural units derived from bisphenol A and bisphenol C. At this time, the total number of moles of the structural unit derived from bisphenol A and the structural unit derived from bisphenol C with respect to the number of moles of all the monomer units constituting the polycarbonate resin is not particularly limited, but is usually 80 mol. % Or more, preferably 90 mol% or more, and more preferably 95 mol% or more. The molar ratio [(BPA) / (BPC)] of the structural unit derived from bisphenol A and the structural unit derived from bisphenol C in the polycarbonate resin is not particularly limited, but is usually 90/10 to 10/90. be. The polycarbonate resin may contain other components such as additives. The content of the other components is usually 10% by mass or less, preferably 5% by mass or less.

The method for producing a polycarbonate resin containing a structural unit derived from bisphenol A and bisphenol C is not particularly limited, and it can be usually produced by transesterifying a diol component (bisphenol A and bisphenol C) with a carbonic acid diester. .. The polycarbonate resin containing a structural unit derived from bisphenol A and bisphenol C is sold by Teijin Limited under the trade name "Panlite", and a commercially available product can be easily obtained.

A polycarbonate resin containing a structural unit derived from isosorbide, an alloy of a bisphenol A type polycarbonate resin and a bisphenol C type polycarbonate resin, and a polycarbonate resin containing a structural unit derived from bisphenol A and bisphenol C can be appropriately used. When chemical resistance is important, it is preferable to use a polycarbonate resin containing a structural unit derived from isosorbide.

The resin constituting the front plate and the resin constituting the back plate may be the same type of resin or different types of resin. From the viewpoint of the adhesiveness between the front plate and the back plate, it is preferable that the resin constituting the front plate and the resin constituting the back plate are the same type of resin (for example, PC resins).

Next, the lighting device of the present invention will be described. The lighting device of the present invention includes the above-mentioned design plate and light irradiation means. In the lighting device of the present invention, the unevenness arranged on the surface of the design plate is arranged so as to face the light irradiation means.

The type of the light emitting means is not particularly limited, and for example, a point light source such as a light emitting diode (LED), a line light source such as a fluorescent lamp, or the like can be used.

In the present invention, it is preferable that the light irradiation means irradiates diffused light. By using a light irradiation means that irradiates diffused light, it is possible to express a design with a clear and three-dimensional effect when lit. As the light irradiating means for irradiating the diffused light, a light irradiating means having a light diffusing plate and a light source is preferably used.

Further, it is preferable to further have a light-shielding means for blocking a part of the light emitted from the light-irradiating means between the light-irradiating means and the design plate. As demonstrated in the examples described later, when a light-shielding tape is attached to the light diffusing plate to block a part of the light emitted from the light irradiation means, the part to which the light-shielding tape is attached becomes a black line. It seemed that uneven shapes emerged on both sides. By using the light-shielding means, it is possible to easily express a pattern having a more three-dimensional effect.

It is also preferable to further have a color filter for coloring the light emitted from the light irradiation means between the light irradiation means and the design plate. By using a color filter, the color at the time of lighting can be easily changed.

The method for manufacturing the lighting device of the present invention is not particularly limited, but the following method (i) or (ii) is preferable from the viewpoint of production efficiency. Select method (i) or (ii) as appropriate in consideration of production cost and production efficiency.

・ Method (i)
Method (i) is a step 1 of injecting resin into the back plate cavity formed between the common mold and the first exchange mold and filling the cavity to form the back plate.
Step 2 of exchanging the first exchange type with the second exchange type,
Step 3 of injecting resin into the front plate cavity formed between the back plate and the second exchange mold and filling the cavity to form the front plate.
Step 4 of cooling the common mold and the second exchange mold and taking out the design plate from the common mold and the second exchange mold.
It is a method including a step 5 of arranging the design plate in a direction in which the unevenness faces the light irradiation means.

In step 1, a resin is injected and filled into the back surface cavity formed between the common mold and the first exchange mold to form the back surface plate. By injecting the resin into the back surface cavity, a primary molded body corresponding to the back surface plate in the design plate is formed. At this time, a common type having an uneven pattern on the surface is used. By using a common mold having an uneven pattern on the surface, the uneven pattern is transferred to one surface of the back surface plate.

The molding conditions at the time of injection molding are not particularly limited, but it is preferable to mold at a cylinder set temperature of 200 to 330 ° C. The common mold and the first exchange mold may each be composed of a plurality of molds.

Then, after the resin is filled in the back surface cavity, compacted, compressed, and cooled, the first exchange mold is replaced with the second exchange mold in the subsequent step 2.

In step 3, the resin is injected and filled into the front plate cavity formed between the back plate and the second exchange mold to form the front plate. By injecting resin into the cavity for the front plate, a secondary molded body corresponding to the front plate in the design plate is molded on the primary molded body. The molding conditions at the time of injection molding are not particularly limited, but it is preferable to mold at a cylinder set temperature of 180 to 350 ° C.

Then, in step 4, the common mold and the second exchange mold are cooled, the design plate is taken out from the common mold and the second exchange mold, and in the subsequent step 5, the unevenness of the design plate faces the light irradiation means. A lighting device is obtained by arranging the design plate in.

In the production method of the present invention, the surface of the front plate can be surface-treated after step 4 or after step 5. For example, the surface of the front plate can be painted or plated. Examples of the coating include spray coating, brush coating, electrodeposition coating, electrostatic coating, ultraviolet curing coating and the like. Examples of plating include electroplating, electroless plating, and thin film deposition. It is also possible to laminate a film on the surface of the front plate. Examples of the film used at this time include an anti-glare film (anti-reflection film) and an anti-finger film (anti-fingerprint film).

・ Method (ii)
Method (ii) is a step 1 of injecting resin into the front plate cavity formed between the common mold and the first exchange mold and filling the cavity to form the front plate.
Step 2 of exchanging the first exchange type with the second exchange type,
Step 3 of injecting resin into the back plate cavity formed between the front plate and the second exchange mold and filling the cavity to form the back plate.
Step 4 of cooling the common mold and the second exchange mold and taking out the design plate from the common mold and the second exchange mold.
It is a method including a step 5 of arranging the design plate in a direction in which the unevenness faces the light irradiation means.

The method (ii) is different from the above-mentioned method (i), in which the resin is injected and filled in the front plate cavity formed between the common mold and the first exchange mold in the subsequent step 3. In the method, the resin is injected and filled into the back surface cavity formed between the front surface plate and the second exchangeable mold. In the method (ii), the uneven pattern is transferred to one surface of the back surface plate by using the second exchange type having the uneven pattern on the surface.

Since steps 2, 4 and 5 of the method (ii) correspond to steps 2, 4 and 5 in the above-mentioned method (i), the description thereof will be omitted. The above-mentioned surface treatment can also be applied to the surface of the front plate of the lighting device obtained by this method (ii).

Here, the design plate used in the present invention is formed by laminating a front plate and a back plate, but the design plate can also be manufactured by insert molding. In general, insert molding has the advantage that equipment costs and mold manufacturing costs are lower than two-color molding, so this molding method may be suitable for high-mix low-volume production. ..

Further, as a method for manufacturing a design plate in the present invention, there is also a method in which a front plate and a back plate are separately molded and then bonded together with an adhesive. However, in this method, the organic solvent contained in the adhesive may cause cracks in the front plate and the back plate. In addition, the adhesive may be visually recognized through the front plate, which may deteriorate the appearance of the lighting device. Another method is to bond the front plate and the back plate by heat fusion. However, in this method, distortion due to heat may occur and the dimensional accuracy may decrease.

The lighting device of the present invention thus obtained has a black and flat appearance when it is turned off, and can express a design having a three-dimensional effect when it is turned on. The black and flat appearance (piano black, sometimes called piano tone) gives a sense of luxury and calmness. On the other hand, the three-dimensional design gives off a unique presence. Therefore, the lighting device of the present invention has high designability both when it is turned off and when it is turned on.

The lighting device of the present invention utilizes the above-mentioned features to decorate vehicles (private cars, commercial vehicles), buildings (stores such as houses and restaurants), consumer devices (electronic devices such as video and audio), and the like. It can be used for lighting. Among them, automobile interior parts are a preferred embodiment of the present invention. Since the interior parts for automobiles are visible to the user and are used both during the day and at night, the lighting device of the present invention can be used as an audio panel, an air conditioner panel, a door trim, a center console, a switch around a seat, and a ceiling. When used for such purposes, it is possible to produce different atmospheres during the daytime (when the lights are off) and at night (when the lights are on).

Hereinafter, the present invention will be described in more detail with reference to examples.

(Type of resin)
-PC-1: Bisphenol A type polycarbonate resin "Panlite L1225Y (black)" manufactured by Teijin Limited Pencil hardness: 2B
-PC-2: Bisphenol A type polycarbonate resin "Panlite L1225Y (clear)" manufactured by Teijin Limited Pencil hardness: 2B
-PC-3: Polycarbonate resin "DURABIO D7340 (smoke)" manufactured by Mitsubishi Chemical Corporation, which contains a structural unit derived from isosorbide. Pencil hardness: F
ABS-1: ABS resin "Clara Stick (Black)" from Nippon A & L Inc.
ABS-2: ABS resin "Clara Stick (Clear)" from Nippon A & L Inc.

Example 1
(Making a design board)
A two-color molding injection molding machine including a common type having a resin injection path for the first color and a molding resin injection path for the second color, a first exchange type, and a second exchange type was used. The surface of the common type has an uneven pattern. By using a common mold having an uneven pattern on the surface, the uneven pattern is transferred to one surface of the back surface plate.

First, 10 parts by mass of the above "PC-1" and 100 parts by mass of "PC-2" are blended as a resin for the first color and put into a hopper (for the first color), and then the above "PC" as a resin for the second color. -1 ”was put into the hopper (for the second color). Then, by injecting the mixed composition of the above "PC-1" and "PC-2" into the cavity for the back plate formed between the common mold and the first exchange mold, the primary corresponding to the back plate is formed. A molded product was molded (cylinder set temperature: 280 ° C., mold temperature: 60 ° C., injection speed: 160 mm / sec, injection pressure: 220 MPa).

Then, after cooling for 40 seconds, the first exchange type was replaced with the second exchange type. Next, by injecting the above-mentioned "PC-2" into the cavity for the front plate formed between the back plate and the second exchangeable mold, a secondary molded body corresponding to the front plate was molded on the back plate (). Cylinder set temperature: 280 ° C., mold temperature: 60 ° C., injection speed: 80 mm / sec, injection pressure: 220 MPa). Next, the common mold and the second exchange mold were cooled, and the design plate was taken out from the common mold and the second exchange mold.

FIG. 1 shows the shape of the obtained design plate 1. FIG. 1A is a view of the design plate 1 viewed from the back plate surface 3 side, and FIG. 1B is a view of the design plate 1 viewed from the side surface. 2 is an enlarged view of the circled portion shown by A in FIG. 1, and FIG. 3 is a schematic cross-sectional view taken along the line BB of FIG. 2. As shown in FIG. 3, both sides of the front plate 2 are flat, one surface of the back plate 3 has a plurality of irregularities, and the other surface is flat.

Here, each dimension of the design plate 1 will be described. In FIGS. 1 and 2, the unit of length is mm. As shown in FIG. 1A, the obtained design plate 1 has a vertical length of 100 mm and a horizontal length of 80 mm. As shown in FIG. 3, the thickness of the front plate 2 is 3 mm, the thickness of the concave portion (A) of the back plate 3 is 0.5 mm, and the thickness of the convex portion (B) is 1.47 mm. The ratio (A / B) of the thickness (A) of the concave portion to the thickness (B) of the convex portion is 0.34. The uneven pitch is 5 mm. Table 1 summarizes each dimension.

(Manufacturing of lighting equipment)
The LED lighting shown in FIG. 4A was prepared. This LED lighting is an illumination in which a white LED light source is arranged on the back side of the light diffuser plate and diffused light can be irradiated. In this embodiment, in order to block a part of the light emitted from the light diffusing plate, two light-shielding tapes are attached to the surface of the light diffusing plate (arrows in FIG. 4B). Then, using this LED lighting and the design plate, a lighting device was obtained by installing the unevenness of the design plate and the LED lighting in opposite directions.

[evaluation]
(Measurement of total light transmittance)
A test piece having a thickness of 2 mm was produced by injection molding with an injection molding machine using a resin to be a back plate or a front plate. Then, the total light transmittance was measured according to JIS K7361-1 (1997). The results are shown in Table 1.

(Appearance evaluation: When the lighting is not turned on)
The design plate was visually observed without turning on the LED lighting and evaluated according to the following evaluation criteria. The results are shown in Table 1.

-Black A: It was a deep black color.
B: It was black, but it looked slightly whitish.
C: It was not black.

-Flatness of the outer surface A: The outer surface was flat, and almost no wavy pattern due to unevenness was confirmed.
B: A little wavy pattern due to unevenness was confirmed.
C: The wavy pattern derived from the unevenness was conspicuous, and the design plate itself was bent.

(Appearance evaluation: When the lights are turned on)
The LED lighting was turned on and the design plate was visually observed and evaluated according to the following evaluation criteria. The results are shown in Table 1. Further, FIG. 5 shows a photograph of the outer surface (the surface arranged on the user side) of the design plate taken at the time of the evaluation. FIG. 5A is a photograph when the outer surface is taken from directly above, and FIG. 5B is a photograph when the outer surface is taken from diagonally above (in the following photographs). Similarly).
A: An uneven pattern with a three-dimensional effect was confirmed.
B: The uneven pattern has a three-dimensional effect, but the three-dimensional effect is insufficient.
C: It was not possible to confirm the uneven pattern with a three-dimensional effect.

Example 2
A design plate and a lighting device were obtained in the same manner as in Example 1 except that the type of resin was changed as shown in Table 1. Then, the lighting device was evaluated in the same manner as in Example 1. The results are shown in Table 1, and a photograph of the appearance when diffused light is applied in the appearance evaluation is shown in FIG.

Example 3
The type of resin was changed as shown in Table 1, the cylinder set temperature, mold temperature, injection speed, and injection pressure were changed as shown in Table 2, except that the thickness of the front plate was 1.5 mm. A design plate and a lighting device were obtained in the same manner as in Example 1. Then, the lighting device was evaluated in the same manner as in Example 1. The results are shown in Table 1, and a photograph of the appearance when diffused light is applied in the appearance evaluation is shown in FIG.

Comparative Example 1
After molding the primary molded body corresponding to the back plate in the same manner as in Example 1, the primary molded body was taken out from the common mold. Then, after replacing with a common mold having a smooth surface, the primary molded body was set in this common mold so that the smooth surface was in contact with the common mold. Then, a design plate and a lighting device were obtained in the same manner as in Example 1. A cross-sectional view of the design plate obtained at this time is shown in FIG. As shown in FIG. 8, the unevenness is not arranged on the surface of the design plate, but is arranged at the boundary between the front plate and the back plate. Then, the design plate was installed so that the back plate and the LED lighting face each other. Table 1 shows the evaluation results of the lighting device, and FIG. 9 shows a photograph of the appearance when diffused light is applied in the appearance evaluation.

Comparative Example 2
A design plate and a lighting device were obtained in the same manner as in Example 1 except that the type of resin was changed as shown in Table 1. Then, the lighting device was evaluated in the same manner as in Example 1. The results are shown in Table 1, and a photograph of the appearance when diffused light is applied in the appearance evaluation is shown in FIG.

Comparative Example 3
The type of resin was changed as shown in Table 1, and a design plate was obtained in the same manner as in Example 1 except that the secondary molded body was not molded on the back plate. The obtained design plate consists only of a primary molded body. Then, a lighting device was produced and evaluated in the same manner as in Example 1. The results are shown in Table 1, and FIG. 11 shows a photograph of the appearance when diffused light is applied in the appearance evaluation.

As shown in Table 1, the lighting device satisfying the configuration of the present invention had a flat and black appearance when turned off. Further, as shown in Table 1 and FIGS. 5 to 7, a three-dimensional uneven pattern was confirmed at the time of lighting. Further, as shown in FIGS. 5 to 7, when a light-shielding tape is attached to the light diffusing plate to block a part of the light emitted from the LED lighting, the part to which the light-shielding tape is attached becomes a black line and both sides thereof. It seemed that the uneven shape emerged (Examples 1 to 3).

On the other hand, when the unevenness was arranged at the boundary between the front plate and the back plate, the three-dimensional uneven pattern could not be confirmed at the time of lighting (Comparative Example 1). When the total light transmittances (X) and (Y) did not satisfy the predetermined values, it was not possible to obtain a lighting device having a black appearance when the lights were turned off (Comparative Example 2). When a design plate made of only a primary molded body was used, a lighting device having a flat appearance could not be obtained (Comparative Example 3).

1 Design plate 2 Front plate 3 Back plate

Claims (10)

It is a lighting device provided with a design plate in which a front plate and a back plate are laminated and a light irradiation means;
Both sides of the front plate are flat,
One surface of the back plate has a plurality of irregularities, and the other surface is flat.
The unevenness is arranged on the surface of the design plate, and the unevenness is arranged.
The thickness of the front plate is 1 to 10 mm.
The thickness (A) of the recess in the back plate is 0.1 to 5 mm, and the thickness (A) is 0.1 to 5 mm.
The ratio (A / B) of the thickness (A) of the concave portion to the thickness (B) of the convex portion in the back surface plate is 0.1 to 0.95.
The unevenness is arranged so as to face the light irradiation means.
The total light transmittance (X) of the resin constituting the front plate is 20 to 95% / 2 mm, and the total light transmittance (Y) of the resin constituting the back plate is 0.01 to 40% / 2 mm. A lighting device characterized in that the difference (XY) between the total light transmittance (X) and the total light transmittance (Y) is 10% or more. The lighting device according to claim 1 , wherein the uneven pitch is 1 to 20 mm. The lighting device according to claim 1 or 2 , wherein at least one of the front plate and the back plate comprises at least one selected from the group consisting of a polycarbonate resin, an ABS resin, and an acrylic resin. The lighting device according to any one of claims 1 to 3 , wherein the light irradiation means irradiates diffused light. The illuminating device according to claim 4 , wherein the light irradiating means has a light diffusing plate and a light source. The lighting device according to any one of claims 1 to 5 , further comprising a light-shielding means for blocking a part of the light emitted from the light-irradiating means between the light-irradiating means and the design plate. The lighting device according to any one of claims 1 to 6 , further comprising a color filter for coloring the light emitted from the light irradiation means between the light irradiation means and the design plate. An automobile interior part comprising the lighting device according to any one of claims 1 to 7 . The method for manufacturing a lighting device according to any one of claims 1 to 7 .
Step 1 of injecting resin into the back plate cavity formed between the common mold having an uneven surface and the flat first exchange mold and filling the cavity to form the back plate.
Step 2 of exchanging the first exchange type with a flat second exchange type,
Step 3 of injecting resin into the front plate cavity formed between the back plate and the second exchange mold and filling the cavity to form the front plate.
Step 4 of cooling the common mold and the second exchange mold and taking out the design plate from the common mold and the second exchange mold.
A method for manufacturing a lighting device, comprising a step 5 of arranging the design plate in a direction in which the unevenness faces the light irradiation means. The method for manufacturing a lighting device according to any one of claims 1 to 7 .
Step 1 of injecting resin into the cavity for the front plate formed between the flat common mold and the flat first exchange mold and filling the cavity to form the front plate.
Step 2 of exchanging the first exchange type with the second exchange type having an uneven pattern on the surface ,
Step 3 of injecting resin into the back plate cavity formed between the front plate and the second exchange mold and filling the cavity to form the back plate.
Step 4 of cooling the common mold and the second exchange mold and taking out the design plate from the common mold and the second exchange mold.
A method for manufacturing a lighting device, comprising a step 5 of arranging the design plate in a direction in which the unevenness faces the light irradiation means.

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