JPH09330048A - Lighting housing - Google Patents

Abstract

In a conventional lighting device having a reflector, a reflector, a lamp holder, a housing, a lamp reflector in an edge-guided lighting device, and the like are individual parts. The total cost is relatively high because these products are assembled into products. A housing for a lighting device is manufactured using a thermoplastic resin composition containing titanium oxide, and
The housing for the lighting device also serves as a reflector for reflecting the light emitted from the light source arranged in the lighting device in a specific direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device housing.

[0002]

2. Description of the Related Art When illuminating devices such as indicator lights (emergency lights), advertising lights, and backlights of liquid crystal display devices are classified according to their illumination system, an edge type light guiding system, an internal lighting type light guiding system, It can be roughly divided into the direct system.

In the edge-type light guide system, a light source is arranged on a side portion inside an illuminating device, light emitted from the light source is guided to a desired direction by a light guide plate, and the light is guided to the light guide plate and a rear surface side of the light guide plate. The light is emitted in a predetermined direction by a reflector provided on the. For example, an edge type light guide type guide light is shown in FIG.
As shown in the schematic cross section of the example, a light source (usually a fluorescent lamp) 61 is arranged on the inner side of the guide light 60, and the light emitted from the light source 61 is composed of a milk white plate or the like by a light guide plate 62. The light is guided to the back of the display unit 63 to guide this light to the light guide plate 6.
2 and the reflector 64 provided on the back side of the light guide plate 62 emits the light toward the display unit 63 side to display a desired display.

In the edge type light guide type guide lamp 60, the side wall 65 on the side where the light source 61 is provided has a cross-sectional shape convex to the outside, and the inner side surface thereof has a metal vapor deposition film or a polyethylene terephthalate foam film (hereinafter referred to as " PET
A foamed film ". ) (Both not shown) are attached. The side wall 65 also serves as a lamp reflector (hereinafter referred to as “lamp reflector 65”), and the side wall and the back wall other than the lamp reflector 65 are formed by the exterior housing 66.
The light source 61 is held by a lamp holder 67 provided at a predetermined position of the lamp reflector 65. Although FIG. 6 shows the light guide plate 62 and the reflector 64 separated from each other, the light guide plate 62 and the reflector 64 are usually laminated in close contact with each other, and in this state, the exterior housing 66. Are laminated on the inner side surface of the sheet in a state where they are in close contact with each other or there is almost no gap.

On the other hand, in the internally-illuminated light guide system, a light source is arranged in a central portion of the lighting device or in the vicinity thereof, light emitted from the light source is guided to a desired direction by the light guide plate, and the light is guided by the light guide plate and the light guide plate. The light is emitted in a predetermined direction by a reflector provided on the back side of the light guide plate. For example, an internally-illuminated light guide type guide lamp has a light source (usually a fluorescent lamp) 7 at the center of the inside of the guide lamp 70, as shown in FIG.
1 is arranged to guide the light emitted from the light source 71 to the light guide plate 7
2 guides the light to almost the entire back of the display unit 73 formed of a milky white plate and the like, and guides this light to the light guide plate 72 and the light guide plate 7
The reflector 74 provided on the rear surface side of the light source 2 emits the light toward the display unit 73 side to provide a desired display.

[0006] In the guide light 70 of the internal lighting type light guide system,
The outer wall other than the display portion 73 is formed by the exterior housing 75. The light source 71 is held by a lamp holder 76 provided at a predetermined position of the exterior housing 75 such that at least a part of the light emitting surface is located in the recess 72a provided on the back surface side of the light guide plate 72. There is. Although FIG. 7 shows the light guide plate 72 and the reflector 74 separated from each other, the light guide plate 72 and the reflector 74 are usually laminated in close contact with each other, and in this state, the exterior housing 75. Are laminated on the inner side surface of the sheet in a state where they are in close contact with each other or there is almost no gap.

In the direct type, a light source is arranged in the central portion of the lighting device or in the vicinity thereof, and a reflector is arranged on the back side of the light source so that direct light and reflected light from the light source are emitted in a predetermined direction. It is what makes me. For example, in a direct-lighting guide light, a light source (usually a fluorescent lamp) 81 is arranged at the center of the inside of the guide light 80, and a rear surface side of the light source 81 is arranged as shown in FIG. A reflector 82 is arranged so that the direct light and the reflected light from the light source 81 are emitted to the side of the display section 83 formed of a milky white plate or the like to perform a desired display.

In the direct light 80 of the direct type, the outer wall other than the display portion 83 is formed by the exterior housing 84. The light source 81 is held by a lamp holder 85 provided at a predetermined position of the exterior housing 84. Further, the reflector 82 is usually the exterior housing 8
The ribs 86 integrally formed with the outer housing 4 are fixedly arranged with a predetermined gap formed between the ribs 86 and the inner surface of the outer housing 84.

In any of the edge-type light guide system, the internally-illuminated light guide system, and the direct-lighting system described above, resin products are often used as the lamp holder and the exterior housing. Resin products are often used as lamp reflectors (excluding metal evaporated films) in. Also, as the reflector, in recent years, resin products such as a PET foam film and a polycarbonate resin composition have been widely used.

The above-mentioned PET foam film is obtained by foaming PET with a white pigment added to form microvoids, thereby having a high reflection function. P
Since the reflector made of the ET foam film is in the form of a film, the light from the light source relatively easily leaks from the PET foam film to the outside, and as a result, the reflector made of the polycarbonate resin composition was used. The brightness (illumination rate) of the lighting device is more likely to decrease than in the case.

On the other hand, the above-mentioned polycarbonate resin composition is a mixture of a polycarbonate resin with a white pigment (mainly titanium oxide), and in order to suppress the decrease in the molecular weight of the polycarbonate resin due to the addition of the white pigment, A polycarbonate resin stabilizer is also included.
The reflector made of this polycarbonate resin composition utilizes the light reflection effect of the white pigment, and since the reflector can be adjusted in light-shielding property by adjusting its thickness, it is made of PET. It is possible to obtain an illuminating device having higher brightness (illumination rate) than when a reflector made of a foamed film is used. As a reflector made of a polycarbonate resin composition containing titanium oxide, one having a titanium oxide content of about 8 to 12% by weight is currently put into practical use.

[0012]

In the conventional lighting device, the reflector, the lamp holder, the housing, the lamp reflector in the edge-type light guide type lighting device, and the like are individual parts, and are assembled by assembling them. Since it is commercialized, the total cost is relatively high.

It is an object of the present invention to provide a lighting device housing capable of reducing the total cost of the lighting device.

[0014]

A housing for a lighting device according to the present invention, which achieves the above object, is made of a thermoplastic resin composition containing titanium oxide, and is emitted from a light source arranged in the lighting device. It is also characterized in that it also serves as a reflector for reflecting a certain light in a specific direction.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. The lighting device housing of the present invention includes:
As described above, it also serves as a reflector for reflecting the light emitted from the light source arranged in the lighting device in a specific direction. By making the housing also function as a reflector, the number of parts of the lighting device can be reduced, and accordingly, the assembly cost can be reduced. As a result, the total cost is reduced.

Depending on the structure of the lighting device, the housing may be divided into an inner housing (a holder for peripheral parts) and an outer housing, but in order to reduce the total cost of the lighting device, it also serves as a reflector. It is preferably an outer housing. Further, it is preferable that the lighting device housing has a lamp holder or a lamp reflector integrally formed.

The reflection characteristics required of the reflector are currently Y
Since the value is approximately 93 or more, preferably 94 or more, the Y value of the lighting device housing of the present invention is 93 or more.
It is preferably at least 94, and more preferably at least 94. Here, the “Y value” referred to in this specification is JI
Sample (molded body) according to the method described in SK 7105
Means the stimulus value Y when the tristimulus values X, Y, and Z for the color are determined by spectral colorimetry, and this Y value corresponds to the luminance rate or the luminous reflectance. The Y value can be measured, for example, using MS2020 Plus manufactured by Mcbeth.

When the housing also serves as a reflector, the wall thickness of the reflector (which also serves as the housing) is desired to be within a range of about 2 to 3 mm in practice. In order to prevent the luminance (illumination rate) of the illuminating device from decreasing due to light leaking from the reflector in the above range, the total light transmittance of the reflector is about 0.6 at 1 mm thickness. % Or less, and more preferably 0.4% or less. Here, the “total light transmittance” as used herein means a value measured based on the method described in JIS K 7105.

When the illuminating device housing of the present invention is applied to an internally illuminating type light guide type or direct type illuminating device, the light source is provided on the illuminating device housing directly or with a predetermined gap. In such a case, the thickness of the reflector (which also serves as the housing) is within the above range, and the total light transmittance thereof is about 1 mm. When it is about 0.4%, the shadow of the light source can be seen through from the back side of the reflector (which also serves as the housing) (the side opposite to the side on which the light source is arranged. The same applies below) when the light source is turned on. Therefore, depending on the use of the lighting device, this “transparency of the light source” may be a problem. The thickness of the reflector that also serves as the housing is within the above range, and in order to prevent the above "light source transparency", the total light transmittance at a thickness of 1 mm is generally 0.2% or less. Need to

As described above, when the illuminating device housing also serves as a reflector, the Y value required for the illuminating device housing is approximately 93 or more irrespective of its use, but the total light transmittance thereof is the same. It depends on the application.

Therefore, in the present invention, the housing for the lighting device is formed of the thermoplastic resin composition containing titanium oxide. If the thermoplastic resin composition is used,
By adjusting the content of titanium oxide, it is possible to easily obtain a molded product having a Y value of 93 or more and a total light transmittance at a thickness of 1 mm of a desired value of approximately 0.6% or less. .

The thermoplastic resin which is the main component in the above-mentioned thermoplastic resin composition can be appropriately selected according to the mechanical characteristics and optical characteristics required for the intended housing for the lighting device, and its concrete Examples include polycarbonate resin, acrylic resin, polystyrene resin (transparent type), polymethylpentene-1 and the like. These thermoplastic resins may be used alone, or 2
More than one species may be used in combination. As the thermoplastic resin, those having high transparency are preferable from the viewpoint of improving the average luminance when titanium oxide is blended, and polycarbonate resins,
Particularly preferred is an acrylic resin such as polymethylmethacrylate, or a mixture of a polycarbonate resin and an acrylic resin such as polymethylmethacrylate. The molecular weight of the above-mentioned thermoplastic resin can be appropriately selected for each resin in consideration of the mechanical strength and moldability required for the intended housing for the lighting device.

For example, when a polycarbonate resin is used as the thermoplastic resin, the viscosity average molecular weight of the polycarbonate resin is preferably 10,000 to 40,000. When a polycarbonate resin having a viscosity average molecular weight of less than 10,000 is used, the resulting molded article has low impact resistance. On the other hand, when a polycarbonate resin having a viscosity average molecular weight of more than 40,000 is used, molding becomes difficult. The viscosity average molecular weight of the polycarbonate resin is 1
More preferably from 2000 to 35000, and 15
It is more preferably 000 to 30,000.

When an acrylic resin is used as the thermoplastic resin, the viscosity average molecular weight of the acrylic resin is 10
It is preferably 0000 to 600,000, and 150
It is more preferably from 000 to 500,000. The acrylic resin referred to in the present invention is a generic term for polymers obtained by polymerizing acrylic acid and its derivatives, and includes polymers and copolymers of acrylic acid and its esters, acrylamide, acrylonitrile, methacrylic acid and its esters and the like. .

The composition of the above-mentioned thermoplastic resin composition, which is the material for the housing for the lighting device of the present invention, can be appropriately selected according to the intended use of the housing for the lighting device, etc., but is oxidized to a thermoplastic resin. With the addition of titanium, the molecular weight of the thermoplastic resin, especially the polycarbonate resin, decreases, and with this decrease in molecular weight, the mechanical strength of the molded product obtained from the thermoplastic resin composition decreases. Therefore, in order to obtain a highly reliable housing, as a component other than the thermoplastic resin and the titanium oxide, a stabilizer for suppressing at least the above-mentioned decrease in molecular weight (hereinafter, referred to as "thermoplastic resin stabilizer Or a “stabilizer” is preceded by a specific name of a thermoplastic resin capable of suppressing the above-mentioned molecular weight reduction by the stabilizer, for example, “polycarbonate resin stabilizer” It is preferable to use a thermoplastic resin composition containing the above.

The composition of the thermoplastic resin composition will be described in detail below, taking as an example the case where a polycarbonate resin is used alone as the thermoplastic resin. As a specific example of a thermoplastic resin composition in which a polycarbonate resin is solely used as a thermoplastic resin (hereinafter, this is referred to as a “polycarbonate resin composition”), the polycarbonate resin and the titanium oxide are contained in a ratio of 5 to 5. It is contained in a total amount of 100 parts by weight in an amount of -30% by weight, and a stabilizer for a polycarbonate resin (hereinafter referred to as "polycarbonate resin stabilizer") with respect to a total of 100 parts by weight of the polycarbonate resin and the titanium oxide. That is) 0.0
It may be contained in an amount of 01 to 5 parts by weight.

The polycarbonate resin can be easily produced by reacting a dihydric phenol with phosgene or a carbonic acid ester compound in the presence of an acid acceptor or a terminal terminating agent, and the kind thereof is not particularly limited.

The above dihydric phenols include hydroquinone, 4,4'-dihydroxydiphenyl and bis (4
-Hydroxyphenyl) alkane, bis (4-hydroxyphenyl) cycloalkane, bis (4-hydroxyphenyl) oxide, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfone,
Examples thereof include bis (4-hydroxyphenyl) ketone, 9,9-bis (4-hydroxyphenyl) fluorene, and halogen derivatives thereof. Among them, bisphenol A,
That is, 2,2-bis (4-hydroxyphenyl) propane is suitable.

Examples of the above carbonic acid ester compounds include diaryl carbonates such as diphenyl carbonate and dialkyl carbonates such as diethyl carbonate and dimethyl carbonate.

The end terminator may be of any structure as long as it is a monohydric phenol and is not particularly limited. Specific examples of the terminal terminator include p-tert-butylphenol, p-tert-octylphenol, p-cumylphenol, phenol, p-
tert-amylphenol, p-nonylphenol, p-
Examples include cresol, tribromophenol, p-bromophenol, 4-hydroxybenzophenone and the like.
One type of terminal stopper may be used alone, or two or more types may be used in combination.

As the polycarbonate resin, those having a branched structure may be used, and the branching agent used for obtaining the polycarbonate resin having the branched structure is 1,1,1-tris (4-hydroxyphenyl). Ethane, α, α ′, α ″ -tris (4-hydroxyphenyl) -1,3,5-triisopropylbenzene, 1-
(Α-methyl-α- (4′-hydroxyphenyl) ethyl) -4- (α ′, α′-bis (4 ″ -hydroxyphenyl) ethyl) benzenephloroglucin, trimellitic acid, isatin bis (o-cresol) For example, compounds having three or more functional groups are suitable.

As described above, the viscosity average molecular weight of the polycarbonate resin is preferably 10,000 to 40,000, more preferably 12,000 to 35,000, and further preferably 15,000 to 30,000.

On the other hand, the titanium oxide may be either rutile type or anatase type, but rutile type is preferable from the viewpoint of excellent thermal stability and weather resistance. In order to suppress the thermal decomposition of the polycarbonate resin, it is preferable that the titanium oxide be treated with various surface treating agents to cover the surface. As the surface treatment agent, hydrated aluminum, silica, zinc and the like are usually used.

The shape of titanium oxide is not particularly limited and can be appropriately selected from scale-like shape, spherical shape, amorphous shape and the like. Further, the size (particle size) is preferably about 0.2 to 5 μm. In order to improve the dispersibility of the titanium oxide in the resin, a silicone oil, a polyol or the like can be used.

The above-mentioned polycarbonate resin stabilizer may be any substance capable of suppressing the decrease in the molecular weight of the polycarbonate resin that occurs due to the addition of titanium oxide to the polycarbonate resin. The type of the polycarbonate resin stabilizer is not particularly limited, and may be a phosphorus compound, an organosiloxane containing an alkoxy group (such as a methoxy group, an ethoxy group, a propoxy group, or a butoxy group), an organohydrogensiloxane, or an alkoxysilane compound. , Epoxy compounds and the like can be used.

Specific examples of the above phosphorus compounds include:
(2,4-di-tert-butylphenyl) biphenylenediphosphonite, trimethyl phosphate, benzyl phosphonate, organic phosphonate, organic phosphonate, dialkyl alkyl phosphonate, and the like. Specific examples of the organosiloxane containing an alkoxy group include an organopolysiloxane containing an organooxysilyl group bonded to a silicon atom via a divalent hydrocarbon group.

Specific examples of the above-mentioned organohydrogensiloxane include polyorganohydrogensiloxane and end-capped polyorganohydrogensiloxane. Specific examples of the above alkoxysilane compound include methyltrimethoxysilane, alkylaminosilane and the like. Specific examples of the epoxy compound include epoxy resin, epoxidized soybean oil, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and the like.

Among these polycarbonate resin stabilizers, from the viewpoint that the generation of silver during molding can be suppressed to a relatively low level even if the concentration of titanium oxide in the polycarbonate resin composition is increased, it contains an alkoxy group. The organosiloxane is particularly preferred. Only one type of polycarbonate resin stabilizer may be used,
Two or more kinds may be used in combination.

The reasons for limiting the contents of titanium oxide and the polycarbonate resin stabilizer in the polycarbonate resin composition having the above-described composition as described above are as follows.

That is, the content of titanium oxide is 10 in total of the titanium oxide and the above-mentioned polycarbonate resin.
If less than 5% by weight (5 parts by weight) with respect to 0 parts by weight, 1 m
It becomes difficult to obtain a polycarbonate resin composition that can be molded into a molded product having a total light transmittance of 0.6% or less in m thickness. On the other hand, in a polycarbonate resin composition containing titanium oxide in an amount of more than 30% by weight (30 parts by weight), silver is remarkably generated when the polycarbonate resin composition is molded into a desired shape. Become.

The content of titanium oxide is generally 5 to 100 parts by weight of the total amount of the polycarbonate resin and titanium oxide.
By setting it to 10% by weight, the total light transmittance at a Y value of 93 or more and a thickness of 1 mm is approximately 0.4 to 0.6%.
Thus, a polycarbonate resin composition that can be molded into a molded article can be obtained. Further, by setting the above content of titanium oxide to approximately 10 to 15% by weight, Y
A polycarbonate resin composition that can be molded into a molded product having a value of 93 or more and having a total light transmittance of about 0.2 to 0.4% at a thickness of 1 mm can be obtained. Then, the content of titanium oxide is approximately 15 to 30% by weight.
By doing so, it is possible to obtain a polycarbonate resin composition that can be molded into a molded article having a Y value of 93 or more and a total light transmittance of about 0.2% or less at a thickness of 1 mm.

From the viewpoint of the balance between the moldability in obtaining a molded product and the optical characteristics (in particular, the total light transmittance) of the resulting molded product, the total light transmittance at a thickness of 1 mm is approximately 0.2 to 0.
When it is intended to obtain a molded product of 6%, the content of titanium oxide is preferably set to 8 to 15% by weight,
It is particularly preferred that the content be 10 to 12% by weight. And
In order to obtain a molded article having a total light transmittance of 0.2% or less at a thickness of 1 mm, the content of titanium oxide is set to 2%.
The content is preferably set to 0 to 25% by weight.

When the content of the polycarbonate resin stabilizer is less than 0.001 parts by weight based on 100 parts by weight of the total amount of the polycarbonate resin and titanium oxide, the polycarbonate resin produced by adding titanium oxide to the polycarbonate resin is The effect of suppressing the decrease in molecular weight is small. On the other hand, if it exceeds 5 parts by weight, depending on the type of the polycarbonate resin stabilizer, poor dispersion of titanium oxide and coloring of the polycarbonate resin stabilizer itself may occur. In some cases, the reflectivity may be reduced.
The more preferable content of the polycarbonate resin stabilizer with respect to the total of 100 parts by weight of the polycarbonate resin and the titanium oxide depends on the kind of the polycarbonate resin stabilizer and the content of the titanium oxide. Department.

In the polycarbonate resin composition having the composition described above, the content of titanium oxide is 2 based on 100 parts by weight of the total amount of the polycarbonate resin and titanium oxide.
When it is about 5% by weight or more, silver is likely to be generated during the molding process, and when this silver is generated, the appearance of the obtained molded product is impaired.

In order to obtain a housing for an illuminating device having a Y value of 93 or more, a total light transmittance of 1 mm in thickness of 0.2% or less, and a good appearance, polycarbonate resin and titanium oxide are used. The ratio of the titanium oxide is 10
100 parts by weight in total so as to be 25% by weight,
In addition, 0.001 to 5 parts by weight of a polycarbonate resin stabilizer and 0.01 to 3 parts by weight of a light diffusing agent are used with respect to a total of 100 parts by weight of the polycarbonate resin and the titanium oxide.
It is preferable to use a polycarbonate resin composition containing each part by weight.

As the polycarbonate resin, titanium oxide and polycarbonate resin stabilizer in this polycarbonate resin composition, those mentioned above can be used.

The above-mentioned light diffusing agent is a useful component for lowering the total light transmittance without substantially lowering the Y value of the molded product made of the polycarbonate resin composition. By using this light diffusing agent, the content of titanium oxide in the polycarbonate resin composition that can be molded into a molded product having a total light transmittance of about 0.2% or less at a thickness of 1 mm (polycarbonate resin and titanium oxide) And a total of 10
The lower limit of the ratio of titanium oxide in 0 part by weight) can be lowered to 10% by weight, and the upper limit can be suppressed to 25% by weight. When the content of titanium oxide is 25% by weight or less, a polycarbonate resin composition in which silver is unlikely to be generated during molding is obtained.

The light diffusing agent may be made of a solid which is optically transparent and has a refractive index different from that of the above-described polycarbonate resin. Only one kind of the light diffusing agent may be used, or 2 You may use together 1 or more types. In any case, it is preferable that the size (particle size) is approximately 0.2 to 50 μm. Specific examples of the light diffusing agent include acrylic beads, silica beads, silicone resin beads, and glass beads, and hollow beads, amorphous powders, and plate-like powders of the same material.

The acrylic beads have an average diameter of 0.2 to
About 20 μm is preferable, and silica beads having an average diameter of about 2 to 20 μm, particularly 2 to 5 μm
It is preferably made of high-purity synthetic silica having a true spherical shape of m. Moreover, as the silicone resin beads, those having an average diameter of about 0.5 to 20 μm are preferable. As the glass beads, various glass beads such as those made of low alkali glass (E glass) and those having high refractive index glass (having a refractive index of about 1.9 to 2.2) can be used. Can be made, but the average diameter of E glass, which is inexpensive, is 5
.About.50 .mu.m, more preferably about 5 to 7 .mu.m, and most preferably about 10 to 12 .mu.m. Whichever beads are used, the beads are preferably monodisperse beads, and are preferably spherical beads having a retroreflective function.

From the viewpoint that it is easy to obtain a polycarbonate resin composition that can be molded into a molded product having a high light-shielding property and a high Y value, silica beads, glass beads and crystallinity excellent in a light diffusing function are used as the light diffusing agent. Irregular powders of the material, especially crystalline silica powders, are particularly preferred.

The reasons for limiting the contents of titanium oxide, the polycarbonate resin stabilizer and the light diffusing agent in the polycarbonate resin composition containing the light diffusing agent as described above are as follows.

That is, when the content of titanium oxide is less than 10% by weight based on 100 parts by weight of the total of the polycarbonate resin and titanium oxide, a molded product having a total light transmittance of about 0.2% or less at a thickness of 1 mm is formed. It becomes difficult to obtain a polycarbonate resin composition that can be used. on the other hand,
If it exceeds 25% by weight, the occurrence frequency of silver increases when the polycarbonate resin composition is molded into a desired shape. Total of polycarbonate resin and titanium oxide 1
A more preferable ratio of titanium oxide in the 00 parts by weight is
It is 15 to 20% by weight.

On the other hand, the reason for limiting the content of the polycarbonate resin stabilizer to 0.001 to 5 parts by weight based on 100 parts by weight of the total amount of the polycarbonate resin and titanium oxide is that the above-mentioned polycarbonate containing no light diffusing agent is used. The same as in the resin composition.

When the content of the light diffusing agent is less than 0.01 parts by weight based on 100 parts by weight of the total of the polycarbonate resin and titanium oxide, a molded product having a total light transmittance of about 0.2% or less at a thickness of 1 mm. It becomes difficult to obtain a polycarbonate resin composition that can be molded into On the other hand, when it exceeds 3 parts by weight, it becomes difficult to obtain a polycarbonate resin composition which can be molded into a molded product having a Y value of 93 or more. The content of the light diffusing agent with respect to the total 100 parts by weight of the polycarbonate resin and the titanium oxide depends on the content of the titanium oxide, but the ratio of the titanium oxide to the total 100 parts by weight of the polycarbonate resin and the titanium oxide is 15 to 15. When it is 20% by weight,
It is particularly preferable that the amount is 1 to 1.5 parts by weight.

The composition of the thermoplastic resin composition (polycarbonate resin composition) has been described above with reference to the case where the polycarbonate resin is used alone as the thermoplastic resin. However, when the thermoplastic resin other than the polycarbonate resin is used alone, Even when two or more thermoplastic resins are used in combination, the proportions of titanium oxide, the thermoplastic resin stabilizer and the light diffusing agent in the composition may vary depending on the optical characteristics and mechanical characteristics of the intended housing for the lighting device. According to the above, the polycarbonate resin can be appropriately selected within the range when the polycarbonate resin is used alone as the thermoplastic resin.

Titanium oxide and a light diffusing agent used in obtaining a thermoplastic resin composition using a thermoplastic resin other than a polycarbonate resin alone or a thermoplastic resin composition using two or more thermoplastic resins in combination are as follows: Examples are the same as those mentioned above in the description of the polycarbonate resin composition. Further, the thermoplastic resin stabilizer can be appropriately selected according to the type of the thermoplastic resin, and the same ones used for the above-mentioned polycarbonate resin composition can be used as well.

The composition of the thermoplastic resin composition used as the material of the housing for the lighting device of the present invention has been described above. The thermoplastic resin composition contains various fillers, additives, Other synthetic resins, elastomers, etc. can be contained as necessary. Specific examples of the above fillers include glass fiber, carbon fiber, potassium titanate whiskers, mineral fibers, fibrous fillers such as wollastonite, and plate fillers such as talc, mica, glass flakes, and clay. Can be mentioned.

Specific examples of the above additives include antioxidants such as hindered phenols, phosphites, and phosphates, ultraviolet absorbers such as benzotriazole and benzophenone, and hindered amines. Such as light stabilizers, aliphatic carboxylic acid ester-based, paraffin-based, internal lubricants such as silicone oil and polyethylene wax, or commonly used flame retardants, flame retardant aids, release agents, antistatic agents, colorants, etc. To be

Specific examples of the other synthetic resin include polyester (polyethylene terephthalate, polybutylene terephthalate, etc.), polyamide, polyarylate, polyethylene, polypropylene, polymethylmethacrylate, polystyrene, ABS resin, AS resin and the like. Specific examples of the above elastomer include isobutylene-isoprene rubber, styrene-butadiene rubber, ethylene-propylene rubber, acrylic elastomer, and MBS and MAS which are core-shell type elastomers.
And the like.

The illuminating device housing of the present invention made of the thermoplastic resin composition described above is used as an indicator light such as a guide light (emergency light) or an advertising light, a backlight of a liquid crystal display device, an illuminated push switch, a photoelectric switch. And the like, and the shape thereof can be appropriately selected according to the intended use and the like. Further, as described above, the housing for a lighting device of the present invention may have the lamp holder or the lamp reflector integrally formed. The shape of the lighting device housing in this case is not particularly limited as long as it can be integrally molded.
It can be appropriately selected according to its application.

The lighting device housing of the present invention includes a ribbon blender, a Henschel mixer, a drum tumbler,
After obtaining a thermoplastic resin composition having a desired composition by a method using a single-screw extruder, a twin-screw extruder, a co-kneader, a multi-screw extruder, etc., the thermoplastic resin composition is injection-molded and extrusion-molded. It can be obtained by molding into a desired shape by a method such as rotational molding. The molding temperature can be appropriately selected within a range of approximately 260 to 300 ° C. The mold temperature can be appropriately selected within a range of approximately 80 to 120 ° C.

[0062]

EXAMPLES Examples of the present invention will be described below with reference to comparative examples. The raw materials used for obtaining the thermoplastic resin compositions used in the examples and comparative examples will be described in advance.

(1) Thermoplastic resin (i) Polycarbonate resin Tafflon FN1900A (viscosity average molecular weight 19,000) manufactured by Idemitsu Petrochemical Co., Ltd. (ii) Polymethyl methacrylate Sumipec MHF manufactured by Sumitomo Chemical Co., Ltd. (viscosity average molecular weight 400) , 000)

(2) Titanium oxide CR63 (rutile type titanium oxide powder surface-treated with hydrous aluminum) manufactured by Ishihara Sangyo Co., Ltd.

(3) Thermoplastic resin stabilizer (i) Organopolysiloxane containing organooxysilyl group bonded to silicon atom through divalent hydrocarbon group BY1 manufactured by Toray Dow Corning Silicone Co., Ltd.
6-160 (ii) Polyorganohydrogensiloxane SH1 manufactured by Toray Dow Corning Silicone Co., Ltd.
107

(4) Light diffusing agent (i) Glass beads EMB20 (average particle size 1
5 μm) (ii) Silica beads P-500 (average particle size 2 μm) manufactured by Catalyst Kasei Co., Ltd. (5) Antioxidant tris (2,4-di-tert-butylphenyl) phosphite

Examples 1 to 3 (Housing for Edge-type Light Guide Type Illumination Device) (1) Production of Thermoplastic Resin Composition A polycarbonate resin is used as the thermoplastic resin, and the polycarbonate resin and titanium oxide are used. , A polycarbonate resin stabilizer in the proportions shown in Table 1, and after dry blending, a cylinder temperature of 280 ° C. using a vented twin-screw extruder (TEM-35 manufactured by Toshiba Machine Co., Ltd.).
Were kneaded to obtain pellets of the polycarbonate resin composition for each example.

(2) Fabrication of housing for lighting device After drying the pellet obtained in (1) above for 8 hours at 120 ° C., injection molding was performed under the conditions of molding temperature of 280 ° C. and mold temperature of 90 ° C. The illuminating device housing 1 having the shape shown in (a) and (b) was obtained for each example. The housing 1 for a lighting device is suitable as a housing (which also serves as a reflector) for a lighting device of the edge type light guide system. As the mold, a mold whose surface was mirror-polished with water paper (# 1000) was used.

The lighting device housing 1 shown in FIGS. 1A and 1B is formed on a flat plate-shaped bottom portion 2 having a rectangular shape in plan view, and four edge portions of the bottom portion 2. Side wall 3
It is a box body having a depth of 12 mm having a, 3b, 3c, 3d, and a side serving as a light extraction surface at the time of use being an open surface of 160 × 150 mm (inner size), and the bottom portion 2 described above.
Is the back of the lighting device when in use. The three side walls 3a, 3b, 3c are formed so as to rise vertically from the edge of the bottom 2, and the remaining side walls 3d are formed to rise outwardly from the edge of the bottom 2 while curving outward. . The side wall 3d functions as a lamp reflector (hereinafter, also referred to as "lamp reflector 3d"). On the inner side surface of the side wall 3a, on the lamp reflector 3d side, a lamp holder 4 formed of a grooved rib
Is protruding. Similarly, a lamp holder (not shown) formed of a groove-shaped rib is also provided on the inner surface of the side wall 3c on the lamp reflector 3d side. The bottom part 2, the side walls 3a, 3b, 3c, 3d and the lamp holder are integrally molded, and the bottom part 2 and the side walls 3a, 3b,
The wall thicknesses of 3c and 3d are both 2.5 mm.

In the illumination device using the illumination device housing 1, for example, one end of one fluorescent lamp (light source) 5 is held by the lamp holder 4 on the side wall 3a side, and
By holding the other end of the fluorescent lamp (light source) 5 by a lamp holder (not shown) on the side wall 3c side, the fluorescent lamp (light source) 5 is held, and there is almost no space above the bottom portion 2 of the light guide plate 6.
Can be obtained by arranging them in close contact with each other and disposing the display portion 7 on the release surface side (see FIG. 1B).

(3) Evaluation of optical characteristics The lighting device housing obtained in (2) above and a diameter of 4 mm
Cold cathode tube (HMB manufactured by Harrison Electric Co .; brightness 2
0000 cd / m ² ), a light guide plate, and an acrylic opal white plate (thickness: 2 mm; L432 manufactured by Mitsubishi Rayon Co., Ltd.) as a display unit, to manufacture an illuminating device for each example.

At this time, as shown in FIGS. 2 (a) and 2 (b), a 150 × 150 × 10 mm acrylic resin plate is used as the light guide plate 10, and the back surface at the time of use is subjected to maximum light diffusion treatment. 2 mm diameter conical drill (vertical angle 6
0 °) using a lathe and increasing the hole diameter with increasing distance from the light source, with a minimum depth of 0.0
5mm (smallest hole diameter = hole closest to the light source),
1. Form the holes 11 having the maximum depth of 0.5 mm (the one having the largest hole diameter = the hole farthest from the light source) in a matrix of 60 rows and 60 columns.
The holes were drilled at a pitch of 5 mm. Further, the light guide plate 10 was laminated on the inner surface of the bottom portion 2 of the lighting device housing 1 so as to be in close contact with almost no space. 2B, the diameter and depth of the hole 11 are exaggerated.

With respect to each of the lighting devices manufactured as described above, the average brightness of the display surface when the cold cathode tube was lit was measured using LS-110 manufactured by Minolta Camera Co., Ltd. Further, it was determined whether or not the shadow was visible from the back surface of the lamp reflector 3d (see FIG. 1) when the cold cathode tube was lit. Further, for each lighting device housing 1,
The presence or absence of silver was visually determined. Table 2 shows the results.

Using the polycarbonate resin composition obtained in (1) above, a test piece consisting of a flat plate of 25 × 35 × 1 mm was obtained for each example by injection molding under the same conditions as above. As the mold for obtaining the test piece, a mold whose surface was mirror-polished was used as in (2) above. Then, the total light transmittance and the Y value of each of the above test pieces were measured. At this time, the total light transmittance was measured using SZ Sigma 90 manufactured by Nippon Denshoku Industries Co., Ltd., and the Y value was MS20 manufactured by Macbeth.
It measured using 20 plus. Table 2 also shows these results.

Examples 4 to 6 (Housing for Internal Illumination Type Light Guide Type Illumination Device) (1) Production of Thermoplastic Resin Composition A polycarbonate resin is used as the thermoplastic resin, and the polycarbonate resin and titanium oxide are used. And a polycarbonate resin stabilizer and a light diffusing agent were mixed in the proportions shown in Table 1, and after dry blending, a cylinder temperature was measured by using a vented twin-screw extruder (TEM-35 manufactured by Toshiba Machine Co., Ltd.). Kneading was carried out at 280 ° C. to obtain pellets of the polycarbonate resin composition in each example.

(2) Fabrication of housing for illumination device Illumination having a shape shown in FIGS. 3 (a) and 3 (b) was performed in the same manner as in Example 1 to Example 3 (2) except that the shape of the mold was changed. A device housing 20 was obtained for each example. The illuminating device housing 20 is suitable as a housing (also serving as a reflector) for an internally illuminating light guide type illuminating device.

The lighting device housing 20 shown in FIGS. 3A and 3B is formed on a flat plate-like bottom portion 21 having a rectangular shape in plan view, and four edge portions of the bottom portion 21. It is a 12 mm deep box having side walls 22a, 22b, 22c, 22d, and the side that becomes the light extraction surface during use is an open surface of 150 × 150 mm (inner size), and the bottom portion 21 is It becomes the back of the lighting device when in use. The four side walls 22a, 22b, 22c, 22d are formed so as to rise vertically from the edge of the bottom portion 21. Of these side walls, a pair of grooves 22a and 22c, which face each other, extend from the central part to the lower part of the inner side surfaces of the pair of side walls 22a and 22c to form a grooved rib for holding a light source (a fluorescent lamp is assumed in this embodiment). Each lamp holder 23 is formed. Bottom 21, side walls 22a, 22
b, 22c, 22d and the lamp holder 23 are integrally formed, and the bottom 21 and the side walls 22a, 22b, 2 are formed.
The wall thicknesses of 2c and 22d are both 3 mm.

The illumination device using the illumination device housing 20 is, for example, the lamp holder 2 on the side wall 22a side.
One end of one fluorescent lamp (light source) 24 is sandwiched by 3 and the other end of the fluorescent lamp (light source) 24 is sandwiched by a lamp holder (not shown) on the side wall 22c side. This can be obtained by holding and stacking the light guide plate 25 on the bottom portion 21 so as to be in close contact with each other with almost no space therebetween and disposing the display portion 26 on the release surface side (see FIG. 3B).

(3) Evaluation of optical characteristics The lighting device housing obtained in (2) above and a diameter of 4 mm
Cold cathode tube (HMB manufactured by Harrison Electric Co .; brightness 2
0000 cd / m ² ), a light guide plate, and an acrylic opal white plate (thickness: 2 mm; L432 manufactured by Mitsubishi Rayon Co., Ltd.) as a display unit, to manufacture an illuminating device for each example.

At this time, as shown in FIG.
Is a 150 x 150 x 10 mm acrylic resin plate, and the length is 150 mm, the width is 5 mm, and the depth is 4.5 m in the center part on the back side when used.
The groove 31 of m was provided. Further, on the back surface of the light guide plate 30, the hole diameter is increased as the distance from the light source increases,
A hole (not shown) with a minimum depth of 0.05 mm (smallest hole diameter = hole closest to the light source) and maximum depth 0.5 mm (largest hole diameter = hole farthest from the light source) Drilling was performed in the same manner as in Examples 1 to 3 (3). The light guide plate 30 was laminated on the inner surface of the bottom portion 21 of the lighting device housing 20 so as to be in close contact with it with almost no gap.

For each of the above lighting devices, the average luminance of the surface of the display portion when the cold cathode tube is lit is shown in Examples 1 to 3.
It measured like (3). In addition, it was determined whether or not the shadow was visible from the back surface of the bottom portion 21 of the lighting device housing 20 (see FIG. 1) when the cold cathode tube was lit. further,
The presence or absence of silver was visually determined for each lighting device housing 20. Table 2 shows the results.

Using the polycarbonate resin composition obtained in (1) above, a test piece consisting of a flat plate of 25 × 35 × 1 mm was obtained for each example by injection molding under the same conditions as above, and these tests were carried out. Total light transmittance and Y for one piece
The value was measured in the same manner as in Example 1 to Example 3 (3).
Table 2 also shows these results.

Example 7 (Housing for Edge-Type Light Guide Type Illumination Device) First, polymethylmethacrylate was used as a thermoplastic resin, and this polymethylmethacrylate, titanium oxide, and polymethylmethacrylate stabilizer were shown. After blending in a ratio shown in 1 and dry blending, kneading was performed at a cylinder temperature of 230 ° C. using a vented twin-screw extruder (TEM-35 manufactured by Toshiba Machine Co., Ltd.) to form a pellet made of a polymethylmethacrylate composition. Got After that, a housing for an illumination device (for edge type light guide system) was obtained in the same manner as in Examples 1 to 3 except that the molding temperature was 250 ° C and the mold temperature was 50 ° C. In addition, a test piece for optical property evaluation was obtained. The optical characteristics of the lighting device housing and the test piece were evaluated in the same manner as in Examples 1 to 3. Table 2 shows the results.

Example 8 (Housing for Edge-type Light Guide Type Lighting Device) First, a polycarbonate resin and polymethylmethacrylate were used as the thermoplastic resin, and these thermoplastic resin, titanium oxide, and a stabilizer were used. , And an antioxidant in the proportions shown in Table 1, dry blended, and then kneaded at a cylinder temperature of 250 ° C. using a vented twin-screw extruder (TEM-35 manufactured by Toshiba Machine Co., Ltd.) Pellets of the plastic resin composition were obtained. After this, the molding temperature is set to 28
A housing for an illumination device (for edge type light guide system) was obtained in the same manner as in Examples 1 to 3 except that the temperature was 0 ° C and the mold temperature was 80 ° C. In addition, a test piece for optical property evaluation was obtained. The optical characteristics of the lighting device housing and the test piece were evaluated in the same manner as in Examples 1 to 3. Table 2 shows the results.

Comparative Example 1-Comparative Example 2 Example 4-except that the amounts shown in Table 1 were used for the respective components.
After producing a polycarbonate resin composition for each comparative example in the same manner as in Example 6 (1), Examples 4 to 6 (2)
In the same manner as above, a housing for an internally illuminated light guide type lighting device was manufactured. Then, using these housings, an illuminating device was produced in the same manner as in Example 4 to Example 6 (2), and the average luminance of the surface of the display portion when the cold cathode tube was lit was measured in Example 4 to Example 6 (3). ). Further, it was determined whether or not the shadow was visible from the back surface of the bottom of the housing when the cold cathode tube was lit. Furthermore, the presence or absence of silver in each housing was visually determined. Table 2 shows the results. Further, Examples 4 to 6 except that the above polycarbonate resin composition was used.
In the same manner as in (3), a test piece composed of a flat plate of 25 × 35 × 1 mm was obtained for each comparative example, and the total light transmittance and the Y value of these test pieces were compared with those in Examples 4 to 6 (3). It measured similarly. Table 2 also shows these results.

Reference Example 1 A housing was prepared in the same manner as in Examples 4 to 6 (2) except that ABS resin (ABS10 manufactured by Japan Synthetic Rubber Co., Ltd.) was used in place of the polycarbonate resin composition. A PET foam film (Ref White RW188 manufactured by Kimoto Co., Ltd .; thickness 190 μm) was adhered to the entire inner surface of the housing, and then, Example 4 to Example 6 (3).
A lighting device was manufactured in the same manner as in. With respect to this illuminating device, the average luminance of the surface of the display portion when the cold cathode tube was lit was measured in the same manner as in Example 4 to Example 6 (3). Also,
It was determined whether the shadow was visible from the back surface of the bottom of the housing when the cold cathode tube was lit. Furthermore, the total light transmittance and the Y value of the above PET foam film were measured in the same manner as in Examples 4 to 6 (3). Table 2 shows the results.

[0087]

[Table 1]

[0088]

[Table 2]

As shown in Table 2, Examples 1 to 3
The average brightness of the edge-type light guide type illuminators manufactured in each of Examples 7 to 8 is 250 to 300 cd /.
m ² and the brightness of the cold cathode tube used as the light source is 200
Considering that it is 00 cd / m ² , each of the housings for lighting devices obtained in these examples has a reflecting function practically sufficient as a reflector. In addition, in each of the housings for lighting devices obtained in each of Examples 1 to 3 and Examples 7 to 8, silver is not generated or even if there is little silver, the appearance is good.

On the other hand, the average brightness of the internally-illuminated light guide type illuminators manufactured in Examples 4 to 6 is 310 to 3 respectively.
Was 40 cd / m ^2, the luminance of the cold cathode tube using a light source in view of the fact is 20000 cd / m ^2, even practically sufficient reflection function as reflectors each lighting device housing obtained in these examples have. In addition, in each of the housings for lighting devices obtained in Examples 4 to 6, silver is not generated, so that the appearance is good. Further, in each of the lighting devices obtained in Examples 4 to 6, the shadow of the cold cathode tube as the light source could not be visually recognized from the back surface of the bottom of the housing for the lighting device at the time of lighting. Therefore, these lighting devices can be used as lighting devices for various purposes.

As is clear from the comparison with Reference Example 1, when the housings for the respective lighting devices of Examples 1 to 8 are used, the lighting device can be obtained with a small number of parts, and Since the step of attaching the reflector to the housing is not necessary, the total cost for manufacturing the lighting device is reduced.

On the other hand, the average luminance of the internally illuminated light guide type lighting device obtained in Comparative Example 1 was 210 cd / m ² , and the luminance of the cold cathode tube used as the light source was 20000 cd / m ^2.
Therefore, the reflecting function of the housing obtained in Comparative Example 1 is not practical. Since the total light transmittance of the test piece is 0.72%, it is speculated that this low reflection function is caused by a large amount of light leaked from the housing. Further, the average luminance of the lighting device obtained in Comparative Example 2 was 305 cd / m ² , and the reflection function of the housing obtained in Comparative Example 2 can be said to be practical, but silver is intensely generated in this housing. Therefore, it is not practical as an exterior housing.

As described above, the lighting device obtained in Reference Example 1 has a larger number of parts and a larger number of manufacturing steps than the lighting devices obtained in Examples 1 to 8. The total cost required is high.

Although the housing for the lighting device of the present invention has been described above with reference to the embodiments, the housing for the lighting device of the present invention is not limited to these embodiments.
Including various modifications and applications.

For example, as shown in FIG. 5, the lighting device housing 40 has two side walls facing each other.
An integrally molded box whose light extraction surface at the time of use is an open surface is formed, and the bottom surface is formed with a flat flat surface 41 parallel to a pair of side walls facing each other in the central portion. Between the flat surface 41 and the pair of side wall side edges facing each other, the inclined surfaces 42a, 42b are provided.
With such a shape, it can also be used for a direct illumination device using a fluorescent lamp as a light source.
In FIG. 5, reference numeral 43 indicates a lamp holder,
The lamp holders 43 are integrally formed on the inner side surfaces of the other pair of side walls facing each other so as to be located at the ends of the flat surface 41 in the longitudinal direction. An illumination device using the illumination device housing 40 shown in FIG. 5 is obtained, for example, by holding one fluorescent lamp (light source) 44 by a lamp holder 43 and disposing a display unit 45 on the release surface side. be able to.

[0096]

As described above, since the illuminating device housing of the present invention also serves as a reflector, the total cost of the illuminating device can be reduced by using this illuminating device housing.

[Brief description of drawings]

FIG. 1 (a) is a perspective view showing an outline of a housing for each lighting device produced in Examples 1 to 3 and Examples 7 to 8, and FIG. It is the sectional view on the AA line shown in (a).

2 (a) is a bottom view schematically showing a light guide plate used in manufacturing the lighting device in each of Examples 1 to 3 and Examples 7 to 8. FIG. b) is shown in FIG.
It is sectional drawing which shows the outline of the light-guide plate shown to (a).

FIG. 3A is a perspective view showing an outline of a housing for each lighting device manufactured in Examples 4 to 6;
3B is a sectional view taken along line BB shown in FIG.

FIG. 4 is a side view showing an outline of a light guide plate used when manufacturing an illumination device in each of Examples 4 to 6.

FIG. 5 is a cross-sectional view showing an example of a housing for a lighting device of the present invention, which is suitable for a direct type lighting device.

FIG. 6 is a cross-sectional view showing an example of a conventional edge-type light guide type illumination device.

FIG. 7 is a cross-sectional view showing an example of a conventional internally illuminated light guide type illumination device.

FIG. 8 is a sectional view showing an example of a conventional direct-type illumination device.

[Explanation of symbols]

1 ... Housing for lighting device (for edge type light guide system),
3d ... Side wall also serving as a lamp reflector, 4 ... Lamp holder, 5 ... Light source, 6, 10 ... Light guide plate, 7
... Display section, 20 ... Illumination device housing (for internally illuminated light guide system), 23 ... Lamp holder, 24 ... Light source,
25, 30 ... Light guide plate, 26 ... Display unit, 40 ... Illumination device housing (for direct system), 43 ... Lamp holder, 44 ... Light source, 45 ... Display unit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaya Okamoto 1 Inezaki Kaigan, Ichihara-shi, Chiba Idemitsu Petrochemical Co., Ltd.

Claims (8)

[Claims] 1. A thermoplastic resin composition containing titanium oxide, which also serves as a reflector for reflecting light emitted from a light source arranged in an illuminating device in a specific direction. Housing for lighting equipment. 2. The housing for a lighting device according to claim 1, which has a lamp holder or a lamp reflector integrally molded. 3. The thermoplastic resin composition contains a thermoplastic resin and titanium oxide in a total amount of 100 parts by weight such that the proportion of the titanium oxide is 5 to 30% by weight, and the thermoplastic resin and The housing for a lighting device according to claim 1, further comprising 0.001 to 5 parts by weight of the thermoplastic resin stabilizer with respect to a total of 100 parts by weight of the titanium oxide. 4. A thermoplastic resin composition comprising a thermoplastic resin and titanium oxide in a proportion of 10 to 25% by weight of the titanium oxide.
100 parts by weight in total so that 0.001 to 5 parts by weight of a thermoplastic resin stabilizer is added to 100 parts by weight of the thermoplastic resin and the titanium oxide, and a light diffusing agent. The lighting device housing according to claim 1 or 2, further comprising 0.01 to 3 parts by weight. 5. The housing for a lighting device according to claim 1, wherein the thermoplastic resin contained in the thermoplastic resin composition is a polycarbonate resin and / or an acrylic resin. 6. When the thermoplastic resin composition is molded into a molded product having a thickness of 1 mm, the total light transmittance of the molded product is 0.4.
The housing for a lighting device according to any one of claims 1 to 5, which is less than or equal to%. 7. The housing for a lighting device according to claim 1, wherein the Y value of the inner surface is 93 or more. 8. The housing for a lighting device according to claim 1, which is an exterior housing of the lighting device.