JP5952028B2 - Light diffusion cover and light source - Google Patents

Description

  The present invention relates to a light diffusion cover used for, for example, a straight tube type LED lamp. The present invention also relates to a diffusion light source such as a straight tube LED lamp using a light emitting diode (LED).

In a light diffusion cover of a straight tube type LED lamp, a light diffusion film is provided inside the lamp tube to diffuse light.
Further, in order to join the LED main body and the lamp tube, a portion (aperture) in which the light diffusion film is not formed is created in the adhesive application portion to avoid a decrease in adhesive force due to the light diffusion film.

  In addition, a film of an organic material such as a resin has a greater influence on the light absorption due to the thickness than a film formed of only an inorganic material such as a metal oxide.

JP 2006-049280 A JP 2009-259529 A JP 2001-283376 A

  When a light diffusion film is provided inside the lamp tube, the light flux is reduced by the light diffusion film.

  Therefore, it is desirable to provide a light diffusing cover having a light diffusing film that increases light transmittance while maintaining light diffusibility.

The light diffusion cover according to this invention is
Glass,
A protective film of metal oxide X formed on one side of the glass;
A light diffusion film formed of a low-melting-point glass that is formed on a surface opposite to the surface where the glass of the protective film is present and melts at a temperature lower than the melting temperature of the glass and the metal oxide Y,
The protective film is made of a metal oxide X having an average particle diameter of 0.05 to 0.3 μm,
The thickness of the protective layer is from 0.5 to 3. 0 μm,
The light diffusion film is
Average particle diameter of Ri 0.05~20.0μm der, and a metal oxide Y that is used as a light diffusion agent,
It has a melting point lower than the melting point of the glass, and comprises a low melting point glass used for forming the metal oxide Y particles as a film ,
The metal oxide Y is present in a volume ratio of 30 to 60% with respect to the light diffusion film,
The light diffusing film has a thickness of 5.0 to 20.0 μm.

  According to the present invention, it is possible to increase the light transmittance while maintaining the light diffusibility of the light diffusion film.

FIG. 3 shows a diffuse light source 50 according to the first embodiment. FIG. 3 is a cross-sectional view taken along line AA of the diffuse light source 50 according to the first embodiment. FIG. 4 is a partially cutaway view of a glass tube 56 of the light diffusion cover 40 of the first embodiment. The enlarged view of the A section of FIG. 3 of Embodiment 1. FIG. FIG. 4 shows light diffusion according to the first embodiment. The data figure of Comparative Examples 1-3. The data figure of Comparative Examples 4-7. The graph of Comparative Examples 4-7. FIG. 3 is a data diagram of Examples 1 to 5 of the first embodiment. FIG. 6 is a data diagram of Examples 6 to 9 of the first embodiment. The data figure of Example 10, 11, 12 and preferred value of Embodiment 1. FIG. The figure of the comparative example with the aperture 91 of Embodiment 2. FIG.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a diffused light source 50 according to the first embodiment. The diffuse light source 50 is, for example, a light emitting diode lamp.
The diffusion light source 50 includes a cylindrical glass tube 56. The glass tube 56 is a transparent or translucent straight tube glass tube. The glass of the glass tube 56 is desirably a high melting point glass that does not melt at a temperature of 900 degrees Celsius or lower.

The light emitting unit 60 includes a light emitting diode LED 51 (LED 51), a substrate 52, and a heat sink 54.
The light emitting unit 60 is housed in the glass tube 56 and emits light in the light emitting direction. The light emitting unit 60 extends in the longitudinal direction of the glass tube 56.

The LED 51 is an example of a light source, and includes an LED (light emitting diode) alone or an LED module. The LED 51 is also referred to as an LED chip.
The substrate 52 has a plurality of LEDs 51 arranged and arranged uniformly.

  The heat sink 54 is made of metal such as aluminum and serves as a pedestal to which the substrate 52 is attached and a heat radiating member.

There are a pair of caps 55 at both ends of the glass tube 56.
Each base 55 includes a pair of power supply terminals 58. The number and shape of the power supply terminals 58 are not limited to the drawing and may be other numbers or shapes.

  The pair of caps 55 covers both ends of the glass tube 56 and is fixed to both ends of the heat sink 54 of the light emitting unit 60 and both ends of the glass tube 56.

  The diffused light source 50 has a structure that prevents dust from entering the lamp that impairs safety during use from the viewpoint of long-term use. That is, the glass tube 56 and the base 55 are bonded together, and the light emitting unit 60 is sealed.

  The diffused light source 50 has the same shape as a commercially available straight tube fluorescent lamp having a glass outer shape and a conventional outer shape. The diffused light source 50 is a straight tube LED lamp system that cannot be permanently disassembled without losing its function.

FIG. 2 is an AA end view of the diffused light source 50 of FIG.
A protective film 70 is formed on the entire inner peripheral surface of the glass tube 56. The protective film 70 is sometimes called a protective layer.
Further, a light diffusion film 80 is formed on the entire inner peripheral surface of the protective film 70. The light diffusion film 80 is sometimes called a light diffusion layer.
An adhesive 90 is applied to a part of the lower surface (back surface) of the heat sink 54 and adhered to the light diffusion film 80.
The cross-sectional shape of the heat sink 54 by a plane orthogonal to the longitudinal direction is a D-shape or a half-moon shape. The heat sink 54 is a single integrally formed part composed of a flat plate portion 62 and an arc-shaped portion 63. There is a hollow portion 64 in the center of the cross section of the heat sink 54. An arc-shaped portion 63 is provided below the arc portion of the hollow portion 64, and a flat plate portion 62 is provided on the chord portion above the hollow portion 64.

FIG. 3 is a perspective view in which a part of the glass tube 56 is cut away.
The light diffusion cover 40 includes a glass tube 56, a protective film 70, and a light diffusion film 80.
On the glass tube 56, a protective film 70 and a light diffusion film 80 are deposited over the entire length of the glass tube 56 and over the entire inner circumference of the glass tube 56.

  FIG. 4 is an enlarged view of a portion A in FIG. 3, and is a schematic diagram of the glass tube 56, the protective film 70, and the light diffusion film 80.

  A glass inner surface scratch 57 exists on the inner surface of the glass tube 56. The glass inner surface scratch 57 visually appears as streaks and lines on the outer appearance of the glass tube 56, and causes the appearance of the film skin to be impaired.

The protective film 70 is made of a metal oxide X.
The metal oxide X is, for example, fine particle silica having an average particle diameter of 0.05 to 0.3 μm (50 to 300 nm).
Hereinafter, “particle diameter” is also simply referred to as “particle diameter”.
The thickness of the protective film 70 is, for example, 0.5 to 5.0 μm.
Hereinafter, “film thickness” is also referred to as “film thickness”.

  For example, the protective film 70 is prepared by dispersing a metal oxide X such as fine silica in a liquid such as water or a mixture of water and polyethylene oxide, and pouring the suspension into the glass tube 56. The suspension is applied to the inner surface of the glass tube 56, and the suspension is dried with warm air.

The light diffusion film 80 has a metal oxide Y and a low melting point glass 83. The low melting point glass 83 has a melting point lower than the melting point of the glass of the glass tube 56, and is, for example, a glass that melts at 500 to 800 degrees Celsius. The low melting point glass 83 is a transparent or translucent glass.
For example, the content of the metal oxide Y in the light diffusion film 80 is 30% or more and 50% or less in the volume ratio. Or the content rate of the low melting glass 83 in the light-diffusion film 80 is 70% or more and 50% or less by volume ratio.
When the light diffusing film 80 is composed only of the metal oxide Y and the low melting point glass 83, the light diffusing film 80 has a volume ratio, the content of the metal oxide Y is not less than 30% and not more than 50%, and low The content of the melting point glass 83 is 70% or more and 50% or less.
The content of the metal oxide Y in the light diffusion film 80 is 30% to 60% by volume, and the content of the low melting point glass 83 in the light diffusion film 80 is 70% to 40% by volume. There may be.
The metal oxide Y is, for example, silica having an average particle diameter of 0.05 to 20 μm (50 to 20000 nm).
The thickness of the light diffusion film 80 is, for example, 5.0 to 20.0 μm.

  The light diffusion film 80 is prepared by dispersing particles of the low melting point glass 83 and particles of metal oxide Y such as silica in a resin solution, and pouring the film solution onto the surface of the protective film 70 in the glass tube 56. The film solution is applied by heating at 500 to 800 degrees Celsius, the resin is blown off, and the low melting point glass 83 is dissolved. The particles of the metal oxide Y such as silica remain in the melted low melting point glass 83, and the light melting film 80 is formed by solidifying the low melting point glass 83 by heat radiation.

  If the content of the metal oxide Y as the diffusing material in the light diffusion film 80 increases, the film becomes brittle and easily peels off, and the diffusion becomes too strong and the light becomes weak. When the low-melting glass 83 increases in the light diffusion film 80, the diffusion effect decreases. There should be an optimal place.

The protective film 70 has the following functions.
1. Filling glass inner surface scratch 57 with metal oxide X The protective film 70 enters the glass inner surface scratch 57 on the inner periphery of the glass tube 56 so that the glass inner surface scratch 57 cannot be seen from the outside. For this reason, the aesthetic appearance of the glass tube 56 is improved.
When there is a glass inner surface scratch 57, there is a problem that the optical refractive index changes, or there is a problem that the liquid flow becomes irregular due to fine scratches on the glass surface, resulting in uneven coating. When the glass inner surface scratch 57 is filled with the metal oxide X, the roughness of the film skin due to the glass inner surface scratch 57 can be eliminated from the appearance, and the aesthetic appearance is improved.
2. Prevention of melting of glass tube 56 Low melting point glass 83 contains boron. When the low-melting glass 83 is melted at 500 to 800 degrees Celsius, the boron makes the glass tube 56 easily melted at a temperature of 500 to 800 degrees Celsius. The presence of the protective film 70 on the inner surface of the glass tube 56 can reduce the influence of the boron of the low melting point glass 83 on the glass tube 56 and prevent the melting of the glass tube 56 when the low melting point glass 83 is melted. be able to.
3. Light diffusion Light is diffused by the metal oxide X of the protective film 70.

The light diffusion film 80 has the following functions.
1. The low melting point glass 83 of the light diffusion film 80 is used to maintain the strength of the light diffusion film 80. The light diffusion film made only of the metal oxide Y is easy to peel off.
2. The low melting point glass 83 of the light diffusion film 80 is used for forming metal oxide Y particles as a film inside the glass tube.
3. The metal oxide Y of the light diffusing film 80 is used as a light diffusing agent for diffusing and dispersing light.

  As shown in FIG. 5, the light incident on the light diffusion film 80 passes through the low melting point glass 83 and is reflected in multiple directions on the surface of the metal oxide Y. Thus, the light is diffused in the light diffusion film 80.

  Light that has entered the protective film 70 from the light diffusion film 80 is diffused to some extent by the metal oxide X of the protective film 70 because the protective film 70 is thin, reaches the glass tube 56, and is emitted from the glass tube 56. .

In the light diffusion cover 40 of the present embodiment, when the light flux incident on the light diffusion film 80 is 100%, the light flux emitted from the glass tube 56 is 98% or more in a preferred case.
In the case of a conventional light diffusion film made of a general resin without the protective film 70, assuming that the light flux incident on the light diffusion film 80 is 100%, the light flux emitted from the glass tube 56 is 85%. The form of the light diffusion cover 40 improves the luminous flux ratio by 13% or more.

  Hereinafter, the case where the metal oxide X is silica and the metal oxide Y is silica will be described using specific data shown in FIG. In FIG. 6 and subsequent figures, the values in the bold frame in the table are desirable values.

The meanings of the columns in each figure are as follows.
First, items that become specifications of the light diffusion cover 40 are as follows.
“Volume ratio of light diffusion film 80”: Volume ratio of metal oxide Y of light diffusion film 80, low-melting glass 83, and resin.
“A”: When the metal oxide Y is silica.
“B”: When the low melting point glass 83 is a borosilicate low melting point glass.
“C”: When resin is used instead of the low melting point glass 83.
“X protective film 70 silica particle diameter”: silica average particle diameter when metal oxide X of protective film 70 is silica “protective film 70 silica film thickness”: thickness of protective film 70.
“Y light diffusion film 80 silica particle diameter”: silica average particle diameter when the metal oxide Y of the light diffusion film 80 is silica “light diffusion film 80 silica film thickness”: thickness of the light diffusion film 80

The result items for the above specifications are as follows.
“Flux ratio”: Light transmittance. 96% or more, preferably 98% or more.
“Diffusion”: degree of light diffusion.
“Film strength”: Adhesive strength of the light diffusion film 80 according to a scratch test defined by JIS.
“Glass strength”: resistance to impact of glass.

The meanings of the evaluation result symbols are as follows.
Double circle: Excellent.
Ichimaru: Good.
Triangle: Normal.
X: Bad.
In the following description, “A to B” means A or more and B or less.
Hereinafter, the “good” and “excellent” states are referred to as a good state.

FIG. 6 is a data diagram of Comparative Examples 1 to 3.
Comparative Example 1 is a case where the content ratio of the metal oxide Y is 70% in the volume ratio of the light diffusion film 80, the resin content is 30%, and the protective film 70 is not provided. is there.
Comparative Example 2 is a case where the light diffusion film 80 is only the metal oxide Y (silica) and there is no protective film 70, but there are difficulties in diffusibility and film strength.
Comparative Example 3 is a case where the light diffusion film 80 is only the low-melting glass 83 and no protective film 70, but there are difficulties in diffusibility and glass strength.

FIG. 7 is a data diagram of Comparative Examples 4-7.
FIG. 8 is a graph showing the relationship between the film thickness and the luminous flux with respect to the silica volume ratio of Comparative Examples 4 to 7.
In Comparative Examples 4 to 7, the volume ratio of the metal oxide Y (silica) in the light diffusion film 80 was changed, and the thickness of the light diffusion film 80 was changed.
When the metal oxide Y (silica) was 70%, the film strength was lowered. Moreover, as shown in FIG. 8, when the metal oxide Y (silica) is 70%, the luminous flux ratio is lowered.
As a result, the metal oxide Y (silica) is preferably less than 70%. Desirably, 60% or less is preferable, and if possible, about 50% ± 10% or 50% is preferable.

FIG. 9 is a data diagram of Examples 1 to 5.
In Examples 1-5, the protective film 70 was formed with respect to the comparative example 5, the thickness of the protective film 70 was changed, and the thickness of the light-diffusion film 80 was changed.
As shown in Examples 1 to 5, when the thickness of the protective film 70 is 0.5 to 5.0 μm and when the thickness of the light diffusion film 80 is 5 to 20 μm, compared to Comparative Example 5, Glass strength was improved. It can be seen that the protective film 70 increases the glass strength.
However, when the thickness of the protective film 70 was 5.0 μm, the film strength decreased. Therefore, in the conditions of Examples 1 to 5, the thickness of the protective film 70 is desirably less than 5.0 μm, desirably 4.0 μm or less, desirably 3.0 μm or less.
Further, as the thickness of the light diffusion film 80 increases, the light flux ratio decreases, but the diffusibility is improved.

FIG. 10 is a data diagram of Examples 6-9.
In Examples 6 to 9, the protective film 70 was formed with respect to Comparative Example 6, the thickness of the protective film 70 was changed, and the thickness of the light diffusion film 80 was changed.
As shown in Examples 6 to 9, when the thickness of the protective film 70 is 0.5 to 5.0 μm, and when the thickness of the light diffusion film 80 is 5 to 20 μm, compared with Comparative Example 6, Glass strength was improved to the same or better level. When the thickness of the protective film 70 was 10.0 μm, the film strength decreased.
Further, as the thickness of the light diffusion film 80 increases, the light flux ratio decreases, but the diffusibility is improved.

  FIG. 11 is a data diagram of Example 10, Example 11, Example 12, and preferred values.

In Example 10, when the content of the metal oxide Y of Example 8 was 50% and the content of the low-melting glass 83 was 50%, the particle size of the metal oxide Y was changed.
As shown in Example 10, when the particle size of the metal oxide Y is 0.05 to 20 μm, the luminous flux ratio is slightly lowered, but a satisfactory state is satisfied. When the particle size of the metal oxide Y is 0.05 to 1 μm, the luminous flux ratio is 97.5% or more and the diffusibility is excellent, which is desirable.
When the particle size of the metal oxide Y is 30 μm, the light flux ratio, diffusivity, and film strength are lowered.

In Example 11, when the particle size of the metal oxide Y of Example 10 was 15 μm, the particle size of the metal oxide X was changed.
As shown in Example 11, when the particle diameter of the metal oxide X is 0.05 to 0.3 μm, the luminous flux ratio is slightly lowered, but the luminous flux ratio is 96% or more and a satisfactory state is satisfied. When the particle size of the metal oxide X is 0.05 to 1 μm, the luminous flux ratio is 97.0%, which is desirable.
When the particle size of the metal oxide X is 0.5 μm, the film strength decreases.

Example 12 is a combination of “optimum values” obtained from the results of Examples 1 to 11 and other tests. As the “optimum value”, a combination of the following values is preferable. Alternatively, a range of ± 10% (desirably ± 5%, more desirably ± 2%) of the following values is preferable.
“Light diffusion film 80 volume ratio”: the content of the metal oxide Y is 50% ± 10%, and the content of the low melting point glass 83 is 50% ± 10%.
“X protective film 70 silica particle diameter”: 0.1 μm ± 10%
“Protective film 70 silica film thickness”: 1.0 μm ± 10%
“Y light diffusion film 80 silica particle diameter”: 1.0 μm ± 10%
“Light diffusion film 80 silica film thickness”: 10.0 μm ± 10%
When the content rate of the metal oxide Y is 50% + 10%, the content rate of the low-melting glass 83 is 50% -10%. When the content of the metal oxide Y is 50% -10%, the content of the low-melting glass 83 is 50% + 10%. That is, the light diffusion film 80 is composed of only the metal oxide Y and the low melting point glass 83, and the content ratio of the metal oxide Y + the content ratio of the low melting point glass 83 = 100%.
At this time, the luminous flux ratio becomes 98%, the diffusibility and the glass strength become good, and the film strength becomes excellent.

Further, from the results of Examples 1 to 11 and other tests, the following combinations of values are preferable as shown in the “preferred value” in the bottom row of FIG.
“Light diffusion film 80 volume ratio”: the content of the metal oxide Y is 30% to 50%, and the content of the low melting point glass 83 is 70% to 50%.
“X protective film 70 silica particle diameter”: 0.05 to 0.3 μm
“Protective film 70 silica film thickness”: 0.5 to 5.0 μm
“Y light diffusing film 80 silica particle diameter”: 0.05 to 20 μm
“Light diffusion film 80 silica film thickness”: 5.0 to 20.0 μm

  Hereinafter, the specifications that the luminous flux ratio becomes 97% or more, the diffusibility, the film strength, the glass strength, and the good state will be described along Examples 1 to 11.

From the results of Examples 1 to 9, the following combinations of values are preferable.
“Light diffusion film 80 volume ratio”: the content of the metal oxide Y is 30% to 50%, and the content of the low melting point glass 83 is 70% to 50%.
“X protective film 70 silica particle diameter”: 0.05 μm
“Protective film 70 silica film thickness”: 0.5 to 5.0 μm
“Y light diffusing film 80 silica particle diameter”: 0.1 μm
“Light diffusion film 80 silica film thickness”: 5.0 to 20.0 μm
In the above specifications, if importance is placed on the luminous flux ratio, the “light diffusion film 80 silica film thickness” is preferably set to 5.0 μm.
In the above specifications, if importance is attached to the diffusibility, the “light diffusion film 80 silica film thickness” is preferably 20.0 μm.
In the above specifications, if both the light flux ratio and the diffusivity are important, it is preferable to set the “light diffusion film 80 silica film thickness” to 10.0 μm.

From the results of Example 10, the following combinations of values are preferable.
“Light diffusion film 80 volume ratio”: The content of the metal oxide Y is 50%, and the content of the low melting point glass 83 is 50%.
“X protective film 70 silica particle diameter”: 0.05 μm
“Protective film 70 silica film thickness”: 5.0 μm
“Y light diffusion film 80 silica particle size”: 0.05 to 20.0 μm
“Light diffusion film 80 silica film thickness”: 20.0 μm
In the above specifications, if importance is placed on the luminous flux ratio and diffusivity, the “Y light diffusion film 80 silica particle diameter” is preferably 0.05 to 1.0 μm.

From the results of Example 11, the following combinations of values are preferable.
“Light diffusion film 80 volume ratio”: The content of the metal oxide Y is 50%, and the content of the low melting point glass 83 is 50%.
“X protective film 70 silica particle diameter”: 0.05 to 3.0 μm
“Protective film 70 silica film thickness”: 5.0 μm
“Y light diffusion film 80 silica particle size”: 15.0 μm
“Light diffusion film 80 silica film thickness”: 20.0 μm
In the above specifications, if importance is placed on the luminous flux ratio, the “X protective film 70 silica particle diameter” is preferably 0.05 to 0.1 μm.

As described above, the light diffusion cover 40 of this embodiment is preferably used for a light diffusion cover of a straight tube LED lamp.
The light diffusion cover 40 of this embodiment uses a glass tube 56 as a material, and after forming a protective film 70 having a thickness of 0.5 to 5.0 μm made of metal oxide X on the inner surface of the glass tube 56, A light diffusion film 80 having a thickness of 5.0 μm to 20.0 μm is formed inside.
Since the low-melting-point glass 83 is used for the light diffusing film 80, the light beam transmission by the light diffusing film 80 can be improved as compared with the case of using a resin.

  The light diffusion film 80 of the light diffusion cover 40 of this embodiment uses a low-melting glass 83 and metal oxide Y particles having an average particle diameter of 0.05 μm to 20.0 μm. The content of the metal oxide Y is 30% to 50%. The light diffusion film 80 is formed with a thickness of 5.0 to 20.0 μm inside the protective film 70 in the glass tube 56.

  A protective film 70 made of metal oxide X particles having an average particle diameter of 0.05 μm to 0.3 μm is formed between the glass tube 56 and the light diffusion film 80.

  According to the light diffusing film 80 of the light diffusing cover 40 of this embodiment, the thickness can be reduced, and the LED device becomes difficult to see while maintaining the light diffusibility. In addition, since the light diffusion film 80 is thin, it absorbs less light, and the ratio of light that goes straight or diffuses out of the lamp is greater than when the film is thick.

As described above, in the light diffusion cover 40 of the LED lamp of this embodiment, the protective film 70 of the metal oxide X is formed on the inner surface of the glass tube 56, and the light diffusion film 80 is formed on the upper surface of the protective film 70. Light diffusion cover.
The light diffusion film 80 is composed of the metal oxide Y and the low melting point glass 83 that melts at a temperature lower than the melting temperature of the glass tube 56.

By using the low-melting glass 83, the light diffusion cover 40 of the LED lamp of this embodiment can avoid coloring due to aging that occurs in the resin, and can suppress a decrease in luminous flux.
In addition, the low melting point glass 83 has better light transmittance compared to the resin, so it is less colored even after a long time, and has a high diffusive function and an LED lamp equipped with a bright light diffusion cover. can do.

  The protective film 70 is made of a metal oxide X having an average particle diameter of 50 to 300 nm, and the thickness of the protective film 70 is 0.5 to 5.0 μm.

By forming such a protective film 70, it breaks due to a decrease in glass strength as in the case of only the light diffusion film 80 formed of the metal oxide Y and the low melting point glass 83 (for example, Comparative Examples 4 to 6). There is nothing.
In addition, by controlling the particle size of the metal oxide X and the thickness of the protective film 70, an LED lamp that does not weaken the adhesion strength and film strength to the light diffusion film 80 and the glass tube 56 by the protective film 70 is realized. it can.

The light diffusion film 80 includes a metal oxide Y having an average particle diameter of 50 to 2000 nm and a low melting point glass 83, and the metal oxide Y is present in a volume ratio of 30 to 60% with respect to the light diffusion film 80. The light diffusion film 80 has a thickness of 5.0 to 20.0 μm.
For the light diffusion film 80, the metal oxide Y is preferably less than 70%, for example, 60% or less, and more preferably 50% ± 10%.

  Thus, by using the light diffusion film 80 formed by combining the metal oxide Y and the low melting point glass 83, the light diffusion effect is improved, the particle size of the metal oxide Y, the content of the metal oxide Y, the light By optimizing the film thickness of the diffusion film 80, it is possible to realize an LED lamp having a large light diffusion effect even if it is thin while maintaining the film strength.

  The metal oxide X and the metal oxide Y each contain at least one of titania, silica, alumina, and zinc oxide. The metal oxide X and the metal oxide Y are preferably the same metal oxide. Moreover, it is desirable that the metal oxide X and the metal oxide Y are silica. At that time, it is desirable to use silicone as an adhesive.

  The low melting point glass 83 includes at least one of bismuth borosilicate salt glass, bismuth zinc borate glass, aluminophosphate glass, zinc phosphate glass, and borosilicate glass. The low melting glass 83 is preferably a borosilicate low melting glass.

Even if each of the above values changes within a range of ± 10% (preferably ± 5%, more preferably ± 2%) of each value, the same effect as that of each value or a similar effect can be obtained.
Further, the protective film 70 and the light diffusion film 80 may be mixed with substances other than those described above within a range of, for example, about 10%.

Embodiment 2. FIG.
Hereinafter, differences from the first embodiment will be described.
As shown in FIG. 3, the light diffusion film 80 formed on the inner surface of the glass tube 56 of the second embodiment is on the entire circumference.
On the other hand, although FIG. 12 is a comparative example, the light-diffusion film | membrane 80 currently formed in the inner surface of the glass tube 56 does not exist in a perimeter. In the aperture 91, the light diffusion film 80 does not exist. In the comparative example, the adhesive 90 is applied to the aperture 91 of the light diffusion film 80 to bond the inner surface of the glass tube 56 and the outer peripheral surface of the heat sink 54.

In the light diffusion cover 40 of the second embodiment, the adhesive 90 is silicone, the metal oxide X is silica, and the metal oxide Y is crystalline silica.
For this reason, even if the adhesive 90 is applied from above the light diffusing film 80, the adhesive force does not drop, and the light diffusing film 80 can be applied without forming the aperture 91.
Thereby, the application part of the adhesive 90 becomes inconspicuous, and productivity can be improved by not having to pay attention to the width of the adhesive application.
Moreover, the thermal conductivity from the LED main body (heat sink 54) to the glass tube 56 can be improved by using the metal oxide X as silica and the metal oxide Y as crystalline silica.

As described above, the light diffusion cover 40 of this embodiment includes the glass tube 56, the metal oxide Y and the low melting point glass 83 provided on the entire inner periphery of the glass tube 56, and diffuses light. A film 80.
The diffusion light source 50 of this embodiment uses a silicone-based adhesive 90 for joining the glass tube 56 and the LED main body (heat sink 54).

The specification of the light diffusion film 80 may be the same as the specification of the light diffusion film 80 of the first embodiment.
Further, the protective film 70 may be omitted from the viewpoint of adhesion between the light diffusing film 80 and the heat sink 54 by the adhesive 90 of this embodiment, and the light diffusing cover 40 of the second embodiment includes the adhesive. 90 may be silicone and the metal oxide Y may be crystalline silica. Of course, if the protective film 70 is provided, the function of the protective film 70 is exhibited.

Embodiment 3 FIG.
In each of the above-described embodiments and examples, a cylindrical glass tube is used as the material of the light diffusion cover 40, but the applied shape of the present invention is not necessarily tubular. For example, if a light diffusion film is formed on at least one side of a flat or curved glass plate, it can be applied to a flat or curved diffusion light source.

For example, the shape of the glass (glass plate) of the light diffusion cover 40 is not limited to a cylindrical shape, but is a flat plate shape, a box shape, a spherical shape, a ball shape, a bell shape, a dome shape, a conical shape, a pyramid shape, a columnar shape, a bowl shape, A mountain shape, a donut shape, a ring shape, a ring shape, a belt shape, a radial shape, or a combination thereof may be used.
Here, when the glass (glass plate) is simply referred to, it is a glass different from the low melting point glass 83, and the low melting point glass 83 is the same as the glass tube 56 described in each of the above-described embodiments and examples. It means glass (glass plate) having a melting point equal to or higher than the melting point.
The diffused light source 50 is not limited to a cylindrical shape, but a flat plate shape, a box shape, a spherical shape, a ball shape, a bell shape, a dome shape, a conical shape, a pyramid shape, a column shape, a bowl shape, a mountain shape, a donut shape, a ring shape, Annular, belt-like, radial, or a combination thereof may be used.
Furthermore, the light source does not have to be an LED, but may be anything that emits light.
Alternatively, the diffusion light source 50 may be manufactured by covering an existing light source (off-the-shelf lamp) such as a commercially available illumination lamp with the light diffusion cover 40 described in each of the above-described embodiments.

As described above, the light diffusion cover 40 of this embodiment is
Glass,
A protective film 70 of metal oxide X formed on one side of the glass;
The protective film 70 includes a light diffusing film 80 formed on the surface opposite to the surface on which the glass is present and made of the metal oxide Y and the low melting point glass 83 that melts at a temperature lower than the melting temperature of the glass. Is a feature.

It should be noted that each value shown in each of the above embodiments has the same effect as or similar to each value even if it changes within a range of ± 10% (preferably ± 5%, more preferably ± 2%) of each value. There is an effect.
Further, the protective film 70 and the light diffusion film 80 may be mixed with substances other than those described above within a range of, for example, about 10% or about 5%.

  As described above, the light diffusion covers of the first to third embodiments are
  Glass,
  A protective film of metal oxide X formed on one side of the glass;
  A light diffusing film formed of a low melting point glass and a metal oxide Y, which is formed on a surface opposite to the surface on which the glass of the protective film is present and melts at a temperature lower than the melting temperature of the glass;
It is provided with.

  The protective film is made of a metal oxide X having an average particle diameter of 0.05 to 0.3 μm,
  The protective film has a thickness of 0.5 to 5.0 μm.

  The light diffusion film is
  A metal oxide Y having an average particle diameter of 0.05 to 20.0 μm;
  A low melting glass having a melting point lower than the melting point of the glass;
Consists of
  The metal oxide Y is present in a volume ratio of 30 to 60% with respect to the light diffusion film,
  The light diffusing film has a thickness of 5.0 to 20.0 μm.

  In the volume ratio of the light diffusion film,
  The content of the metal oxide Y is 50% ± 10%,
  The content of the low melting point glass is 50% ± 10%.

  The particle diameter of the metal oxide X is 0.1 μm ± 10%,
  The film thickness of the protective film is 1.0 μm ± 10%
It is characterized by being.

  The particle diameter of the metal oxide Y is 1.0 μm ± 10%,
  The thickness of the light diffusion film is 10.0 μm ± 10%
It is characterized by being.

  Each of the metal oxide X and the metal oxide Y includes at least one of titania, silica, alumina, and zinc oxide.

  The low melting point glass includes at least one of bismuth borosilicate salt glass, zinc bismuth borate glass, aluminophosphate glass, zinc phosphate glass, and borosilicate glass. .

  The diffused light source of Embodiments 1-3 is
  The light diffusion cover;
  And a light emitting unit equipped with a light emitting diode (LED),
  The light diffusing film and the light emitting part are bonded with an adhesive.

  The metal oxide Y is crystalline silica, and the adhesive is a silicone-based adhesive.

  40 Light diffusion cover, 50 Diffuse light source, 51 LED, 52 Substrate, 54 Heat sink, 55 Base, 56 Glass tube, 57 Glass inner surface scratch, 58 Power supply terminal, 60 Light emitting part, 62 Flat plate part, 63 Arc part, 64 Hollow part, 70 protective film, 80 light diffusion film, 83 low melting point glass, 90 adhesive, 91 aperture, X metal oxide, Y metal oxide.

Claims (8)

Glass,
A protective film of metal oxide X formed on one side of the glass;
A light diffusion film formed of a low-melting-point glass that is formed on a surface opposite to the surface where the glass of the protective film is present and melts at a temperature lower than the melting temperature of the glass and the metal oxide Y,
The protective film is made of a metal oxide X having an average particle diameter of 0.05 to 0.3 μm,
The thickness of the protective layer is from 0.5 to 3. 0 μm,
The light diffusion film is
Average particle diameter of Ri 0.05~20.0μm der, and a metal oxide Y that is used as a light diffusion agent,
It has a melting point lower than the melting point of the glass, and comprises a low melting point glass used for forming the metal oxide Y particles as a film ,
The metal oxide Y is present in a volume ratio of 30 to 60% with respect to the light diffusion film,
The light diffusion cover has a thickness of 5.0 to 20.0 μm. In the volume ratio of the light diffusion film,
The content of the metal oxide Y is 50% ± 10%,
Low melting point glass content 50% ± 10%
The light diffusing cover according to claim 1, wherein The particle diameter of the metal oxide X is 0.1 μm ± 10%,
The film thickness of the protective film is 1.0 μm ± 10%
The light diffusion cover according to claim 1, wherein the light diffusion cover is a light diffusion cover. The particle diameter of the metal oxide Y is 1.0 μm ± 10%,
The thickness of the light diffusion film is 10.0 μm ± 10%
The light diffusion cover according to claim 1, wherein the light diffusion cover is a light diffusion cover.   The light diffusion cover according to any one of claims 1 to 4, wherein each of the metal oxide X and the metal oxide Y includes at least one of titania, silica, alumina, and zinc oxide.   The low melting point glass includes at least one of bismuth borosilicate salt glass, zinc bismuth borate glass, aluminophosphate glass, zinc phosphate glass, and borosilicate glass. The light-diffusion cover in any one of Claims 1-5. The light diffusion cover according to any one of claims 1 to 6,
And a light emitting unit equipped with a light emitting diode (LED),
A diffusion light source characterized in that a light diffusion film and a light emitting part are bonded with an adhesive.   The diffused light source according to claim 7, wherein the metal oxide Y is crystalline silica, and the adhesive is a silicone-based adhesive.

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