JPS581962Y2 - Shingoto - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to the improvement of road traffic signal lights.

A road traffic signal light 5 which has been put into practical use in the past is usually formed by attaching an incandescent light bulb 4 to a lamp 3 having a reflector 1 and a lens 2, as shown in FIGS. 1 and 2. It is.

Due to the nature of the signal light 5, the incandescent light bulb 4 used in the signal light 5 is designed such that almost the entire surface of the third lens 2 of the light fixture is easily visible to passersby from a predetermined distance under sunlight. It is required that the light shine uniformly and with high brightness.

On the other hand, the reflecting mirror 1 of the lamp 3 is usually formed into a parabolic reflecting surface so that the reflected light can be taken out as almost parallel rays based on the light emitted from the center of the light of the incandescent light bulb 4 to which it is attached. It is.

This reflector 1 has a circular shape with a diameter of about 200mm, and as is clear from the above, the light source of the light bulb attached to it is closer to a point light source than the reflector 1 of the lamp 3. It is designed to be light and heavy because it can be easily formed.

Therefore, a point light source in which the light center of the filament of the light bulb 4 is small so that the light bulb 4 can match the reflecting mirror 1 as much as possible is particularly heavy.

This is because if this is not done, a complex paraboloid will be required for one surface of the reflecting mirror.

From the above, there are various difficulties in satisfying either of the conditions, and conventional light bulbs are insufficient.

By the way, as a light bulb that meets the above conditions, a light bulb with a matte interior is used.

However, this frosted light bulb uses hydrofluoric acid to etch the inside of the bulb, but the use of hydrofluoric acid causes pollution and poses a danger to the human body. is becoming difficult.

For this reason, there is a strong demand for a light bulb that meets the above conditions, but there is still no light bulb that can be installed in a signal light and fully fulfill its function as a signal light, and the inventors of the present invention are satisfied with this. We investigated various types of light bulbs.

First of all, I installed a clear bulb light bulb 4 in which the central light of the filament can be directly used.

In this case, looking at the brightness generated on the lens surface 20, the center surface of the lens is brighter than necessary.

The luminous intensity emitted from this lens surface is approximately 2 on the central axis of the lamp 3.
80 cd (the signal light standard requires a central luminous intensity of 1,700 d or more), but as shown in Figure 5, at a position of 300 d with respect to the above central axis, only about 30 cdL can be obtained (the standard requires that it not be 45 cd or more). (Does not pass) Fails.

Then, in order to reduce the brightness on the central axis, we used a light bulb coated with a glass bulb diffuser coating.

When this was measured, it showed a high luminous intensity of 159 cd on the central axis, and 53 cd at a position 30 degrees to the central axis.

When viewed from a distance in the axial direction, dark areas appear around the periphery.

This will not give you full satisfaction.

The reason for this is that the reflecting surface of the reflecting mirror does not match the light source.

In other words, the light source is too harsh and does not match well with the reflective surface of the lamp, resulting in a lack of compatibility, and special equipment is required, which is not light and heavy.

The light bulb with a diffuser coating used for this purpose has a light transmittance of about 94%, assuming the luminous flux transmittance of a light bulb with a clear (glass bulb without a diffuser coating) bulb as 100%, and can be seen with the naked eye. And the filament inside is barely visible.

In this case, the diffusion effect of the light-diffusing coating becomes excessive and is not practical.

The inside of the signal light fixture is sealed and is a small room, so the light bulbs that are installed tend to reach high temperatures (approximately 200 degrees Celsius).

When the bulb wall of a light bulb is exposed to high temperatures in this manner, harmful gases may be generated from the material of the light diffusing coating, which may shorten the life of the filament.

The reason for this is that high temperatures (approximately 500°C) are required when forming the light-diffusing film.
) for several minutes to remove moisture from the diffuser film.

Therefore, if the light-diffusing film is thick, it is not preferable because there is a possibility that water cannot be almost completely removed.

Removal of the moisture is important because the light bulbs used in the signal lights are specified to have a particularly long lifespan of about 4,000 hours or more.

For the above reasons, although it is not a great idea to use a light-diffusing film that easily brings moisture into the bulb, we purposely used it and conducted various experiments to ensure that all of the above conditions were satisfied.

First, the amount of the light-diffusing coating should be as small as possible so that as little moisture as possible is brought into the bulb.

However, it is possible to reduce the amount of light that enters the center of the lens of the lamp and move it to the periphery by providing a predetermined light scattering property.In addition, the center of the light source made up of the filament is maintained and this light source is aligned with the lamp reflector. It fully accomplishes various objectives.

In other words, we took full advantage of the conditions in a small, sealed room like a signal light, and focused on the special relationship between the temperature of the bulb, the light source, the reflector, and the lens.

The reason for this is that the transmittance of the glass bulb for the light from the filament is 97% or more, with the clear bulb being 100%.

When looking inside this light bulb from the surface, the filament is barely visible to the naked eye.

This film with a transmittance of 97% is extremely thin, and moisture can be almost completely removed by baking it at 500° C. for several minutes during film production.

Therefore, even when used at a high temperature of about 200° C., almost no evaporation of water is observed, and rather, it has been found that at this temperature, it has an unexpected effect of acting as a getter to adsorb harmful gases from other parts.

This thin coating has strong adhesive strength, maintains the optical center of the filament, diffuses light appropriately, and is extremely light and heavy.

However, when considering a light bulb with a transmittance of 96% with only a difference in transmittance of only 1%, the film thickness increases during manufacturing (because moisture cannot be completely removed during baking, the difference in transmittance is only 1%). Water evaporation occurs, and a so-called water cycle is likely to occur in the filament, resulting in a short life and loss of reliability.

Furthermore, the above conditions are not met.

Note that when the above-mentioned coating is heated to a temperature of about 500° C. or higher, moisture evaporates in a large amount in any case, resulting in a short service life.

However, in the case of signal lights, the maximum temperature is about 200°C, so they can withstand the above usage.

Next, embodiments of the present invention will be described.

FIG. 3 is a side view of the road traffic signal light of the present invention, which includes a light body 10 and a cover 12 fixed to the light body 10.

As shown in FIGS. 4A and 4B, an incandescent light bulb 15 having a glass bulb 14 enclosing a double coil filament 13 is mounted inside the lamp body 10.

The entire inner surface of the glass bulb 14 of the incandescent light bulb 15 is coated with a light diffusing coating 17 made of fine silica powder (average particle diameter of about 50 mμ) coated to a thickness of about 6 μm.

A reflecting mirror 18 and a lens 19 are attached to this incandescent light bulb 150 portion to constitute a road traffic signal light 20.

When the signal light in this example is turned on, 1 on its central axis
00 has a luminous intensity increase of 171 cd, which is about 10% higher than the conventional signal lamp using a matte bulb, and has the effect that the signal can be clearly seen from a distance even in a bright place under sunlight.

Then, the third angle is about 30 degrees from the center axis.
Even when viewed from the direction of Figure X, a luminous intensity of 51 cd is obtained, which is higher than that of a frosted light bulb when viewed from the same direction.

Next, fine silica powder was coated to various thicknesses on the inner surface of a glass bulb sealed with a filament with a rating of 110V-118W, and the luminous flux transmittance (based on the clear bulb as 100%)
When it was attached to a lamp and measured at a center luminous intensity and an inclination angle of 300, the values shown in the following table were obtained.

As is clear from the table above, it was found that those with a luminous flux transmittance of 97% or more and coated with a silica film had good results.

It is assumed that the luminous flux transmittance exceeding 100% is due to a decrease in the reflectance of the inner surface of the glass bulb due to the application of the silica film, but the reason for this is unknown.

Furthermore, the average particle diameter of the silica coating used was about 50 mμ.

In addition, when the silica coating thickness was less than 1.0 μm, the luminous flux transmittance and central luminous intensity satisfied the specifications, but the luminous intensity at an inclination angle of 300 decreased, and a light and heavy incandescent lamp for signal lamps could not be obtained.

When the above-mentioned light diffusion coated light bulb I is installed in a road traffic signal lamp with a conventional frosted light bulb (2) and a clear light bulb (2), their light distribution characteristics are compared as shown in FIG.

As is clear from this figure, the light distribution characteristic is that curve ① is the one coated with the thin film according to the present invention, and the center luminous intensity is sufficiently maintained at 170 cd or more, which is about 10 % or more brightness can be obtained.

However, the value was low for the light bulb with clear bulb (■).

However, in the part with an inclination angle of 3000, a luminous intensity of 45 cd or more is obtained, and as seen in curve I, the decreasing gradient of luminous intensity from the center to the periphery is gentler than the other two curves, which is extremely preferable.

As shown in Figure 6, a coating is applied to the inner surface of the valve.
When this thickness is changed, as is clear from the figure, the clear glass bulb does not transmit all of the light from the filament due to internal reflection, etc.
When an extremely thin film is attached, it is estimated that the internal reflection of light is reduced to some extent, and it has been confirmed that the light transmittance is improved to more than 100% compared to the case using clear glass.

However, as the thickness gradually increases to 6 μm of pure silver, the transmittance decreases to less than 97%, making it impossible to achieve the intended purpose.

As described in detail above, the present invention is based on applying 1.0 mm of fine silica powder with an average diameter of about 50 mμ to the surface of the glass bulb so that the luminous flux transmittance is 97% or more based on the clear bulb.
A road traffic signal light equipped with an incandescent light bulb coated with a thickness of ~6.0μ to form a light diffusing film, which allows passersby to see the signal from a distance even in bright sunlight. It is something.

Since the diffusion coating 17 is applied extremely thinly, it has good adhesion to the glass bulb wall and is stable and lightweight even in road traffic signal lights with strong vibrations such as automobiles, and has a getter effect during operation. It has various features such as a long service life of over 4,000 hours and improved reliability.

[Brief explanation of drawings]

Figure 1 is a front view of a road traffic signal light, Figure 2 is a side view of a conventional traffic light, Figure 3 is a side view of the signal light of the present invention, and Figure 4A.
, B is a partially cutaway front view and partially enlarged sectional view of the incandescent light bulb used in the signal light of the present invention, and Figure 5 is a light distribution characteristic diagram showing the light distribution characteristics of the signal light of the present invention in comparison with conventional ones. FIG. 6 is a transmittance characteristic diagram. 10... Lamp body, 15... Incandescent light bulb, 17... Light diffusion coating, 18... Reflector, 19... Lens.

Claims (1)

[Scope of utility model registration request] When an incandescent bulb is attached to the lamp, the incandescent bulb has an average particle size of approximately 50% on the surface of the glass bulb so that the luminous flux transmittance is 97% or more based on the clear bulb.
A road traffic signal lamp characterized in that a light diffusing coating is formed by applying fine silica powder of mμ to a thickness of 1.0 to 6.0μ.