JPS6054158A - Bulb for signal lamp - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a light bulb whose performance can be improved as a light source for a signal lamp.

[Technical background of the invention and its problems]

Signal lamps have a light bulb installed inside a projector type reflector, and the aperture of the reflector is closed with a lens.When viewed from the front within a specified angle range, the lens surface has uniform brightness. It is required to be visible.

For this reason, in conventional light bulbs for signal lights, a filament (C-9 type) that revolves around a shaft is sealed inside a glass bulb, and the bulb is frosted to impart appropriate light scattering properties. When such a conventional light bulb is used, the light that is directly emitted from the light bulb to the lens periphery is emitted forward beyond the above-mentioned predetermined angle, and that amount of light is wasted.

As an improvement on this, for example, as seen in Japanese Patent Publication No. 57-15471, a band-shaped reflector is provided at the top of the bulb to prevent light from directly hitting the lens periphery and to return the reflected light to the vicinity of the filament. A proposal was made to make effective use of this information. However, using this light bulb has the disadvantage that the brightness distribution on the lens becomes discontinuous.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a light bulb for a signal lamp which can be incorporated into a signal lamp and which emits less light in undesired directions, has a uniform luminance distribution on the lens, and provides a continuous visual effect.

[Summary of the invention]

A filament having a sawtooth shape in the axial direction and orbiting the shaft is sealed in the glass bulb, and a light-diffusing film is formed on at least one of the inner and outer surfaces of the bulb, and the top side of the light-diffusing film is set higher than the other parts. By increasing the reflectance, the amount of radiation directed to the sides is increased, increasing efficiency, and by reducing the amount of light that hits the lens directly, the brightness distribution on the lens is made uniform and continuous. be.

[Embodiments of the invention]

The details of the invention are illustrated by the following examples.

(1) is a glass bulb with a spherical top side such as A type or PS type, (2) is a light diffusing film formed on the inner surface of this bulb, (
3) is a stem that seals the base end of the bulb (1), (4) is a cane glass protruding from this stem (3), (5L (
5) 1 introduced into the valve (1) from the stem (3)
The inner conductors of the pair, ('6) are the filaments installed between these inner conductors (5), (5), and (7), (7)... are the spring filaments protruding from the cane glass (4). (6) is an anchor that supports the middle part, and (8) is a cap attached to the end of the valve (↓). The valve (1) is filled with an inert gas such as argon.

The light scattering film (2) has a particle size of, for example, several mμ to several hundred mμ.
It is electrostatically coated with a mixture of fine silica powder of It is formed. For example, as shown in the figure, the top portion may be thickest and the thickness may become progressively thinner toward the base, or the top portion may be uniformly thick and the other portions may be uniformly thin.

The filament (6) is called C-7 type,
A single coil filament is bent into a sawtooth shape in the direction of the valve axis and revolves around the valve axis.

Then, connect both ends of the filament (6) to the inner conductor (5), (
5) Attach the two joints and anchor the bending points (7), (7) -
c-Supported.

Then, the direction parallel to the line connecting the two points connected to the in-plane conductors (5) and (5) is called the longitudinal direction, and the filament (
The maximum diameter in the longitudinal direction of the filament (6) is referred to as Lmm, the direction perpendicular to this longitudinal direction is referred to as the lateral direction, the maximum diameter in the lateral direction of the filament (6) is referred to as wIIlrrl, and the projected length in the bulb axial direction is referred to as the height. , Hmm.

In this embodiment, the following relationship is preferable: L:W:H=(2-5):(2-5):1.

Next, an example of a signal lamp using the light bulb of this example is shown in the fourth example.
As shown in the figure. In the figure, (11) is the light bulb of this embodiment, (12) is a socket that supports this light bulb (11), and (13) is a paraboloid of rotation that is attached to this socket (12) and surrounds the light bulb (11). The reflecting mirror (14) is a lens that closes the aperture of this reflecting mirror (13). Thus, the light center of the light bulb (11) is close to the focal point of the reflecting mirror (13).

In this signal lamp, when the light bulb (Il,) is turned on, light (Rh'), '(R
2) is reflected by a reflecting mirror (13), transmitted through a lens (14), and radiated forward. Further, the light (R3) emitted forward from the top directly enters the lens (14) and is emitted forward, and furthermore, the light (R3) emitted obliquely forward from the top.
4) directly enters the periphery of the lens (14) and is radiated diagonally forward, making it useless for signals.

However, in the light bulb of this example, the filament (6
) has a C-7 shape, most of the emitted light is emitted and reflected to the side, enters the lens (14) almost uniformly, and is emitted forward. The incidence of light at the center of the lens (14) is slightly smaller. In addition, a light-diffusing film (
Since the filament 2) is formed particularly thick, the reflectance of light is high, and therefore, this reflected light returns to the vicinity of the filament (6) and is emitted again. In addition, relatively little light flows forward from the top but enters the lens (14), and the light distribution is the brightest at the center and darkest at the periphery. Therefore, both direct light and reflected light enter the central part of the lens (14), and the sum of both lights is appropriately adjusted, so this central part is not particularly bright. Since the light that directly hits the peripheral area of 14) is attenuated by the light-diffusing film (2), the luminous intensity is low, and therefore there is little waste of light. Furthermore, since the light scattering film (2) is formed on the entire inner surface of the bulb (1) and the emitted light is scattered appropriately, there is no discontinuity in the brightness distribution on the lens (4). In particular, since the brightness distribution at the center of the lens (14) is continuous, visibility is good.

As is clear from the above description, the shape of the filament (6) has a significant bearing on the effectiveness of the lamp. Therefore, the effects of varying the ratios of the length L, width W, and height H of the filament (6) were investigated. The light bulb is A
70, and the filament rating was 100V and 60W. The results are shown in the table below.

From this result, as described above, it was found that L:W:H=(2-5): (2-5):1 had good light distribution and excellent vibration resistance.

In addition, for the test, in a 60W rated light bulb with the above structure, H was varied in the range of 3.5 to 6.5 mm, and L and W were each changed to HX (2 to 5).
When we fabricated a number of prototypes with variations in the range of 1 and investigated their light distribution and vibration resistance, all of them yielded good results.

Next, the correlation between the reflectance distribution of the light diffusing film (2) and the luminance distribution on the lens was investigated. First, five types of prototype light bulbs A to E with different film thickness distributions of the light-diffusing film (2) were manufactured. All of these use filaments with a rating of 100V60W,
The ratio of L:W:H was set to 3=3=1. FIG. 5 shows the reflectance distribution of the diffuser film (2) of five types of light bulbs.

In the figure, the horizontal axis shows the creepage position of the bulb in the axial direction, and the vertical axis shows the reflectance in %.Curves A, , B□, C,
,D,,E indicate the reflectance distribution of the diffuser film of each prototype light bulb.

Next, these five types of prototype light bulbs were incorporated into the signal lamp shown in Figure 4, and the light distribution of the signal lamp as seen from the front was investigated. The results are shown in FIG.

In the figure, the horizontal axis shows the light projection direction in angles (degrees) with the central axis as 0, and the vertical axis shows the luminous intensity in units of cd.The curves A2, B2, C2-D2, and E2 are shown above. The results of prototype light bulbs A to E are shown. From this figure 6, light bulb A
In the case of , the luminous intensity unevenness could be resolved, but an effective central luminous intensity could not be obtained. In addition, although the light bulb E can obtain an effective central luminous intensity, the luminous intensity at the periphery decreases, causing luminous intensity unevenness. And light bulbs B to D are good. Therefore, in this embodiment, the reflectance at the maximum portion was set to 10% or less, and the reflectance at the minimum portion was set to 1% or more.

Furthermore, the electrostatically coated film made of fine silica powder is particularly excellent as the light-diffusing film (2) because it is easy to obtain a fine powder with an extremely small particle size, and the amount of charge is one order of magnitude lower than that of other fine powders. When electrostatically coated, the particles adhere in a dendritic manner, and the particles have a moderate bonding force with each other, and as they overlap and form layers in a cotton-like manner, they have sufficient optical diffusivity. In other words, the reflectance distribution can be adjusted arbitrarily.

Therefore, the preferable light scattering property of such a light bulb is determined by the brightness ratio, that is, the ratio of the maximum brightness (LA) within the same field of view to the brightness (L12) of a point 2011Ill away from this point LA
When I investigated ÷Ln, it was less than 1000 when viewed from the side.
It has also been found that 50 or less is preferable when viewed from the top direction.

Furthermore, in order to obtain preferable light distribution characteristics and to make maximum use of the light output of the light bulb, it is an effective method to use a transparent glass bulb. Apart from this, in order to improve visibility, it is necessary to reduce uneven brightness on the lens surface. The purpose of the lens element is to refract the light from the light source to obtain a wide light distribution. To achieve this, it is necessary to increase the refraction of the lens, which causes light loss in the lens and makes it impossible to obtain a desirable luminous intensity. To obtain good visibility, consider these drawbacks and make the light bulb diffusive so that the light that enters the lens is uniform and even. For this reason, although a coating film with high diffusivity is required, it is necessary to make the coating film extremely thin and reduce light loss without sacrificing the desired light distribution characteristics. In order to satisfy these points, the characteristic of the formation of this diffusive film is the maximum brightness point (L) of the bulb.
Brightness (L
11) The ratio (LA/LB) was calculated to be 1.000.
It is desirable that it is below, and the most preferable range is 200 to
It turned out to be in the range of 500. In addition, the ratio (L
It was also found that a preferable range for A/LC) is 50 or less.

As mentioned above, this is also an optical feature obtained because the base end side of the bulb is painted thinner than the top side.

Note that fine powder made of other materials may be used for the light scattering film, and the coating method is not limited to the above-mentioned example. Further, it may be provided on at least one of the inner and outer surfaces of the valve.

In addition, in the above-mentioned embodiment, the reflectance of the light-diffusing film was successively increased on the top side, but the present invention is not limited to this.
For example, the reflectance may be uniformly increased on the top side, and the reflectance may be uniformly decreased on the other parts, or the reflectance may be changed in steps. is not necessary, there may be some wavy changes, and the reflectance of the apex may be slightly smaller than other apexes,
The key is to appropriately suppress the light that directly strikes the periphery of the lens, and to control the illumination distribution of light that enters the lens at a low angle of incidence.

Further, the filament may be of a double coil type.

Furthermore, although many types of bulbs such as A-type, Ps-type, and G-type bulbs can be used, bulbs with a spherical top are particularly convenient for light distribution.

〔Effect of the invention〕

The light bulb for signal lights of the present invention has a filament enclosed in a glass bulb that has a sawtooth shape in the axial direction and revolves around the shaft, and further has a light diffusing film on at least one of the inner and outer surfaces of the bulb, the top side of which has a higher reflectance than the other parts. By providing a light bulb, it is possible to suppress radiation toward the top and increase radiation toward the sides. When this bulb is incorporated into a signal lamp, the brightness distribution of the second lens is uniform and continuous. This has the advantage of improving effectiveness by reducing radiation in undesired directions.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an embodiment of a signal light bulb of the present invention;
Fig. 2 is a side view of the filament, Fig. 3 is a plan view of the filament, Fig. 4 is a cross-sectional view of a signal lamp incorporating the above-mentioned example light bulb, and Fig. 5 is a reflection of various diffuser films of the above-mentioned light bulb. Fig. 6 is a light distribution diagram of the above-mentioned signal lamp. (1)...Bulb (2)...Diffusing film (6)...
Diffusing film (11)...Light bulb (11)...Reflector (
14)... Lens agent Patent attorney Inoue - Male Figure 1 Figure 4 15 Figure 6

Claims (5)

[Claims] (1) A glass bulb, a filament sealed in the bulb, having a sawtooth shape in the axial direction of the bulb and orbiting the axis, and a filament formed on at least one of the inner and outer surfaces of the bulb and located on the top of the bulb A light bulb for a signal lamp, characterized in that the side is equipped with a diffuser film having a higher reflectance than other parts. (2) The light bulb for a signal lamp according to claim 1, wherein the bulb has a spherical top side. (3) The maximum diameter in the direction (vertical) parallel to the line connecting two points connected to the in-plane conductor of the filament is L+nm, the maximum diameter in the direction (horizontal) perpendicular to this longitudinal direction is Wmm, and the axis The signal light according to claim 1, characterized in that when the height difference (height) in the direction is HnlIll, L:W:H=(2-5):(2-5):1. A handy light bulb. (4) The light bulb for a signal lamp according to claim 1, wherein the reflectance of the diffuser film is 10% or less at its maximum portion and 1% or more at its minimum portion. (5) The light bulb for a signal lamp according to claim 4, wherein the luminance ratio in the top direction is 50 or less and the luminance ratio from the side is 1000 or less.