JPH07234135A - Illumination device and display device using the same - Google Patents

Abstract

PURPOSE:To provide an illumination device requiring no special heating means, having a simple structure and capable of being inexpensively produced and a display device using the same. CONSTITUTION:A reflecting surface 3 is formed on one side surface of a printed wiring board 2 formed into a strip like shape and a plurality of small-sized incandescent electric bulbs are arranged on the reflecting surface 3 along the longitudinal direction of the printed wiring board 2 and the lead wires 62, 62 of the incandescent electric bulbs 6 are allowed to pierce through the printed wiring board to be connected to the printed wiring formed to the other side surface of the printed wiring board.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device suitable for a backlight for illuminating the display plates of various meters from the back and a display device using the same.

[0002]

2. Description of the Related Art For example, in an instrument panel used for a vehicle speedometer, a light source is installed on the back of a graduation plate formed by a light-diffusing and transmissive plate, and graduation is performed by the light emitted from this light source. The structure that illuminates the back of the board and displays the scale formed on the scale board with this light is adopted.

Conventionally, as the above-mentioned backlight light source, a hot cathode or cold cathode fluorescent lamp has been used because it can illuminate the entire surface of a graduation plate having a predetermined spread with uniform brightness.

That is, an example of a conventional instrument panel will be described with reference to FIGS. 7 and 8. In the figure, 10 is a graduation plate made of a light diffusion / transmission plate such as acrylic. A scale 11 is provided along the circumferential direction on the surface of the. The scale 11 is indicated by a pointer (not shown).

A low-pressure mercury vapor discharge lamp as a light source is provided on the back of the dial 10. A hot cathode fluorescent lamp or a cold cathode fluorescent lamp 20 as shown is used as the low-pressure mercury vapor discharge lamp. The cold cathode fluorescent lamp 20 has a bulb 21 bent in a semi-circular shape (almost U-shaped) along the arrangement direction of the scale 11, and the cold cathode 22 is provided at both ends of the bent bulb 21. , 22
And a phosphor coating (not shown) is formed on the inner surface of the bulb 21.

Such a bent type cold cathode fluorescent lamp 2
0 is accommodated in the reflector 25. The reflector 25 is made of a metal or a synthetic resin, has a planar shape of a semicircular shape (almost U-shaped) along the shape of the bulb 21, and has a substantially semicircular cross section. Therefore reflector 2
5 has a gutter-like shape with an overall U-shape. On the inner surface of the reflector 25, a reflecting surface 26 formed of a metal surface or a white or metal vapor deposition film is formed.

The cold cathode fluorescent lamp 20 housed in the reflector 25 as described above is provided with a heater 27 for temperature compensation at a low temperature. The heater 27 is a laminated heater in which a heat resistant insulating film 29 such as a polyester resin sheet is laminated on one side of the heater body 28 made of a metal mesh such as stainless steel. Is valve 2
1 is attached to the lower surface.

A light diffusion / transmission plate 15 is attached to the upper opening of the reflector 25 so as to diffuse the light emitted from the lamp 20 and the light reflected by the reflector 25.

In such a structure, when the cold cathode fluorescent lamp 20 is turned on, this light is reflected directly or by the reflecting surface 26 toward the opening of the reflector 25, and is diffused by the light diffusion / transmission plate 15. To be done. Then, this diffused light illuminates the back surface of the graduation plate 10, and this illumination light illuminates the graduation plate 10.
To diffuse and transmit the display scale 11.

[0010]

However, in the conventional display device, the cold cathode fluorescent lamp 20 is used as a backlight light source, and although this type of cold cathode fluorescent lamp 20 is excellent in luminous efficiency. Since the bulb 21 has to be formed in a bent shape and the phosphor coating must be formed on the inner surface, the manufacturing is complicated and expensive.

Moreover, a low-pressure mercury vapor discharge lamp typified by a fluorescent lamp generally has a low mercury vapor pressure when attempted to be started in a low temperature atmosphere, so that the starting voltage becomes high and a rise time until a rated luminous flux is obtained. However, if the ambient temperature is low even during stable lighting, the vapor pressure of the enclosed mercury will be low and the luminous efficiency will be reduced.

In order to improve the starting characteristic and the light emitting characteristic in such a low temperature condition, a means for attaching a heater 27 to the lamp 20 and heating the bulb 21 by the heater 27 is adopted. However, the provision of such heating means complicates the structure for controlling the heater 27,
The number of components used also increases, and the overall structure of the backlight becomes complicated.

For this reason, this type of backlight using the conventional low-pressure mercury vapor discharge lamp as a light source has a drawback that it becomes expensive. The present invention has been made based on such circumstances, and an object thereof is to provide a lighting device which does not require a special heating means, has a simple structure, and can be manufactured at low cost, and a display device using the same. It is the one we are trying to provide.

[0014]

According to a first aspect of the present invention, there is provided a compact incandescent light bulb in which a reflecting surface is formed on one side surface of a wiring board formed in a strip shape and a pair of lead wires are extended in the same direction. Arrange a plurality along the longitudinal direction of the wiring board,
The lead wire of the incandescent lamp is connected to a printed wiring formed on the other side surface of the wiring board by penetrating the wiring board.

According to a second aspect of the present invention, the small incandescent light bulb is
A filament is arranged along an axial direction in an elongated bulb whose both ends are sealed, lead wires connected to this filament are led out from both ends of the bulb, and these lead wires are extended in the same direction. .

According to a third aspect of the present invention, the small incandescent light bulb is
At least the surface opposite to the reflection surface is a diffusion surface. The invention of claim 4 relates to claim 1 to claim 3.
The display device is characterized in that the illuminating device according to any one of items 1 to 4 is arranged on the back of the display plate, and the back surface of the display plate is illuminated by the light emitted from the incandescent lamp. A fifth aspect of the present invention is a display device, wherein a light diffusion / transmission plate is provided between the illumination device and the display plate.

[0017]

According to the invention of claim 1, since the small incandescent lamp is attached along the longitudinal direction to the wiring board formed in the long strip shape, the light emission pattern is similar to that of the conventional low-pressure mercury vapor discharge lamp. Can present a pattern. Moreover,
Since each incandescent light bulb is connected to the printed wiring formed on the back surface of the wiring board, mounting and electrical connection are easy. Then, on the wiring substrate, the surface on which the light bulb is attached is integrally formed with a reflecting surface that is formed directly or separately, so that a part of the light emitted from these light bulbs is reflected in one direction. The light loss is reduced. Furthermore, since the incandescent light bulb can be instantly turned on even in a low temperature atmosphere, no special heating means is required, and the structure is simplified in this respect.

According to the invention of claim 2, in the small incandescent light bulb, a filament is arranged along an axial direction in an elongated bulb whose both ends are sealed, and lead wires connected to the filament are provided from both ends of the bulb. Since the lead wire is led out and these lead wires are extended in the same direction, the light emitting portion becomes long, and it becomes easy to arrange the light emitting portion along the longitudinal direction of the wiring board formed in the long strip shape. Also, mounting on a wiring board becomes easy.

According to the invention of claim 3, since at least the surface of the small incandescent light bulb on the side opposite to the reflection surface is used as the diffusion surface, the light directly from the filament toward the irradiation surface is diffused, and the light emitting surface is planar. Therefore, the luminance distribution can be made uniform.

According to the invention of claim 4, the illuminating device according to any one of claims 1 to 3 is arranged at the back of the display plate, and the back surface of the display plate is moved by the light emitted from the incandescent lamp. Since irradiation is performed, compared with the case where a low-pressure mercury vapor discharge lamp is used as a light source, instantaneous lighting is possible without a special heater, and the structure is simplified.

According to the invention of claim 5, since the light diffusion and transmission plate is provided between the illuminating device and the display plate, the light reflected by each light bulb and the reflecting surface is diffused to illuminate the display plate, and The brightness distribution is even.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the first embodiment shown in FIGS. This embodiment shows an example applied to a display device used as a vehicle speedometer,
Reference numeral 10 is a graduation plate which may be similar to the conventional example of FIG. The graduation plate 10 corresponds to the display plate of the present invention, and is made of a light-diffusing and transmissive plate such as acrylic, and has graduations 11 along the circumferential direction on the surface. The scale 11 is indicated by a pointer (not shown).

The graduation plate 11 is adapted to be illuminated from the back by the illumination device 1 provided on the back. The illuminating device 1 will be described. Reference numeral 2 denotes a wiring board, and the wiring board 2 has an elongated strip shape in a plan view, and in the case of this example, the entire shape is a horseshoe shape. A reflective surface 3 is formed on the entire side surface of the wiring board 2. The reflective surface 3 of this example is formed by directly forming a metal vapor deposition film of aluminum or the like on one side surface of the wiring board 2, or by applying a white or metallic color paint, or by adhering a metal plate of aluminum or the like having excellent reflection characteristics. It is formed by means such as stacking, and the whole has a flat surface.

On the other side surface of the wiring board 2, that is, on the back surface, as shown in FIG. 4, two printed wiring lines 4a and 4b having mutually different polarities are formed over substantially the entire length,
Power supply terminals 5a and 5b are connected to the respective ends of the printed wirings 4a and 4b.

On such a wiring board 2, the reflecting surface 3 is formed.
A plurality of small incandescent light bulbs 6 ... Are attached to the surface on which is formed. As shown in FIG. 3, these incandescent light bulbs 6 ...
A filament 61 is housed along an axial direction in a bulb 60 made of an elongated straight glass tube, and lead wires 62, 62 are integrally extended or connected to both ends of the filament 61. The valve 6
It is led out to the outside from the both end sealing portion of 0. The lead wires 62, 62 are bent outside the valve 60, for example, in an L shape so as to extend in the same direction. The valve 60 is filled with a rare gas such as argon.

The incandescent light bulb 6 having such a structure is a non-base light bulb that does not use a base, and includes the pair of lead wires 62,
Reference numeral 62 denotes a through hole 3 formed in the reflecting surface 3 and the wiring board 2.
The lead wires 62, 62 are penetrated through a, 2a and led to the back surface, and these lead wires 62, 62 are soldered and connected to the printed wirings 4a, 4b having different polarities on the back surface of the wiring board 2, respectively.

The plurality of incandescent light bulbs 6 ... Are arranged along the longitudinal direction of the wiring board 2, that is, so as to have a horseshoe shape as a whole, and the filaments 61 ... Are almost directly above the center line of the wiring board 2. It is arranged to be located. The lead wires 62, 62 of the plurality of incandescent light bulbs 6 ... Are connected to the printed wirings 4a, 4b on the back surface of the wiring board 2, and thus the incandescent light bulbs 6 ... Are connected in parallel with each other. The incandescent light bulbs 6 may be connected in series with each other.

Further, each bulb 60 of the incandescent bulb 6 ... Has a light diffusing surface 65 formed by frost processing on the outer surface thereof.
Has been formed. The light diffusing surface 65 may be partially formed on another surface while avoiding the surface facing the reflecting surface 3, but in the case of the present embodiment, the light diffusing surface 65 formed by frost processing on the entire surface of the bulb 60. Has been formed. Such a light diffusion surface 6
5 is formed, the light emitted from the filament 61 is diffused when passing through the bulb 60.
The light emitting surface becomes wide as if the entire surface of 0 emits light, and the luminance distribution can be evenly approximated.

The lighting device 1 as described above is housed in the reflection container 30. That is, the reflection container 30
May have the same shape and structure as the conventional reflector 25 shown in FIGS. 7 and 8, and is formed of metal or synthetic resin, the plane of which is horseshoe-shaped, and the cross section of which is substantially semicircular or square. Therefore, the reflection container 30 is in the shape of a gutter having a substantially U shape as a whole. On the inner surface of the reflective container 30, a reflective surface 31 made of white or a metal deposition film is formed.
Are formed.

The lighting device 1 is housed in such a reflection container 30. That is, the wiring board 2 of the lighting device 1 is fitted in the reflection container 30, and in this case, the surface of the wiring board 2 on which the reflecting surface 3 is formed and the incandescent bulbs 6 are attached is the opening of the reflection container 30. Is desired.

The opening of the reflection container 30 faces the back surface of the scale 10 and is along the scale 11. A light diffusion / transmission plate 15 made of acrylic resin or the like similar to the conventional one is provided in the opening of the reflection container 30.

The operation of the display device having such a configuration will be described. When the power supply terminals 5a and 5b projecting from the end of the wiring board 2 are connected to a power source, a current flows through each incandescent light bulb 6 ... Connected in parallel to the pair of printed wirings 4a and 4b to light up. Each incandescent light bulb 6 has a light diffusing surface 65 formed by frost processing on the entire surface of the bulb 60. Therefore, the light emitted from the filament 61 is diffused on the bulb surface and the entire surface of the bulb 60 emits light. It emits light with a wide light emitting surface.

Since the plurality of incandescent light bulbs 6 ... Are arranged substantially along the center line of the horseshoe-shaped wiring board 2, the incandescent light bulbs 6 ... Similar to the case where the cold cathode fluorescent lamp 20 is turned on, the shape of light emission is along the scale 11 of the scale 10.

A part of the light emitted from the incandescent light bulb 6 ... Directly goes to the opening of the reflection container 30, and the other part is reflected by the reflection surface 3 formed on one side surface of the wiring board 2. , The rest is reflected by the reflecting surface 31 of the reflecting container 30, and goes to the opening of the reflecting container 30, respectively. Since the light diffusion / transmission plate 15 is provided in the opening of the reflection container 30, the direct light and the reflected light directed toward the opening of the reflection container 30 are further diffused by the light diffusion / transmission plate 15 and are graduated. The back surface of the board 10 is illuminated. This light diffuses and transmits through the graduation plate 10 and brings up the display graduation 11. That is, in the display portion of the scale 11 of the scale board 10, the brightness becomes uniform.

In the embodiment as described above, the lighting device 1 has a structure in which the small incandescent light bulbs 6 ... Are attached to the wiring board 2 formed in the shape of a long strip along the longitudinal direction of the wiring board 2. The pattern can exhibit a pattern similar to that of a conventional low-pressure mercury vapor discharge lamp, and each incandescent lamp 6
Since the lead wires 62, 62 are connected and attached to the printed wirings 4a, 4b formed on the back surface of the wiring substrate 2 by penetrating the wiring substrate 2, the attachment and the electrical connection are easy.

On the wiring board 2, the incandescent light bulb 6 ...
Since the reflecting surface 3 which is directly or separately formed is integrally formed on the surface on which is attached, the light emitted from these light bulbs 6 is reflected upward and the loss of light is reduced.

Each of the small incandescent light bulbs 6 ... Arranges a filament 61 along an axial direction in an elongated bulb 60 whose both ends are sealed, and a lead wire 6 connected to the filament 61.
Since the lead wires 62 and 62 are led out from both ends of the bulb 60 and the lead wires 62 and 62 are extended in the same direction, the light emitting portion becomes long and the number of bulbs 6 ... Can be reduced. At the same time, it becomes easy to dispose the long light emitting portion along the longitudinal direction of the wiring board 2 formed in the long strip shape. Further, since the lead wires 62, 62 extending in the same direction are joined to the wiring board 2, the mechanical and electrical connection structure of the incandescent light bulbs 6 becomes simple and the number of parts is small. The incandescent light bulb 6 ... Can be manufactured at a low unit price, and even if a plurality of incandescent light bulbs are used, the manufacturing cost is lower than that of a conventional single cold cathode discharge lamp.

Each of the small incandescent light bulbs 6 has at least the surface opposite to the reflection surface 3 as the diffusion surface 63, so that the light directly from the filament 61 toward the irradiation surface is diffused and the light emitting surface spreads in a plane. And the luminance distribution approaches evenly.

In the display device using the illuminating device 1 as a light source, in addition to the light distribution of the light emitted from the illuminating device 1 being almost even, the light is diffused by the light diffusion / transmission plate 15. , The scale plate 10 is illuminated evenly.

The light emitted from each incandescent light bulb 6 is reflected by the reflection surface 3 of the wiring board 2 and the reflection surface 31 of the reflection container 30 and is directed to the light diffusion / transmission plate 15, so that the loss of light is caused. There is no.

Since the incandescent lamps 6 ... Are used as the light source, instantaneous lighting is possible without the need for a special heater as in the prior art, and the structure is simplified. In the above embodiment, the reflecting surface 3 formed on one side surface of the wiring board 2 is formed as a flat surface, but the present invention is not limited to this, and as shown in the second embodiment shown in FIGS. 5 and 6. , The cross section is an arc,
A gutter-shaped reflecting surface 41 such as a parabola may be used. That is, in this example, the reflection container 30 shown in FIGS. 1 and 2 is used.
Has the same configuration as that installed on the upper surface of the wiring board 2,
A gutter-shaped separate reflector 40 is previously formed by press forming a metal plate such as aluminum, or by injection molding a resin, and the reflector 40 is bonded to one side surface of the wiring board 2. It is fixed with an agent or other joining means. The incandescent light bulbs 6 ... Are arranged inside the reflector 40 along the longitudinal direction, and the lead wires of these incandescent light bulbs 6 penetrate the reflector 40 and the wiring board 2 and are led to the back surface of the wiring board 2. , Connected to printed wiring.

In the case of such a configuration, FIG. 1 and FIG.
The reflecting surface 3 and the reflecting container 3 in the first embodiment shown in FIG.
Since 0 is shared by one reflector 40, the number of parts is reduced, the formation of the reflecting surface 3 and the like is not required, and the cost is reduced.

In the above embodiment, the wiring board 2 has a horseshoe shape corresponding to the arrangement of the scales 11 on the scale board 10, and a plurality of incandescent lamps are arranged substantially along the center line.
These incandescent light bulbs are also arranged so as to have a horseshoe shape as a whole, but the present invention is not limited to this. For example, the shape of the wiring board may be triangular, square, or the like, depending on the shape of the scale plate or other display plate to be irradiated. The configuration may be such that it is polygonal and the incandescent light bulb is arranged in a polygonal shape as a whole, or the wiring board is W-shaped and the incandescent light bulb is also arranged in a W-shaped shape as a whole.

The display plate is not limited to the graduation plate as in the above embodiment, but may be a liquid crystal display panel or the like, and the liquid crystal display panel may be illuminated by the illumination device of the present invention.

[0045]

As described above, according to the present invention, since a small incandescent lamp is attached along the longitudinal direction to a wiring board formed in the shape of a long strip, the light emission pattern is the conventional low-pressure mercury vapor discharge. It can have the same pattern as an electric lamp, and since each incandescent lamp is connected to the printed wiring formed on the back surface of the wiring board, mounting and electrical connection are easy. Since the wiring board is provided with a reflecting surface which is directly or separately provided on the surface on which the light bulb is attached, a part of the light emitted from these light bulbs is reflected in one direction, Less loss. In addition, since an incandescent light bulb is used as the light source, no special preheating is required even in a low temperature atmosphere, and since a heating device is not needed, the structure is simple and the cost is low.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention and disassembled when applied to a display device of an instrument.

FIG. 2 is a sectional view of the same embodiment in an assembled state.

FIG. 3 is a cross-sectional view showing a state where the incandescent light bulb of the embodiment is attached to a wiring board.

FIG. 4 is a rear view showing the printed wiring of the wiring board of the embodiment.

FIG. 5 is a perspective view showing a second embodiment of the present invention and disassembled when applied to a display device of an instrument.

FIG. 6 is a partial cross-sectional view of the same embodiment in an assembled state.

FIG. 7 is an exploded perspective view of a conventional display device.

FIG. 8 is a sectional view of the conventional assembly state.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Illumination device 2 ... Wiring board 3 ... Reflective surface 4a, 4b ... Printed wiring 5a, 5b ...
Power supply terminal 6 ... Small incandescent light bulb 10 ... Scale plate 11 ... Scale 15 ... Light diffusion / transmission plate 30 ... Reflective container 31 ... Reflective surface 40 ... Reflector 41 ... Reflective surface 60 ... Bulb 61 ... Filament 62 ... Lead wire.

Claims (5)

[Claims] 1. A side surface of a wiring board formed in a strip shape,
A plurality of small incandescent light bulbs that form a reflective surface and extend a pair of lead wires in the same direction are arranged along the longitudinal direction of the wiring board, and the lead wires of the incandescent light bulb pass through the wiring board. An illumination device connected to a printed wiring formed on the other side surface. 2. The small incandescent light bulb comprises a filament bulb arranged axially in an elongated bulb whose both ends are sealed, and lead wires connected to the filament are led out from both ends of the bulb. The lighting device according to claim 1, wherein the lighting devices are extended in the same direction. 3. The small incandescent light bulb according to claim 1, wherein at least a surface opposite to the reflection surface is a diffusion surface.
Alternatively, the lighting device according to claim 2. 4. The lighting device according to claim 1, wherein the lighting device is arranged on a back portion of a display plate, and the back surface of the display plate is illuminated by light emitted from the incandescent lamp. Display device. 5. The display device according to claim 4, further comprising a light diffusion / transmission plate provided between the lighting device and the display plate.