JPH0426162B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to the rear roof, trunk lid,
Lights installed on the rear window or rear tray (also called high mounted lamps)
It is related to.

[Prior art]

Generally, this type of lamp uses an incandescent light bulb as a light source, and is mounted as a high mounted lamp 2 on the rear roof of a vehicle 1, as shown in FIG. However, as described above, since the light source is incandescent, although it is excellent in terms of illuminance, it is weak against vibration and has a short service life.

If only vibration resistance is considered, LEDs can be used as the light source for this type of lamp. This LED
The case where this is used is shown in FIG. 8. That is, LEDs 3 are arranged inside the lamp 2, but since LEDs have a large difference in illuminance compared to incandescent light bulbs, a large number of LEDs must be used. Therefore, a large number of LEDs 3 are attached in parallel to a long rectangular printed circuit board 4, and the printed circuit board 4 is housed in a long housing 5 having a U-shaped cross section, and a lens 6 is installed in the opening of the housing. The configuration is such that it can be installed.

In this case, since a large number of LEDs are used, the lens 6 may have lens cuts such as a plurality of concave or convex lenses on the inside and outside of the lens in order to obtain a desired light distribution pattern as in the conventional example. It becomes difficult. In other words, when a large number of LEDs and a plurality of lens cuts are combined, errors may occur in some parts.
This spreads over the entire area, making it impossible to obtain the desired light distribution, making it difficult in practice, and it is thought that a lens 6 without a lens cut is generally used.

Therefore, when the lens 6 without a lens cut is used, the light flux emitted from the LED 3 is transmitted through the lens 6.
The light distribution pattern formed at a certain distance through the lens is as shown in FIG. The LED 3 used in this case is one whose luminous flux has a diffusion angle of 10° around the central axis
The luminance is required to be about 30 cd in the a range, 20 cd in the b range, and 10 cd in the c range from the center. If this light distribution pattern is examined in the horizontal direction, it will be as shown in FIG. 10, where the solid line A is the actual luminous intensity and the virtual line B is the required standard value. Further, when this light distribution pan is examined in the vertical direction, it becomes as shown in FIG. 11, and in the vertical direction, the shaded portion C is not required. In other words, although the range indicated by the virtual line B is required in the vertical direction, the luminous flux is emitted up to the range of the actual luminous intensity A. Therefore, in order to increase the luminous intensity in the horizontal direction, it is necessary to use a large number of LEDs in close proximity even if there is waste in the luminous intensity in the vertical direction.
There is a problem in that installing LEDs creates waste. In particular, tail lamps and the like conventionally attached to vehicles are located at a low position, and visibility is poor when viewed from a truck or the like where the driver's seat is located at a high position. There is no problem when looking at taillights from a low position, such as in the driver's seat of a passenger car, so the luminous intensity required for high-mounted lamps is the spread to the left and right at the high position, and the spread to the left and right in the low direction is required. I don't.

[Problem that the invention seeks to solve]

The present invention solves the problem of vibration resistance in incandescent light bulbs and
This is an attempt to solve the problems of visibility and light distribution when using LEDs.

[Means for solving problems]

The present invention is a concrete means for solving the above problems, in which a large number of LEDs are mounted on a long printed circuit board.
are arranged in parallel, and the printed circuit board is placed in a rectangular housing that is long and has a U-shaped cross section.
The LED is housed so as to face the opening, a long lens is attached to the opening of the housing, and at least one of the vertically inner sides of the lens is attached to the housing.
An object of the present invention is to provide a vehicle lamp characterized in that a prism cut is applied to the lens so that the diffusion angle of the LED is directed toward the central axis, and the prism cut applied to the lens prevents wasteful movement in the vertical direction. By refracting the expanding light beam toward the central axis, the illuminance on the central axis side is increased, improving visibility and reducing the number of LEDs used.

〔Example〕

Next, the present invention will be explained in more detail with reference to the illustrated embodiment. The lamp 11 used as a high-mounted lamp has an elongated rectangular shape as a whole, and has a large number of lamps arranged at appropriate intervals inside.
The LEDs 12 are arranged in parallel. these
Each LED 12 is connected to a pair of lead frames 13 and 1.
4 to a printed circuit board 15 having an elongated rectangular shape like the lamp 11 at appropriate intervals, and the printed circuit board is housed in a housing 16 of the lamp. The housing 16 has an elongated rectangular shape when viewed from the front, and its cross section has a U-shape as shown in FIG. Then, when storing the printed circuit board 15, the LED 12 is arranged facing the opening side,
A long lens 17 is attached to the opening side.
This lens 17 does not have an uneven lens cut on its entire surface, but has a structure in which a prism cut 18 is provided only on the inside of the lower part.

This prism cut 18 completely refracts the luminous flux directed downward from the LED 12 through the lens 17 and biases it toward the central axis X side. In other words, the LED 12 used in the case is one in which the light beam emitted from the front has a diffusion angle of 10 degrees with respect to the central axis The angled light beam d is emitted as is, and the downward light beam e having an angle of 10° is approximately radiated by the prism cut 18.
The radiation is corrected by 5 degrees toward the central axis X side.

Regarding the light distribution pattern emitted from the lens 17 equipped with such a prism cut 18, the third to
To explain based on Figure 5, Figure 3 shows one LED.
3 is a plan view of a light distribution pattern of a luminous flux emitted from the central axis X, and the spread state of the luminous flux in the vertical direction V and the horizontal direction H with respect to the central axis X forms a special pattern. That is, by correcting the downward luminous flux e by 5 degrees to the central axis X side by the prism cut 18 of the lens 17, the unnecessary downward luminous flux e' is directed toward the central axis X side, and the brightness on the central axis side is reduced. It only increases by that amount. If this state is considered along the H line in the left-right direction, the pattern shown in FIG. 4 will be obtained. In this figure, A is the pattern before the prism cut 18 is applied, and B is the required standard brightness. As is clear from this figure, by providing the prism cut 18, the brightness D near the central axis X increases, exceeding the required brightness B, and also increases the overall illuminance. Furthermore, considering along the vertical V line, the fifth
It can be seen that the pattern shown in the figure is such that the downward luminous flux is directed toward the central axis X side, increasing the brightness near the central axis X and increasing the overall illuminance. In any case, the wasted downward beam e is corrected by the prism cut 18 and used effectively.

The other embodiment shown in FIG.
The LED 12a has a diffusion angle of 15°, and in this case, the upward luminous flux d also crosses the prism cut 1.
9 to direct it toward the center axis X side, and the downward beam e is corrected by 10 degrees by the prism cut 18a and direct it to the center axis X side in the same way. By doing so, the light distribution pattern becomes an ideal pattern that approximates that of the embodiment described above. In short, the prism cut is selected appropriately depending on the diffusion angle of the LED used.
Note that other parts are the same as those in the previous embodiment, so the same reference numerals are given and omitted.

In any case, when using LEDs, the unnecessary downward light flux is cut off and directed towards the central axis, resulting in a relatively bright illuminance that spreads horizontally, and the spacing between the LEDs can also be adjusted. Since the LEDs can be made relatively large, the required brightness can be obtained even with a small number of LEDs.

〔Effect of the invention〕

As explained above, the vehicle lamp according to the present invention has a plurality of lamps arranged in parallel inside the housing.
In a combination of an LED and a lens, the inside of the lens in the vertical direction and at least one of the lenses are
By using a configuration with a prism cut so that the diffused light from the LED is directed towards the center axis, the luminous flux in unnecessary directions is concentrated towards the center axis, increasing the brightness and increasing the illuminance in the lateral direction. This has the excellent effect of being able to satisfy the required illumination standards with a smaller number of LEDs, and providing a lamp with good visibility at a low cost.

In addition, the prism cut provided on the lens can be cut in a line on either the top or bottom of the long lens, which not only improves workability, but also improves workability, unlike conventional lenses that have uneven lens cuts. This has the excellent effect that almost no errors occur, and workability and assembly workability are extremely easy.

Furthermore, unlike incandescent light bulbs, the use of LEDs has the advantage of being able to be used semi-permanently with almost no fear of disconnection.

[Brief explanation of drawings]

Fig. 1 is a front view showing a part of a vehicular lamp according to a first embodiment of the present invention in cross section, Fig. 2 is an enlarged sectional view taken along the - line in Fig. 1, and Fig. 3 is an embodiment of the same. A diagram of the light distribution pattern of one LED obtained by
Figure 4 is a pattern diagram showing the brightness and illuminance of the same light distribution pattern viewed from the horizontal direction, Figure 5 is a pattern diagram showing the brightness and illuminance of the same light distribution pattern viewed from the vertical direction, and Figure 6 is a pattern diagram showing the brightness and illuminance of the same light distribution pattern viewed from the vertical direction. Fig. 7 is a partial side view showing how a conventional high-mounted lamp is installed, and Fig. 8 shows the use of an LED as a light source in a conventional lamp. Fig. 9 is a diagram of the light distribution pattern of one LED in the same lamp, Fig. 10 is a pattern diagram showing the brightness and illuminance of the same light distribution pattern viewed from the horizontal direction, and Fig. 11 is a cross-sectional view of the hypothetical case. It is a pattern diagram which shows the brightness and illumination intensity seen from the vertical direction of the same light distribution pattern. 11...Lighting, 12, 12a...LED, 13,
14...Lead frame, 15...Printed circuit board, 16...Housing, 17...Lens, 1
8, 18a, 19... Prism cut, d... Luminous flux heading upward, e, e'... Luminous flux heading downward, X...
...Central axis.

Claims (1)

[Claims] 1 A large number of LEDs are arranged in parallel on a long printed circuit board, and the printed circuit board is housed in a rectangular housing that is long and has a U-shaped cross section.
A long lens is attached to the opening of the housing, and at least one of the vertically inner sides of the lens is attached to the LED.
A vehicle lamp characterized by having a prism cut so that the diffusion angle of the lamp is directed toward the central axis.