JP4945658B2 - Vehicle headlamp - Google Patents

Description

  The present invention relates to an LED lamp, and in particular, when used as a light source for a headlight of a vehicle, the light distribution characteristic projected in front of the vehicle is that of an incandescent light bulb and a halogen light bulb that are conventionally used. Similar to filaments and the like, the present invention relates to a configuration of an LED lamp that satisfies a requirement and can be substituted for them.

  As a conventional headlight using an LED lamp as a light source, one having a configuration as shown in FIG. 10 is known. In this example, LEDs are arranged in a matrix of 3 rows × 8 columns so that a prescribed brightness can be obtained. Further, a lens or the like is provided on the front surface of these LEDs to provide desired light distribution characteristics. Is obtained. The LEDs arranged in the above-mentioned rows and columns are those in which a plurality of chips are enclosed (multi-chip package) as necessary, and the brightness necessary for a headlight is obtained. It is supposed to be.

  Here, as the LED, a red light emitting LED is used for the LED denoted by 11 and a green light emitting is used for the LED denoted by 12 and denoted by 13. Those emitting blue light are used, and LEDs denoted by reference numeral 14 are those emitting yellow or white light, and the color of the lamp is reduced to a specific color.

Special table 2003-503815 gazette

  However, in the headlight having the above-described conventional configuration, one is required to form a light distribution characteristic having a shape defined for a headlight by combining a plurality of LEDs each having a beam-like light distribution characteristic. One LED also requires work such as precisely aligning the direction to a specified direction. In reality, a high degree of accuracy is required, which complicates the work and lowers the yield, resulting in an increase in product cost. Cause problems.

  In addition, when a large number of LEDs are arranged in a large area as described above, the necessary amount of light is certainly obtained as the total amount of light, but as described above, from each LED. It is impossible to direct the light in the desired direction accurately, so it is not possible to illuminate far away, and the current technology can be used effectively for signal lamps. For example, even if a desired light distribution characteristic is obtained, the reachable distance is insufficient and it cannot be employed.

  However, as a recent market demand, there is a strong demand for a solid state that is maintenance-free, and a headlight is also required to be an LED light source. Therefore, unlike conventional LEDs, there has been a demand for the development of an LED exclusively for headlights that can reflect light to a reflecting mirror in a state as close to a filament as possible and irradiate brightly in the distance.

In the present invention, as a specific means for solving the above-described conventional problems, an LED light source having a rectangular light emitting shape provided with a resin mixed with a phosphor on an LED chip mounted on a base is used as a light source. A vehicle headlamp having a lens having a lens cut that performs appropriate diffusion to the left and right , wherein the ratio of the short side to the long side of the light emitting shape of the LED light source is in the range of 1: 2 to 1: 6. , and the to name a substantially flush plane surface of the resin is substantially no lens effect, provide a vehicle headlamp, characterized in that arranged toward the long side in the lateral direction of the vehicle By doing so, it is possible to obtain a reflected light satisfying a prescribed light distribution characteristic when reflected by an existing headlight reflecting mirror, thereby solving the problem.

  According to the present invention, an LED lamp for a lamp light source in which the ratio of the short side to the long side of the light emitting surface of the LED chip is in the range of 1: 2 to 1: 6 can be obtained. By disposing the LED lamp in the vicinity of the focal point, the light from the LED lamp is converted into a parallel light beam, and means light distribution characteristics similar to those of the conventional headlight can be formed.

  Therefore, even when using a plurality of LED chips, the light from the plurality of LED chips is not diffused over a wide range, and it is transmitted through the lens as a parallel light beam having a small area and high brightness, By forming a lens cut that performs appropriate diffusion on the left and right sides of this lens, it is possible to obtain an epoch-making result that a headlight having a desired light distribution shape and capable of irradiating far is also obtained by an LED lamp. It will be a thing.

1 is a perspective view showing a first embodiment in which a base of an LED lamp for a lamp light source according to the present invention is made of metal. It is sectional drawing which shows 2nd embodiment which similarly formed the base of the LED lamp for lamp light sources which concerns on this invention with the ceramic. It is sectional drawing which similarly shows 3rd embodiment of the LED lamp for lamp light sources which concerns on this invention. It is sectional drawing which similarly shows 4th embodiment of the LED lamp for lamp light sources which concerns on this invention. It is sectional drawing which similarly shows 5th embodiment of the LED lamp for lamp light sources which concerns on this invention. It is explanatory drawing which shows a state when the LED lamp for lamp light sources which concerns on this invention is combined with a lamp. It is explanatory drawing which shows the example of the light distribution characteristic of the headlight which employ | adopted the LED lamp for lamp light sources which concerns on this invention. It is explanatory drawing which shows the light distribution characteristic of the headlight which employ | adopted the LED lamp of the prior art example as a comparative example. It is sectional drawing which similarly shows 6th embodiment of the LED lamp for lamp light sources which concerns on this invention. It is explanatory drawing which shows a prior art example.

  Below, this invention is demonstrated in detail based on embodiment shown in a figure. 1 and FIG. 2 is a lamp light source LED lamp according to the present invention. This lamp light source LED lamp 1 is a first embodiment shown in FIG. 1, a second embodiment shown in FIG. In any of the forms, a base 3 for mounting the LED chip 2 is provided.

  Here, in the LED lamp 1 for a lamp light source of the present invention, since it is desired to obtain as much light as possible by flowing as much current as possible to the LED chip 2, in order to mount the LED chip 2 The base 3 employs a member having excellent thermal conductivity such as a metal such as copper (see FIG. 1), a ceramic such as AlN (aluminum nitride) (see FIG. 2), and the thickness of the base 3 is a heat sink on the back surface. This is necessary and sufficient for thermal diffusion when 22 is bonded.

  In the case where a metal is used for the base 3, an insulating layer 4 is provided at appropriate positions on both sides of the base 3 as shown in FIG. 1, and terminals for supplying power to the LED chip 2. Arrangement is performed in a state where the plate 5 is insulated from the base 3. In the first embodiment (see FIG. 1) and the second embodiment (see FIG. 2), the phosphor that is injected to protect the LED chip 2 after mounting and obtain white light. A cavity 3a, which is a recess for holding the transparent silicone resin 6 mixed with 6a, is provided.

  In the first embodiment shown in FIG. 1, the LED chip 2 having a ratio of the short side to the long side of 1: 3 is used. In the present invention, this ratio is set to 1: 2. Although it is limited to the range of ˜1: 6, the LED chip 2 itself may be formed in a rectangular shape as shown in FIG. 1 or may be described in FIG. 2 below. In this way, the required number (for example, four) of square LED chips may be arranged in a row to obtain a substantially rectangular light emission shape.

  FIG. 2 shows a configuration example in which ceramics such as AlN (aluminum nitride) are used as the base 3 and, in addition, an appropriate number (four in the illustrated case) of LED chips 2 having a square shape are aligned in a line. First, the wiring pattern 3b is printed on the base 3 with a conductive paint or the like, and the cavity 3a is formed on the base 3 by laminating or firing green sheets. In addition, when the cavity 3a is formed, the terminal plate 5 is formed at the same time and is provided for power supply from the outside.

  Then, the LED chip 2 is mounted on the wiring pattern 3b, the LED chips 2 are wired in series by the gold wires 7, and then a transparent silicone resin in which an appropriate amount of the phosphor 6a is mixed in the cavity 3a. 6 is injected into the LED lamp 1 for a lamp light source of the present invention. Here, in the LED lamp 1 for a lamp light source of the present invention, the silicone resin injected into the cavity 3a is substantially flush with the upper surface of the cavity 3a and does not substantially cause a lens action. .

  In FIG. 2, the four LED chips 2 are described as being connected in series. However, the LED chip 2 emits blue light in the vicinity of 3.6 V due to a difference in composition due to a difference in emission color. In some cases, the lighting voltage is different, or the minimum usable voltage required by the vehicle type is different.

  Therefore, when it is demanded that use from 8V to 9V is possible, the LED lamp 1 for a lamp light source shown in FIG. Using two sets of current controlled current circuits to obtain a rectangular light emission shape with an aspect ratio of 1: 4 is an appropriate means. Similarly, when a rectangular light emission shape with an aspect ratio of 1: 6 is required. It is appropriate to use three sets of two connected in series and current controlled.

  When any of the LED lamps 1 for lamp light sources formed as described above is turned on, blue light is emitted from the LED chip 2, and the blue light is emitted from the silicone resin 6. The phosphor 6a mixed when passing through is excited to emit yellow light. Therefore, by optimizing the mixing ratio of the phosphors 6a, blue and yellow are mixed and white suitable for a headlight is obtained.

  Further, the transparent silicone resin 6 is soft and has less protective stress on the LED chip 2 and the gold wire 7. Therefore, the protection of the LED chip 2 and the protection of the gold wire are excellent, but the transparent silicone resin 6 itself has a high hygroscopic property, and the protection performance of the LED chip 2 and the like on the moisture-proof surface is inferior. In addition, when the soft transparent silicone resin 6 is used, the surface becomes sticky and causes other problems such as adhesion of dust. Therefore, as shown in the third embodiment in FIG. It is also conceivable to cover the chip 2, the gold wire and the like with a soft transparent silicone resin 6, and further provide a hard silicone resin 6b film on the upper part thereof to prevent the adhesion of dust and the like. The phosphor 6a can be added to the hard silicone resin 6b side.

  Moreover, as shown in FIG. 4 as a fourth embodiment, the flat cover 8 is formed and attached with transparent resin, transparent glass or the like, and the problem of adhesion of dust is solved and the silicone resin 6 is adopted. However, in this case, an air layer is formed between the silicone resin 6 (or the hard silicone resin 6b) and the flat cover 8, and a difference in refractive index is generated. There is a problem that the light quantity loss of about 5% increases due to the boundary surface.

Furthermore, instead of the flat cover 8 as shown as a fifth embodiment in FIG. 5, SiO ₂ cover the upper surface of the film of the silicone resin 6 shown in FIG. 3 (a hard silicone resin 6b may be provided) (Silicon oxide) 6c is formed in close contact to give stronger moisture proofing, and light loss due to an increase in the interface with the air generated by the flat cover 8 (about 5% per surface) Therefore, any one of the above-described configurations may be selected according to the required performance.

  FIG. 6 shows a state in which the LED lamp 1 for a lamp light source configured as described above according to the present invention is incorporated in a headlight 20 employing a rotary parabolic reflector. The LED lamp 1 for a lamp light source 1 is orthogonal to the horizontal center line Ho of the reflecting mirror 21 with the longitudinal direction of the LED chip 2 in which a plurality (for example, six) of LED lamps 2 are arranged in a straight line as a paraboloid, In addition, it is appropriately positioned forward of the focal point of the paraboloid (provided that light is in contact with the upper half of the reflecting mirror 21).

  Then, for example, if light is reflected only on the upper half of the reflector as in the passing filament of an H4 type halogen bulb, as shown in FIG. 7, a light distribution DN suitable for passing light distribution that irradiates the horizontal line H or lower is obtained. At this time, in the filament for passing the halogen light bulb, the hood is attached to the lower half part from the beginning and half the light quantity is already lost. However, in the LED lamp 1 for a lamp light source of the present invention, Since light is emitted only in one direction, the luminous flux utilization rate is remarkably high.

  Furthermore, since the light emitting surface is rectangular according to the present invention, the light source image projected by the reflector is also wide in the horizontal line H direction suitable for the light distribution of the vehicular lamp, and the light distribution characteristic excellent in the horizontal field of view is easily obtained. It will be obtained. FIG. 8 shows the light distribution characteristic DO when one LED lamp having a so-called dome shape is attached to the same reflector for comparison with the light distribution characteristic of the LED lamp 1 for a lamp light source of the present invention. It is apparent that the irradiation width is narrow and both ends hang down with respect to the horizontal line H, resulting in poor visibility.

  FIG. 9 shows a sixth embodiment of the present invention. The LED lamp 1 for a lamp light source described above is mounted in a cavity 3a in which the LED chip 2 is provided on the base 3, and the cavity 3a is a phosphor 6a. A transparent silicone resin mixed with was filled. The reason is that wire bonding is performed on the upper surface of the chip 2 by the gold wire 7, and it is necessary to protect the gold wire 7.

  Therefore, the size in which the cavity 3a is formed is substantially the light emitting area, which is larger than the LED chip 2 and causes a decrease in luminance. However, the gist of the present invention is the most necessary condition for obtaining a light source having a small area and high brightness.

  Therefore, in the sixth embodiment, by using the flip-chip LED chip 2, the LED chip 2 is mounted on the base 3 having a flat upper surface and no cavity, thereby protruding on the base 3. The LED chip 2 itself is coated with the phosphor 6a. By doing so, the light emitting area including the phosphor 6a can be reduced, and the brightness can be increased. Since the base 3 is also reduced in thickness and size, the entire headlight 20 can be reduced in size and brightness.

DESCRIPTION OF SYMBOLS 1 ... LED lamp for lamp light sources 2 ... LED chip 3 ... Base 3a ... Cavity 3b ... Wiring pattern 4 ... Insulating layer 5 ... Terminal board 6 ... Transparent silicone resin 6a ... Phosphor 6b ... Hard corn resin 6c ... Silicon oxide (SiO2) ₂ )
7 ... Gold wire 8 ... Flat cover 20 ... Headlight 21 ... Reflector 22 ... Heat sink

Claims (1)

A vehicular headlamp having a lens with a lens cut that performs appropriate diffusion to the left and right, using an LED light source having a rectangular light emission shape provided with resin mixed with a phosphor on an LED chip mounted on a base A light,
The ratio between the short side and the long side of the light emitting shape of the LED light source 1: 2 to 1: 6 by weight, Shi name a substantially flush plane surface of the resin is substantially no lens effect The vehicle headlamp is characterized in that the long side is arranged in the left-right direction of the vehicle .

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