JP5384871B2 - LED module - Google Patents

Description

  The present invention relates to an LED module used for a bus destination display device, for example.

  FIG. 4 shows an example of a conventional LED module (see, for example, Patent Document 1). The LED module X shown in the figure includes leads 91A and 91B, an LED chip 92, and a translucent resin 93. The leads 91A and 91B are used for electrically connecting the LED chip 92 to the outside. The LED chip 92 is die-bonded to the lead 91A. The LED chip 92 emits, for example, visible light such as red light, green light, and blue light around an irradiation axis Ir that extends in the z direction. The translucent resin 93 is made of a resin that transmits light emitted from the LED chip 92 and covers the LED chip 92. The translucent resin 93 has a columnar shape as a whole, and an emission surface 93a that bulges in the z direction is formed at the tip portion thereof. The LED module X emits light that spreads evenly in the x and y directions around the irradiation axis Ir.

  The LED module X may be used as a light source for a bus destination display device. This destination display device has a plurality of LED modules X arranged in a matrix, and is configured to display characters and figures for indicating the destination. Most people who see the bus destination display device are on the sidewalk. For this reason, the destination display device is visually recognized from a wider range in the front-rear direction of the bus than in the vertical direction. Therefore, it is required for the LED module X to emit light that spreads more widely only in the x direction out of the x direction and the y direction, for example.

JP 2002-222994 A

  The present invention has been conceived under the circumstances described above, and an object thereof is to provide an LED module capable of emitting light that spreads in a specific direction.

An LED module provided by the present invention includes an LED chip, and a light-transmitting resin that covers the LED chip and has an emission surface that bulges in the first direction irradiation side in which the irradiation axis of the LED chip extends. The module is a module, and the emission surface bulges toward the irradiation side in the first direction on a plane including the irradiation axis and configured by the first direction and a second direction perpendicular to the first direction. A plane that includes the irradiation axis and includes the first direction and a third direction that is perpendicular to the first and second directions, and swells toward the first direction irradiation side. The second curve is a curved surface obtained by moving the first curve. The first curve has an average curvature smaller than the average curvature of the second curve, and the first curve is an arc. In Thus, the LED chip is disposed between the center of the first curve and the emission surface, so that the light of the LED chip in a plane constituted by the first direction and the second direction is reduced. The divergence angle is widened by refraction of the exit surface , the second curve is an arc, and the LED chip is disposed at a position away from the center of the second curve with respect to the exit surface. Thus, the light spreading angle of the LED chip in the plane constituted by the first direction and the third direction is narrowed by refraction of the emission surface .

According to such a configuration, the spread angle in the second direction of the light from the LED chip is larger than the spread angle in the third direction due to refraction by the emission surface. Therefore, when the LED module is used, for example, in a bus destination display device, if the third direction is arranged to be a vertical direction and the second direction is a front-rear direction, the pedestrian can display the display contents more clearly. Visible. Moreover, according to such a structure, it is suitable for irradiating the light from the said LED chip uniformly in the said 2nd direction. Moreover, according to such a structure, it is suitable for irradiating the light from the said LED chip to the wider range in the said 2nd direction. Moreover, according to such a structure, it is suitable for irradiating the light from the said LED chip uniformly in the said 3rd direction. Moreover, according to such a structure, it can restrict | limit that the light from the said LED chip spreads excessively in the said 3rd direction.

  Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

  1 to 3 show an example of an LED module according to the present invention. The LED module A of the present embodiment includes leads 1A and 1B, an LED chip 2, and a translucent resin 3. The LED module A is used as a light source of a bus destination display device, for example.

  The leads 1A and 1B are for supporting the LED chip 2 and conducting the LED chip 2 to an external power source, for example. The leads 1A and 1B are formed by, for example, cutting or pressing a plate made of an alloy such as Fe, Cu, or Ni. Portions of the leads 1A and 1B exposed from the light-transmitting resin 3 are used as terminals for mounting the LED module A on a circuit board or the like. A cup portion 11 is formed on the lead 1A.

  The LED chip 2 has, for example, an active layer and an n-type semiconductor layer and a p-type semiconductor layer sandwiching the active layer. The LED chip 2 is die-bonded to the bottom surface of the cup portion 11 via, for example, Ag paste (not shown). One end of a wire (not shown) is bonded to the upper surface of the LED chip 2. The other end of this wire is bonded to the lead 1B. In the present embodiment, the LED chip 2 is configured to emit visible light such as red light, green light, and blue light, and has a planar view size of about 0.23 mm square and a height of about 0.17 mm. Has been.

  The light emitted from the LED chip 2 spreads almost without deviation in the x and y directions around the irradiation axis Ir, and its luminance distribution is symmetric around the irradiation axis Ir. In general, the luminance of light from the LED chip 2 is maximum on the irradiation axis Ir. However, the irradiation axis Ir referred to in the present invention refers to the axis that is the center of the luminance distribution, and does not necessarily indicate the direction in which the luminance is maximum.

  The translucent resin 3 is made of, for example, a resin that transmits visible light emitted from the LED chip 2, and covers the LED chip 2 and each of the leads 1 </ b> A and 1 </ b> B. The translucent resin 3 is a column having an oval cross section with the z direction as the major axis direction. In this embodiment, the translucent resin 3 has an x-direction dimension of about 4.34 mm, a y-direction dimension of about 2.09 mm, and a z-direction dimension of about 5.0 mm.

  An exit surface 3 a is formed at the tip of the translucent resin 3. The emission surface 3a is a curved surface whose shape is defined as follows using the curves 31 and 32, and bulges upward in the z direction. As shown in FIG. 3, the curve 32 is a circular arc, and in this embodiment, the radius is about 0.85 mm. As shown in FIG. 2, the curve 31 is an arc whose curvature is smaller than the curvature of the curve 32, and in the present embodiment, its radius is about 2.7 mm. The exit surface 3a is a curved surface obtained by moving the curve 32 along the curve 31 so that the plane including the curve 32 always includes the center O1 of the curve 31. Such an exit surface 3a has a shape that is partly cut out from a donut, for example.

  As shown in FIG. 2, the LED chip 2 is disposed between the center O1 and the emission surface 3a. Further, as shown in FIG. 3, the LED chip 2 is arranged at a position away from the center O2 of the curved surface 32 with respect to the emission surface 3a. That is, the LED chip 2 is located between the center O1 and the center O2, and in this embodiment, the distance from the exit slope 3a is 1.4 to 1.5 mm.

  Next, the operation of the LED module A will be described.

  According to the present embodiment, the exit surface 3a has a smaller curvature in the zx plane than in the yz plane. For this reason, the spread angle in the x direction of the light from the LED chip 2 is larger than the spread angle in the y direction due to refraction by the emission surface 3a. Therefore, when the LED module A is used for a bus destination display device, for example, the pedestrian can see the display contents more clearly by arranging the y direction to be the vertical direction and the x direction to be the forward and backward direction.

  Since both the curves 31 and 32 are so-called circular arcs having a constant curvature, the light from the LED chip 2 can be uniformly irradiated in the x direction and the y direction.

  Since the LED chip 2 is closer to the emission surface 3a than the center O1, the light from the LED chip 2 is refracted by the emission surface 3a so as to go to a wider range in the x direction. On the other hand, since the LED chip 2 is farther from the emission surface 3a than the center O2, the light from the LED chip 2 is refracted by the emission surface 3a so as to go to a narrower range in the y direction. This is suitable for the light from the LED module A to spread more widely only in the x direction and to suppress the spread in the y direction.

  In the case of the LED module A of the present embodiment, the irradiation angle indicating a range in which the luminance is 50% or more of the luminance in the irradiation axis Ir direction reaches 140 degrees in the x direction and is limited to 50 degrees in the y direction.

  The LED module according to the present invention is not limited to the above-described embodiment. The specific configuration of each part of the LED module according to the present invention can be changed in various ways.

  The first curve and the second curve referred to in the present invention are not limited to arcs, and are curves that bulge in the first direction, and if the average curvature of the first curve is smaller than the average curvature of the second curve. Good. For example, what is necessary is just to set the shape of a 1st curve and a 2nd curve suitably according to the luminance distribution of the light from an LED chip. The position of the LED chip is preferably located between the centers of the first curve and the second curve, but the present invention is not limited to this. The LED chip is not limited to one that emits visible light, and may emit light of various wavelengths such as infrared rays. The shape of the translucent resin referred to in the present invention may be any shape as long as the shape of the emission surface is as described above, and the shape other than the emission surface can be appropriately changed.

It is a perspective view which shows an example of the LED module which concerns on this invention. It is principal part sectional drawing in alignment with the II-II line of FIG. It is principal part sectional drawing in alignment with the III-III line of FIG. It is a perspective view which shows an example of the conventional LED module.

Explanation of symbols

A LED module Ir Irradiation axis O1 (first curve) center O2 (second curve) center x (second) direction y (third) direction z (first) direction 1A, 1B Lead 2 LED chip 3 Translucent Resin 3a Output surface 31 (first) curve 32 (second) curve

Claims (1)

An LED chip;
A translucent resin that covers the LED chip and has an exit surface that bulges toward the irradiation side in the first direction in which the irradiation axis of the LED chip extends;
An LED module comprising:
The exit surface is
In a plane including the irradiation axis and constituted by the first direction and a second direction perpendicular to the first direction, along a first curve that bulges toward the first direction irradiation side,
A second curve that bulges toward the irradiation side in the first direction is moved on a plane that includes the irradiation axis and is constituted by the first direction and a third direction that is perpendicular to the first and second directions. It is a curved surface obtained by letting
The first curve has an average curvature smaller than the average curvature of the second curve,
The first curve is an arc,
Since the LED chip is disposed between the center of the first curve and the emission surface, the light spreading angle of the LED chip in a plane constituted by the first direction and the second direction. Is expanded by the refraction of the exit surface ,
The second curve is an arc,
Since the LED chip is disposed at a position away from the center of the second curve with respect to the emission surface, the LED chip in a plane constituted by the first direction and the third direction is arranged. An LED module, wherein a light spread angle is narrowed by refraction of the light exit surface .

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