JPH0783142B2 - Light emitting diode structure - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a light emitting diode structure used for various types of illumination lamps, and more particularly to automobile illumination lamps (headlamps, fog lamps, etc.), signal lamps, and The present invention relates to a light emitting diode structure which is most suitable as a light source of a stop lamp for an automobile, among marker lights (tail lamp, stop lamp, turn signal lamp, parking lamp, etc.).

[Prior Art] Currently, except for light emitting sources that require strong luminous intensity, as a light emitting source mainly for visibility such as an ordinary indicator lamp, a plurality of light emitting diodes are used instead of the one using a conventional filament. The light emitting diode structure mounted vertically and horizontally on the substrate has the advantages of longer life and lower power consumption than the filament light source, and in addition, the structure itself can be constructed extremely lightly, so it is frequently used. It has become possible to be.

However, when a light emitting diode structure is used for a stop lamp of an automobile or the like, a sufficient luminous intensity cannot be achieved simply by arranging the light emitting diodes on a substrate. In other words, the brightness was insufficient for a stop lamp, and it was not possible to secure the level of visibility that would strongly warn the eyes of others.

As described above, the light emitting diode structure of the present invention is particularly suitable for a light source of a stop lamp of an automobile, but the stop lamp here is usually attached to a position above a rear bumper of the automobile. It includes not only the stop lamps of the above, but also the stop lamps that are installed in the interior of the passenger compartment at a position that is easily visible from the rear of the car through the rear window glass. This stop lamp should be installed at a higher position than normal stop lamps. Therefore, it is called a high mount stop lamp.

In view of the above-mentioned circumstances, the present applicant previously filed Japanese Patent Application No. 61-177434.
In the specification, a light emitting diode that satisfies the Japanese Industrial Standards (JIS) luminous intensity standard for automotive lamps (D5500) or the American Automobile Manufacturers Association (SAE) luminous intensity standard and can be used as an automotive stop lamp Proposed structure.

FIG. 2 is a sectional view showing one of the embodiments,
Mold part 26 of organic polymer mold light emitting diode 2
Is a convex lens-shaped top portion 261, the outer surface of which is a light emitting diode 21.
Shoulder with a radius of r ₁ centered on the position where
2 and the remaining lower part 263. Most of the light rays emitted from the light emitting diode 21 are directed to the outer surface of the apex 261. Since the apex 261 is processed into a convex lens-like curved surface, it is refracted forward (perpendicular to the substrate 1) and emitted. Further, since the light ray toward the outer surface of the remaining shoulder portion 262 passes through the normal line of the outer surface, it goes straight without being refracted and is reflected forward by the reflecting mirror 31 having a parabolic curved surface (illustration). The ray follows the arrow. Therefore, the light radiated to the front becomes strong in synergy with the light rays that are incident on the top portion 261 and are refracted and condensed.

[Problems to be Solved by the Invention] The present applicant has certainly adopted JIS and S by adopting the above structure.
We have succeeded in obtaining a light emitting diode structure that satisfies the AE luminous intensity standard, but when applying this light emitting diode structure practically, for example, as the above-mentioned high-mount stop lamp, various improvements are required. Met. One of the improvements is the size of the structure itself. The high-mount stop lamp is installed in the vicinity of the rear glass of an automobile, has an effect of essentially obstructing the field of view of the rear portion, and its outer shape is preferably as small as possible. In the conventional mold structure shown in FIG. 2, the curved surface of the shoulder portion 262 is a curved surface having a radius r ₁ centered on the position where the light emitting diode 21 is present, and the light rays directed to the outer surface thereof are reflected without being refracted. The height h _{1 of the} parabolic reflector 31 is diffused in a tapered shape toward the mirror 31.
Must be set high. Since the height h ₁ becomes high, the aperture diameter d ₁ also becomes large because of the parabolic shape, and when a plurality of these are arranged to form a light emitting diode structure, its outer shape naturally becomes large. there were. Further, since the light rays emitted from the outer surface of the shoulder portion 262 are diffused in a tapered shape, it is necessary to form the reflecting mirror 31 into a parabolic shape having a curved surface in order to efficiently emit the light rays to the front surface. There was also a problem that the processing was troublesome and the cost was high.

In addition to high mount stop lamps, it is a natural need of modern society to seek smaller, thinner, higher performance and cheaper ones. As a result of earnest research,
The present invention has been proposed.

[Means for Solving the Problem] The present invention has been made to solve the above-described problems, and is intended to reflect a light-emitting beam to a front surface of a light-emitting diode molded with a translucent organic polymer. In a light emitting diode structure having a reflecting mirror and arranged in a plane, the organic polymer mold light emitting diode has a substantially dharma shape in which an outer surface is formed into a convex lens-like curved surface and at least two parts of a top portion and a shoulder portion are formed. And a convex lens-like curved surface of the shoulder portion is a curved surface that collects incident light rays and radiates them in parallel to the direction of the reflecting mirror. It is a structure.

[Operation] As an example of the light emitting diode structure of the present invention, as shown in the sectional view of FIG. 1, the outer surface of the mold portion 26 of the organic polymer mold light emitting diode 2 is formed into a convex lens-like curved surface. It is formed of a substantially dharma-shaped portion composed of a top portion 261 and a shoulder portion 264, and a remaining lower portion 263. In addition, the convex lens-like curved surface of the shoulder 264 is
It is formed in a curved surface so that the emitted light beam from 1 is condensed and emitted parallel to the direction of the reflecting mirror 32. With such a curved surface, the light rays directed to the outer surface of the apex 261 are condensed and refracted by the curved surface and are radiated forward (the direction perpendicular to the substrate 1), and the light rays directed to the outer surface of the shoulder portion 264 are also concerned. The light is condensed and refracted on the curved surface and is emitted parallel to the direction of the reflecting mirror 32. Therefore, it is sufficient to simply reflect the parallel rays, and therefore the reflecting mirror 32 may be a conical one having no curved surface.

Of the light rays incident on the outer surface of the shoulder 264 in FIG. 1,
A ray incident on a portion near the boundary point a between the apex 261 and the shoulder 264 is refracted downward (closer to the light emitting diode 21) at an angle of θ as shown in the figure, and as a result, the height h of the reflecting mirror 32 is increased. ₂ can be made lower than the height h ₁ of the reflecting mirror 31 in FIG. 2 (obviously, the same luminous intensity can be obtained even if the height is lowered).

[Examples] Hereinafter, a light emitting diode structure of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view of an embodiment of the present invention, in which 1 is a substrate, 2 is a number of organic polymer mold light emitting diodes mounted on the substrate 1 in a grid pattern in a matrix. Is a reflector.

The substrate 1 is made of, for example, glass, ceramic, or an organic polymer (epoxy, glass epoxy, etc.).

The structure of the organic polymer-molded light emitting diode 2 will be described. The light emitting diode 21 is die-bonded to the central recess of the lead frame electrode 22 which has been subjected to silver plating and which exhibits conductivity, with a conductive epoxy resin adhesive. . Further, the light emitting diode 21 is wire-bonded to the upper protruding end of the lead terminal 23 of the positive electrode + using a wire 25 such as gold. The lead frame electrode 22 is connected to the lead terminal 24 of the negative electrode. The light emitting diode 21 having the lead terminals 23 and 24 has a mold portion 26 molded with an organic polymer having an excellent light transmitting property, for example, clear epoxy.

The mold portion 26 is formed of a substantially dharma-shaped portion having a top portion 261 and a shoulder portion 264 each having an outer surface formed into a curved surface having a convex lens shape, and a remaining lower portion 263. As described above, the convex lens-like curved surface of the shoulder portion 264 is formed into a curved surface that collects the light emitted from the light emitting diode 21 and radiates it in parallel to the direction of the reflecting mirror, that is, the shoulder portion 26.
The curved surface of the outer surface of No. 4 is formed with a radius r ₂ such that the curved surface is formed. If the curved surface of the outer surface of the top portion 261 is also formed in this way, it is more effective to effectively radiate light rays to the front surface. It should be noted that the term “parallel” used in the present specification is not limited to a completely parallel state, but includes a state of being substantially parallel. Further, the description of the state of the light beam is the state of the light beam on one section of the light emitting diode structure of the present invention.

FIG. 3 is a sectional view showing another embodiment of the present invention,
The convex lens-like curved surface of the shoulder portion 264 is formed as a curved surface having a radius r ₃ having a center point on a straight line connecting the boundary point a between the shoulder portion 264 and the top portion 261 and the existing position point of the light emitting diode 21. With such a curved surface, among the light rays incident on the outer surface of the shoulder portion 264, the light rays incident on the portion close to the point a are substantially straight toward the reflecting mirror 32 without being refracted. Further radius r
₃ is selected to have a curved surface such that a light ray that enters other than near the point a is refracted and emitted in parallel with a light ray that enters near the point a and is not refracted. That is, shoulder 264
The light rays emitted from the light beams travel in parallel to the conical reflecting mirror 32.

FIG. 4 shows a diagram in which the light emitting diode structure according to the present invention shown in FIG. 3 and the conventional light emitting diode structure shown in FIG. 2 (indicated by a dotted line in the figure) are superimposed and compared. There is. Light rays incident on the shoulders 262 and 264 near the point a go straight without refraction, are reflected by the conical reflecting mirror 32 at the point b in the structure of the present invention, and are reflected by the parabolic reflecting mirror 31 in the conventional structure. It will be reflected at point c. This c
To become parallel to the line of the cross section of the tangential line X-X and the conical reflector 32 at the point, the opening diameter d ₃ and a height h ₃ of the reflecting mirror 32 in the structure of the present invention, the reflection in the conventional structure It can be made much smaller than the aperture diameter d ₁ and the height h ₁ of the mirror.

The light-emitting diode 21 may be a commercially available one, and its emission color is not particularly specified. For example, when it is used for a stop lamp of an automobile, it is red, and when it is a turn signal lamp or an interior light, it is yellow or green. For the signal light, a desired light emission color such as green may be selected according to the application. Therefore, from the viewpoint of satisfying the high standards of JIS and SAE, it is preferable to use one having as high a luminance as possible. As an example thereof, as a light emitting diode used in a structure of the light emitting diode structure of the present invention for a stop lamp of an automobile, Japanese Patent Application No.
It is preferable to use the light-emitting diode described in the specification of No.-92895, that is, an active layer having a carrier concentration of 10 ¹⁵ to 10 ¹⁹ / cm ³ and a double hetero structure.
The light-emitting diode described in the above specification can obtain high light-emission brightness at a lower voltage than a normal light-emitting diode, and the low voltage can reduce the amount of heat generation and the defect in the light-emission brightness in the chip, which enables mass production. The cost can be reduced and it is suitable for the light emitting diode structure of the present invention.

The reflecting mirror 32, which mainly plays the role of radiating the emitted light from the shoulder portion 264 to the front, efficiently reflects the light emitted from the light emitting diode 21 and condenses the light to the front of the reflecting mirror 32 (direction perpendicular to the substrate 1). ) That emits as a focused light, various structures can be used without particular limitation (such as a parabolic reflector), but the light emitting diode structure of the present invention has a shoulder as described above. Part 264
Since the rays emitted from are parallel rays, it is not necessary to use a pabola reflecting mirror having a curved surface. It is sufficient to simply reflect the rays, so a conical shape without a curved surface is sufficient for efficient light rays. Can be radiated to. Again reflector
32 is made of, for example, glass or synthetic resin on which metal such as gold, silver, aluminum, nickel, chromium, zinc, tin, etc. is vapor-deposited or plated, or a mirror-finished stainless plate or aluminum plate. can do.

When this light emitting diode structure is actually used for a high mount stop lamp of a car, as shown in FIG. As shown in the figure, it is installed in the casing 5 of the high-mount stop lamp and mounted in a position where it can be easily seen from the rear of the automobile through the rear window glass in the interior of the automobile. In this case, as long as the light emitted from the red diffusion cover 4 is red, the emission color of the light emitting diode and the color of the diffusion cover are not particularly limited. For example, even if a red light emitting diode and a red diffusion cover are used. However, when the red light emitting diode is used, it is not always necessary to use the red diffusion cover, and for example, a colorless diffusion cover may be used.

[Effects] The light emitting diode structure of the present invention has been proposed by the applicant of the present invention and has a significantly improved luminous intensity as compared with the prior art.
It is an invention made to make the light emitting diode structure described in the specification of 61-177434 more practical, and has the following advantages over the invention described in the above specification.

The reflecting mirror 32 does not need to have a parabolic shape, which requires a particularly high molding die cost, and a conical shape is sufficient, so that the manufacturing cost is low.

Since the same luminous intensity can be obtained even if the height of the reflecting mirror 32 is made lower than the conventional height, the structure itself can be made thin.

The aperture diameter of the reflecting mirror 32 can be made smaller than the conventional aperture diameter, and the light emitting diodes 21 can be arranged at high density. That is, the same luminous intensity can be obtained even if the structure itself is made small.

The light emitting diode structure of the present invention having the above advantages is extremely practical since it can be constructed inexpensively, and the structure itself can be made small and thin, particularly when used for a high mount stop lamp. In addition, it is a useful item that is suitable for the so-called light, thin, short, and small trends that are enjoyed in modern society.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the light emitting diode structure of the present invention, and FIG. 2 is a sectional view of a conventional light emitting diode structure.
FIG. 3 is a sectional view of another embodiment of the light emitting diode structure of the present invention, FIG. 4 is a comparative view in which the light emitting diode structures shown in FIGS. 2 and 3 are overlapped, and FIG. 6 is a sectional view of the structure shown in FIG. 1 when a red diffusion cover is attached for use in a high-mounted stop lamp of an automobile,
The drawing is a perspective view of the structure shown in FIG. 5 when incorporated into a casing of a high mount stop lamp of an automobile. 1 ... Substrate, 2 ... Organic polymer mold light emitting diode, 21 ... Light emitting diode, 26 ... Mold part, 261 ...
… Top, 262,264 …… Shoulder, 31,32 …… Reflector.

Claims (5)

[Claims] 1. A light-emitting diode structure in which light-emitting diodes molded with a translucent organic polymer are arranged on a plane with a reflecting mirror for reflecting emitted light rays on the front surface. The molded light-emitting diode has a shape having a portion having a substantially dharma shape composed of at least two parts of a top portion and a shoulder portion each having an outer surface formed in a convex lens-like curved surface, and the convex lens-like curved surface of the shoulder portion is,
A light-emitting diode structure having a curved surface that collects incident light rays and radiates the light rays in parallel to the direction of the reflecting mirror. 2. The convex lens-like curved surface of the shoulder portion is a curved surface having a center point of a diameter on a straight line connecting the boundary point between the shoulder portion and the top portion and the existing position point of the light emitting diode. The light emitting diode structure according to claim (1). 3. The light emitting diode according to claim 1, wherein the active layer has a carrier concentration of 10 ¹⁵ to 10 ¹⁹ / cm ³ and has a double hetero structure. Light emitting diode structure. 4. The light emitting device according to claim 1, wherein the reflecting mirror has a conical shape in which an opening area of the organic polymer mold light emitting diode is enlarged toward the upper side. Diode structure. 5. The light emitting diode structure according to any one of claims (1) to (4), wherein the light emitting diode structure is an automobile stop lamp.