JP3369896B2 - LED display and signal light using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LED display using a light emitting diode and a signal light using the same, and particularly, an LED display in which a display pattern, visibility, etc. do not largely change even when a viewer moves. And a signal lamp using the same.

[0002]

2. Description of the Related Art Today, a traffic light generally uses an incandescent lamp as a light source. The signal lamp displays each color by irradiating the light of the incandescent lamp through the red, yellow, and blue color filters. In such a traffic light,
When sunlight is emitted from a low position such as in the morning or in the evening, outside light passes through the color filter and enters the inside of the traffic light, is reflected by the reflection mirror provided in the rear part of the incandescent lamp, and is emitted outside the traffic light. In this case, even a signal lamp in which the incandescent lamp is not lit seems to be shining. Further, there is a problem that a pseudo lighting phenomenon occurs such that it becomes difficult to visually recognize which color is lit.

On the other hand, in recent years, a light emitting diode capable of emitting light with an extremely high brightness of 1000 mcd has been developed. A semiconductor light emitting element used for a light emitting diode emits a monochromatic peak wavelength having a narrow spectral width. Therefore, when an LED display using a light emitting diode is used for a signal, it is not necessary to use a color filter, and the pseudo lighting phenomenon as described above does not occur. Further, when the LED display unit using the light emitting diode is used for signals, the signal incandescent light bulb can have a low power consumption of 20 W or less with respect to the power consumption of 60 W to 70 W.

Further, maintenance-free operation, in which the number of times of exchanging the light-emitting portion is small, is a very important factor for a traffic signal in consideration of workability and the like. However, signal bulbs should be used at voltages between 80% and 90% of the rated voltage.
Although the service life is extended to around 00 hours, the usage limit of the signal light bulb is set not to exceed two years. The stop signal, which has a high degree of importance, is replaced in about 7 months.

Since a signal lamp using light emitting diodes uses several hundred light emitting diodes for one lamp, there is almost no problem even if one or two light emitting diodes are not lit. Therefore, it can be used until the end of its life, and can be used for 50,000 hours or more. Due to these advantages, a traffic light using an LED display is considered promising.

[0006] Such a traffic signal or the like is usually placed at a position higher than a viewer and sometimes needs to be visible while moving. Specifically, the vehicular traffic light is usually installed at a certain height above the ground. In addition, the viewer visually recognizes the traffic light even when moving. As described above, it is necessary that the lighting / non-lighting is confirmed and the display shape does not change even when the viewer or the like moves. However, L using a light emitting diode
When using the ED display, the visibility may suddenly deteriorate as it approaches the LED display.

A light emitting diode used in such an LED display has a structure having a semiconductor light emitting element and a mold member which functions as a lens for condensing light from the semiconductor light emitting element. Therefore, in order to improve the visibility at the time of movement, it can be relaxed to some extent by changing the shape of the mold member forming the light emitting diode. Specifically, the LED display uses a light emitting diode having a mold member having a wide directional angle lens shape. As a result, the visibility can be improved to some extent when moving.

[0008]

However, a light emitting diode having a wide directivity angle is arranged on a cup of a mount lead which constitutes the light emitting diode when the half value angle is deviated.
Only a small amount of light emitted directly from the ED chip can be observed. Therefore, even if an LED display is constructed using a light emitting diode having a wide half-value angle, if it deviates from the half-value angle, there is a problem in that it suddenly becomes dark. In view of the above problems, the present invention is to provide an LED display device which is less likely to be deformed in display shape or to be abruptly darkened even when the LED display device is moved and visually recognized.

[0009]

The present invention is an LED display in which two or more kinds of light emitting diodes are arranged, and the first light emitting diode in which the light emitting diode covers at least the LED chip with a molding member and the LED chip A second light emitting diode which is covered with a mold member, has a narrower angle than the directivity angle of the first light emitting diode, and emits more light in the direction perpendicular to the optical axis than the first light emitting diode at the tip of the mold member. An LED display,
The light emitting diode is arranged on a substrate, the height from the substrate surface side to the tip of the molding member of the first light emitting diode is lower than the height of the tip of the molding member of the second light emitting diode, and LE of the first light emitting diode
In the LED display, the height of the D chip is higher than the height of the LED chip of the second light emitting diode. The invention according to claim 2 is an LED display in which the first and second light-emitting diodes are arranged in substantially the same shape as viewed from the light emission observation surface side of the LED display. The invention described in 3 is an LED display in which the emission wavelengths of the first and second light emitting diodes are substantially the same. Preferably, the half-value angle of the first light emitting diode is 25 degrees.
From 60 degrees, the half value of the second light emitting diode
Any LED display having an angle of 5 to 20 degrees may be used.

Further, in a signal lamp in which two or more kinds of light emitting diodes are arranged in the housing, the light emitting diode has a half value angle of point emission near the LED chip when observed from a side surface direction deviating from at least the half value angle. A wide first light emitting diode, and a second light emitting diode that emits light in the vicinity of the LED chip and in the vicinity of the tip portion of the molding member when observed from a side surface side direction narrower than the half value angle of the light emitting diode and deviating from the half value angle, Is a signal lamp having.

[0011]

The present invention utilizes a light emitting diode in which an LED chip, which is a semiconductor light emitting element, is covered with a mold member having a lens effect, and emits point light when observed from the lateral side direction outside the half-value angle of the light emitting diode. And an LED display utilizing the fact that its luminous intensity changes depending on the shape of the mold member. That is, the light from the LED chip is condensed by the lens effect of the molding member and is emitted to the outside. On the other hand, of the light emitted to the outside, the light toward the side surface of the mold member is not emitted to the light emission observation surface side but is emitted to the outside as it is. Such light is extremely weak because it is not collected. This light can be totally reflected because the side surface of the mold member is tapered and there is a difference in refractive index between the surface of the mold member and the outside. The totally reflected light is collected and emitted from the tip of the mold also in the direction perpendicular to the optical axis direction. It is considered that the increase in the amount of light emitted in the lateral direction causes the mold member to appear to emit light as if the LED chip were arranged even at the tip portion thereof.

Therefore, when observing the light emitting diode emitting light in the vicinity of the tip of the mold member from the side direction, the visibility is better than that of the light emitting diode having no or small focus near the tip. Moreover, it is possible to effectively use the light that was originally useless. Therefore, when observing the LED display from outside each half-value angle, by utilizing the characteristics of this light emitting diode, the visibility is improved.
It can be an ED display device.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION As a result of various experiments,
The specific shape of the mold member can confirm remarkable point emission near the cup where the LED chip is arranged and the tip of the mold member, and by utilizing this, it is possible to suppress a sharp decrease in luminance outside the half-value angle such as during movement. As a result, the present invention has been completed.

That is, it is an LED display device in which a sharp decrease in luminance outside the half-value angle is suppressed by utilizing light that emits light in the vicinity of the LED chip or the like. The present invention uses a light emitting diode having a wide directional angle to confirm lighting up to a certain distance, and at the observation points deviating from the half-value angle of the light emitting diode, the number of light emitting points of the light emitting diode is increased. By doing so, a sharp decrease in brightness is prevented. Specifically, there are two types: a light emitting diode having a wide directional angle and a light emitting diode having a narrower half-value angle than that and emitting light at the tip of the mold member.
By constructing an LED display device using more than one type, it is possible to obtain an LED display device with significantly improved visibility when moving.

A light emitting diode having a wide directional angle is shown in FIG.
As shown in (A), even when the user visually recognizes the movement toward the LED display, light emission can be confirmed with high brightness over a wide range for a relatively long time (near the LED display). However, in the observation from the side surface side direction deviating from the half-value angle of the light emitting diode, it seems that only the point emission is confirmed in the vicinity of the LED chip and the light emission luminance is sharply reduced.

On the other hand, a light emitting diode having a narrow directional angle has a narrow directional angle, and therefore, has a relatively short time (far from the LED display).
The brightness decreases at, and when it deviates from the half-value angle, it becomes dark rapidly like a light emitting diode having a wide directional angle. However, unlike a light emitting diode having a wide directional angle as shown in FIG. 3 (B), a light emitting diode having a certain directional angle emits point light not only in the vicinity of the cup where the LED chip is arranged but also in the tip of the mold member. . Therefore, the specific light-emitting diode having a narrow directional angle with respect to the light-emitting diode having a wide directional angle causes less rapid decrease in luminance than the light-emitting diode having a wide directional angle when observed from the side surface side direction deviating from the half-value angle. Therefore, according to the present invention, it is possible to prevent a sharp decrease in luminance during movement or the like by increasing the number of point emission points when observing from the side surface side deviating from the directivity angle of the light emitting diode.

More specifically, the first light emitting diode having a wide directivity angle with a half value angle of about 30 degrees and the second light emitting diode having a narrower half value angle and a half value angle of about 10 degrees than the first light emitting diode. Light emitting diodes of 260 and 160, respectively.
The individual substrates are arranged in a circular shape, which is substantially the same shape. Each light emitting diode 101 is electrically connected to the conductive pattern of the substrate 102 by using an automatic soldering device on the back surface of the substrate 102 (note that each light emitting diode has substantially the same emission wavelength). ing.). After connecting the substrate 102 on which each light emitting diode 101 is arranged and the driving substrate 103 for driving each light emitting diode, the substrate 102 is fixed in the housing 104 in which the resin lens 105 is formed. The wiring 106 electrically connected to the LED display in the housing 104 extends to the outside. Power is supplied to the LED display using the wiring 106 extending to the outside,
It is possible to provide an LED display having light emission characteristics such as the light intensity and the brightness uniformity which satisfy the vehicle traffic signal as shown in FIG. FIG. 4 is a diagram in which a luminance meter is installed at a position 10 m away from the center of the LED display, and the relative luminous intensities in the downward direction and the right and left angles from the center are measured. The thick line indicates the LED display of the present invention, and the thin line indicates the standard of the vehicular traffic signal.

Such an LED display has the first and second LED displays.
Even at the observation position deviating from the half-value angle of the light emitting diode, the number of point light emitting portions does not cause a sharp decrease in luminance. Further, by disposing the first light emitting diode and the second light emitting diode in substantially the same shape, an LED display device can be configured in which the point light emission looks the same during movement and the display shape is not destroyed. it can. Hereinafter, each configuration of the present invention will be described in detail.

(Light Emitting Diode 101) The structure of the light emitting diode 101 used in the present invention is at least an LED chip 301 which is a semiconductor light emitting element, and mold members 311 and 312 having a lens effect for focusing light from the LED chip 301. , Is composed of.
Further, the light emitting diode includes at least a light emitting diode having a wide directional angle and a light emitting diode having a directional angle narrower than that of the light emitting diode and observing from the side surface so that the light emitting point is near the LED chip and at the tip of the mold member which is the lens focus. Two or more types are used. Various semiconductors are preferably used for the semiconductor light emitting element used in such a light emitting diode. Specifically, GaAlN, ZnS, ZnSe, Si are formed on the substrate by a liquid phase growth method or a MOCVD method.
C, GaP, GaAs, GaAlAs, GaAlP, G
aAsP, AlInGaP, InGaN, GaN, Al
Preferable examples are those in which a semiconductor such as InGaN, InN, or AlN is formed as a light emitting layer. Examples of the semiconductor structure include a MIS junction, a homo structure having a PIN junction or a PN junction, a hetero structure, or a double hetero structure. Further, the emission wavelength can be variously selected from ultraviolet light to infrared light depending on the material of the semiconductor and the degree of mixed crystal thereof. Further, the light emitting layer may have a single quantum well structure or a multiple quantum well structure in order to have a quantum effect.

LED in a place where external light is relatively strong, such as outdoors
When a display is used, it is preferable to use gallium nitride-based compound semiconductors for the green and blue colors. Also,
It is preferable to use gallium-aluminum-arsenic-based semiconductors or aluminum-indium-gallium-phosphorus-based semiconductors for red and yellow systems.

As a concrete light emitting diode, an LED is used.
The chip is fixed to the mount lead cup by die bonding, and the positive and negative electrodes or one electrode of the LED chip and the inner lead are electrically connected by a conductive wire such as gold wire, platinum or aluminum wire. . When the conductive wire is used only for the electrode of one polarity, the LED chip is fixed with a conductive paste in which a conductive material such as Ag, C, ITO or SnO2 is mixed with a resin binder, and the mount lead is mounted. And make an electrical connection. Next, L where electrical continuity was taken
In order to protect the ED chip, the metal wire for electrical connection thereof, and the like from the force and moisture from the external environment, the ED chip is covered with a mold member to form a light emitting diode.

(Molding Members 311 and 312) The molding members 311 and 312 used in the present invention can be selected in various shapes according to desired light emitting characteristics. In general, by selecting the mold member of the light emitting diode, the front luminous intensity decreases as the directivity angle increases. On the other hand, as the directivity angle is narrowed, the front luminous intensity tends to be improved. By thus forming the mold member into a desired shape, it is possible to provide a lens effect of converging or diffusing the light emitted by the LED chip 301. In particular, in the present invention, by selecting the mold member, not only the control of the directivity angle and the front luminous intensity but also the point emission as viewed from the side surface deviating from the half-value angle is controlled.
Therefore, various shapes such as a perfect circle and an ellipse can be formed when viewed from the side of the light emission observation surface of the light emitting diode as long as it has a lens effect and can control the point emission from the side surface outside the half-value angle. The mold member may be in direct contact with the LED chip or may simply cover it as long as it has a lens effect and a protective function. As a material for such a mold member, a transparent resin having excellent weather resistance such as an epoxy resin or a urea resin, or glass is preferably used. Further, the mold member constituting the light emitting diode may contain various additives such as a diffusing agent, a colorant, a light stabilizer and a fluorescent substance, if desired.
As a result, it is possible to adjust the light emission peak from the LED chip, relax the directivity, and increase the viewing angle. Alternatively, a light emitting diode having a desired emission wavelength can be used. Furthermore, the light emitting diode can be weather-resistant even when used outdoors.

As the diffusing agent, barium titanate, titanium oxide, aluminum oxide, silicon oxide and the like are preferably used. The colorant is included in the mold member and has a filter effect of cutting out an undesired wavelength of the light emitted by the LED chip to improve the light emission characteristics. Therefore, various dyes and / or pigments are variously selected according to the emission color of the light emitting diode (main emission wavelength which is the main peak of emitted light).

Since the light emitted from the semiconductor light emitting device has a monochromatic peak wavelength, it is possible to form a light emitting diode displaying a white color by combining it with a fluorescent substance or the like. In this case, by using a blue gallium nitride-based compound semiconductor with a large emission wavelength energy and a ytrim / aluminum oxide-based fluorescent material added with cerium or a fluorescent material that is a perylene-based derivative, it is possible to achieve high brightness efficiently. It can emit light.

Further, the colorant, the diffusing agent, the light stabilizing member, the fluorescent substance and the like may be dispersed in the mold member in various proportions, if desired. That is, the content concentration can be increased or decreased as it approaches the LED chip, and various selections can be made. Such a mold member is a tip of an LED chip arranged on a mount lead in a mold that can be formed into a desired mold member shape such as a bullet shape after mixing and stirring various additives in the raw material of the mold member. It can be formed by putting together with a part and curing.

In order to use an LED chip as a light emitting diode capable of full-color light emission, a red light emission wavelength is 600 nm to 700 nm, a blue light emission green light wavelength is 495 nm to 565 nm, and a blue light emission wavelength is 430 nm.
It is preferable to use an LED chip using a semiconductor of nm to 490 nm.

In the present invention, the point emission and the directional angle in the observation from the side surface side deviating from the directional angle are the LED chip surface (the cup surface when the LED chip is arranged in the cup of the mount lead) from the mold member. Can be variously controlled by the distance to the tip of the mold member, the lens curvature of the mold member, and the side surface shape in the cross section of the mold member.

The tip portion of the mold member in the present invention is located substantially at the lens apex of the mold. In such a tip portion, as shown in FIG. 3B, the light emitted from the LED chip is totally reflected by the difference in the refractive index of the molding member, further refracted at the lens apex, and emitted in a direction other than the direction parallel to the optical axis. By selecting the shape or the like of the molding member, the tip portion of the molding member emits light as if the LED chips were also arranged in the tip portion of the molding member. In addition, the directivity angle means an angle representing the spread of the emitted light with respect to the optical axis. The half-value angle is a value obtained by expressing the width of the distribution corresponding to ½ of the maximum value in the distribution curve of luminous intensity as an angle with respect to the optical axis. If a shell-shaped mold member is used, a light emitting diode having a wide FWHM and a narrow FWHM can be obtained. Further, the phrase "out of half-value angle" refers to a portion outside the half-value angle with respect to the optical axis, where the luminous intensity sharply decreases.

(Mount Lead 302) As the mount lead 302, the LED chip 301 is arranged, and it is sufficient that the mount lead 302 has a size large enough to be loaded by a die bond device or the like. Further, when a plurality of LED chips 301 are installed and the mount leads 302 are used as a common electrode of the LED chips 301, sufficient electrical conductivity and connectivity with bonding wires and the like are required. In addition, LE is placed in the cup on the mount lead 302.
When the D chip is arranged and the inside of the phosphor is filled, it is possible to prevent the pseudo lighting by the light from another light emitting diode arranged in close proximity.

LED chip 301 and mount lead 3
Bonding of No. 02 with the cup can be performed with a thermosetting resin or the like. Specifically, an epoxy resin, an acrylic resin, an imide resin, or the like can be given. In addition, an Ag paste, a carbon paste, a metal bump, or the like can be used in order to adhere to and electrically connect to a mount lead with a face-down LED chip or the like.
Further, in order to improve the light utilization efficiency of the light emitting diode, the surface of the mount lead on which the LED chip is arranged may be mirror-finished and the surface may have a reflecting function. In this case, the surface roughness is preferably 0.1 S or more and 0.8 S or less. The specific electric resistance of the mount lead 302 is preferably 300 μΩ · cm or less, more preferably 3 μΩ · cm or less. In addition, when a plurality of LED chips are stacked on the mount lead, the amount of heat generated from the LED chips is large, and thus the thermal conductivity is required to be good. Specifically, 0.01 cal / cm ² / c
m / ° C or higher is preferable and more preferably 0.5 cal /
It is at least cm ² / cm / ° C. Examples of materials satisfying these conditions include iron, copper, iron-containing copper, tin-containing copper, and ceramics with a metallized pattern.

(Inner Lead 303) As the inner lead 303, the connection between the LED chip 301 arranged on the mount lead 302 and the conductive wire 304 connected thereto is intended. Mount lead 3
When a plurality of LED chips 301 are provided on 02, it is necessary to have a configuration in which the conductive wires 304 can be arranged so as not to contact each other. Specifically, as the distance from the mount lead increases, the area of the end surface of the inner lead to be wire-bonded increases in order, or the height of the end surface increases in order to connect to the inner lead that is farther from the mount lead. It is possible to prevent the contact of the conductive wire. Roughness of the connection end face with the conductive wire is 1.6 S or more in consideration of adhesion.
It is preferably 0S or less. In order to form the tips of the inner leads into various shapes, the lead frame shape may be preliminarily determined by a mold and punched out, or after all the inner leads are formed, the inner lead upper portion is formed. It may be formed by cutting a part of the. Furthermore, after the inner lead is punched and formed, a desired end face area and end face height can be simultaneously formed by applying pressure from the end face direction.

The inner lead is required to have good connectivity and electrical conductivity with a bonding wire or the like which is a conductive wire. Specific electrical resistance is 3
00 μΩ · cm or less is preferable, and more preferably 3 μΩ
・ It is below cm. Examples of materials that satisfy these conditions include iron, copper, iron-containing copper, tin-containing copper and copper, gold-plated aluminum, iron, and copper.

(Conductive Wire 304) The conductive wire 304 is required to have good ohmic contact with the electrodes of the LED chip 301, mechanical connectivity, electrical conductivity and thermal conductivity. The thermal conductivity is 0.01 cal /
cm ² / cm / ° C. or higher is preferable, and more preferably 0.
It is 5 cal / cm ² / cm / ° C. or higher. Also, the diameter of the conductive wire in consideration of workability, preferably,
Φ10 μm or more and Φ45 μm or less. Specific examples of such a conductive wire include a conductive wire using a metal such as gold, copper, platinum, or aluminum, or an alloy thereof. Such conductive wire is used for each LE.
The electrodes of the D chip and the inner leads and mount leads can be easily connected by a wire bonding device.

(Substrate 102) The substrate 102 is preferably used for arranging the light emitting diodes 101 in a desired shape and electrically connecting them. Such a substrate 102 may be used not only as an arrangement of the light emitting diodes but also as a substrate 103 for a driving circuit. Therefore, the substrate 102
Is preferably high in mechanical strength and less in thermal deformation.
Specifically, ceramics such as copper foil on which a conductive pattern is formed, glass epoxy resin, metal or alloy having an insulating layer on its surface, and the like can be preferably used. Since the surface of the substrate on which the light emitting diode is mounted coincides with the display surface of the LED display, it may be colored dark brown or black for improving the contrast. Moreover, you may make it uneven | corrugated in order to improve the adhesiveness with a filler. The substrate may be omitted by directly connecting the lead frames of the light emitting diode.

When the LED indicator is used as a traffic light, two or more circuits may be provided to improve reliability. In this case, even if one of the circuits is turned off due to disconnection or the like, it is necessary to turn on the display without causing a large change in the display shape. As the arrangement of the light emitting diodes 101, it is preferable to arrange the light emitting diodes on the substrate 102 in a spiral shape drawing an outer garden from the center. In addition, it is preferable that both the first light emitting diode and the second light emitting diode according to the present invention are provided for each circuit so that the display shape does not change significantly even during movement. Therefore, even in this case, it is more preferable that the first light emitting diode and the second light emitting diode are arranged in substantially the same shape.

(Case 104) As the case 104, an LED display in which each light emitting diode 101 is arranged is mechanically protected from the outside, and various shapes and shapes can be formed. It can be used preferably in the present invention. It is more preferable that the housing 104 is provided with a lens 105 that further collects the light of the light emitting diode. Since the casing 104 may be exposed to the external environment, the condenser lens 105 and the casing, the opening of the electric cord 106 for electrically connecting the casing and the light emitting diode to prevent water and dust from entering. And are preferably sealed with packing. Further, it is possible to form an opening for circulating the air inside the housing in which the light emitting diode 101 is arranged or for discharging the air to the outside.

The casing 104 is the light emitting diode 101.
Those having a small coefficient of thermal expansion are preferred because they are affected by heat from the above. Further, it is desirable to use a material that can be easily molded because it is formed into a desired shape. Specific examples of the material for such a casing include polycarbonate resin and ABS.
Various resins such as resin, epoxy resin and phenol resin, aluminum and alloys thereof are preferable.

When the power source for driving the light emitting diode 101 is an alternating current, a rectifying circuit may be provided in the housing to serve as a power source for the LED display. Further, in the LED display provided with two or more circuits, when the light emitting diodes connected in parallel cannot be lit, it is possible to provide a control circuit for detecting the power change of the light emitting diode group and detecting an abnormality. . In particular, when one of the circuits connected in parallel is broken, a large amount of power flows to the other circuit, so that the brightness is improved. Therefore, it is preferable to set the allowable amount of the light emitting diode in consideration of the increase in current. Hereinafter, specific examples of the present invention will be described in detail, but it goes without saying that the present invention is not limited thereto.

[0039]

【Example】

Example 1 As a LED chip used for a light emitting diode, a blue-green light emitting diode (emission wavelength 495 nm) having a light emitting layer of InGaN was used. The light emitting diode is LE on the mount lead via epoxy resin.
The D chip is die bonded. Each electrode of the LED chip and the mount lead and the inner lead are electrically connected by wire bonding with a gold wire.

Thereafter, two types of shell-shaped cups were prepared, the tip of the lead terminal on which the LED chip was arranged was placed in each cup, and epoxy resin was injected. After the injection, the epoxy resin was cured to form a mold member, and the first and second light emitting diodes of the present invention were formed. The first light emitting diode thus formed was a light emitting diode having a wide half-value angle, as shown in FIG. 3 (A). In this first light emitting diode, the distance between the tip of the mold member and the LED chip is 4.3 mm, and the half-value angle is about 30 degrees. When the first light emitting diode is caused to emit light and observed from the side surface direction outside the directional angle, it can be confirmed that point emission occurs in the vicinity of the LED chip.

On the other hand, the second light emitting diode is shown in FIG.
As shown in (B), the directivity angle is narrower than that of the first light emitting diode. In addition, the front end of the mold member and the L end so that the light from the LED chip is also emitted from the front end of the mold in a substantially lateral direction.
The distance to the ED chip is 5.5 mm and the half-value angle is 10
There is a degree. When the second light emitting diode was made to emit light and observed from the side surface direction outside the half-value angle, it was confirmed that point emission was performed near the LED chip and at the tip of the mold member.

Such first and second light emitting diodes are arranged on the substrate as shown in FIG. The placement on the board is
Even if only the first light emitting diode is lit, it is arranged so that it can emit light in a substantially circular shape. Similarly, even if only the second light emitting diode is turned on, the second light emitting diode is arranged so that it can emit light in a substantially circular shape. Further, the height from the substrate to the LED chip is higher in the first light emitting diode than in the second light emitting diode, and the mold tip is higher in the second light emitting diode than in the first light emitting diode. It is arranged.

Each light emitting diode 101 and each substrate 10
Power cord 106 to connect external power from 2, 103
Each of them was connected with solder and then fixed in the housing. On the display surface of the housing, a white lens is provided on the display surface side of the LED display in order to further collect light from the LED display. In addition, the electrical wiring of the LED display was sealed from the inside of the housing through rubber packing from the back surface of the housing.

The LED display thus formed has a light emission observation surface side (mold) when the LED display in which the first and second light emitting diodes are arranged is viewed from the side surface side direction deviating from each half-value angle. Point emission from the tip of the second light emitting diode from the direction of the tip of the member) to the substrate side.
Next, point emission near the LED chip of the first light emitting diode. Furthermore, point emission near the LED chip of the second light emitting diode is sequentially observed. Therefore, the brightness in the lateral direction is larger than that of an LED chip in which a light emitting diode is simply arranged, and the brightness does not sharply decrease even at an angle away from the directivity angle. Further, since the first and second light emitting diodes are respectively arranged in a substantially circular shape, it is possible to provide an LED display in which the change in the light emitting shape due to movement or the like is extremely small. Further, by disposing the LED chip of the second light emitting diode having a narrow directional angle lower than that of the first light emitting diode having a wide directional angle when viewed from the substrate side, the directional angle emitted from the first light emitting diode is increased. It is possible to provide an LED display device capable of emitting light with high efficiency because there are few portions where the spread light is applied to the second light emitting diode.

[0045]

According to the structure of claim 1 of the present invention, the luminous efficiency is more excellent, the reliability of the LED display is improved, and the LED is visible even when it is viewed from outside the half-value angle of the light emitting diode due to movement or the like. It is possible to provide an LED display in which the light emission brightness of the display does not significantly decrease.

With the configuration of claim 2 of the present invention, an LED display in which the change in the display shape of the LED display does not greatly decrease the emission brightness even when viewed from outside the half-value angle of the light emitting diode due to movement or the like. can do.

[0047]

With the structure of claim 3 of the present invention, the LED display device does not change the display shape of the LED display device and the emission brightness does not significantly decrease even when viewed from outside the half-value angle of the light emitting diode due to movement or the like. Can be

[0049]

[0050]

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a traffic signal using an LED display device of the present invention.

FIG. 2 is a schematic plan view showing an LED display device of the present invention.

FIG. 3 is a schematic cross-sectional view of a light emitting diode showing an operation of the present invention, FIG. 3 (A) is a diagram in which a light emitting diode having a wide directional angle is turned on, and FIG. 3 (B) is FIG. 6 is a schematic cross-sectional view when a light emitting diode having a narrow directional angle and emitting light at the tip of the mold member is turned on.

FIG. 4 (A), FIG. 4 (B), FIG. 4 (C), FIG.
(D) represents the relative luminous intensities in the downward direction and the right and left angles from the front, the solid line represents the luminous intensity of the LED display device of the present invention, and the broken line represents the standard for vehicle signals.

[Explanation of symbols]

101 ... Light emitting diode 102 ... Substrate on which light emitting diodes are arranged 103 ... Driving substrate 104 ... body 105 ... Lens 106 ... electric cord 201 ... First light emitting diode 202 ... Second light emitting diode 203 ... substrate 301 ... LED chip 302 ... Mount lead 303 ... Inner lead 304 ... Gold wire 311, 312 ... Mold member

Claims (3)

(57) [Claims] 1. An LED display in which two or more types of light emitting diodes are arranged, wherein the light emitting diode has a first light emitting diode in which at least an LED chip is covered with a molding member, and the LED chip is covered with a molding member. The second light emitting diode is narrower than the directivity angle of the first light emitting diode and emits more light in the vertical direction with respect to the optical axis than the first light emitting diode at the tip of the mold member. In the LED display, the light emitting diode is arranged on a substrate, and the height from the substrate surface side to the mold member tip of the first light emitting diode is higher than the height of the mold member tip of the second light emitting diode. And the LE of the first light emitting diode
An LED display in which the height of the D chip is higher than the height of the LED chip of the second light emitting diode. 2. The first and second light emitting diodes are L
The LED display device according to claim 1, wherein the LED display devices are arranged in substantially the same shape when viewed from the light emission observation surface side of the ED display device. 3. The LED display according to claim 1, wherein the emission wavelengths of the first and second light emitting diodes are substantially the same.