JPH11162234A - Light source using light emitting diode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide various light distributions by a light source itself and to easily constitute a surface light source. SOLUTION: A plurality of light emitting diode elements 1 are arranged with an arrangement density according to a light distribution design. A surface light source can be easily provided by arranging the light emitting diodes 1. Further, since the arrangement density of the light emitting diode elements 1 is set according to the light distribution design, the light source itself is conformable to the light distribution design. The light emitting diode is desirably a bare chip.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source using a light emitting diode suitable for illumination and display.

[0002]

2. Description of the Related Art Generally, a light source used for illumination is a point light source or a line light source. For example, a point light source has a light distribution characteristic as shown in FIG. The horizontal axis of FIG. 16 represents the horizontal distance from the reference point taken vertically below the point light source, normalized by dividing the horizontal distance from the light source to the reference point.

As is apparent from FIG. 16, when illumination is performed only with a light source, the illuminance distribution on an irradiated surface is not uniform.
In general, an illumination device is configured by attaching a light source to an instrument including a light distribution control element such as a reflector or a lens. In addition, as a light source used for display, a surface light source capable of clearly recognizing display contents is necessary, but there is no surface light source such as a point light source or a line light source that can be easily obtained. In such a case, it is difficult to make the entire display content uniform brightness or to change the brightness for each region of the display surface according to the display content.

[0004]

However, as described above, the lighting apparatus requires a device having the light distribution control element, and thus has a problem that a relatively large device is required. Further, if the light distribution is to be changed, the lighting device must be replaced or the position of the lighting device must be changed, and it is not easy to change the lighting design after the lighting device is once installed.

As described above, surface light sources are not widely used, and there is a demand for inexpensive surface light sources for illumination and display. The present invention has been made in view of the above circumstances, and an object of the present invention is to use a light emitting diode that can obtain various light distributions by a light source itself and can easily constitute a surface light source. It is to provide a light source.

[0006]

According to the first aspect of the present invention, a plurality of light emitting diode elements are arranged at an arrangement density according to a light distribution design. According to this configuration, the surface light source can be easily obtained by arranging the light emitting diode elements, and the light source itself can be obtained by setting the arrangement density of the light emitting diode elements according to the light distribution design. It can respond to light distribution design. In other words, since a device having a light distribution control element is almost unnecessary, a relatively small illuminating device can be configured, and if a light source having a different arrangement density of light emitting diode elements is replaced,
Even after the construction, the light distribution can be easily changed.
Further, the light emitting diode element has the same or longer life as compared with a generally used light source such as an incandescent lamp or a fluorescent lamp, so that the number of replacements is reduced.

According to a second aspect of the present invention, in the first aspect, the light emitting diode element is a bare chip. According to this configuration, it is possible to obtain a light source with high luminance by increasing the arrangement density of the light emitting diode elements.
According to a third aspect of the present invention, in the first aspect of the invention, the arrangement density at the center of the arrangement range of the light emitting diode elements is made smaller than that at the periphery so that the illuminance on the irradiation surface is constant. According to this configuration, the illuminance on the irradiation surface becomes substantially uniform.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the arrangement density of the central portion of the arrangement range of the light emitting diode elements is larger than that of the peripheral portion. According to this configuration, the illuminance on the irradiation surface increases near immediately below, and illumination with partially increased illuminance becomes possible. That is, partial illumination such as a downlight or a spotlight becomes possible. Claim 5
According to the invention, each light emitting diode element is connected to each group so that a plurality of light emitting diode elements constitute a plurality of groups, and the lighting state of each light emitting diode element can be controlled for each group. According to this configuration, by performing lighting or dimming for each group,
It is possible to change the light distribution.

The invention according to claim 6 includes a plurality of light emitting diode elements, and a drive circuit connected to an output of a lighting circuit for a discharge lamp and lighting the light emitting diode elements. According to this configuration, illumination by a light-emitting diode element becomes possible by diverting an illumination device used for a normal discharge lamp such as a fluorescent lamp and replacing only the light source. That is, by providing the output of the lighting circuit to the driving circuit, the light emitting diode element can be stably lit without applying an overvoltage or flowing an overcurrent to the light emitting diode element.

According to a seventh aspect of the present invention, in the sixth aspect of the present invention, the drive circuit includes a power supply unit including a rectifier circuit connected to a lighting circuit, and a current supplied from the power supply unit to the light emitting diode element. And a current limiting element for limiting the pressure. According to this configuration, since the power supply unit is provided with the rectifier circuit, the output of the lighting circuit can be used with either DC or AC. In addition, it is possible to prevent an overcurrent from flowing through the light emitting diode element by the current limiting element.

According to an eighth aspect of the present invention, in the sixth aspect of the present invention, the driving circuit includes a power supply section including a rectifier circuit and a power factor improving means connected to a lighting circuit, and energizes the diode element from the power supply section. And a current limiting element for limiting the current to be applied, and the input characteristics of the power supply unit simulate the load characteristics of the discharge lamp. According to this configuration, since the input characteristics of the power supply unit simulate the load characteristics of the discharge lamp, there is no trouble in the lighting circuit even when the discharge lamp is used instead. In addition, by providing a rectifier circuit in the power supply unit, the output of the lighting circuit can be used in either DC or AC.Furthermore, since the power factor improving circuit is provided, the output of the lighting circuit is AC. The power use efficiency is high. Further, it is possible to prevent an overcurrent from flowing to the light emitting diode element by the current limiting element.

According to a ninth aspect of the present invention, in the invention of the eighth aspect, the load characteristic is a current-voltage characteristic during stable lighting of the discharge lamp. According to this configuration, the lighting circuit operates in the same manner as when the discharge lamp is stably lit, and the stress on the lighting circuit is small. According to a tenth aspect, in the ninth aspect, the discharge lamp is a fluorescent lamp. According to this configuration, a fluorescent lamp, which is a discharge lamp most frequently used in general lighting, is simulated. Therefore, a high economic effect is produced by replacing the fluorescent lamp with the fluorescent lamp.

According to an eleventh aspect of the present invention, in accordance with the eighth aspect of the present invention, the plurality of light emitting diode elements are connected to each other such that the plurality of light emitting diode elements form a plurality of groups. Can be controlled for each group. According to this configuration, it is possible to change the light distribution by performing lighting or dimming for each group.

According to a twelfth aspect of the present invention, there is provided a light guide plate for leaking light introduced from a light source disposed opposite to the peripheral surface of a plate-like body from at least one of the front and back surfaces, and a light emitting diode element serving as the light source. Things. According to this configuration,
A relatively inexpensive surface light source can be provided by a combination of a light guide plate and light emitting diode elements. Claim 13
According to a twelfth aspect of the present invention, in the twelfth aspect, a plurality of light emitting diode elements are arranged facing the peripheral surface of the light guide plate. According to this configuration, the brightness of each region of the light guide plate can be changed by the arrangement of the light emitting diode elements and the lighting control.

According to a fourteenth aspect, in the thirteenth aspect, light emitting diode elements of a plurality of luminescent colors are arranged. According to this configuration, the emission color of the light guide plate can be changed according to the emission color and arrangement of the light emitting diode elements. According to a fifteenth aspect of the present invention, in the illuminating device according to the thirteenth aspect, a display pattern is provided on at least one of the front and back surfaces of the light guide plate, and a portion of the display pattern having a larger amount of transmitted light has a larger amount of light leakage from the light guide plate. The light emitting diode elements are arranged in such a manner. According to this configuration, since the amount of leakage light from the light guide plate is increased in a portion of the display pattern where the amount of transmitted light is large, the contrast between a bright portion and a dark portion of the display pattern is emphasized so that the display pattern can be recognized. It will be easier.

According to a sixteenth aspect of the present invention, in the illuminating device according to the thirteenth aspect, a display pattern is provided on at least one of the front and back surfaces of the light guide plate, and the color of the colored portion in the display pattern and the light leaking from the light guide plate. A plurality of light-emitting diode elements of a plurality of emission colors are arranged so as to match the colors. According to this configuration, the color contrast can be emphasized in the colored display pattern, so that the display pattern can be easily recognized.

According to a seventeenth aspect, in the thirteenth aspect, the light output of each light emitting diode element is dimmed by dimming means. According to this configuration, the light intensity of the light guide plate can be adjusted by dimming the light emitting diode elements. According to an eighteenth aspect of the present invention, the plurality of light emitting diode elements are connected to each other so as to form a plurality of groups, and the lighting state of each light emitting diode element can be controlled for each group. . According to this configuration, it is possible to change the light distribution by performing lighting or dimming for each group.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) In this embodiment, as shown in FIG. 1, a plurality of light emitting diode elements 1 having diffuse light distribution characteristics are arranged on one plane. 1 indicates that the light-emitting diode elements 1 are arranged). The light emitting diode element 1 may have a lens or may be a bare chip. The light emitting diode elements 1 are arranged according to a sinusoidal rule so that the arrangement density changes in each region of the arrangement range. Here, the sinusoidal rule means that when the distance from the center of the arrangement range of the light emitting diode elements 1 is x, the density of the light emitting diode elements 1 is set so that a + sin (x / b · π) is satisfied. It is to be. Here, a and b are constants. The light distribution in this case is as shown by the solid line in FIG. FIG. 2 shows the distance to the irradiation surface parallel to the plane on which the light emitting diode elements 1 are arranged as a unit distance, and the distance from the reference point facing the center of the arrangement range of the light emitting diode elements 1 in the irradiation surface as the unit distance. The result is shown on the horizontal axis after division.

In FIG. 2, the arrangement range of the light-emitting diode elements 1 is ± 2, and a = 1.5 and b = 4. At this time, the illuminance difference is small in the range of ± 1.5,
It was found that the illuminance suddenly decreased outside the range. That is, uniform illuminance can be obtained in a place where the distance from the reference point is within a predetermined range on the irradiation surface. As a comparative example,
The light distribution when the light emitting diode elements 1 are arranged at a uniform density on one plane is shown by a broken line in FIG. When the light emitting diode elements 1 are arranged in the range of ± 2 similarly to the above-described configuration, the illuminance higher than the illuminance obtained at the position of ± 2.5 in the above-described configuration is obtained in the range of ± 3.5. However, the illuminance difference due to the distance is larger than in the above configuration.

As is apparent from the above description, it is desirable to arrange the light emitting diode elements 1 according to a sinusoidal rule as in the present embodiment in order to obtain a uniform illuminance within the target range of the irradiation surface. . Further, when the light emitting diode elements 1 are arranged so as to be in close contact with each other, there is a possibility that the temperature of the central part becomes higher than that of the peripheral part due to heat generation of the light emitting diode elements 1, but the arrangement density of the central part is higher than that of the peripheral part. The temperature difference between the central part and the peripheral part can be reduced by reducing the temperature. Such an arrangement can also be obtained with a sinusoidal rule as described above. When the temperature of the light-emitting diode element 1 rises, the light-emitting characteristics may change or the light-emitting diode element 1 may be destroyed. However, as described above, it is necessary to reduce the temperature difference between the central portion and the peripheral portion in the arrangement range. As a result, variations in light emission characteristics are reduced, and reliability is improved.

(Embodiment 2) In the first embodiment, a light emitting diode element 1 having a diffuse light distribution characteristic is used as the light emitting diode element 1, but in the present embodiment, a light emitting diode element 1 having a point light source light distribution characteristic is used. ing. FIG. 3 shows a light distribution when such a light emitting diode element 1 is arranged in the same manner as in the first embodiment. The solid line in FIG. 3 shows the light distribution of the present embodiment arranged according to a sine rule, and the broken line shows the light distribution of a comparative example arranged at a uniform density.

According to FIG. 3, there is no significant difference in the uniformity of the illuminance between the present embodiment and the comparative example. However, in the present embodiment, the illuminance attenuation factor outside the specific range is larger. The present embodiment is desirably used for applications in which illumination is performed with uniform illuminance. Other configurations are the same as in the first embodiment. In order to obtain a light source that locally increases the illuminance as in the present embodiment, the arrangement density of the central portion of the arrangement range of the light emitting diode elements 1 may be higher than that of the peripheral portion.

(Embodiment 3) In this embodiment, as shown in FIG. 4, the light emitting diode elements 1 are arranged on concentric circles as shown by a dashed line in FIG. 4, and the light emitting elements are arranged on the same circumference. By connecting the diode elements 1 in common, the light emitting diode elements 1 on each circumference are group G
1, G2,.... Here, a light emitting diode element 1 having a diffuse light distribution characteristic is used.

The lighting state of the light emitting diode element 1 is controlled by the control circuit 2 for each of the groups G1, G2,. The lighting state of the light emitting diode element 1 means distinction of lighting / extinguishing and dimming.
The light distribution can be changed by individually controlling the light distribution for each of the two. For example, if the light output of the light emitting diode element 1 in the central part of the arrangement range is smaller than that of the light emitting diode element 1 in the peripheral part, this is equivalent to making the arrangement density in the central part smaller than in the peripheral part. Therefore,
By simply controlling the light output of the light emitting diode element 1 by the control circuit 2, it is possible to obtain the light distribution shown by the solid line and the light distribution shown by the broken line in FIG. If the light emitting diode element 1 having a light distribution characteristic of a point light source as in the second embodiment is used, it is possible to obtain the light distribution shown by the solid line and the light distribution shown by the broken line in FIG. is there. Further, since the lighting state of the light emitting diode element 1 can be arbitrarily changed by the control circuit 2, the light distribution other than the light distribution shown in FIGS. 2 and 3 can be set.

(Embodiment 4) In this embodiment, as shown in FIG. 5, a plurality of light emitting diode elements 1 are housed in a cylindrical tube 3 formed in the same shape and dimensions as a ready-made fluorescent lamp. Things. At both ends of the tube body 3 are provided bases 4 which can be attached to and detached from fluorescent light sockets. That is, the external appearance is formed in the same manner as a ready-made fluorescent lamp. A drive circuit as shown in FIG. 6 is housed inside the tube 3 together with the light emitting diode element 1. The drive circuit is configured so that the light emitting diode element 1 can be turned on by the output of the lighting circuit for the fluorescent lamp. That is, a rectifier circuit RE composed of a diode bridge is provided as a power supply unit, and a series circuit of a resistor R as a current limiting element and a plurality of light emitting diode elements 1 is connected between the DC output terminals of the rectifier circuit RE. An AC input terminal of the rectifier circuit RE is connected to one terminal pin 5 of a base 4 provided at each end of the tube 3. That is, one of the two terminal pins 5 provided on each base 4 is used for power supply.

With such a configuration, it can be used in place of a fluorescent lamp in a conventional fluorescent lamp lighting device. Further, since the light emitting diode elements 1 are connected in series and the resistors R are connected in series, the light emitting diode elements 1 can be turned on without providing a step-down circuit. In addition, since the current is limited by the resistor R, no overcurrent flows through the light emitting diode element 1 even when a relatively high voltage is applied between the AC input terminals of the rectifier circuit RE. Furthermore, since the rectifier circuit RE is provided, the power supply can be used regardless of whether the power supply is a DC power supply or an AC power supply.
Further, since the rectifier circuit RE is a full-wave rectifier circuit, it is non-polarized, and the polarity of the power supply does not matter even when a DC power supply is used.

(Embodiment 5) In this embodiment, as shown in FIG. 7, a power supply section 6 including a rectifier circuit and a power factor improvement circuit as a drive circuit and a resistor R as a current limiting element are provided. The rectifier circuit constituting the power supply unit 6 is a full-wave rectifier circuit including a diode bridge, as in the fourth embodiment.
The power factor improvement circuit is configured by a chopper circuit, for example.
It outputs a DC voltage. Although the configuration of the chopper circuit is not particularly limited, various chopper circuits such as a step-down type, a step-up type, and a polarity inversion type can be used according to the number of the light emitting diode elements 1 connected in series. Regardless of the type, this type of chopper circuit includes a series circuit of an inductor and a switching element, and has a configuration in which the output of a rectifier circuit flows to the inductor at a high frequency by turning the switching element on and off at a high frequency. Therefore, when an AC power supply is connected, the input current flows at a high frequency to prevent an increase in input current distortion, and furthermore, the envelope of the input current can be made proportional to the input voltage, thereby increasing the input power factor. It is.

A series circuit of a resistor R and a plurality of light emitting diode elements 1 is connected between the output terminals of the power supply section 6,
The input terminal of the power supply unit 6 is connected to one terminal pin 5 of each base 4 as in the fourth embodiment. By the way, the power supply unit 6
Is provided with a power factor improvement circuit having the above configuration,
The input characteristics can be changed by appropriately controlling the switching elements. Therefore, in the present embodiment, the input characteristics of the power supply unit 6 are designed so as to simulate the load characteristics of the discharge lamp. In particular, since the present embodiment is used in place of a fluorescent lamp, the present embodiment is adapted to the load characteristics of the fluorescent lamp, and in particular, is matched to the current-voltage characteristics during stable lighting (at rated lighting) of the fluorescent lamp. Other configurations and operations are the same as those of the fourth embodiment.

In the fourth and fifth embodiments, similarly to the third embodiment, the light emitting diode elements 1 may be divided into groups, and the lighting state may be controlled for each group. In each of the above-described embodiments, the light-emitting diode elements 1 having different emission colors are used to mix colors or use a white light-emitting diode (there is one that emits white light by irradiating blue light to a yellow-emitting phosphor). In this case, it is desirable to obtain a white light emission color.

(Embodiment 6) This embodiment is mainly used for display, and as shown in FIG. 8, a plurality of light emitting diode elements 1r are arranged so as to face end faces of a flat light guide plate 7. , 1g, and 1b. Red, green, and blue light emitting diode elements 1r, 1g, and 1b are used. By using the light emitting diode elements 1r, 1g, and 1b having different emission colors, the mixed color light becomes almost white. The light guide plate 7 is a transparent plate and is formed so as to guide light while reflecting a part of the light introduced from the end face, and to leak the rest from at least one of the front and back surfaces. Therefore, the light guide plate 7
In (2), a diffuser plate having diffuse transmittance is provided on a surface where light is leaked to assist light leakage, and a reflector is provided on a surface where light is not leaked. The reflection plate is a small reflection plate having a diffuse reflection property and a mirror surface superimposed on the back surface side of the small reflection plate. The small reflection plate has an area such that the amount of leaked light is substantially uniform regardless of the position of the light guide plate 7. And placement is taken into account. In short, in the vicinity of the light emitting diode elements 1r, 1g, and 1b, the area of the small reflector per unit area is reduced.
The larger the distance from r, 1g, 1b, the larger the area of the small reflector per unit area.

In the example shown in FIG. 8, the light emitting diode elements 1r, 1g, 1b are arranged in a line on the end face of the light guide plate 7, but as shown in FIG.
If r, 1g, and 1b are arranged, light can be emitted with high luminance. As shown in FIG. 10, the light emitting diode elements 1 (1r, 1g, 1b) are provided on all end faces of the light guide plate 7.
By arranging the pixels, it is possible to increase the luminance and the uniformity of the luminance.

Light emitting diode element 1 of the present embodiment
r, 1g, and 1b are connected in series as a group for each emission color, and as shown in FIG. 11, the switching transistors Qr, Qg. It is connected in series between the collector and the emitter of Qb. Switching transistors Qr, Q
g. Qb is individually controlled by the control circuit 2. Therefore, switching transistors Qr, Qg. The luminance of each light emitting diode element 1r, 1g, 1b can be adjusted by changing the on / off duty of Qb. That is, it is possible to change the light color by changing the color mixture ratio of each color, or to change the overall luminance. That is, the control circuit 2 can be used as a light control unit and a color control unit.

(Embodiment 7) In order to perform display using the light guide plate 7 described in Embodiment 6, as shown in FIG.
The display panel 8 provided with the display pattern is disposed so as to overlap the light guide plate 7. In FIG. 12, the light guide plate 7 is sandwiched between the display panel 8 and the reflection plate 9. The reflecting plate 9 is the same as that described in the sixth embodiment.

In the present embodiment, the light-emitting diode elements 1 are arranged in a sinusoidal manner as in the first embodiment so that one surface of the light guide plate 7 on which the display panel 8 is superimposed has a uniform brightness. That is, the arrangement density at the central portion in the longitudinal direction of the end surface of the light guide plate 7 is smaller than that at the peripheral portion. By employing such a configuration, it is possible to improve the uniformity of the brightness of the surface of the light guide plate 7. Further, the light emitting diode elements 1 may be divided into a plurality of groups, and the lighting state may be controlled for each group. In this case, a difference can be provided in the brightness of each region of the light guide plate 7. Here, the control of the lighting state of the light emitting diode element 1 is performed by adopting the same configuration as the control circuit 2 of the sixth embodiment.
Can be used as light control means.

As shown in FIG. 13, by providing the terminal pins 5 arranged in the same manner as the fluorescent lamp, it is possible to use a normal fluorescent lamp socket. That is, it can be used in place of a display device using a fluorescent lamp and a light guide plate. Other configurations and operations are the same as those of the sixth embodiment. (Embodiment 8) In order to make it easier to recognize a display pattern when the display panel 8 is provided as in Embodiment 7, it is conceivable to increase the contrast of the display pattern. As a technique for increasing the contrast, it is desirable to arrange the light emitting diode elements 1 such that the greater the amount of transmitted light in the display pattern, the greater the amount of light leakage from the light guide plate 7. It should be noted that the increase / decrease of the amount of leaked light can also be controlled by the reflection plate 9.

As shown in FIG. 14, when the display pattern is colored (in the illustrated example, the regions Dr, D
g and Db are colored red, green and blue, respectively), and as shown in FIG.
It is desirable to dispose the light emitting diode elements 1r, 1g, and 1b, which emit light having colors similar to those of the regions Dr, Dg, and Db, near g and Db. With this configuration, the color of the colored portion of the display pattern becomes clear, the color contrast is enhanced, and the recognizability of the display pattern can be improved. Note that this configuration may be applied as needed.

[0037]

According to the first aspect of the present invention, a plurality of light emitting diode elements are arranged at an arrangement density according to a light distribution design. Since the arrangement density of the light emitting diode elements is set according to the light distribution design, there is an advantage that the light source itself can cope with the light distribution design. In other words, since a device having a light distribution control element is almost unnecessary, it is possible to configure a relatively small lighting device. However, there is an advantage that the light distribution can be easily changed.
Furthermore, the light emitting diode element has an advantage that the number of replacements is reduced because the life of the light emitting diode element is equal to or longer than that of a generally used light source such as an incandescent lamp or a fluorescent lamp.

In the case where the light emitting diode elements are bare chips as in the second aspect of the present invention, there is an advantage that the arrangement density of the light emitting diode elements can be increased and a light source with high luminance can be obtained. Like the invention of claim 3,
When the arrangement density at the center of the arrangement range of the light emitting diode elements is made smaller than that at the periphery so that the illuminance on the irradiation surface is constant, there is an advantage that the illuminance on the irradiation surface becomes almost uniform.

In the case where the arrangement density at the center of the arrangement range of the light-emitting diode elements is higher than that at the periphery, the illuminance on the irradiation surface becomes large immediately below and the illuminance is partially increased. There is an advantage that it is possible to provide an improved illumination. According to a fifth aspect of the present invention, the plurality of light emitting diode elements are connected to each other so as to form a plurality of groups, and the lighting state of each light emitting diode element can be controlled for each group. There is an advantage that it is possible to change the light distribution by performing lighting or dimming for each group.

The invention according to claim 6 comprises a plurality of light emitting diode elements and a drive circuit connected to the output of a lighting circuit for a discharge lamp and for lighting the light emitting diode elements. There is an advantage that the illumination by the light emitting diode element becomes possible if only the light source is replaced by diverting the lighting equipment used for the ordinary discharge lamp. That is, by providing the output of the lighting circuit to the driving circuit, there is an advantage that the light emitting diode element can be stably lighted without applying an overvoltage or flowing an overcurrent to the light emitting diode element.

According to a seventh aspect of the present invention, the drive circuit includes a power supply unit including a rectifier circuit connected to a lighting circuit;
In the case where the power supply unit includes a current limiting element for limiting a current supplied to the light emitting diode element, the power supply unit includes a rectifier circuit. is there. Moreover, there is an advantage that overcurrent can be prevented from flowing through the light emitting diode element by the current limiting element.

According to an eighth aspect of the present invention, the drive circuit includes a power supply unit including a rectifier circuit connected to a lighting circuit and a power factor improving unit, and limits a current supplied from the power supply unit to the diode element. If the input characteristics of the power supply unit simulate the load characteristics of the discharge lamp, the input characteristics of the power supply unit simulate the load characteristics of the discharge lamp. There is an advantage that the circuit does not interfere, and the rectifier circuit in the power supply unit allows the output of the lighting circuit to be used with either direct current or alternating current. In addition, there is an advantage that the power use efficiency is high when the output of the lighting circuit is AC. Furthermore, there is also an effect that overcurrent can be prevented from flowing through the light emitting diode element by the current limiting element.

According to a ninth aspect of the present invention, the load characteristic is a current-voltage characteristic at the time of stable lighting of the discharge lamp. Therefore, stress on the lighting circuit is small, and there is no need to separately design a lighting circuit, so that the lighting circuit can be used as a light source of a ready-made lighting device. In the case where the discharge lamp is a fluorescent lamp as in the invention of claim 10, the fluorescent lamp which is the most frequently used discharge lamp in general lighting is simulated. This will produce a high economic effect.

According to the eleventh aspect of the present invention, the plurality of light emitting diode elements are connected to each other so as to form a plurality of groups, and the lighting state of each light emitting diode element is controlled for each group. In the case where it is possible, there is an advantage that the light distribution can be changed by performing lighting or dimming for each group.

According to a twelfth aspect of the present invention, there is provided a light guide plate for leaking light introduced from a light source disposed opposite to a peripheral surface of a plate-like body from at least one of the front and back surfaces, and a light emitting diode element serving as the light source. This is advantageous in that a relatively inexpensive surface light source can be provided by a combination of a light guide plate and a light emitting diode element. In the case where a plurality of light emitting diode elements are arranged facing the peripheral surface of the light guide plate as in the invention of claim 13, the brightness of each region of the light guide plate is changed by the arrangement of the light emitting diode elements and lighting control. There is an advantage that it becomes possible to attach.

According to the fourteenth aspect of the present invention, in the case where light emitting diode elements of a plurality of light emitting colors are arranged, the light emitting color of the light guide plate can be changed according to the light emitting color and arrangement of the light emitting diode elements. There are advantages. Claim 1
As in the invention of the fifth aspect, the present invention is used for a lighting device provided with a display pattern on at least one of the front and back surfaces of the light guide plate. In the arrangement, the greater the amount of transmitted light in the display pattern, the greater the amount of light leakage from the light guide plate, so that the contrast between the bright and dark portions of the display pattern is emphasized so that the display pattern can be easily recognized. There is an advantage that it becomes.

As in the sixteenth aspect, the present invention is used for an illuminating device having a display pattern provided on at least one of the front and back surfaces of a light guide plate, and matches the color of a colored portion in the display pattern with the light color leaking from the light guide plate. The arrangement of the light emitting diode elements of a plurality of emission colors as described above has an advantage that the display contrast can be easily recognized because the color contrast can be enhanced in the colored display pattern.

According to a seventeenth aspect of the present invention, in which the light output of each light emitting diode element is dimmed by the dimming means, the light quantity of the light guide plate can be adjusted by dimming the light emitting diode element. There is. The invention according to claim 18 is that in which the plurality of light emitting diode elements are connected to each other so as to form a plurality of groups, and the lighting state of each light emitting diode element can be controlled for each group. In addition, there is an advantage that the light distribution can be changed by performing lighting or dimming for each group.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment.

FIG. 2 is an operation explanatory view of the above.

FIG. 3 is an operation explanatory diagram of the second embodiment.

FIG. 4 is a schematic configuration diagram showing a third embodiment.

FIG. 5 is a perspective view showing a fourth embodiment.

FIG. 6 is a circuit diagram of the same.

FIG. 7 is a circuit diagram showing a fifth embodiment.

FIG. 8 is a perspective view showing a sixth embodiment.

FIG. 9 is a perspective view of a main part showing another example of the sixth embodiment.

FIG. 10 is a perspective view of a main part showing another example of the sixth embodiment.

FIG. 11 is a circuit diagram of the same.

FIG. 12 is a plan view showing a seventh embodiment.

FIG. 13 is a front view of the same.

FIG. 14 is an exploded perspective view showing an eighth embodiment.

FIG. 15 is a perspective view of the same.

FIG. 16 is an operation explanatory view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light-emitting diode element 1r, 1g, 1b Light-emitting diode element 2 Control circuit 3 Tube 4 Base 5 Terminal pin 6 Power supply part 7 Light guide plate 8 Display panel 9 Reflector Dr, Dg, Db area G1, G2, ... Group R resistance RE rectifier circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Sakuo Kamada 1048, Kazuma, Kadoma, Osaka Prefecture Inside Matsushita Electric Works, Ltd. (72) Inventor Shoichi Koyama 1048, Kazuma, Kazuma, Kadoma, Osaka Prefecture Inside Matsushita Electric Works ( 72) Inventor Nobuyuki Asahi 1048 Kadoma Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Works, Ltd. 1048 Kadoma-shi Kadoma Matsushita Electric Works Co., Ltd. (72) Inventor Koji Tanaka Osaka Kadoma-shi Kazuno 1048 Matsushita Electric Works Co., Ltd. Within a stock company

Claims (18)

[Claims] 1. A light source using a light emitting diode, wherein a plurality of light emitting diode elements are arranged at an arrangement density according to a light distribution design. 2. The light source according to claim 1, wherein the light emitting diode element is a bare chip. 3. A light source using a light emitting diode according to claim 1, wherein the arrangement density at the center of the arrangement range of the light emitting diode elements is made smaller than that at the periphery so that the illuminance on the irradiation surface is constant. . 4. The light source using a light emitting diode according to claim 1, wherein the arrangement density at the center of the arrangement range of the light emitting diode elements is higher than that at the periphery. 5. A light-emitting diode element is connected to each group so that a plurality of light-emitting diode elements form a plurality of groups, and a lighting state of each light-emitting diode element can be controlled for each group. Light source using a light emitting diode. 6. A light source using a light-emitting diode, comprising: a plurality of light-emitting diode elements; and a drive circuit connected to an output of a lighting circuit for a discharge lamp and lighting the light-emitting diode elements. 7. The driving circuit includes a power supply unit including a rectifier circuit connected to a lighting circuit, and a current limiting element for limiting a current supplied from the power supply unit to the light emitting diode element. A light source using the light emitting diode according to claim 6. 8. The drive circuit includes a power supply unit including a rectifier circuit connected to a lighting circuit and a power factor improving unit, and a current limiting element for limiting a current supplied from the power supply unit to the diode element. 7. The light source according to claim 6, wherein the input characteristics of the power supply unit simulate the load characteristics of a discharge lamp. 9. The light source according to claim 8, wherein the load characteristic is a current-voltage characteristic when the discharge lamp is stably operated. 10. The light source according to claim 9, wherein the discharge lamp is a fluorescent lamp. 11. A plurality of light emitting diode elements are connected to each other such that a plurality of light emitting diode elements form a plurality of groups, and a lighting state of each light emitting diode element can be controlled for each group. A light source using the light emitting diode according to claim 8. 12. A light guide plate which leaks light introduced from a light source disposed opposite to a peripheral surface of a plate-like body from at least one of front and back surfaces, and a light emitting diode element serving as the light source. Light source using light emitting diodes. 13. The light source using a light emitting diode according to claim 12, wherein a plurality of light emitting diode elements are arranged facing the peripheral surface of the light guide plate. 14. A light source using a light emitting diode according to claim 13, wherein light emitting diode elements of a plurality of light emitting colors are arranged. 15. A lighting device having a display pattern provided on at least one of the front and back surfaces of a light guide plate, wherein light emitting diode elements are arranged so that a portion of the display pattern having a larger amount of transmitted light has a larger amount of light leakage from the light guide plate. A light source using the light emitting diode according to claim 13. 16. A lighting device having a display pattern provided on at least one of the front and back surfaces of a light guide plate, wherein a plurality of emission colors are used so that the color of a colored portion in the display pattern matches the light color leaking from the light guide plate. 14. The light source using a light emitting diode according to claim 13, wherein light emitting diode elements are arranged. 17. The light source using light emitting diodes according to claim 13, wherein the light output of each light emitting diode element is dimmed by dimming means. 18. A light-emitting diode element is connected to each group so that a plurality of light-emitting diode elements form a plurality of groups, and a lighting state of each light-emitting diode element can be controlled for each group. A light source using the light emitting diode according to claim 13.