JPH11260572A - Lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly change the output energy of emitted light corresponding to the energy quantity of outside light, regarding a lighting system employed for lighting a room (an indoor space). SOLUTION: This lighting system 11 comprises a sensor 20 in an end face of a light guide plate 13 and the variation quantity of the emitted energy of an illuminating part 12 at the time when the emitted energy is instantaneously changed is detected by the sensor 20. Based on the output of the sensor 20, the energy in each wavelength band of outside light is detected and the detection result is fed back to correct the emitted energy of light rays of respective wavelength bands of an LED(light emitting diode) module 16, which is a light source. Consequently, the emitted energy of the light emitted out of the LED module 16 can properly be changed corresponding to the variation of the energy quantity of the outside light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device mainly used for indoor (indoor) illumination, and more particularly to an illumination device capable of appropriately changing the output energy of output light in accordance with the energy amount of external light. It was made.

[0002]

2. Description of the Related Art Conventionally, incandescent lamps and fluorescent lamps are mainly used as light sources for indoor lighting devices. Instead of these light sources, light emitting diodes (LEDs), which are fixed light emitting elements using semiconductors, are used. It is considered to be used as a light source for indoor lighting. That is, the LED is expected as a lighting means in the future because of its features such as small size, high brightness and long life. At present, its conversion efficiency is not so good at about 1/6 that of general fluorescent lamps, so it is not widely used in the field of lighting. However, considering the above features and the possibility of LEDs, in the near future, LED Could become the mainstream of lighting. By the way, in order to use an LED as a light source for an indoor lighting device, since the LED is originally a point or linear light source, it must be changed to a planar light source.

Conventionally, as a planar light source device using an LED as a light source, a surface light source device for a backlight of a liquid crystal display screen of various electric appliances and the like has been known. A conventional light guide type surface light source device using an LED as a light source is shown in a perspective view of FIG. 7 and a sectional view of FIG. The surface light source device 100 includes a light guide plate 2 for confining light, a light emitting unit 3 and a reflection plate 4. The light guide plate 2 is formed of a transparent resin having a large refractive index such as a polycarbonate resin or a methacryl resin, and a diffusion pattern P is formed on the lower surface of the light guide plate 2 by uneven processing or dot printing of a diffuse reflection ink. I have. The light emitting section 3 has a so-called point light source 3b such as a plurality of LEDs mounted on a circuit board 3a, and faces a side surface (light incident surface 7) of the light guide plate 2. Reflector 4
Is formed of, for example, a white resin sheet having high reflectivity, and both side portions thereof are attached to the lower surface of the light guide plate 2 by the double-sided tape 8.

As shown in FIG. 8, light f emitted from the light emitting section 3 and guided from the light incident surface 7 to the inside of the light guide plate 2 is totally reflected inside the light guide plate 2 so that the light guide plate is reflected. 2 is trapped inside. When the light f inside the light guide plate 2 enters the diffusion pattern P, the light f is diffusely reflected, and the light f reflected toward the light exit surface 6 at an angle smaller than the critical angle of total reflection is transmitted from the light exit surface 6 to the outside. To be taken out. Further, the light f transmitted through a portion of the lower surface of the light guide plate 2 where the diffusion pattern P does not exist is reflected by the reflection plate 4 and returns to the inside of the light guide plate 2 again, so that loss of light amount from the lower surface of the light guide plate 2 is prevented. Can be.

Means for realizing an indoor lighting device using an LED as a light source include a method for enlarging a light guide type surface light source device as shown in FIGS. 7 and 8 and a method similar to a conventional lighting device. A method of spreading light using a bulk, a diffusion member, or the like can be considered. In any case, when the LED is used as a light source of the lighting device, whitening of the light source is inevitable. As a method of whitening this light source, for example,
A method of using three types of LEDs that emit light of three primary colors of red (R), green (G), and blue (B) and mixing the light emitted from these three LEDs to produce white light, A method of applying a fluorescent material that generates ultraviolet rays to the surface of the LED and emitting white light is mentioned. However, considering the light conversion efficiency and the possibility of color adjustment, the former whitening by mixing the three colors is more effective. It is.

[0006]

By the way, in a current indoor (indoor) lighting device, the irradiation light emitted from the lighting device toward the irradiation surface includes light from another lighting device, sunlight, or the like. Irrespective of the presence or absence of light (hereinafter, referred to as outside light) emitted from devices other than the above-mentioned lighting device. For this reason, there has been a problem that, when external light is applied to the irradiation surface, the brightness and color of the irradiation surface change under the influence of the external light. As a method to solve this problem, a sensor is installed on the irradiation surface, and based on the measurement result of the brightness and color of the irradiation surface by this sensor, the irradiation device controls the brightness and the color on the irradiation surface to be constant. A method of adjusting the light amount and the wavelength band of the irradiation light has been considered, and this method can keep the light amount or the absolute value of the wavelength band of the irradiation surface obtained by combining the external light and the illumination light constant.

However, in the above-described method, for example, (1) light corresponding to external light is irradiated from an irradiation device,
(2) When the outside of the window is bright, the inside of the room is bright. Conversely, when the outside of the window is dark, the room light is slightly darkened. The amount of light emitted from the illuminating device could not be changed appropriately in accordance with the absolute value of the amount of light or the like. Also, as in the method above,
In order to capture only external light, the sensor must be installed outside the lighting device so that light (including stray light) from the irradiation device does not enter the sensor, and the sensor head becomes dirty or scratched. There was a case.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem. In an indoor (indoor) lighting device, the amount of external light energy is captured, and the amount of external light energy is adjusted. An illumination device that can appropriately change the emission energy of the emitted light and that can prevent the sensor head from being stained or scratched by incorporating a sensor for detecting the energy amount of external light inside the device. The purpose is to provide.

[0009]

According to one aspect of the present invention, there is provided an illumination unit having at least two or more light sources for emitting lights having different wavelength bands from each other. A sensor for measuring the energy of the light of the light source, and control means for controlling the emission energy of the light of each wavelength band of the light source. The control means instantaneously changes the emission energy of the irradiation unit, The energy of the external light in each wavelength band is detected from the output of the sensor corresponding to the above, and the emission energy of the light in each wavelength band of the light source is adjusted based on the detection result.

In this configuration, the control means detects the energy of each wavelength band of the external light from the sensor output when the emission energy of the irradiation unit is instantaneously changed, and feeds back this detection result to the light source. Since the emission energy of the light in each wavelength band is corrected, the emission energy from the light source can be appropriately changed in accordance with the change in the energy of the external light. Thereby, for example, when a large amount of external light is irradiated on the irradiation surface illuminated by the illumination device, the energy output from the illumination unit is reduced, or a shadow due to the external light is generated on the irradiation surface. If this is the case, irradiate the light corresponding to the external light from the lighting unit to irradiate the light with the optimal output energy according to the place where the lighting device is used and the application, such as erasing shadows. Can be.

According to a second aspect of the present invention, there is provided an illumination unit comprising at least two or more light sources for emitting light having different wavelength bands from each other, and a conversion unit for converting light from the light source into a planar shape. A sensor for measuring the energy of light in the wavelength band of the light source, and control means for controlling the energy of light in each wavelength band of the light source, wherein the sensor is configured to be able to receive external light via the conversion means. The control means instantaneously changes the emission energy of the irradiation unit, detects the energy of each wavelength band of the external light from the output of the sensor corresponding to the change of the emission energy, and based on the detection result, The light emission energy of each wavelength band is adjusted.

In this configuration, in addition to the function of the first aspect, the light emitted from the light source can be converted into a surface light source by the conversion means. Also, when external light reflected on the irradiation surface enters the conversion means, a part of this light is received by the sensor through the conversion means, so that the energy of the external light can be reduced without installing the sensor outside the device. Detection can be performed, and it is possible to prevent the sensor head from being scratched or stained.

Further, the sensor may be installed close to the light source with its light receiving surface facing the light emitting direction of the light source. In this configuration, in addition to the function of claim 2, the external light reflected in the same direction as the light arriving from the illuminating unit on the irradiation surface has the same optical path as the light emitted from the light source due to the reciprocity of the photoelectric element. , And is collected near the light source, so that much external light is incident on the sensor. Thus, the energy of each wavelength band of the external light can be accurately detected, so that the emission energy of each wavelength band of the light source can be accurately adjusted. Further, since the sensor is provided close to the light source, the wiring of the sensor can be reduced.

According to a fourth aspect of the present invention, there is provided a light guide plate made of a flat transparent medium for confining light and guiding the light, a light extraction pattern member provided on the flat plate of the light guide plate, and a light guide. An illumination unit comprising at least two or more points or linear light sources that emit light in different wavelength bands and is installed so that light is incident on the end face of the light plate, and measures the energy of light in a plurality of wavelength bands. And a control means for controlling the energy of light in each wavelength band of the light source,
The sensor is installed with its light receiving surface in close contact with the light guide plate, and the control means instantaneously changes the output energy of the irradiating section, and the output from the sensor corresponding to the change in the output energy is outside. The energy of each wavelength band of light is detected, and the emission energy of light of each wavelength band of the light source is adjusted based on the detection result.

In this configuration, in addition to the function described in the first aspect, after the light emitted from the point or linear light source is repeatedly reflected on the light guide plate to form a surface light source, the light is transmitted through the pattern member. Is emitted. Further, since the sensor is installed with its light receiving surface in close contact with the light guide plate, external light reflected within the irradiation surface and incident on the light guide plate is captured by the sensor through the light guide plate. This makes it possible to capture external light without installing a sensor outside the lighting device.

Further, the sensor may be provided on an end face of a light guide plate. In this configuration, the end surface of the light guide plate is a surface from which light corresponding to loss that does not contribute to illumination is emitted, and therefore, even if a sensor is provided on this end surface, the efficiency of illumination does not decrease.

Further, the sensor may be provided on an end face of the light guide plate on the light source side. In this configuration,
When light travels in the opposite direction on the optical path due to the reciprocity of the photoelectric element, the light travels in the same optical path in the opposite direction. Therefore, when the external light is reflected at a certain point in the irradiation area, a part of the light is returned to the vicinity of the light source, so that the external light can be detected. Therefore, more external light can be captured, and the emission energy of each wavelength band of the light source can be accurately adjusted. Further, since the sensor is provided close to the light source, the wiring of the sensor can be reduced.

Further, the energy of the external light may be detected based on the output of the sensor when the control unit instantaneously makes the output energy of the illumination unit substantially zero.
In this configuration, the amount of light incident on the sensor from the illumination unit can be reduced, so that the energy of external light can be detected more accurately.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a schematic external view of a lighting device according to a first embodiment of the present invention, and FIG. 2 is an enlarged view of a portion A in FIG. The illuminating device 11 is a light-guiding surface light source device that mixes red, green, and blue lights having different wavelength bands to generate white light, and illuminates the light from a point light source in a planar shape and emits the light. From a unit 12, a sensor 20 for measuring the energy of light in a plurality of wavelength bands, and a control device 21 (control means) for controlling the emission energy of light in each wavelength band included in the light emitted from the illumination unit 12. It consists of

The illuminating section 12 includes a light guide plate 13 (conversion means), which is a flat transparent medium for confining light and guiding the light, and a sheet or a sheet provided on the flat plate on the non-emission surface 13a side of the light guide plate 13. A thin reflecting plate 14, a diffusing plate 15 (pattern member) provided on a flat plate on the emission surface 13 b side of the light guide plate 13, and an LED module 16 installed so that light enters from an end face of the light guide plate 13. It is composed of LED
Module 16 includes red (λ = 680 nm) and green (λ = 680 nm).
565 nm) and three types of LEDs of R, G, and B that emit blue (λ = 450 nm) light, respectively. In addition, a diffusion pattern P (see FIG. 3) is formed on the non-emission surface 13a of the light guide plate 13 by unevenness processing, dot printing of diffuse reflection ink, or the like. The mechanism for extracting light from the illumination unit 12 is basically the same as that described in the above-described conventional technique.
The R, G, and B lights introduced into the light guide plate 13
The light is totally reflected inside, mixed to form white light, and when reflected by the reflector 14 in the direction of the light emitting surface 13b, the light is made uniform by the diffuser 15 and extracted to the outside. The size of the light guide plate 13 is, for example, 1
000 mm × 1000 mm × 10 mm is used.

The sensor 20 is for capturing the energy of light (external light) emitted from a device other than the lighting device 11, such as light from another lighting device or sunlight. On the end face 13c on the module side,
It is installed with its light receiving surface in close contact with the light guide plate 13. The sensor 20 includes R, G, and B LEDs on the light emitting side.
Accordingly, it is desirable to use photoelectric elements having the same wavelength band. R, G, B measured by this sensor 20
The measurement results of the energy of light in each wavelength band of
It is input to the control device 21 via the electric wire cord 17. The control device 21 detects the energy of each wavelength band of the external light from the output of the sensor 20, and based on the detection result, R,
The emission energy of light of each wavelength band of the G and B LEDs is adjusted.

Here, an optical path of external light incident on the sensor 20 will be described with reference to FIG. FIG. 3 shows an optical path where light is guided from the LED module 16 as a light source through the light guide plate 13 and light is emitted toward the irradiation surface 22. Due to the reciprocity of the optical element, when the light travels in the opposite direction in the optical path shown in the figure, the light travels in the same optical path in the opposite direction. Therefore, the irradiation surface 22
When the external light is reflected at a certain point, a part of the light (a component reflected in the same direction as the light reaching from the illumination unit 12) returns to the vicinity of the LED module 16 as the light source via the light guide plate 13 and the like. Therefore, a lot of external light is collected near the LED module 16. Further, it has been found that part of the external light reaches the end face near the LED module 16 due to the influence of the diffusion pattern P and the like provided on the light guide plate 13. From the above, it can be understood that a large amount of external light is incident on the sensor 20 by providing the sensor 20 close to the LED module 16.

Next, a method of changing the emission energy of the illumination and obtaining the energy of the light in each wavelength band of the external light based on the sensor output corresponding to each emission energy will be described with reference to FIG. . (1) Measurement of Data First, by changing the voltage applied to each LED constituting the LED module 16 with time, (V
, V2, V3,...), The output energy of light from each LED is changed, and the output of the sensor 20 corresponding to each is measured (E1, E2, E3,...). In the figure, circle points indicate measurement points. The change over time of the voltage is performed within an instantaneous time (for example, 10 ms to 100 ms) at which the change in light energy is not visually perceived. (2) Function Approximation Next, an approximate curve passing through these measurement points is obtained. In the case of an LED, the function used for the approximation is preferably an exponential function having a shape close to the VI characteristics. (3) Calculation of external light From the function obtained in the above (2), the sensor output Eg at V = 0 or a voltage V at which the emission energy of the illumination becomes almost zero.
Is calculated. This Eg is a value when only external light is measured. FIG. 4 shows a case where external light is present and a case where external light is zero. With the above-described method, the energy of light in each wavelength band of external light can be detected. Further, in the present measurement algorithm, even if the light emitted from the LED module 16 enters the sensor 20, the energy of the external light can be detected without any trouble. It is suitable for a configuration like a form.

As described above, according to this embodiment, the energy of the external light in each wavelength band is detected, and the detection result is fed back to correct the emission energy of the light in each wavelength band of the LED module 16. And an LED module 1 corresponding to the change in energy of each wavelength band of external light.
6 can change the emission energy of light in each wavelength band. Thereby, for example, when a large amount of external light is irradiated on the irradiation surface 22, energy saving is achieved by reducing the emission energy from the illumination unit 12, or the external light is generated in the irradiation surface 22. When a shadow is generated, the light corresponding to the external light is emitted from the illumination unit 12 to eliminate the shadow in the irradiation surface 22, and so on.
It is possible to irradiate light having an optimum output energy according to the use of the lighting device 11. Further, when the present invention is applied as a lighting device for a show window, when the outside of the window is bright, the inside of the room is bright, and when the outside of the window is dark, the inside of the room is slightly dark. The energy of the emitted light can be adjusted as described above.

Further, in the conventional light source (fluorescent lamp, incandescent lamp, neon), the rising speed (response speed) is slow, and it is not possible to change the emission energy suddenly for a moment during irradiation. Since the emitted energy can be instantaneously changed by using the LED as the light source, the energy of the external light can be measured without being visually recognized during the irradiation.

Further, by installing the sensor 20 inside the lighting device 11, it is possible to prevent the head portion of the sensor 11 from being scratched or stained, thereby reducing the detection accuracy. In addition, since the sensor 20 is provided close to the LED module 16, the sensor 20 can capture a large amount of external light condensed near the LED module 16 from an area wider than the reciprocity of the optical element. This allows
Since the energy of external light can be detected accurately,
The emission energy of light in each wavelength band from the LED module 16 can be adjusted with high accuracy. In addition, LED
Since the module 16 and the sensor 20 are brought close to each other, the wiring can be simplified. The sensor head and the light guide plate 13 are desirably bonded with a transparent medium or the like.

(Second Embodiment) FIGS. 5 and 6 are optical system configuration diagrams of a lighting device according to the second embodiment, each part of which is different. FIG. 5 shows an indirect lighting device. This device comprises a projection light source 30 having three kinds of LEDs of R, G, and B built therein, and a diffuse reflection plate 31 that diffusely reflects light emitted from the projection light source 30. And a sensor 20 that captures the light reflected by the diffuse reflection plate 31 via a mirror 32, detects external light based on a signal from the sensor 20, and detects R, G, and B LEDs based on the detection result. A control device (not shown) for adjusting the emission energy. FIG. 6 shows a direct-type illuminating device, which comprises a light source 40 in which three types of LEDs 40a of R, G, and B are arranged in an array, and a diffusion plate for diffusing light emitted from the light source 40. 41, a sensor 20 provided in close proximity to the light source 40 so as to receive reflected light from a mirror 32 provided on the diffusion plate 41, and R, G based on signals from the sensor 20. ,
A control device (not shown) for adjusting the emission energy of the B LED. Even in such a configuration, the first
As in the embodiment, the light source 3 according to the energy amount of the external light
It is possible to change the emission energy of light from 0, 40 as appropriate. Further, since the light sources 30, 40 and the sensor 20 are installed close to each other, the wiring can be shortened.

The present invention is not limited to the above embodiment, but can be variously modified. For example, the LED may be one in which at least two or more semiconductor chips that emit light of different colors are modularized in one element. Further, the controller 21 may detect the energy of the external light based on the output from the sensor 20 when the output energy of the illumination unit 12 is instantaneously reduced to almost zero. In this case, since the light emitted from the LED module 16 hardly enters the sensor 20,
It is possible to more accurately detect the energy of external light. Furthermore, the sensor 20 may be installed on an end surface of the light guide plate 13 other than the end surface 13c on the LED module 16 side. In this case, the amount of external light detected by the sensor 20 decreases, but the irradiation efficiency of the irradiation unit 12 does not decrease. In addition, the sensor 20 may be provided on the non-emission surface 13a. In this case, the energy of the external light can be detected without lowering the irradiation efficiency of the illumination unit 12.

[0029]

As described above, according to the illumination device of the first aspect, the energy of each wavelength band of the external light is detected by the sensor, and the emission energy of each wavelength band light of the light source is determined based on the detection result. Is appropriately changed, so that it is possible to irradiate light having an optimum emission energy according to the use place and use of the lighting device, and this lighting device is suitable for indoor and indoor lighting.

Further, according to the illumination device of the second aspect of the present invention, since the illuminating section is provided with the converting means for converting the light from the light source into a planar shape, the illuminating section can be made a surface light source. Further, since the sensor is configured to be able to receive external light via the conversion means, it is possible to install the sensor inside the device, and it is possible to prevent the sensor head from being scratched or stained. Further, by disposing the sensor close to the light source, external light condensed near the light source can be captured due to the reciprocity of the optical element. This allows
A lot of external light is incident on the sensor, so that the energy of each wavelength band can be accurately detected, and therefore, the emission energy of each wavelength band of the light source can be adjusted with high accuracy. Further, it is possible to reduce the wiring of the sensor.

According to the illuminating device of the fourth aspect of the present invention, the same effect as that of the first aspect is obtained in an illuminating device which spreads and emits light from a point or linear light source in a planar manner. be able to. In addition, by installing a sensor on the end face of the light guide plate, the energy of external light can be detected without lowering the efficiency of illumination. Also, by installing the sensor on the end face of the light guide plate on the light source side, as described above, much external light condensed near the light source is incident on the sensor due to the reciprocity of the optical element. The output energy of each wavelength band can be adjusted. Further, it is possible to reduce the wiring of the sensor.

Further, by detecting the energy of the external light based on the output of the sensor when the output energy of the illumination unit is instantaneously reduced to almost zero, the output light from the illumination unit is transmitted to the sensor. The amount of incident light can be reduced, and only the energy of external light can be detected more accurately. Therefore, it is possible to more accurately adjust the emission energy of each wavelength band from the light source.

[Brief description of the drawings]

FIG. 1 is a schematic external view of a lighting device according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of a portion A in FIG.

FIG. 3 is a diagram for explaining an incident path of external light to a sensor.

FIG. 4 is a diagram for explaining a method of calculating the energy of external light.

FIG. 5 is an optical system configuration diagram of an illumination device according to an example of a second embodiment.

FIG. 6 is an optical system configuration diagram of an illumination device according to another example of the second embodiment.

FIG. 7 is a perspective view of a conventional surface light source device.

FIG. 8 is a cross-sectional view of a conventional surface light source device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Illumination device 12 Illumination part 13 Light guide plate (conversion means) 13a End face of light guide plate, light source side end face of light guide plate 15 Diffusion plate (pattern member) 16 LED module (light source) 20 Sensor 21 Control device (control device) 30 Projection Light source (light source) 40 light source 40a LED (light source)

Claims (7)

[Claims] An illumination unit having at least two light sources that emit light in different wavelength bands, a sensor that measures energy of light in a plurality of wavelength bands, and emission of light in each wavelength band of the light source. Control means for controlling the energy, the control means instantaneously changes the emission energy of the irradiating section, from the output of the sensor corresponding to the change of this emission energy, the energy of each wavelength band of external light And adjusting the emission energy of light of each wavelength band of the light source based on the detection result. 2. An illumination unit comprising at least two or more light sources for emitting light having different wavelength bands from each other, a conversion unit for converting light from the light source into a planar shape, and energy of light in a plurality of wavelength bands. And a control unit for controlling the energy of light in each wavelength band of the light source, wherein the sensor is configured to receive external light via the conversion unit, and the control The means instantaneously changes the emission energy of the irradiation unit, detects the energy of each wavelength band of the external light from the output of the sensor corresponding to the change of the emission energy, and based on the detection result, the light source. An illumination device, wherein the emission energy of light in each wavelength band is adjusted. 3. The lighting device according to claim 2, wherein the sensor is installed close to the light source with its light receiving surface facing the emission direction of the light source. 4. A light guide plate made of a flat transparent medium for confining light and guiding the light, a pattern member for light extraction provided on the flat plate of the light guide plate, and light incident on an end face of the light guide plate. An illumination unit including at least two or more points or linear light sources that emit light in different wavelength bands, and a sensor that measures the energy of light in a plurality of wavelength bands; Control means for controlling the energy of light in each wavelength band, wherein the sensor is installed with its light receiving surface in close contact with the light guide plate, and the control means controls the emission energy of the irradiating section. The energy is instantaneously changed, the energy of the external light in each wavelength band is detected from the output of the sensor corresponding to the change in the output energy, and the output energy of the light in the respective wavelength bands of the light source is detected based on the detection result. Lighting apparatus characterized by adjusting the ghee. 5. The lighting device according to claim 4, wherein the sensor is provided on an end face of the light guide plate. 6. The lighting device according to claim 4, wherein the sensor is provided on an end face of the light guide plate on a light source side. 7. The apparatus according to claim 1, wherein the control unit detects the energy of the external light based on the output of the sensor when the output energy of the illumination unit is instantaneously reduced to substantially zero. The lighting device according to claim 1.