BACKGROUND OF THE INVENTION
Field of Invention
[0001] The present invention relates to an illuminating device and a luminance switching
device thereof, and more particularly to a luminance switching device with a built-in
memory unit for providing a multi-stage switching of various illuminating devices.
Related Art
[0002] In recent years, light emitting diodes (LEDs) has been widely used in daily life,
for example, in monitors, home appliances, electronic components for vehicles, and
lighting lamps. Taking domestic lighting lamps as an example, a conventional domestic
lighting lamp usually has a plurality of bulbs, and when a user wants to change the
luminance state of the environment, a changeover switch is used to sequentially switch
the plurality of bulbs in multiple stages according to a set value, so as to turn
off the bulbs. For example, when the changeover switch is just turned on, all of the
bulbs are in a turn-on state. When the changeover switch is turned off and then turned
on again, at least one bulb is in a turn-off state, which results in the weakening
of luminance of the light emitted by the entire lighting lamp. When the changeover
switch is turned off and then turned on again, at least one bulb that is in the turn-on
state in the previous stage assumes the turn-off state. Thus, the luminance of the
lighting lamp can be switched in multiple stages. However, when the bulbs of the lighting
lamp are replaced by LEDs, as the unit number of LEDs required in the bulbs is large,
the luminance of the light emitted from the entire lighting lamp will be uneven if
the LEDs of the lighting lamp are turned off sequentially according to the operating
mode described above.
[0003] In order to solve the aforementioned problem of uneven luminance of the devices using
the LEDs as the light sources, US Patent Publication No.
U.S. 6,344,641 has disclosed a control method of a display system using LEDs as a light source.
FIG. 1 is a schematic view of a conventional display system. Referring to FIG. 1,
the conventional display system 10 includes two LEDs 12A, 12B, a display device 14,
and a luminance detecting and control circuit 20 disposed in the display device 14.
The display device 14 includes an image display array 18 to display images of the
display device 14. In addition, the display device 14 further includes a controller
22 electrically connected to the luminance detecting and control circuit 20, for transmitting
a timing and control signal to the luminance detecting and control circuit 20. The
two photo-detectors 16A and 16B are aligned with the LEDs 12A and 12B, and are electrically
connected to the luminance detecting and control circuit 20 for detecting luminance
of the light emitted by the LEDs 12A and 12B respectively.
[0004] When the photo-detectors 16A and 16B detect the luminance of the light emitted by
the LEDs 12A and 12B respectively, the detected luminance of the light is converted
into a current signal, which is then transmitted to the luminance detecting and control
circuit 20. At this time, if the luminance of the LEDs 12A and 12B needs to be changed,
the controller 22 will output a modulation signal to the luminance detecting and control
circuit 20 according to requirements of the user. Then, the luminance detecting and
control circuit 20 integrates the signals from the photo-detectors 16A and 16B and
the controller 22, and sends a voltage signal to modulate the luminance to be adjusted
of the LEDs 12A and 12B respectively. Thus, the luminance control of the light emitted
from the LEDs 12A and 12B of the display device 14 is realized.
[0005] However, though the luminance detecting and control circuit 20 controls the luminance
of the light emitted by the LEDs 12A and 12B individually, the compensation can only
be performed according to the insufficient luminance of the LEDs 12A, 12B detected
by the photo-detectors 16A, 16B or the luminance to be adjusted. If the user wants
to individually adjust the luminance of the light emitted by the LEDs 12A, 12B to
luminance of different states, such that the display device 14 uses the LEDs 12A,
12B to show different brightness. As the photo-detectors 16A and 16B are influenced
by the light emitted by the neighboring LEDs 12A, 12B, for example, the photo-detector
16A also detects the light emitted by the LED 12B, the object to control the LEDs
12A, 12B to emit light of different luminance cannot be achieved. Moreover, when the
display device 14 uses a large number of LEDs, the luminance detecting and control
circuit 20 cannot control the light of different luminance emitted by the LEDs in
a specific state at the specific state again while prevent the problem of uneven luminance
at the same time.
SUMMARY OF THE INVENTION
[0006] In view of the aforementioned problems, the object of the present invention is to
provide a luminance switching device for switching luminance of a plurality of light
emitting states produced by an LED light source composed of at least one LED. The
luminance switching device includes a changeover switch electrically connected to
the luminance switching device, for switching the light emitting states of the LEDs,
wherein the changeover switch has a plurality of switching modes corresponding to
the light emitting states; a detecting circuit electrically connected to the changeover
switch, for detecting the switching modes of the changeover switch; a memory unit
electrically connected to the detecting circuit, for storing luminance values of the
LEDs corresponding to the switching modes of the changeover switch detected by the
detecting circuit, converting the luminance values of the LEDs to a luminance control
signal, and transmitting the luminance control signal to the detecting circuit; and
a power conversion circuit, electrically connected to the LED light source, for receiving
the luminance control signal transmitted from the detecting circuit, such that the
LED light source produces luminance of the light-emitting states corresponding to
the switching modes.
[0007] Moreover, the present invention also provides an illuminating device, which comprises
an LED light source composed of at least one LED, and having a plurality of light
emitting states; a changeover switch, for switching the light emitting states of the
LED source and having a plurality of switching modes corresponding to the light emitting
states; a detecting circuit electrically connected to the changeover switch, for detecting
the switching modes of the changeover switch; a memory unit, electrically connected
to the detecting circuit, for storing luminance values of the LEDs of the LED light
source corresponding to the switching modes of the changeover switch detected by the
detecting circuit, converting the luminance values of the LEDs to a luminance control
signal, and transmitting the luminance control signal to the detecting circuit; and
a power conversion circuit, electrically connected to the LED light source, for receiving
the luminance control signal transmitted from the detecting circuit, such that the
LEDs produce luminance of the light-emitting states corresponding to the switching
modes.
[0008] The illuminating device and the luminance switching device of the present invention
both include a built-in memory unit, for storing the luminance value of the light
emitted by each of the LEDs in each setting state. Therefore, each time after the
changeover switch is switched, the LEDs will present the luminance value of the emitted
light, and will not have the problem of uneven light that is caused by the influence
of the light emitted from neighboring LEDs. Thus, the multi-stage switching of the
luminance of the LED light source is provided.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009]
FIG. 1 is a schematic view of a conventional display system;
FIG. 2A is a block diagram of functions of the illuminating device and the luminance
switching device thereof according to the present invention;
FIG. 2B is a simplified circuit diagram of the detecting circuit of FIG. 2A; and
FIG. 3 is a schematic view of another implementation aspect of the LED light source
of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0010] FIG. 2A is a block diagram of functions of the illuminating device and the luminance
switching device thereof according to the present invention. Referring to FIG. 2A,
the illuminating device of the present invention includes an LED light source 110
and a luminance switching device 100. The LED light source is composed of at least
one light emitting diode (LED) 120, and the luminance switching device 100 is used
for switching the luminance of a plurality of light emitting states produced by each
of the LEDs 120 of the LED light source 110. The luminance switching device 100 includes
a changeover switch 130, a detecting circuit 60, a memory unit 70, and a power conversion
circuit 90. Moreover, the LEDs 120 of the LED light source 110 can be connected in
series, in parallel, or in series and parallel, so as to form some special patterns.
[0011] The changeover switch 130 is electrically connected to the detecting circuit 60 of
the luminance switching device 100, so as to switch the plurality of light emitting
states produced by the LEDs 120 of the LED light source 110. Moreover, the changeover
switch 130 has a plurality of switching modes corresponding to the light emitting
states.
[0012] The detecting circuit 60 is electrically connected to the changeover switch 130,
for detecting the corresponding switching modes of the changeover switch 130. The
memory unit 70 is electrically connected to the detecting circuit 60, for storing
a luminance value of light emitted by each of the LEDs 120 corresponding to a certain
switching mode of the changeover switch 130 detected by the detecting circuit 60,
and converting the luminance value of each of the LEDs 120 into a luminance control
signal.
[0013] In this embodiment, the power conversion circuit 90 is an alternate current (AC)/
direct current (DC) converter, which is electrically connected between the detecting
circuit 60 and the LED light source 110, for transmitting the luminance control signal
from the detecting circuit 60 to the LED light source 110, and converts the AC power
input to the luminance switching device 100 of the light source by an external power
source 150 into a DC power that can be received and used by the luminance switching
device 100 and the LED light source 110. Furthermore, the power conversion circuit
90 of the present invention can also be a DC/DC converter. At this time, the external
power source 150 is a DC power source, for providing power to the luminance switching
device 100 and the LED light source 110.
[0014] FIG. 2B is a simplified circuit diagram of the detecting circuit 60 of FIG. 2A. Referring
to FIG. 2A, the detecting circuit 60 of the present invention includes an amplifier
62 and an analog/digital conversion circuit 64. A forward input end of the amplifier
62 is used for receiving the luminance signal e.g. a current signal of each of the
LEDs 120 in the LED light source 110, and a backward input end of the amplifier 62
is electrically connected to the changeover switch 130. The analog/digital conversion
circuit 64 is electrically between the amplifier 62 and the memory unit 70, for converting
an analog control signal transmitted from the amplifier 62 and the memory unit 70
into a digital control signal, and transmitting the digital control signal to the
power conversion circuit 90. The power conversion circuit 90 then converts the digital
control signal into a luminance control signal, which is used to control the luminance
of the light emitted by each of the LEDs 120 in the LED light source 110.
[0015] The luminance switching device 100 according to the present invention can adjust
the luminance value of the light emitted by each of the LEDs 120 in the LED light
source 110 precisely, and the operating principle is described as follows. Referring
to FIGs. 2A and 2B again, when the changeover switch 130 is OFF, the luminance switching
device 100 detects the luminance of the light emitted by each of the LEDs 120 in the
LED light source 110, and a luminance signal 112 is input to the forward input end
of the detecting circuit 60 via a signal feed-in end 102 of the luminance switching
device 100. The luminance signal 112 can be a current signal, which carries the luminance
value of the light emitted from each of the LEDs 120 of the LED light source 110.
After being amplified by the amplifier 62 of the detecting circuit 60, the luminance
signal 112 is then converted into a digital signal by the analog/digital conversion
circuit 64 and transmitted to the memory unit 70. At this time, the memory unit 70
stores the luminance state of the light emitted by each of the LEDs 120. When the
changeover switch 130 is turned on, the plurality of LEDs 120 in the LED light source
110 assumes the same or different luminance states according to an originally set
state (it is assumed that all of the LEDs 120 are in the turn-on state, and the luminance
of the light emitted by the LEDs 120 is the same), and the memory unit 70 stores the
luminance value of the light emitted by each of the LEDs 120. The luminance state
of each of the LEDs 120 stored in the memory unit 70 is converted into an analog signal
by a conversion interface (not shown), and the analog signal is transmitted to the
analog/digital conversion circuit 64. Then, the control signal of the luminance value
of the light emitted by each LED 120 that is required to reach the originally set
state is transmitted to the power conversion circuit 90, so as to convert the control
signal into a luminance control signal 114 that can be received by the LED light source
110, such that each LED 120 assumes the preset luminance value. The luminance control
signal 114 can be a pulse width modulation (PWM) signal, a voltage control signal,
or a current control signal.
[0016] When the changeover switch 130 is turned off and then is turned on, the luminance
switching device 100 controls the luminance value of the light emitted by each LED
120 according to the originally set state. For example, at this time, the luminance
of the light emitted by at least one LED 120 is reduced, such that the image presented
by the entire LED light source 110 shows different visual effects due to the luminance
change of the LEDs 120. As the memory unit 70 of the present invention can store different
luminance values that the LEDs 120 will present according to the original setting
each time after the changeover switch 130 is turned on, the luminance value that each
of the LEDs 120 in the LED light source 110 will present can be controlled, and the
problem of uneven light caused by the influence of neighboring LEDs 120 will not occur.
[0017] FIG. 3 is a schematic view of another implementation aspect of the LED light source
110 of the present invention. Referring to FIG. 3, in this embodiment, a DC power
source 140 is connected to the LED light source 110 externally, which is used as the
power source of the LEDs 120 directly. Other parts of this embodiment are the same
as those of the above embodiment, and will not be described herein again.
[0018] The changeover switch 130 of the present invention can be a common switch, which
provides an external trigger signal to the luminance switching device 100 through
a manual switching motion. The external trigger signal can be a continuous pressing
signal. A user can press the changeover switch 130 with a hand continuously, with
the increase of the time that the user presses and holds the changeover switch, the
luminance of the LEDs 120 of the LED light source 110 in the continuous switching
mode will increase or reduce accordingly. In addition, the external trigger signal
can also be a multi-stage pressing signal. The user can set the changeover switch
130 to a plurality of switching modes according to a preset interval of time. When
the user presses the changeover switch 130 continuously by hand, with the increase
of the time that the user presses and holds the changeover switch, the luminance of
the LEDs 120 of the LED light source 110 in this continuous switching mode will increase
in multiple stages or decrease in multiple stages. Moreover, the external trigger
signal can also be a multi-stage switching signal. The user can define the switching
times of the changeover switch 130 to a plurality of switching modes. When the user
switches the changeover switch 130 by hand, the luminance of the LEDs 120 of the LED
light source 110 in this switching mode will increase in multiple stages or decrease
in multiple stages as well. Furthermore, the changeover switch 130 can also be a programmable
circuit used with a computer, so as to realize the multi-stage switching of the LEDs
120 of the LED light source.
[0019] It should be noticed that the luminance switching device 100 of the present invention
is not only applicable to general LED display devices, but also to multi-stage lighting
lamps, decorating lamps with variable colors, lighting lamps with variable colors,
and the like, as long as the LED light source is composed of LEDs emitting light of
different colors (R, G, and B).
[0020] Compared with the conventional art, the illuminating device and the luminance switching
device 100 thereof according to the present invention include a built-in memory unit,
which stores the luminance value of the light emitted by each of the LEDs in each
of the preset switching mode of the changeover switch 130. Therefore, each time after
the changeover switch is switched, the LEDs can present the required luminance values
of the light, and the problem of uneven light caused by the influence of the light
emitted by neighboring LEDs 120 is prevented.
1. A luminance switching device (100), for switching luminance of a plurality of light-emitting
states produced by a light-emitting diode (LED) light source (110) including at least
one LED (120), the luminance switching device (100) comprising:
a changeover switch (130), electrically connected to the luminance switching device
(100), for switching the light-emitting states of the LEDs (120), wherein the changeover
switch (130) has a plurality of switching modes corresponding to the plurality of
light-emitting states;
a detecting circuit (60), electrically connected to the changeover switch (130), for
detecting the switching modes of the changeover switch (130);
a memory unit (70), electrically connected to the detecting circuit (60), for storing
luminance values of the LEDs (120) corresponding to the switching modes of the changeover
switch (130) detected by the detecting circuit (60), converting the luminance values
of the LEDs (120) into a luminance control signal (114), and transmitting the luminance
control signal (114) to the detecting circuit (60); and
a power conversion circuit (90), electrically connected to the LED light source (110),
for receiving the luminance control signal (114) transmitted from the detecting circuit
(60), such that the LEDs (120) produce luminance of the light-emitting states corresponding
to the switching modes.
2. The luminance switching device (100) as claimed in claim 1, wherein the luminance
of at least one LED (120) of the LED light source (110) is different under a different
switching mode of the changeover switch (130).
3. The luminance switching device (100) as claimed in claim 1, further comprising an
external power source (150), for providing power to the luminance switching device
(100) through the switching of the changeover switch (130).
4. The luminance switching device (100) as claimed in claim 1, further comprising a direct
current (DC) power source (140) electrically connected to the LED light source (110),
for providing power to the LED light source (110).
5. The luminance switching device (100) as claimed in claim 1, wherein the detecting
circuit (60) comprises:
an amplifier (62), having a forward input end for receiving the light-emitting states
of the LED light source (110), and a backward input end electrically connected to
the changeover switch (130) for receiving the switching modes of the changeover switch
(130); and
an analog/digital conversion circuit (64), electrically connected to the amplifier
(62) and the memory unit (70), for converting an analog control signal transmitted
from the amplifier (62) and the memory unit (70) into a digital control signal.
6. The luminance switching device (100) as claimed in claim 2, wherein the changeover
switch (130) performs the switching modes of the LED light source (110) through an
external trigger signal.
7. The luminance switching device (100) as claimed in claim 6, wherein the external trigger
signal is a continuous pressing signal, and the luminance values of the LEDs (120)
of the LED light source (110) are in direct or inverse proportion to time when the
changeover switch (130) is pressed.
8. The luminance switching device (100) as claimed in claim 6, wherein the external trigger
signal is a multi-stage switching signal, and the luminance values of the LEDs (120)
of the LED light source (110) increase in multiple stages or decreases in multiple
stages according to a number of times that the changeover switch (130) is switched.
9. The luminance switching device (100) as claimed in claim 6, wherein the external trigger
signal is a multi-stage pressing signal, a predetermined time interval exists between
the switching modes, and the luminance values of the LEDs (120) of the LED light source
(110) increase in multiple stages or decreases in multiple stages according to the
time when the changeover switch (130) is pressed.
10. The luminance switching device (100) as claimed in claim 6, further comprising a signal
input end for receiving the external trigger signal.
11. The luminance switching device (100) as claimed in claim 1, wherein the changeover
switch (130) is a programmable circuit.
12. The luminance switching device (100) as claimed in claim 1, wherein the power conversion
circuit (90) is an alternate current (AC)/ direct current (DC) converter.
13. The luminance switching device (100) as claimed in claim 1, wherein the power conversion
circuit (90) is a DC/DC converter.
14. The luminance switching device (100) as claimed in claim 1, wherein the luminance
control signal (114) output from the power conversion circuit (90) is a pulse width
modulation (PWM) signal or a voltage signal or a current signal.