Illumination adjusting device, illumination system using the same and illumination adjusting method

An illumination adjusting device for receiving power from a power supply and supplying output voltage to a lighting unit is provided herein. The illumination adjusting device includes a detector for detecting ambient illumination intensity and generating an ambient illumination value according to the ambient illumination intensity; a comparator for comparing the ambient illumination value with a predetermined value, the comparator outputting a first power signal when the ambient illumination value is lower than a predetermined value; an adjustor for adjusting the output voltage according to the first power signal, as a result, light emitted by the lighting unit is controlled within a predetermined illumination intensity range. A related illumination adjusting method is also provided.

BACKGROUND

1. Field of the Invention

The present invention relates to detecting and adjusting devices, and particularly to an illumination adjusting device and method for adjusting an illumination intensity of a lighting unit.

2. Description of Related Art

Nearsightedness or myopia occurs mostly in our childhood or early teen years (between 8 and 14 years of age). The risk of developing myopia is increased if there is a family history of myopia because myopia is generally hereditary. There may also be links between myopia and prolonged close-up work, such as reading or sitting close to the television, and between myopia and prolonged work in places with inadequate illumination intensity, although there is little scientific evidence for these. Many people use lamps with the same operating voltage in their living rooms and bedrooms. In fact, 250-300 LUX is the correct horizontal illumination intensity range for the living room, 100-150 LUX for the bedroom, and 300-500 LUX for a library. Even if a person has adopted the right lamps there is also a problem, the illumination intensity decreases when the lamps are used. As a result, the illumination intensity may be inadequate when the lamps are used over an extended period of time, and this may affect the people's vision.

Therefore, an improved illumination adjusting device and method are needed to address the aforementioned deficiency and inadequacies.

SUMMARY

An illumination adjusting device for receiving power from a power supply and supplying output voltage to a lighting unit is provided herein. The illumination adjusting device includes a detector for detecting ambient illumination intensity and generating an ambient illumination value according to the ambient illumination intensity; a comparator for comparing the ambient illumination value with a predetermined value, the comparator outputting a first power signal when the ambient illumination value is lower than a predetermined value; an adjustor for adjusting the output voltage according to the first power signal, as a result, the light emitted by the lighting unit is controlled to be within a predetermined illumination intensity range. A related illumination adjusting method is also provided.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made to the drawings to describe a preferred embodiment of the present illumination adjusting device.

Referring toFIG. 1, an illumination adjusting device2is connected between a power supply32and a lighting unit34. The lighting unit34may include at least a fluorescence lamp and/or at least an incandescent lamp, etc. The illumination adjusting device2is configured for realizing a plurality of selections including a plurality of illumination intensity ranges, such as a living room intensity range, a bedroom intensity range, and a library intensity range. Thus, the illumination intensity range of the lighting unit34can be selected as required. After one of the plurality of illumination intensity ranges is selected (selected illumination intensity range, in a range from 300 LUX to 500 LUX for example), the illumination adjusting device2receives power from the power supply32, and supplies a corresponding output voltage to the lighting unit34according to the selected illumination intensity range, as a result, the lighting unit34emits light at an illumination intensity corresponding to the selected illumination intensity range. Furthermore, the illumination adjusting device2is configured for detecting ambient illumination intensity, and adjusting the output voltage according to the ambient illumination intensity. Thus, the illumination intensity of light emitted by the lighting unit34can be controlled to be within the selected illumination intensity range.

Referring toFIG. 2, the illumination adjusting device2includes a detector20, a selector22, a comparator24, a first notifier26, a controller28, an adjustor30, and a second notifier36.

The selector22is configured for realizing the number of selections including the plurality of illumination intensity ranges for the user, and outputting a corresponding level signal according to the selected illumination intensity range. The detector20is configured for detecting the ambient illumination intensity, and generating a corresponding ambient illumination value according to the ambient illumination intensity.

The comparator24is configured for comparing the ambient illumination value with a predetermined value, outputting a first power signal to the first notifier26when the ambient illumination value is higher than or equal to the predetermined value, and outputting a second power signal to the controller28when the ambient illumination value is lower than the predetermined value. In the embodiment, if the ambient illumination intensity is higher than or equal to a lowest illumination intensity of the selected illumination intensity range, the ambient illumination value is higher than or equal to the predetermined value, if the ambient illumination intensity is lower than the lowest illumination intensity of the selected illumination intensity range, the ambient illumination value is lower than the predetermined value. The first notifier26is configured for outputting a first feedback signal to indicate that the ambient illumination intensity is within the selected illumination intensity range. In the preferred embodiment, the first feedback signal is a green light signal.

The controller28is configured for generating a third power signal and an adjusting signal in response to the second power signal. The controller28outputs the third power signal to the second notifier36, and outputs the adjusting signal to the adjustor30. The second notifier36is configured for outputting a second feedback signal to indicate that the ambient illumination intensity is outside the selected illumination intensity range. In the preferred embodiment, the second feedback signal may be a red light signal or a sound signal.

The adjustor30is configured for adjusting the output voltage supplied to the lighting unit34, as a result, the light emitted by the lighting unit34is controlled to be within the selected illumination intensity range. In detail, the adjustor30outputs a corresponding output voltage to the lighting unit34in response to the level signal from the selector22, and increasing the output voltage at a constant rate (by predetermined increments) in response to the adjusting signal from the controller28.

Referring toFIG. 3, the detector20includes a photoconductive unit. The photoconductive unit may be a photoconductive cell, or a photodiode, etc. In the preferred embodiment, the photoconductive unit is a photoconductive cell R10in which resistance decreases when surrounding illumination intensity increases. The selector22includes resistors R1, R2, R3, and a switch K. The comparator24includes a resistor R4, bipolar junction transistors (BJTs) T1, T2, T3, T4, and a capacitor C1. The first notifier26includes a resistor R5and a light-emitting diode (LED) L1. The second notifier36includes a LED L2connected to the controller28. The controller28is a control integrate circuit, such as the chip model PIC16F877A. The adjustor30is an integrate circuit including integrated lighting unit driver with digital and pulse-width modulation (PWM) brightness control.

The adjustor30includes a first input port P1, a second input port P2, a third input port P3, a output port P4connected to the lighting unit34, a ground port GND grounded, and a control port P6connected to the controller28. An end of the photoconductive cell R10is connected to a voltage collector to collector (VCC) source that supplies voltage of +5 volts. The other end of the photoconductive cell R10is connected to the switch K. The switch K includes four fixed contacts (“b,” “c,” “d,” and “f”) and a moveable contact (“e”) that is movable with respect to the fixed contacts. The contact “b” is connected to a first input port of the adjustor30, an end of the resistor R1, and a base of the BJT T1. The contact “c” is connected to a second input port of the adjustor30, an end of the resistor R2, and a base of the BJT T2. The contact “d” is connected to a third input port of the adjustor30, an end of the resistor R3, and a base of the BJT T3. The other ends of the resistors R1, R2, R3are grounded. The collectors of the BJT T1, T2, T3, and the base of the BJT T4are connected to an end of the resistor R4and a cathode of the LED L1. The emitters of the BJT T1, T2, T3are grounded. The other end of the resistor R4is connected to the VCC source. An anode of the LED L1is connected to the VCC source via the resistor R5. The collector of the BJT T4is connected to the VCC source. The emitter of the BJT T4is connected to the controller28and an anode of the capacitor C1. The cathode of the capacitor C1is grounded. The LED L2is connected to the controller28.

In operation, the contact “b” of the switch K corresponds to a first illumination intensity range, the living room intensity range (250-300 LUX) for example. The contact “c” of the switch K corresponds to a second illumination intensity range, the bedroom intensity range (100-150 LUX) for example. The contact “d” of the switch K corresponds to a third illumination intensity range, the library intensity range (300-500 LUX), for example. The contact “f” is configured for turning off the lighting unit34. When the moveable contact “e” is connected to the contact “f,” the adjustor30has no output, thus the lighting unit34is turned off.

For example, if the first illumination intensity range is selected, that is, the contact “e” is connected to the contact “b,” the adjustor30receives a voltage (that is, the level signal) via the first input port P1and outputs a first output voltage to the lighting unit34. Thus the lighting unit34emits light within the first illumination intensity range. If a first voltage (that is, the ambient illumination value) applied on the resistor R1is higher than or equal to the predetermined value (0.7 volts for example), the BJT T1turns on. A third voltage (that is, the first power signal) is applied to the cathode of the LED L1and the base of the BJT T4. As a result, the BJT T4turns off, and the LED L1is turned on and outputs the first feedback signal to indicate that the ambient illumination intensity is within the first illumination intensity range.

However, the illumination intensity decreases when the lighting unit34is used over an extended period of time. As the ambient illumination intensity decreases, the resistance of the photoelectric cell R10increases accordingly. Therefore, a second voltage applied on the photoelectric cell R10increases and the first voltage applied on the resistor R1decreases. When the ambient illumination intensity becomes lower than a lowest illumination intensity of the first illumination intensity range, and the first voltage becomes lower than the predetermined value (0.7 volts for example), the BJT T1turns off, the 5 volts voltage is applied to the cathode of the LED L1and the base of the BJT T4. Thus, the LED L1is turned off, and the BJT T4turns on to output a current (that is, the second power signal) to the controller28. The controller28generates the third power signal and the adjusting signal in response to the second power signal. In response to the third power signal, the second notifier36outputs the second feedback signal to indicate that the ambient illumination intensity is outside the selected illumination intensity range. In response to the adjusting signal, the adjustor30increases the output voltage at a constant rate. As a result, the light emitted by the lighting unit34is controlled within the first illumination intensity range.

In the other embodiments, the resistor R4and the controller28can be omitted, the LED L2can be connected between the VCC source and the collector of the BJT T4, and the control port P6of the adjustor30can be connected to the emitter of the BJT T4. As described above, the ambient illumination intensity can be maintained within a predetermined illumination intensity range, thus a user's vision can be protected.