KR20090040704A - Operating method of light emitting diode projector for using digital variable resistance and light emitting diode projector enabling of the method - Google Patents

Operating method of light emitting diode projector for using digital variable resistance and light emitting diode projector enabling of the method Download PDF

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Publication number
KR20090040704A
KR20090040704A KR1020070106180A KR20070106180A KR20090040704A KR 20090040704 A KR20090040704 A KR 20090040704A KR 1020070106180 A KR1020070106180 A KR 1020070106180A KR 20070106180 A KR20070106180 A KR 20070106180A KR 20090040704 A KR20090040704 A KR 20090040704A
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KR
South Korea
Prior art keywords
led
voltage
constant current
projector
supplying
Prior art date
Application number
KR1020070106180A
Other languages
Korean (ko)
Inventor
박용수
Original Assignee
엘지전자 주식회사
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Publication date
Application filed by 엘지전자 주식회사 filed Critical 엘지전자 주식회사
Priority to KR1020070106180A priority Critical patent/KR20090040704A/en
Publication of KR20090040704A publication Critical patent/KR20090040704A/en

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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • G03B21/2006—Lamp housings characterised by the light source
    • G03B21/2013—Plural light sources
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • G03B21/2006—Lamp housings characterised by the light source
    • G03B21/2033—LED or laser light sources
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
    • H04N9/3141—Constructional details thereof
    • H04N9/315—Modulator illumination systems
    • H04N9/3155—Modulator illumination systems for controlling the light source
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
    • H04N9/3141—Constructional details thereof
    • H04N9/315—Modulator illumination systems
    • H04N9/3164—Modulator illumination systems using multiple light sources

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Projection Apparatus (AREA)

Abstract

An operating method of a light emitting diode projector for by a digital variable resistor and a light emitting diode projector by using the same are provided to cool an LED efficiently by measuring the temperature of the LED and operating a fan according to the temperature of the LED. An operating method of a light emitting diode projector for by a digital variable resistor comprises: a sub micro computer(203) which periodically measures the voltage of a constant current driving circuit(202) supplying the constant current to an LED(201); and a controller(204) which determines whether the measured voltage is the voltage for supplying maximum current to the LED. The controller controls the digitally variable resistor(205) connected with the constant current driving circuit in case the voltage fed back is not the voltage for supplying the maximum current to the LED. According to the temperature of the LED, the rotation speed of a fan(207) near to the LED is controlled with the controller.

Description

LED projector using digital variable resistor and LED projector employing the same method

The present invention relates to a light emitting diode (LED) projector, and more particularly, by adjusting a digital variable resistor connected to the LED at a predetermined cycle, so that the brightness of the LED can be kept constant and the life of the LED can be extended. A method of operating an LED projector and an LED projector employing the method.

In order to optimize the brightness of the LED of the prior art LED projector, the oscilloscope finds the current when the LED operates at the maximum brightness, and sets a variable resistor so that the current flows into the LED.

1 is a view showing an embodiment of setting a variable resistor in the LED projector of the prior art.

Referring to FIG. 1, in order to set the variable resistor in the LED projector of the related art, an oscilloscope is connected to the points A, B, and C where current flows into each of the red LED, the green LED, and the blue LED. The variable resistors R1 (101), R2 (102), and R3 (103) were set directly by the user to maximize the current flowing therein.

However, the LED projector of the prior art as described above has a problem that the current value set once flows continuously to the LED, so that even if the surrounding environment changes, it cannot be properly applied.

In addition, when the set current value is not constant, there is a problem in that the brightness of the LED is changed and the white balance is not matched, and the LED is damaged and the life is shortened.

Therefore, by solving this problem, the active current in response to changes in the surrounding environment to ensure that the maximum current flows in the LED, so that the brightness of the LED is kept constant, the life of the LED can be extended, and also it is sensitive to temperature There is an urgent need for the development of LED projectors that can efficiently cool LEDs.

The present invention solves the problems of the prior art as described above to actively respond to changes in the surrounding environment to ensure that the maximum current flows in the LED, so that the brightness of the LED is kept constant, and to extend the life of the LED It is also an object of the present invention to provide a method of operating an LED projector that can efficiently cool a temperature sensitive LED and an LED projector employing the method.

Method of operating an LED projector according to an embodiment of the present invention comprises the steps of measuring the voltage of the constant current driving circuit for supplying a constant current to the LED at a predetermined period and feedback to the control unit; Determining whether the feedback voltage is a voltage capable of supplying a maximum current to the LED; And controlling the constant current driving circuit to supply the maximum current to the LED by adjusting a digital variable resistor connected to the constant current driving circuit when the feedback voltage is not a voltage capable of supplying a maximum current to the LED. do.

In addition, the LED projector according to another embodiment of the present invention includes a sub-microcom measuring the voltage of the constant current driving circuit for supplying a constant current to the LED at a predetermined period and feeding back to the control unit; It is determined whether the feedback voltage is a voltage capable of supplying a maximum current to the LED, and when the feedback voltage is not a voltage capable of supplying a maximum current to the LED, the digital variable resistor connected to the constant current driving circuit is adjusted to adjust the voltage. And a control unit for controlling a constant current driving circuit to supply the maximum current to the LED.

The present invention feeds back the voltage of the constant current driving circuit at predetermined cycles, and controls the digital variable resistor according to the fed back voltage to allow the maximum current to flow, thereby actively responding to changes in the surrounding environment to maximize the LED. The current flows, the brightness of the LED is kept constant, and there is an effect of extending the life of the LED.

In addition, the present invention has the effect of efficiently cooling the LED sensitive to the LED temperature by adjusting the digital variable resistor at a predetermined period, and by adjusting the rotation speed of the fan.

Hereinafter, an operation method of an LED projector and an LED projector employing the method will be described in detail with reference to the accompanying drawings.

2 is a block diagram showing the configuration of an LED projector according to an embodiment of the present invention. Referring to FIG. 2, the constant current driving circuit 202 supplies a constant current to the LED 201.

The sub microcomputer 203 measures the voltage of the constant current driving circuit 202 that supplies the constant current to the LED 201 at a predetermined cycle and feeds it back to the controller 204.

In this case, the period in which the sub micom 203 feeds back a voltage to the controller 204 may be variously applied according to a user's setting. For example, the sub microcomputer 203 may be a frame unit of an image signal input to the LED projector. For example, the period in which the sub micom 203 feeds back a voltage to the controller 204 may be 60 Hz, which is a frame unit of an image signal input to the LED projector.

The controller 204 determines whether the feedback voltage is a voltage capable of supplying a maximum current to the LED. In this case, when the feedback voltage is analog, the controller may reduce the amount of calculation by changing the feedback voltage to a digital value using an analog to digital converter (ADC).

The controller 204 controls the constant current driving circuit to supply the maximum current to the LED by adjusting a digital variable resistor connected to the constant current driving circuit when the feedback voltage is not a voltage capable of supplying a maximum current to the LED. do.

For example, when the voltage that can supply the maximum current to the LED is 10V, and the feedback voltage is 8V, the controller controls the constant current driving circuit to take 10V by adjusting the digital variable resistor value.

Accordingly, the present invention feeds back the voltage of the constant current driving circuit at predetermined intervals, and adjusts the digital variable resistor according to the fed back voltage to control the maximum current to flow through the LED, thereby actively responding to changes in the surrounding environment. By allowing the maximum current to flow through the LED, the brightness of the LED is kept constant, and there is an effect of extending the life of the LED.

On the other hand, the performance of the LED is sensitive to temperature, the present invention, in order to improve the characteristics of the temperature-sensitive LED, the temperature sensor unit 206 is installed near the LED 201. The temperature sensor unit 206 measures the temperature value of the LED at predetermined intervals. The sub micom 203 transmits the temperature value measured by the temperature sensor unit 206 to the control unit 204. The period may be variously applied according to a user's setting. For example, the period may be a frame unit of an image signal input to an LED projector.

The controller 204 increases the rotation speed of the fan 207 proximate to the LED when the transmitted temperature value is higher than the reference value and lowers the rotation speed of the fan 207 if the temperature value is lower than the reference value. At this time, the fan 207 forms a passage from the inlet port to the exhaust port and passes cold air, thereby maintaining the temperature of the LED 201 at an appropriate level.

Therefore, the present invention has the effect of efficiently cooling the LED sensitive to the LED temperature by adjusting the digital variable resistance at a predetermined period, and by adjusting the rotation speed of the fan.

Meanwhile, according to an embodiment, the LED may include a red LED, a green LED, and a blue LED, and the above-described digital variable resistance adjustment process and the rotation speed adjustment process of the fan may be performed for each of the LEDs.

3 is a block diagram illustrating a configuration of an LED projector that performs digital variable resistance adjustment and rotation speed adjustment of a fan for each of the red LED, the green LED, and the blue LED according to an embodiment of the present invention.

Referring to FIG. 3, an LED projector according to an embodiment of the present invention includes a red LED 301, a green LED 302, and a blue LED 303, and each LED includes a constant current driving circuit 304, 305, 306).

The sub microcomputer 307 measures the voltage of each of the constant current driving circuits 304, 305, and 306 at predetermined intervals and feeds it back to the controller 308.

The controller 308 determines whether the feedback voltage is a voltage capable of supplying a maximum current to each of the LEDs.

The controller 308 adjusts the digital variable resistors 309, 310, and 311 when the feedback voltage is not a voltage capable of supplying a maximum current to the LED so that each constant current driving circuit provides the maximum current to each LED. Control to supply.

In addition, the temperature sensor units 312, 313, and 314 installed in the respective LEDs 301, 302, and 303 measure temperature values of the LEDs at predetermined intervals, and the sub-microcom 307 measures the temperature sensor units 312, 313, and the like. The temperature value measured at 314 is transmitted to the controller 308.

The controller 308 increases the rotation speed of the fan close to the LED where the temperature sensor unit is located when the temperature value transmitted from each temperature sensor unit is higher than the reference value, and lowers the rotation speed of the fan when the temperature value is lower than the reference value.

 4 is a flowchart illustrating a process of adjusting a variable resistance value of a red LED, a green LED, and a blue LED according to an embodiment of the present invention.

Referring to FIG. 4, in step S401, the LED projector sets the maximum current that can flow through each LED and the voltage applied to the constant current driving circuit when the maximum current flows.

In step S402, the LED projector receives and reads the voltage of the constant current driving circuit that supplies the constant current to the red LED, and determines whether the voltage fed back in the step S403 is a voltage when the maximum current flows in the red LED.

If the feedback voltage is not the voltage at which the maximum current flows in the red LED, the LED projector adjusts the digital variable resistor connected to the red LED in step S404, and the feedback voltage of the maximum current flows in the red LED. In the case of a voltage, in step S405, the voltage of the constant current driving circuit that supplies the constant current to the green LED is fed back and read, and it is determined whether the voltage fed back in the step S406 is the voltage at which the maximum current flows in the green LED.

If the feedback voltage is not the voltage at which the maximum current flows in the green LED, the LED projector adjusts the digital variable resistor connected to the green LED in step S407, and the feedback voltage of the maximum current flows in the green LED. In the case of the voltage, in step S408, the voltage of the constant current driving circuit that supplies the constant current to the blue LED is fed back and read.

In step S409, the LED projector determines whether the fed back voltage is the voltage when the maximum current flows in the blue LED, and if the fed back voltage is not the voltage when the maximum current flows in the blue LED, in step S410 Adjust the digital potentiometer connected to the LED.

If the fed back voltage is the voltage at which the maximum current flows in the blue LED, the LED projector terminates the setting in step S411. The process of FIG. 4 may be performed at the predetermined cycle described above.

As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above-described embodiments, which can be variously modified and modified by those skilled in the art to which the present invention pertains. Modifications are possible. Accordingly, the spirit of the present invention should be understood only by the claims set forth below, and all equivalent or equivalent modifications thereof will belong to the scope of the present invention.

1 is a diagram illustrating an embodiment of setting a variable resistor in a LED projector of the prior art.

Figure 2 is a block diagram showing the configuration of an LED projector according to an embodiment of the present invention.

Figure 3 is a block diagram showing the configuration of the LED projector to perform the digital variable resistance adjustment and the rotation speed adjustment of the fan for each of the red LED, green LED, blue LED according to an embodiment of the present invention.

4 is a flowchart illustrating a process of adjusting a variable resistance value of a red LED, a green LED, and a blue LED according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

201: Light Emitting Diode (LED)

202: constant current driving circuit

203: sub micom

204: control unit

205: digital potentiometer

206: temperature sensor

207: fan

Claims (8)

In the method of operating an LED (Light Emitting Diode) projector, Measuring a voltage of a constant current driving circuit for supplying a constant current to a light emitting diode (LED) at a predetermined cycle and feeding it back to the controller; Determining whether the feedback voltage is a voltage capable of supplying a maximum current to the LED; And Controlling the constant current driving circuit to supply the maximum current to the LED by adjusting a digital variable resistor connected to the constant current driving circuit when the feedback voltage is not a voltage capable of supplying a maximum current to the LED. Operating method of the LED projector comprising a. The method of claim 1, The period is an operation method of the LED projector, characterized in that the frame unit of the image signal input to the LED projector. The method of claim 1, The LED includes a red LED, a green LED, a blue LED, and the steps are performed for each of the LEDs. The method of claim 1, Feeding back a temperature value measured at a predetermined period in a temperature sensor unit installed in the LED to the controller; Increasing the rotational speed of the fan close to the LED when the temperature value is higher than the reference value and lowering the rotational speed of the fan when the temperature value is lower than the reference value by the controller; Operation method of the LED projector, characterized in that it further comprises. A sub-microcom which measures a voltage of a constant current driving circuit for supplying a constant current to a light emitting diode (LED) at predetermined intervals and feeds it back to the controller; And It is determined whether the feedback voltage is a voltage capable of supplying a maximum current to the LED, and when the feedback voltage is not a voltage capable of supplying a maximum current to the LED, the digital variable resistor connected to the constant current driving circuit is adjusted to adjust the voltage. Control unit for controlling the constant current drive circuit to supply the maximum current to the LED LED projector comprising a. The method of claim 5, The period is an LED projector, characterized in that the frame unit of the image signal input to the LED projector. The method of claim 5, Wherein the LED comprises a red LED, a green LED, a blue LED, and the steps are performed for each of the LEDs. The method of claim 5, A temperature sensor unit installed in the LED and measuring a temperature value at a predetermined cycle and feeding back to the controller; More, The control unit increases the rotation speed of the fan close to the LED when the temperature value is higher than the reference value, and lowers the rotation speed of the fan when the temperature value is lower than the reference value.
KR1020070106180A 2007-10-22 2007-10-22 Operating method of light emitting diode projector for using digital variable resistance and light emitting diode projector enabling of the method KR20090040704A (en)

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Application Number Priority Date Filing Date Title
KR1020070106180A KR20090040704A (en) 2007-10-22 2007-10-22 Operating method of light emitting diode projector for using digital variable resistance and light emitting diode projector enabling of the method

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Application Number Priority Date Filing Date Title
KR1020070106180A KR20090040704A (en) 2007-10-22 2007-10-22 Operating method of light emitting diode projector for using digital variable resistance and light emitting diode projector enabling of the method

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101126610B1 (en) * 2009-12-16 2012-03-26 주식회사 티엘아이 LED driving circuit controlling supply voltage with digital data
KR102105798B1 (en) * 2019-11-07 2020-04-28 주식회사 애즈원 Led electronic display system with current control for preventing reducing display quility
KR102451458B1 (en) * 2022-03-02 2022-10-07 주식회사 시스메이트 White balance control system and method for LED display screen

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101126610B1 (en) * 2009-12-16 2012-03-26 주식회사 티엘아이 LED driving circuit controlling supply voltage with digital data
KR102105798B1 (en) * 2019-11-07 2020-04-28 주식회사 애즈원 Led electronic display system with current control for preventing reducing display quility
WO2021091129A1 (en) * 2019-11-07 2021-05-14 Asone Co., Ltd. Led electronic display board system with current control for preventing reducing display quality
KR102451458B1 (en) * 2022-03-02 2022-10-07 주식회사 시스메이트 White balance control system and method for LED display screen

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