JP5452369B2 - Multi-screen display device - Google Patents

Description

  The present invention relates to a multi-screen display device in which screens of a plurality of video display devices are arranged, and more particularly to cooling control of a plurality of video display devices.

  As a display device that displays a large image, a multi-screen display device in which the screens of a plurality of projection-type image display devices are arranged is known. Conventionally, a discharge lamp has been widely used as a light source in the projection-type image display device. However, in recent years, with the advancement of technology, the output luminance of a light emitting diode (LED) can withstand use as a light source of a projection-type image display device. As disclosed in US Pat. No. 4, an LED is used as a light source for the device.

  However, in general, since the LED's self-heating temperature is low, the LED's temperature is likely to change according to the environmental temperature, and the LED's luminance characteristics tend to change according to the LED's temperature. The characteristics are likely to change according to the environmental temperature. Therefore, a video display device using an LED as a light source is more likely to change the video brightness due to a change in environmental temperature or the like, compared to a video display device using a discharge lamp as a light source.

JP 2005-274484 A JP 2000-165076 A

  Now, in the multi-screen display device, each video display device receives heat nonuniformly from other video display devices installed without gaps in the top, bottom, left, and right, and in the air conditioning capability and the installation position. Since the environmental temperature is different, the temperature of the light source in each of the plurality of video display devices is also different from each other. As a result, in the multi-screen display device using LEDs as a light source, there is a problem that the video luminance of the entire screen varies from screen to screen of the video display device. This problem similarly occurs when a flat panel image display device using LEDs as a backlight is used instead of the projection image display device.

  In order to solve such a problem, a technique for matching the temperatures of light sources in a plurality of video display devices with each other has been proposed. However, as disclosed in Patent Document 1, a technique in which a plurality of video display devices are enclosed in a single casing and the entire casing is cooled cannot be efficiently cooled, and the temperatures of the plurality of video display apparatuses are accurately controlled. Could not match. In addition, a technology has been proposed in which a cooling device is provided for each of a plurality of video display devices, and each video display device is cooled in a state of being substantially closed by a housing, but the cooling control is independently performed for each video display device. As a result, it has been impossible to accurately match temperatures in a plurality of video display devices.

  Therefore, the present invention has been made in view of the above problems, and provides a technique capable of making the temperatures of light sources in a plurality of video display devices coincide with each other in a multi-screen display device. Objective.

  The multi-screen display device according to the present invention is a multi-screen display device in which the screens of a plurality of video display devices are arranged, wherein the plurality of video display devices are connected to each other via communication means, Includes a light source, a temperature sensor that detects the temperature of the light source, a cooling device that cools the light source, and a control unit. The control unit of any one of the video display devices is detected by the temperature sensor of the plurality of video display devices other than the temperature detected by the temperature sensor of the video display device and the communication unit. One target temperature is obtained based on the measured temperature. The control unit of each of the video display devices controls the cooling device based on the temperature detected by its temperature sensor and the target temperature.

  As another configuration, the multi-screen display device according to the present invention is a multi-screen display device in which screens of a plurality of video display devices are arranged, and the plurality of video display devices are connected via a communication unit. Are connected to each other, and each includes a housing, a light source provided in the housing, a first temperature sensor that detects a temperature in the housing, a first cooling device that cools the inside of the housing, and a control A part. The control unit of any one of the video display devices includes a temperature detected by the first temperature sensor of the video display device, and the first temperatures of the video display devices other than the self obtained through the communication unit. One target temperature is obtained based on the temperature detected by the sensor. The control unit of each of the video display devices controls the first cooling device based on the temperature detected by the first temperature sensor and the target temperature.

  According to the present invention, the control unit of each video display device controls the cooling device based on the temperature detected by its own temperature sensor and one target temperature. Therefore, in each video display device, the temperature detected by the temperature sensor can be brought close to one target temperature, and the temperatures of the respective light sources can be made to coincide with each other. Thereby, the brightness | luminance of each light source of a some video display apparatus can be made mutually correspond.

1 is a diagram illustrating a configuration of a multi-screen display device according to Embodiment 1. FIG. 1 is a block diagram showing a configuration of a video display device according to Embodiment 1. FIG. 2 is a diagram illustrating a configuration of a light source circuit according to Embodiment 1. FIG. 3 is a flowchart showing an operation of the multi-screen display device according to the first embodiment. 3 is a flowchart showing an operation of the multi-screen display device according to the first embodiment. FIG. 5 is a diagram illustrating a configuration of a light source circuit according to a second embodiment.

<Embodiment 1>
FIG. 1 is a schematic diagram showing the configuration of the multi-screen display device according to the first embodiment. The multi-screen display device according to the present embodiment includes nine video display devices 100 arranged in three rows and three columns, and uses the screens of the nine video display devices 100 as one screen. Thereby, the multi-screen display device according to the present embodiment can display a large image.

  The nine video display apparatuses 100 can communicate with each other via a cable 110, and include one master apparatus 101 and eight slave apparatuses 102 to 109 that can communicate with the master apparatus 101.

  The master device 101 transmits one temperature (hereinafter referred to as “target temperature T0”) to be targeted in the nine video display devices 100 to the slave devices 102 to 109. Then, the master device 101 and each of the slave devices 102 to 109 bring the temperature of the light source provided therein closer to the target temperature T0. As a result, in the multi-screen display device according to the present embodiment, even when the distribution of the installation environment temperature is non-uniform or when the heat from other video display devices 100 is non-uniform, The temperature of the light source in each of the video display devices 100 can be matched with each other.

  FIG. 2 is a block diagram showing a configuration of one video display device 100. Each of the master device 101 and each of the slave devices 102 to 109 has the block configuration shown in FIG. 2, and these block configurations are the same as each other. The video display device 100 according to the present embodiment includes a transmission / reception unit 1 serving as communication means, a control circuit 2, a light source circuit 3, a light valve 4, a projection lens 5, a screen 6, a signal processing unit 7, And an image input unit 8.

  When the video display device 100 is the master device 101, the transmission / reception unit 1 can communicate with the slave devices 102 to 109 via the cable 110. Specifically, the transmission / reception unit 1 of the master device 101 transmits information from the control circuit 2 of the master device 101 to the slave devices 102 to 109, and transmits information from the slave devices 102 to 109 to the control circuit of the master device 101. Output to 2.

  On the other hand, when the video display device 100 is one of the slave devices 102 to 109, the transmission / reception unit 1 can communicate with the master device 101 via the cable 110. Specifically, the transmission / reception unit 1 of the slave devices 102 to 109 transmits information from the control circuit 2 of the slave devices 102 to 109 to the master device 101, and transmits information from the master device 101 to the slave devices 102 to 109. Output to the control circuit 102.

  The control circuit 2 controls the light source circuit 3, outputs information from the transmission / reception unit 1 to the light source circuit 3, and outputs information from the light source circuit 3 to the transmission / reception unit 1. The light source circuit 3 is a circuit that emits light, and the light from the light source circuit 3 is output to the light valve 4.

  A video signal from the outside of the video display device 100 is input to the image input unit 8. The signal processing unit 7 performs signal processing such as enlargement / reduction on the video signal, converts the signal after the signal processing into a drive signal for driving the light valve 4, and sends the drive signal to the light valve 4. Output. The light valve 4 intensity-modulates the light output from the light source circuit 3 according to the drive signal, and emits the intensity-modulated light to the screen 6 via the projection lens 5. Thereby, an image is projected on the screen 6.

  FIG. 3 is a block diagram showing a configuration of the light source circuit 3. As shown in FIG. 3, the light source circuit 3 drives the LED 10 that is a semiconductor light emitting element, a heat receiving block 11, a light source drive circuit 13, a temperature sensor 14, a cooling fan 17 that is a cooling device, and a cooling fan 17. A drive / control circuit 18 to be controlled and a housing 19 are provided. As shown in FIG. 3, a heat receiving block 11, a light source drive circuit 13 and a drive / control circuit 18 are provided in the housing 19, and a cooling fan 17 is provided on the wall surface of the housing 19. Yes.

  The heat receiving block 11 holds the LED 10 inside thereof, and a heat sink 12 is provided outside thereof. The heat sink 12 is configured by integrating a fin 12a that radiates its own heat and a heat pipe 12b that transmits heat bidirectionally between the LED 10 and the fin 12a. In such a heat receiving block 11, when the heat sink 12 is cooled, the LED 10 is transmitted and cooled.

  The LED 10 is turned on by pulse driving under the control of the light source driving circuit 13.

  The cooling fan 17 cools the inside of the housing 19, particularly the heat sink 12. When the heat sink 12 is cooled, the LED 10 is transmitted and cooled, so that the cooling fan 17 substantially cools the LED 10.

  The temperature sensor 14 is disposed in the heat receiving block 11 and detects the temperature of the LED 10. Then, the temperature sensor 14 outputs the detected temperature of the LED 10 to the drive / control circuit 18.

  The drive / control circuit 18 is connected to the control circuit 2. The drive / control circuit 18 and the control circuit 2 constitute a control unit 9 that controls the cooling fan 17. Further, the drive / control circuit 18 is also connected to the temperature sensor 14 and can periodically acquire the detected temperature output by the temperature sensor 14.

  When the drive / control circuit 18 acquires the temperature detected by the temperature sensor 14, the drive / control circuit 18 drives the cooling fan 17 by PWM (Pulse Width Modulation) almost simultaneously. Specifically, the drive / control circuit 18 sets and sets a fan coefficient as an execution value of PWM drive based on the detected temperature of the temperature sensor 14 connected to itself and the above-described target temperature T0. The rotational speed of the cooling fan 17 is driven and controlled based on the fan coefficient.

  That is, the drive / control circuit 18 of each video display device 100 controls the cooling fan 17 based on the temperature of the LED 10 detected by its own temperature sensor 14 and the target temperature T0. Hereinafter, the fan coefficient set in the drive / control circuit 18 may be referred to as a “set fan coefficient”.

  The drive / control circuit 18 according to the present embodiment can also detect an error such as a failure of the cooling fan 17.

<Operation for obtaining target temperature T0>
The target temperature T0 necessary for controlling the cooling fan 17 is obtained in the control circuit 2 of the master device 101 (hereinafter also referred to as “master control circuit 2”). Next, how the target temperature T0 is obtained will be described.

  The drive / control circuit 18 of each of the slave devices 102 to 109 transmits the detected temperature of the temperature sensor 14 and the set fan coefficient to the master device 101 via the control circuit 2, the transmission / reception unit 1, and the cable 110 shown in FIG. To do. The transmission / reception unit 1 of the master device 101 outputs the detected temperature and the set fan coefficient from the slave devices 102 to 109 to the master control circuit 2. In parallel with this, the drive / control circuit 18 of the master device 101 outputs its detected temperature and set fan coefficient to the master control circuit 2. Then, the master control circuit 2 obtains one target temperature T0 based on the detected temperatures and the set fan coefficients in the nine video display devices 100.

  The master control circuit 2 transmits the obtained target temperature T0 to the slave devices 102 to 109 via the transmission / reception unit 1 and the cable 110, and outputs it to the drive / control circuit 18 of the master device 101. The transmission / reception unit 1 in each of the slave devices 102 to 109 outputs the target temperature T0 from the master control circuit 2 to the drive / control circuit 18 of the light source circuit 3 via the control circuit 2.

<Operation using target temperature T0>
The drive / control circuit 18 of each video display device 100 controls the cooling fan 17 based on the temperature of the LED 10 detected by the temperature sensor 14 and the target temperature T0 obtained by the master control circuit 2. Specifically, the drive / control circuit 18 of each video display device 100 feedback-controls the cooling fan 17 so that the temperature of the LED 10 detected by the temperature sensor 14 approaches one target temperature T0. In the present embodiment, since this control is performed periodically, the temperature of the LED 10 in each of the nine video display devices 100 can be periodically brought close to one target temperature T0, and the temperature of each LED 10 Can be reliably matched.

  Next, the operation for obtaining the target temperature T0 described above and the operation using the target temperature T0 will be described in detail with reference to flowcharts.

<Operation flow for obtaining the target temperature T0>
FIG. 4 is a flowchart showing an operation performed by the multi-screen display device when the master control circuit 2 obtains the target temperature T0. Hereinafter, this operation will be described with reference to FIG. This operation is performed by the control unit 9 executing a program incorporated therein.

  In step s1, the master control circuit 2 obtains one set of detected temperature T1 and set fan coefficient F1 output from the drive / control circuit 18 of the master device 101, and the eight slave devices 102 to 109 respectively transmit. Eight sets of detected temperatures T2, T3,..., T9 and set fan coefficients F2, F3,.

  In the present embodiment, each of the set fan coefficients Fn (n = 1 to 9 is a natural number) is assigned any one of 15 levels of drive levels L1 to L15 indicating the drive capability of the cooling fan 17. The driving levels L1 to L15 indicate that the larger the number, the higher the driving capability of the cooling fan 17 and the higher the rotational speed, that is, the higher the rotational speed per unit time. For example, the cooling fan 17 for which Fn = L1 is set operates with the lowest driving capability among the driving capabilities, and the cooling fan 17 for which Fn = L15 is set has the highest driving capability. It will work with ability.

  In step s2, the master control circuit 2 obtains the maximum temperature Tmax and the minimum temperature Tmin from the detected temperatures T1 to T9 of the nine video display devices 100. That is, the master control circuit 2 calculates the maximum temperature Tmax that satisfies Tmax = Max (T1, T2,..., T9) and the minimum temperature Tmin that satisfies Tmin = Min (T1, T2,..., T9). Then, the master control circuit 2 obtains a set fan coefficient Fn that is set with the detected temperature Tn equal to the maximum temperature Tmax, and sets the set fan coefficient Fn as the maximum fan coefficient FTmax. For example, when the maximum temperature Tmax = T5, FTmax = F5. Similarly, the master control circuit 2 obtains a set fan coefficient Fn set as a set with the detected temperature Tn equal to the minimum temperature Tmin, and sets the set fan coefficient Fn as the minimum fan coefficient FTmin.

  In step s3, the master control circuit 2 determines that the maximum fan coefficient FTmax obtained from the set fan coefficients Fn of all sets (9 sets in the present embodiment) is the maximum drive level, that is, FTmax = L15. Determine whether. If it is determined in step s3 that the maximum fan coefficient FTmax is the maximum drive level, the process proceeds to step s4, and if it is determined that the maximum fan coefficient FTmax is not the maximum drive level, the process proceeds to step s5.

  In step s4, since the maximum fan coefficient FTmax is the maximum drive level, the maximum temperature Tmax cannot be lowered by increasing the rotational speed of the cooling fan 17 any more. Therefore, in step s4, the master control circuit 2 sets the target temperature T0 to the maximum temperature Tmax so that the detected temperatures Tn of the nine video display devices 100 become the maximum temperature Tmax.

  In step s5, the master control circuit 2 determines that the minimum fan coefficient FTmin obtained from the set fan coefficients Fn of all sets (9 sets in the present embodiment) is the minimum drive level, that is, FTmin = L1. Determine whether. If it is determined in step s5 that the minimum fan coefficient FTmin is the minimum drive level, the process proceeds to step s6, and if it is determined that the minimum fan coefficient FTmin is not the minimum drive level, the process proceeds to step s7.

  In step s6, since the minimum fan coefficient FTmin is the minimum drive level, the rotation speed of the cooling fan 17 cannot be further reduced to increase the minimum temperature Tmin. Therefore, in step s6, the master control circuit 2 sets the target temperature T0 to the minimum temperature Tmin so that the detected temperatures Tn of the nine video display devices 100 become the minimum temperature Tmin.

  In step s7, the master control circuit 2 determines whether or not a value Ts (= Tmax−Tmin) obtained by subtracting the minimum temperature Tmin from the maximum temperature Tmax is smaller than a predetermined threshold th. That is, the master control circuit 2 determines whether the maximum temperature difference between the detected temperatures T1 to T9 is smaller than the threshold value th. If it is determined in step s7 that the value Ts is smaller than the threshold th, the process proceeds to step s4 described above, and the master control circuit 2 sets the target temperature T0 to Tmax. For example, if th = 5 ° C. and the maximum temperature difference between the detected temperatures T1 to T9 is within 5 ° C., the process proceeds to step s4, where T0 = Tmax. If it is determined in step s7 that the value Ts is greater than or equal to the threshold th, the process proceeds to step s8.

  In step s8, the maximum temperature difference between the detected temperatures T1 to T9 is relatively large. Therefore, in step s8, the master control circuit 2 sets the target temperature T0 to a value between the minimum temperature Tmin and the maximum temperature Tmax. Specifically, the master control circuit 2 sets the target temperature T0 to (Tmax−A). Here, A defines a temperature range for performing temperature control, and 0 <A <Tmax−Tmin. For example, when th = A = 5 ° C., Tmin = 25, and Tmax = 35 ° C., Tmax−Tmin (= 10 ° C.)> Th (= 5 ° C.). Since T0 is determined as (Tmax−A), it is 30 ° C.

  When step s8 is performed, the target temperature T0 becomes a value between the minimum temperature Tmin and the maximum temperature Tmax. Therefore, in the video display device 100 in which the detected temperature Tn higher than the target temperature T0 is obtained, the detected temperature Tn is controlled to decrease, and in the video display device 100 in which the detected temperature Tn lower than the target temperature T0 is obtained, The detection temperature Tn is controlled to increase. Therefore, it is possible to efficiently match the detected temperatures Tn in the nine video display devices 100 with the target temperature T0. Therefore, an energy saving effect can be expected.

  In step s9 performed after steps s4, s6, and s8, the master control circuit 2 outputs the target temperature T0 obtained in steps s4, s6, and s8 to the drive / control circuit 18 of the master device 101 and the slave device. 102 to 109, respectively.

  In step s10, each of the nine video display devices 100 controls the cooling fan 17 so that the detected temperature Tn of its own temperature sensor 14 matches the target temperature T0. In the present embodiment, the drive / control circuit 18 of the master device 101 periodically outputs the detected temperature T1 and the set fan coefficient F1 to the master control circuit 2, and the slave devices 102 to 109 have the detected temperatures T2 to T9 and The set fan coefficients F2 to F9 can be periodically transmitted to the master control circuit 2. Therefore, the master control circuit 2 can periodically perform a series of operations of steps s1 to s10, and can obtain a suitable target temperature T0 at any given time.

<Flow of operation using target temperature T0>
FIG. 5 is a flowchart showing in detail the operation in step s10. Hereinafter, the operation in step s10 will be described with reference to FIG.

  In step s21, the target temperature T0 output from the master control circuit 2 is input to the drive / control circuit 18 of the master device 101. In addition, the target temperature T0 transmitted from the master control circuit 2 is input to the drive / control circuit 18 of the slave devices 102 to 109.

  Hereinafter, the operations in steps s22 to s28 will be described. These operations are performed in each of the nine video display devices 100.

  In step s22, the temperature sensor 14 detects the temperature of the LED 10, and the drive / control circuit 18 acquires the temperature as the current temperature Tp. In step s23, the drive / control circuit 18 determines whether the value Ts1 (= Tp−T0) obtained by subtracting the target temperature T0 from the current temperature Tp is smaller than the first threshold th1 determined in advance, that is, the current temperature Tp is It is determined whether the temperature is smaller than a value obtained by adding the first threshold th1 to the target temperature T0. If it is determined in step s23 that the value Ts1 is greater than or equal to the first threshold th1, the process proceeds to step s24, and if it is determined that the value Ts1 is smaller than the first threshold th1, the process proceeds to step s26.

  In step s24, the drive / control circuit 18 determines whether or not the current set fan coefficient Fp is the maximum drive level, that is, Fp = L15. If it is determined in step s24 that the current set fan coefficient Fp is the maximum drive level, the current temperature Tp cannot be lowered by further increasing the number of revolutions of the cooling fan 17, so that End the operation. If it is determined in step s24 that the current set fan coefficient Fp is not the maximum drive level, the process proceeds to step s25.

  In step s25, the drive / control circuit 18 changes the drive level of the current set fan coefficient Fp to a drive level one level higher. For example, if step s25 is performed when Fp = L3 before performing step s25, Fp = L4. By this change, the number of rotations of the cooling fan 17 increases and the current temperature Tp higher than the target temperature T0 decreases, so that the current temperature Tp can be brought close to the target temperature T0. After step s25, the operation after step s22 is performed again.

  In step s26, the drive / control circuit 18 determines whether the value Ts2 (= T0−Tp) obtained by subtracting the current temperature Tp from the target temperature T0 is smaller than a predetermined second threshold th2, that is, the current temperature Tp is It is determined whether it is larger than a value obtained by subtracting the second threshold th2 from the target temperature T0. If it is determined in step s26 that the value Ts2 is smaller than the second threshold th2, the current temperature Tp is already close to the target temperature T0, so this flow is performed without changing the drive level of the current set fan coefficient Fp. Exit. If it is determined in step s26 that the value Ts2 is greater than or equal to the second threshold th2, the process proceeds to step s27.

  In step s27, the drive / control circuit 18 determines whether or not the current set fan coefficient Fp is the minimum drive level, that is, Fp = L1. If it is determined in step s27 that the current set fan coefficient Fp is the minimum drive level, the number of revolutions of the cooling fan 17 cannot be further reduced to increase the current temperature Tp. End the operation. If it is determined in step s27 that the current set fan coefficient Fp is not the minimum drive level, the process proceeds to step s28.

  In step s28, the drive / control circuit 18 changes the drive level of the current set fan coefficient Fp to a drive level one level below. For example, if Fp = L12 before performing step s28, if step s28 is performed, Fp = L11. As a result of this change, the rotational speed of the cooling fan 17 decreases and the current temperature Tp lower than the target temperature T0 increases, so the current temperature Tp can be brought closer to the target temperature T0. After step s28, the operations after step 22 are performed again.

  By performing the above flow, for example, when th1 = th2 = 3 ° C., Fp = L7, and T0 = 30 ° C., the current temperature Tp is converged to 30 ° C. ± 3 ° C. Here, if the current temperature Tp is 25 ° C., the current set fan coefficient Fp decreases in the order of L7, L6,... Until 27 <Tp <33 or Fp = 1. The flow shown in 5 is repeated. On the other hand, if the current temperature Tp is 35, the current set fan coefficient Fp increases in order of L7, L8,... Until 27 <Tp <33 or Fp = 15, as shown in FIG. The flow shown is repeated.

  According to the multi-screen display device according to the present embodiment as described above, the drive / control circuit 18 (control unit 9) of each video display device 100 has the temperature detected by its own temperature sensor 14 and one temperature. Based on the target temperature T0, the cooling fan 17 is controlled. Therefore, in each video display device 100, the temperature of the LED 10 detected by the temperature sensor 14 can be brought close to one target temperature T0, and the temperatures of the respective LEDs 10 can be matched with each other. Thereby, the brightness | luminance of LED10 of each of the some video display apparatus 100 can mutually be made to correspond.

  In particular, in a certain video display device 100, for example, when the current set fan coefficient Fp is already at the maximum drive level and the maximum temperature Tmax of the detected temperature Tn cannot be changed, the master control circuit 2 (control unit 9) sets the temperature of the one video display device 100 as the target temperature T0. Therefore, even in such a situation, the temperature of the one video display device 100 and the temperature of the other video display device 100 can be matched, so that the temperatures of the LEDs 10 can be reliably set. Can be matched.

  In addition, although the case where the number of the video display apparatuses 100 was nine was demonstrated above, the number should just be two or more and is not restricted to nine.

<Embodiment 2>
FIG. 6 is a diagram showing a configuration of the light source circuit 3 provided in the multi-screen display device according to the second embodiment. In the following description of the multi-screen display device according to the present embodiment, parts that are the same as those in the multi-screen display device according to the first embodiment are denoted by the same reference numerals, and redundant descriptions are omitted.

  The light source circuit 3 according to the present embodiment is provided with first and second temperature sensors 31 and 32 instead of the temperature sensor 14 in the light source circuit 3 according to the first embodiment, and instead of the cooling fan 17. First and second cooling fans 33 and 34 are provided, and a drive / control circuit 35 is provided instead of the drive / control circuit 18. In the first embodiment, the drive / control circuit 18 brings the temperature of the LED 10 detected by the temperature sensor 14 closer to the target temperature T0, whereas in the present embodiment, the drive / control circuit 35 The temperature in the casing 19 (temperature in the cabinet) detected by the one temperature sensor 31 is brought close to the target temperature T0. Hereinafter, the multi-screen display device according to the present embodiment will be described in detail.

  The first temperature sensor 31 is disposed in the housing 19 at a position that can be correlated with the outside air temperature, and detects the temperature in the housing 10. Then, the first temperature sensor 31 outputs the detected temperature in the housing 10 to the drive / control circuit 35.

  The first temperature sensor 31 is disposed in the heat receiving block 11 and detects the temperature of the LED 10. Then, the first temperature sensor 31 outputs the detected temperature of the LED 10 to the drive / control circuit 35.

  The first cooling fan 33 cools the inside of the casing 19 and cools the entire casing 19. The second cooling fan 34 also cools the inside of the housing 19, but is disposed in the vicinity of the heat sink 12 so as to mainly cool the LED 10.

  The drive / control circuit 35 and the control circuit 2 constitute a control unit 29 that controls the first and second cooling fans 33 and 34. In addition, the drive / control circuit 35 is connected to the first and second temperature sensors 31 and 32 and can periodically acquire the temperatures detected by the first and second temperature sensors 31 and 32. It has become.

  When the drive / control circuit 35 acquires the temperature detected by the first temperature sensor 31, the first cooling fan 33 is PWM-driven almost simultaneously with the temperature. Similarly, when the detected temperature of the second temperature sensor 32 is acquired, the drive / control circuit 35 drives the second cooling fan 34 by PWM at substantially the same time. The drive / control circuit 35 can also detect errors such as failure of the first and second cooling fans 33 and 34.

<Operation related to the first temperature sensor>
The operation relating to the first temperature sensor 31 is substantially the same as that of the first embodiment. Hereinafter, an operation related to the first temperature sensor 31 will be described. In the following description regarding the first temperature sensor 31, “detected temperature” indicates the detected temperature of the first temperature sensor 31, and “set fan coefficient” indicates the set fan coefficient of the first cooling fan 33. To do.

  The drive / control circuit 35 sets the fan coefficient of the first cooling fan 33 based on the detected temperature of the first temperature sensor 31 connected to itself and the target temperature T0, and sets the fan coefficient obtained thereby. Based on this, the rotational speed of the first cooling fan 33 is driven and controlled. That is, the drive / control circuit 35 of each video display device 100, like the drive / control circuit 18 according to the first embodiment, detects the temperature in the casing 19 detected by its own first temperature sensor 31 and the target. The first cooling fan 33 is controlled based on the temperature T0.

<Operation for obtaining target temperature T0>
The target temperature T0 necessary for controlling the first cooling fan 33 is obtained in the master control circuit 2 as in the first embodiment. Specifically, the target temperature T0 is obtained as in the flowchart shown in FIG.

  Briefly explaining this operation, each of the drive / control circuits 35 of the slave devices 102 to 109 determines the detected temperature and the set fan coefficient of the first temperature sensor 31 by using the control circuit 2, the transmission / reception unit 1 and the control circuit 2 shown in FIG. The data is transmitted to the master device 101 via the cable 110. The transmission / reception unit 1 of the master device 101 outputs the detected temperature and the set fan coefficient from the slave devices 102 to 109 to the master control circuit 2. In parallel with this, the drive / control circuit 35 of the master device 101 outputs its detected temperature and set fan coefficient to the master control circuit 2. Then, the master control circuit 2 obtains one target temperature T0 based on the detected temperatures and the set fan coefficients in the nine video display devices 100.

  The master control circuit 2 transmits the obtained target temperature T0 to the slave devices 102 to 109 via the transmission / reception unit 1 and the cable 110, and outputs it to the drive / control circuit 35 of the master device 101. The transmission / reception unit 1 in each of the slave devices 102 to 109 outputs the target temperature T0 from the master control circuit 2 to the drive / control circuit 35 of the light source circuit 3 via the control circuit 2.

<Operation using target temperature T0>
The drive / control circuit 35 of each video display device 100 controls the cooling fan 17 based on the temperature in the housing 19 detected by the first temperature sensor 31 and the target temperature T0 obtained by the master control circuit 2. Control. Specifically, as in the flowchart shown in FIG. 5, the drive / control circuit 35 of each video display device 100 determines the temperature inside the casing 19 detected by the first temperature sensor 31 as one target temperature T0. The first cooling fan 33 is feedback-controlled so as to be close to. In the present embodiment, since this control is performed periodically, the temperature in the housing 19 in each of the nine video display devices 100 can be periodically brought close to one target temperature T0. As a result, the temperatures of the LEDs 10 in the respective housings 19 of the nine video display devices 100 can be periodically brought close to one target temperature T0, and the temperatures of the LEDs 10 can be matched with each other.

<Operation related to the second temperature sensor>
In the following description regarding the second temperature sensor 32, “detected temperature” indicates the temperature detected by the second temperature sensor 32, and “set fan coefficient” indicates the fan coefficient of the second cooling fan 34.

  The drive / control circuit 35 sets the fan coefficient of the second cooling fan 34 based on the detected temperature of the second temperature sensor 32 connected to itself, and based on the set fan coefficient obtained thereby, the second The rotational speed of the cooling fan 34 is driven and controlled. That is, the drive / control circuit 35 of each video display device 100 controls the second cooling fan 34 based on the temperature of the LED 10 detected by the second temperature sensor 32 thereof.

  Specifically, each drive / control circuit 35 increases the rotation speed of the second cooling fan 34 when the detected temperature is equal to or higher than the threshold value Tled1. Thereby, the temperature of LED10 falls. Further, each drive / control circuit 35 reduces the rotation speed of the second cooling fan 34 when the detected temperature is equal to or lower than the threshold value Tled2. Thereby, the temperature of LED10 goes up.

  Thereby, for example, when the threshold value Tled1 is set to 50 ° C., the temperature of the LED 10 can be made lower than 50 ° C., so that it is possible to suppress a failure in the LED 10 that is likely to fail at 50 ° C. or higher. Further, when the threshold value Tled2 is set to 40 ° C., the rotation speed of the second cooling fan 34 can be reduced when the temperature of the LED 10 becomes 40 ° C. or lower, so that the LED 10 is prevented from being cooled more than necessary. be able to.

  As described above, in the present embodiment, the drive / control circuit 35 of each video display device 100 performs the second operation so that the temperature of the LED 10 detected by the second temperature sensor 32 of the video display device 100 becomes a temperature within a predetermined range. The cooling fan 34 is feedback-controlled.

  According to the multi-screen display according to the present embodiment as described above, the drive / control circuit 18 (the control unit 29) of each video display device 100 has the temperature detected by its own first temperature sensor 31 and 1 The first cooling fan 33 is controlled based on the two target temperatures T0. Therefore, in each video display device 100, the temperature in the casing 19 detected by the first temperature sensor 31 can be brought close to one target temperature T0, and as a result, the temperatures of the respective LEDs 10 are made to coincide with each other. Can do. Thereby, the brightness | luminance of LED10 of each of the some video display apparatus 100 can mutually be made to correspond.

  Further, in the present embodiment, the drive / control circuit 18 (control unit 29) of each video display device 100 controls the second cooling fan 34 based on the temperature detected by its own second sensor. Therefore, the temperature of the LED 10 can be kept within an appropriate range, so that the failure of the LED 10 can be suppressed.

  In the above description, the drive / control circuit 35 controls the first cooling fan 33 when the temperature detected by the first temperature sensor 31 approaches the target temperature T0. However, the present invention is not limited to this. The two cooling fans 34 may also be controlled.

  DESCRIPTION OF SYMBOLS 1 Transmission / reception part, 9,29 Control part, 10 LED, 14 Temperature sensor, 17 Cooling fan, 19 Case, 31 1st temperature sensor, 32 2nd temperature sensor, 33 1st cooling fan, 34 2nd cooling fan, 100 Video display device, 101 master device, 102-109 slave device.

Claims (7)

A multi-screen display device comprising a plurality of video display device screens arranged,
The plurality of video display devices include
Each connected via a communication means, each comprising a light source, a temperature sensor for detecting the temperature of the light source, a cooling device for cooling the light source, and a control unit,
The control unit of any one of the video display devices is detected by the temperature sensor of the plurality of video display devices other than the temperature detected by the temperature sensor of the video display device and the communication unit. One target temperature based on the measured temperature,
The control part of each said video display apparatus is a multi-screen display apparatus which controls the said cooling device based on the temperature detected with the said temperature sensor, and the said target temperature. The multi-screen display device according to claim 1,
The plurality of video display devices include
One master device,
Including other slave devices,
The slave device transmits the temperature detected by its own temperature sensor to the master device via the communication means,
The control unit of the master device calculates the target temperature based on the temperature detected by the temperature sensor of the master device and the temperature transmitted from the slave device,
The master device is a multi-screen display device that transmits the target temperature to the slave device via the communication unit. The multi-screen display device according to claim 2,
The slave device is a multi-screen display device that periodically transmits the temperature detected by its temperature sensor to the master device via the communication means. A multi-screen display device according to any one of claims 1 to 3,
The cooling device is a cooling fan;
The multi-screen display device, wherein the control unit of each of the video display devices controls a rotation speed of the cooling fan based on a temperature detected by its temperature sensor and the target temperature. A multi-screen display device comprising a plurality of video display device screens arranged,
The plurality of video display devices include
Each is connected via a communication means, and each includes a housing, a light source provided in the housing, a first temperature sensor for detecting a temperature in the housing, and a first cooling for cooling the inside of the housing. A device and a control unit,
The control unit of any one of the video display devices includes a temperature detected by the first temperature sensor of the video display device, and the first temperatures of the video display devices other than the self obtained through the communication unit. Based on the temperature detected by the sensor, find one target temperature,
The said control part of each said video display apparatus is a multi-screen display apparatus which controls the said 1st cooling device based on the temperature detected with the said 1st temperature sensor, and the said target temperature. The multi-screen display device according to claim 5,
Each of the plurality of video display devices is
A second temperature sensor for detecting the temperature of the light source;
A second cooling device for cooling the light source,
The multi-screen display device, wherein the control unit of each of the video display devices controls the second cooling device based on a temperature detected by the second temperature sensor. A multi-screen display device according to any one of claims 1 to 6,
The multi-screen display device, wherein the light source is a semiconductor light emitting element.

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