JP6395569B2 - Multi-screen display device - Google Patents

Description

  The present invention relates to a multi-screen display device, and more particularly to a multi-screen display device that forms a single screen by combining a plurality of image display devices.

  As a device for displaying video on a large screen, there is a multi-screen display device for displaying video on a multi-screen composed of the screens of a plurality of projection type video display devices. As a light source of each projection-type image display device that constitutes the multi-screen display device, for example, an optical device such as a high voltage discharge lamp or an LED (Light Emitting Diode) as a semiconductor light emitting element is used. Due to manufacturing variations and aging degradation, individual differences occur in the characteristics of these optical devices. The brightness of the display image may vary among the plurality of projection type video display devices. When such luminance variation exists, the luminance difference between the screens in the multi-screen becomes conspicuous, and the sense of unity of the video displayed on the entire multi-screen may be impaired.

  Thus, Patent Document 1 discloses a technique for suppressing variation in luminance between screens in a multi-screen display device. Specifically, in each projection type video display device, the luminance of light used to form a video is measured as needed, and the measured luminance is shared among a plurality of projection type video display devices. For example, the lowest luminance among the measured plurality of luminances is set as the target luminance. Next, each projection type video display device uses the relationship between the luminance value and the current value passed through the light source, so that the luminance of the video displayed by the projection type video display device becomes the target luminance. Set. Thereby, the brightness | luminance of the image | video which each projection type video display apparatus displays is brought close. Also in Patent Document 2, as in Patent Document 1, a technique for suppressing variation in luminance is disclosed.

  A light source composed of a light emitting element such as an LED changes not only the luminance but also the chromaticity when the current flowing through the light source is changed. The color between the screens of the projection type video display devices constituting the screen display device varies. For this reason, multi-screen display devices generally have a plurality of luminance modes for which the current value to be supplied to the light source is determined in advance, and the color between screens is adjusted in advance for each luminance mode, so that the variation of the light source over time varies. The control for suppressing the luminance difference due to is adjusted by the level of the video signal.

JP 2001-249652 A JP 2012-150149 A

  However, in general, light emitting elements such as LEDs have the property of aging, and the luminance decreases according to the elapsed time. Furthermore, due to the influence of the temperature environment depending on the installation position of each projection type video display device that constitutes the multi-screen display device and the individual variations of light emitting elements such as each LED, the time elapsed from the initial installation of the multi-screen display device Thus, there may be a case where the luminance difference between the projection type video display devices constituting the multi-screen display device becomes large. At this time, if the control is performed so as to reduce the brightness of the other projection type video display devices so as to match the projection type video display device having the lowest brightness, there is a problem that the brightness of the entire multi-screen display device is significantly reduced. there were.

  The present invention has been made to solve the above-described problems, and provides a multi-screen display device that suppresses a luminance difference between image display devices without significantly reducing the luminance of the entire multi-screen display device. Objective.

The multi-screen display device according to the present invention is a multi-screen display device that constitutes one screen by combining a plurality of image display devices, and any one of the plurality of image display devices is a master image display device, The master image display device is connected to a plurality of image display devices other than the master image display device via communication means, and each of the plurality of image display devices includes at least one light source and the luminance of light emitted from the light source. A luminance sensor for measuring the light source, a light source driving circuit for driving the light source, and a storage unit storing a first threshold value, and each of the plurality of image display devices has a luminance measured by the luminance sensor as the first. The master image display device determines whether or not the first condition that the first condition is greater than the threshold value of the image display device is satisfied. The light source driving circuit of the image display device, which is determined to satisfy the first condition by setting the common target luminance based on the luminance information based on the luminance measured by the luminance sensor and received from the image display device, The image display device that drives the light source so as to be close to the target luminance and does not satisfy the first condition does not perform luminance correction based on the target luminance, and displays the adjustment menu displayed at the time of adjustment of the light source. The output brightness is changed so that it can be seen that the output brightness has decreased below the first threshold value from the factory default state , and the storage unit further stores a second threshold value that is smaller than the first threshold value. The image display device that is determined not to satisfy the first condition determines whether or not the second condition that the luminance measured by the luminance sensor is greater than the second threshold is satisfied, and does not satisfy the second condition. Image judged as A light source driving circuit of a display device, the light source is driven on a lower driving ability.

  In the present invention, all the image display devices constituting the multi-screen display device measure the output luminance of the light source by the internal luminance sensor. Then, the master image display device calculates the target luminance by excluding image display devices that have a large luminance drop. As a result, it is possible to always keep the luminance and chromaticity of image display devices other than the image display device having a large luminance reduction rate uniform. By excluding image display devices that have a large decrease in luminance due to deterioration over time, etc., and setting the target luminance, the luminance of the entire multi-screen display device will decrease depending on some image display devices that have a large decrease in luminance. There is no.

  Further, in an image display device with a large decrease in luminance, a warning mark is displayed on the OSD menu displayed when the image display device is adjusted. As a result, an image display device that has a large decrease in luminance and is not automatically adjusted for brightness cannot be recognized by the user during normal operation, but can be easily recognized when the adjustment menu is displayed during maintenance. Become. That is, it is possible to easily recognize an image display device that requires light source replacement during maintenance.

1 is a diagram schematically showing a configuration of a multi-screen display device according to Embodiment 1. FIG. 2 is a functional block diagram of the image display apparatus according to Embodiment 1. FIG. 3 is a functional block diagram of a light source circuit of the image display device according to Embodiment 1. FIG. It is a figure which shows the luminance fall characteristic of LED in a normal mode. 3 is a flowchart showing an operation of the multi-screen display device according to the first embodiment. It is a figure which shows an example of the luminance fall characteristic of LED. 10 is a flowchart illustrating an operation of the multi-screen display device according to the third embodiment. It is a figure which shows the luminance fall characteristic of LED in a low current mode. 10 is a flowchart illustrating an operation of the multi-screen display device according to the fourth embodiment. 10 is a flowchart illustrating an operation of the multi-screen display device according to the fourth embodiment.

<Embodiment 1>
<Configuration>
FIG. 1 is a diagram schematically showing the configuration of the multi-screen display device according to the first embodiment. The multi-screen display device according to the present embodiment is configured by combining a plurality of image display devices to form one large display screen (large screen). In the example of FIG. 1, the display surface is configured by arranging image display devices in three rows and three columns. In FIG. 1, one image display device is a master image display device 101. The remaining image display devices are slave image display devices 102-109. The master image display device 101 and the slave image display devices 102 to 109 generally have the same configuration. In the following description, the master image display device 101 is also referred to as the master device 101. The slave image display devices 102 to 109 are also referred to as slave devices 102 to 109. Further, when the master image display device 101 and the slave image display devices 102 to 109 are not distinguished, they are simply referred to as image display devices.

  As shown in FIG. 1, the master device 101 and the slave devices 102 to 109 are bidirectionally connected to each other via a communication cable 110.

  FIG. 2 is a functional block diagram of the image display apparatus (for example, the master apparatus 101). Note that the slave devices 102 to 109 have the same configuration as the master device 101, and thus description thereof is omitted. As shown in FIG. 2, the master device 101 is a projection-type image display device using LEDs as light sources. The master device 101 includes a light source circuit 3, a storage unit 9, a light valve 4, a projection lens 5, an image input unit 8, a signal processing unit 7, a control unit 2, a transmission / reception unit 1, and a luminance sensor 10. And a screen 6.

  The light source circuit 3 includes a light source, and inputs the light output of the light source to the light valve 4. A video signal is input to the image input unit 8 from an external control device. The signal processing unit 7 performs processing such as level conversion of the video signal input from the external control device via the image input unit 8 and enlargement / reduction of the video signal. Then, the processed video signal is converted into a drive signal for driving the light valve 4.

  The light valve 4 modulates the intensity of the light output from the light source circuit 3 based on the drive signal input from the signal processing unit 7 and outputs it to the projection lens 5. The projection lens 5 projects the input image light on the screen 6.

  The luminance sensor 10 is disposed between the light valve 4 and the projection lens 5. The luminance sensor 10 measures the luminance of light output from the light valve 4. When, for example, a DMD element is used as the light valve 4, the luminance sensor 10 measures the luminance of the DMD element such as off light. The luminance sensor 10 is controlled by the control unit 2. The arrangement position of the luminance sensor 10 is not limited to between the light valve 4 and the projection lens 5.

  The transmission / reception unit 1 performs transmission / reception of brightness information, target brightness, and the like described later with another image display device via the communication cable 110. The storage unit 9 is, for example, a RAM (random access memory). The control unit 2 is, for example, a CPU, and controls operations of the light source circuit 3, the storage unit 9, the signal processing unit 7, the transmission / reception unit 1, and the luminance sensor 10.

  In the present embodiment, the master device 101 and the slave devices 102 to 109 are rear projection type image display devices including the screen 6. Further, the master device 101 and the slave devices 102 to 109 may be projection type image display devices that project image light onto the external screen 6.

  Further, the master device 101 can communicate with the slave devices 102 to 109 via the transmission / reception unit 1. One of a plurality of luminance modes can be set in the master device 101 and the slave devices 102 to 109. The luminance mode has three stages, for example, a high luminance mode, a normal mode, and a low luminance mode. In addition, although the three-step luminance mode is illustrated here, it is not limited to three steps.

  FIG. 3 is a functional block diagram of the light source circuit 3 of the image display device (for example, the master device 101) according to the first embodiment. Note that the configuration of the light source circuit 3 of the slave devices 102 to 109 is the same as that of the light source circuit 3 of the master device 101, and a description thereof will be omitted.

  As shown in FIG. 3, the light source of the master device 101 includes a red LED 14, a green LED 15, and a blue LED 16. The drive current value of the red LED 14 is controlled by being pulse-driven by the red light source drive circuit 11. Similarly, the drive current values of the green LED 15 and the blue LED 16 are controlled by being pulse-driven by the green light source drive circuit 12 and the blue light source drive circuit 13, respectively.

  The storage unit 9 of each image display device stores a measurement result by the brightness sensor 10 in each brightness mode at the time of factory shipment. The luminance sensor 10 can measure the luminance for each of R, G, and B. Initial luminance values YIR2_i, YIG2_i, YIB2_i for R, G, and B in the high luminance mode, initial luminance values YIR1_i, YIG1_i, YIB1_i for R, G, and B in the normal mode, R in the low luminance mode, Respective initial luminance values YIR0_i, YIG0_i, and YIB0_i for G and B are stored in the storage unit 9. Here, i = 1 corresponds to the master device 101, and i = 2 to 9 corresponds to the slave devices 102 to 109, respectively.

<Operation>
There are variations in the characteristics of the output of the light source circuit 5, the light valve 4, the projection lens 5, and the screen 6 among the image display devices constituting the multi-screen display device. For this reason, even if currents of the same magnitude are supplied to the light source circuit 5 of each image display device, the luminance and chromaticity outputs are not the same. Therefore, the video signal level is adjusted so that the luminance and chromaticity outputs of all the image display devices constituting the multi-screen display device are uniform.

  Actually, as shown in Equation 1 below, the following 3 × 3 matrix operation is performed on the R, G, and B signals input in the signal processing unit 7 in each image display device. The light valve 4 is controlled using Ro, Go, and Bo adjusted in luminance and chromaticity.

  Each of FIGS. 4A, 4B, and 4C shows the luminance reduction characteristics of the R, G, and B LEDs. As shown in FIG. 4, in general, the brightness of an LED decreases with age. Further, this luminance reduction characteristic varies depending on individual LEDs. Furthermore, as shown in FIG. 4, the luminance reduction characteristics of the R, G, and B LEDs are not uniform. For this reason, if time passes since the time of installation of a multi-screen display apparatus, the brightness | luminance and chromaticity between each image display apparatus will shift | deviate. In order to suppress this deviation in luminance and chromaticity, each image display device measures the luminance of RGB by the luminance sensor 10 at regular intervals, and the luminance chromaticity of each image display device constituting the multi-screen display device is determined. It is necessary to adjust the luminance chromaticity at regular intervals so as to be uniform.

  However, since the absolute value of the luminance measurement result of each image display device varies as described above, the luminance is normalized so that the luminance value when the luminance and chromaticity of the multi-screen display device are initially set is 1. It is necessary to make it. That is, the brightness measurement results YSRi, YSGi, YSBi (i = 1 to 9) of each image display device at the time of initial setting of the multi-screen display device are stored in the storage unit 9 as normalization parameters.

  FIG. 5 is a flowchart showing the brightness adjustment operation of the multi-screen display device according to the first embodiment. The brightness and chromaticity adjustment operation will be described with reference to FIG. The master apparatus 101 transmits a luminance transmission request to the slave apparatuses 102 to 109 via the communication cable 110 at regular time intervals (step S101). Further, the master device 101 measures the luminances YR1, YG1, and YB1 of each current color light source (R, G, B) with the luminance sensor 10 (step S102).

  On the other hand, each slave device receives a luminance transmission request (step S201), and the luminance sensor 10 measures the luminance YRi, YGi, YBi (i = 1 to 9) of each current color light source (R, G, B) (step 1). S202).

  Each of the master device 101 and the slave devices 102 to 109 compares the measured luminance value (YRi, YGi, YBi) with the first threshold value to determine the luminance deterioration of the light source (steps S103, S203). The first threshold value is stored in the storage unit 9. Here, the first threshold value is a value obtained by multiplying the initial luminance value of the currently set luminance mode by the first coefficient TH1. For example, it is assumed that the current mode is the normal mode (YIR1_i, YIG1_i, YIB1_i), and the first coefficient TH1 is 0.4. Specifically, the determination is performed on the R, G, and B LEDs by the inequality (that is, the first condition) expressed by the following Expression 2.

  If any of R, G, and B satisfies the inequality (ie, the first condition) according to Equation 2, YEr_i = 0. In other cases, YEr_i = 1.

  Further, each image display device calculates the luminance decrease rate DRi, DGi, DBi from the luminance measurement result of each image display device at the time of initial setting using the following Expression 3.

  The luminance information (that is, the luminance reduction rate DRi, DGi, DBi) and the determination result YEr_i (i = 1 to 9) of the slave devices 102 to 109 calculated as described above are transmitted to the master device 101 (step S204). The master device 101 receives the luminance information and the determination result transmitted from each of the slave devices 102 to 109 (step S104).

  Next, the master device 101 sets the target brightness of the entire multi-screen display device based on the determination result and brightness information of each image display device (step S105). The master device 101 sets the target luminance based on the luminance information of the remaining image display devices, except for the image display devices whose determination result is YEr_i = 1 from all the image display devices including itself. Specifically, according to the following formulas 4 and 5, the lowest luminance reduction rate of the image display device whose determination result is YEr_i = 0 is selected as the target luminance Emin.

  Next, the master device 101 transmits the target brightness Emin to each of the slave devices 102 to 109 (step S106). Each slave device 102-109 receives the target luminance Emin (step S206). Further, the master device 101 and the slave devices 102 to 109 determine whether or not the determination result YEr_i is 0 (steps S107 and S207). The image display device with YEr_i = 0 performs the luminance correction represented by Expression 6 so that the luminance of the light source becomes equal to the target luminance Emin (steps S108 and S208). That is, the signal processing unit 7 in each image display device multiplies the right side of Equation 1 by a parameter of Emin / DRi (i = 1 to 9) as follows. As a result, among the image display devices constituting the multi-screen display device, it is possible to automatically adjust the output luminance of the image display device having the determination result YEr_i = 0 to be uniform.

  On the other hand, the image display device that is determined not to have YEr_i = 0 in steps S107 and S207 (ie, YEr_i = 1) performs luminance correction based on the target luminance Emin because the luminance of the LED is equal to or lower than the first threshold value. Absent. Further, in the image display device with YEr_i = 1, the OSD displayed when the image display device is adjusted so that the output brightness of the LED is reduced to the first threshold value or less from the initial factory setting. A warning mark is displayed on the (On Screen Display) menu (steps S109 and S209). Instead of displaying a warning mark, a mechanism may be provided in which a part of the color of the OSD menu displayed at the time of adjustment is changed, or a warning display can be displayed on the back of each image display device. That is, it is impossible to recognize an image display device that has not been automatically adjusted due to a decrease in luminance during normal operation, and there is no problem if an image display device whose luminance has been decreased easily during maintenance can be recognized.

  In addition, as shown in FIG. 6, the characteristics of the aging degradation of the LED may increase in luminance for a while after energization with respect to the luminance value at the time of factory shipment. Accordingly, if the brightness reduction determination of each image display device is performed based on the brightness reduction rate (Equation 3) based on the brightness measurement result of each image display device at the time of initial setting of the multi-screen display device, the life of the LED light source can be appropriately determined. Can not. By separately dividing the luminance reduction rate necessary for controlling the multi-screen display device and the luminance reduction rate used for determining the life of the LED light source, it is possible to perform automatic multi-screen luminance adjustment with high accuracy.

  For example, when the initial setting of the multi-screen display device is performed at the time T1 in FIG. 6 and the brightness reduction of each image display device is determined from the value of Equation 3, the brightness reduction rate is more than the value measured at the time of factory shipment. However, even though it is not actually necessary to replace the LED, it is excluded from the automatic adjustment due to a decrease in brightness. In addition, when the initial setting of the multi-screen display device is performed in the state of T2, some of the image display devices are actually operated due to the LED light source being cut off even though the LEDs must actually be replaced. May go out.

  In the first embodiment, the image display device with reduced brightness displays a warning when the adjustment menu is displayed during maintenance so that the brightness reduction can be easily recognized. Note that the external device communicates with the master device 101 via the LAN / RS 232C or the like from the external device, so that the external device transmits information regarding the luminance reduction of each image display device in the multi-screen display device (determination result YEr_i, etc.). May be available.

<Effect>
The multi-screen display device according to the first embodiment is a multi-screen display device that forms a single screen by combining a plurality of image display devices, and any one of the plurality of image display devices is a master image display device 101. The master image display device 101 is connected to a plurality of image display devices other than the master image display device 101 via communication means (that is, the communication cable 110), and each of the plurality of image display devices is at least one. Two light sources (ie, red LED 14, green LED 15, blue LED 16), a luminance sensor 10 for measuring the luminance of light emitted from the light source, and a light source driving circuit (red light source driving circuit 11, green light source driving circuit 12) for driving the light source. , Blue light source driving circuit 13) and a storage unit 9 in which the first threshold value is stored, and a plurality of image display devices Each of them determines whether or not the first condition that the luminance measured by the luminance sensor 10 is greater than the first threshold is satisfied, and the master image display device 101 determines that the first condition is satisfied. A common target luminance Emin is set for the display device based on the luminance information based on the luminance measured by the luminance sensor 10 received from the image display device, and the image display device determined to satisfy the first condition The light source driving circuit drives the light source so that the luminance of the light source approaches the target luminance Emin, and the image display device determined not to satisfy the first condition changes the display of the adjustment menu displayed at the time of adjustment. .

  Therefore, in the first embodiment, all the image display devices constituting the multi-screen display device measure the output luminance of the LED light source by the internal luminance sensor 10. Then, the master device 101 calculates a target luminance by excluding image display devices that have a large luminance drop. As a result, it is possible to always keep the luminance and chromaticity of image display devices other than the image display device having a large luminance reduction rate uniform. In the first embodiment, the target luminance is set by excluding image display devices that have a large luminance drop due to aging degradation or the like, so that the entire multi-screen display device depends on some image display devices that have a large luminance drop. Luminance does not decrease.

  Further, in the first embodiment, in the image display device having a large luminance drop, a warning mark is displayed on the OSD menu displayed when the image display device is adjusted. As a result, an image display device that has a large decrease in luminance and is not automatically adjusted for brightness cannot be recognized by the user during normal operation, but can be easily recognized when the adjustment menu is displayed during maintenance. It has become. That is, it is possible to easily recognize an image display device that requires replacement of the LED light source during maintenance.

  Further, as shown in FIG. 4, the LED light source is not turned on due to the lifetime when the luminance is lowered more than a certain level. In the first embodiment, since the image display device with reduced brightness can be grasped at the time of maintenance, it is possible to avoid a situation in which some of the image display devices of the multi-screen display device are turned off due to the light source not being lit. Further, in the conventional control method for reducing the brightness of another image display device so as to match the brightness of the image display device whose brightness has been reduced, which image display device in the multi-screen display device has a reduced brightness, It cannot be recognized at first glance. On the other hand, in the first embodiment, since the luminance correction is performed on the image display devices other than the image display device whose luminance is decreased, if the luminance decrease of the image display device whose luminance is decreased is large, The image display device can be easily recognized.

  Further, in the multi-screen display device according to the first embodiment, master image display device 101 receives the determination result whether or not the first condition is satisfied and the luminance information from each of a plurality of image display devices including itself. .

  Therefore, the master image display device 101 can obtain the light source states of all the image display devices. Further, when the determination result and the luminance information are received, it is possible to confirm whether or not the master image display device 101 and each of the slave image display devices 102 to 109 are connected.

  In the multi-screen display device according to the first embodiment, the first threshold value is a value obtained by multiplying the first coefficient TH1 by the initial luminance of the light source measured by the luminance sensor 10.

  Therefore, by setting the first coefficient TH1 to 0.4, for example, it is possible to determine whether or not the current luminance of the light source is reduced by 40 percent from the initial luminance.

<Embodiment 2>
The configuration of the multi-screen display device screen, the configuration of the functional blocks of each image display device, and the configuration of the functional blocks of the light source circuit 3 in the second embodiment are the same as those in the first embodiment (FIGS. 1, 2, and 3). The description is omitted.

  In the first embodiment, all the slave devices 102 to 109 transmit the luminance information and the determination result YEr_i to the master device 101 in step S204 of FIG.

  On the other hand, in the second embodiment, only the image display device with the determination result YEr_i = 0 (that is, the image display device that satisfies the first condition) transmits the luminance information to the master device 101. That is, the image display device with the determination result YEr_i = 1 does not transmit the luminance information to the master device 101. In the second embodiment, the master device 101 determines that the image display device that has transmitted the luminance information satisfies the first condition.

  In step S105 of FIG. 5, the master device 101, based on the luminance information of the image display device that has transmitted the luminance information (including the luminance information of the master device if the determination result of the master device 101 is YEr_i = 0). A target brightness Emin is set. The target luminance Emin is calculated based on the equations 4 and 5 as in the first embodiment. Since the subsequent operation is the same as that of the first embodiment, the description thereof is omitted.

<Effect>
In the multi-screen display device according to the second embodiment, only the image display device determined to satisfy the first condition transmits luminance information to the master image display device 101, and the master image display device 101 transmits the luminance information. It is determined that the transmitted image display apparatus satisfies the first condition.

  Therefore, in the second embodiment, only the image display device determined to satisfy the first condition (that is, the slave device with the determination result YEr_i = 0) transmits the luminance information to the master device 101. 101 does not need to determine whether the determination result YEr_i is 0 or 1. Compared to the first embodiment, the amount of data transmitted and received between the master device 101 and the slave devices 102 to 109 can be reduced. Further, since the master device 101 calculates the target brightness using only the brightness information of the slave device that has responded, even if some of the communication cables 110 are disconnected in FIG. Brightness adjustment can also be performed.

<Embodiment 3>
The configuration of the multi-screen display device screen, the functional block configuration of each image display device, and the functional block configuration of the light source circuit 3 in the third embodiment are the same as those in the first embodiment (FIGS. 1, 2, and 3). The description is omitted.

  FIG. 7 is a flowchart showing the brightness adjustment operation of the multi-screen display device according to the third embodiment. The operations from Step S301 to Step S309 and the operations from Step S401 to Step S409 in FIG. 7 are the same as Steps S101 to S109 and Steps S201 to S209 in FIG.

  In the first embodiment, the luminance correction based on the target luminance Emin is not performed on the image display device that is determined not to satisfy the first condition. For an image display device that is determined not to satisfy the first condition, a warning mark is displayed on the OSD menu displayed during adjustment.

  In the third embodiment, after each of steps S309 and S409, each of the image display devices determined not to satisfy the first condition compares the measured luminance value (YRi, YGi, YBi) with the second threshold value. Then, the luminance deterioration determination of the light source is performed. The second threshold value is stored in the storage unit 9. Here, the second threshold is a value obtained by multiplying the luminance value of the currently set luminance mode by the second coefficient TH2. For example, it is assumed that the current mode is the normal mode (YIR1_i, YIG1_i, YIB1_i), and the second coefficient TH2 is, for example, 0.3, which is smaller than the first coefficient TH1. More specifically, the determination is performed for the R, G, and B LEDs by the inequality (that is, the second condition) expressed by the following Expression 7.

  If any of R, G, and B satisfies the inequality (ie, the second condition) according to Equation 7, YEr2_i = 0. In other cases, YEr2_i = 1.

  Next, each of the image display apparatuses determined not to satisfy the first condition determines whether or not the second condition is satisfied (that is, whether YEr2_i = 0) (steps S310 and S410). . In the image display device that is determined not to satisfy the second condition (that is, YEr2_i = 1), it is determined that the LED light source is nearing the end of its life and is driven with a lower driving capability. For example, the brightness mode of the LED is lowered by one step. When the current luminance mode is the normal mode, control is performed to switch to the low luminance mode (steps S311 and S411).

  On the other hand, if it is determined in steps S310 and S410 that the second condition is satisfied, the driving capability is maintained without switching the luminance mode.

  In general, the lifetime of an LED depends on the current. If the current supplied to the LED decreases, the luminance of light emission decreases, and the amount of heat generated by the LED decreases accordingly. For example, if the luminance mode is switched from the normal mode to the low current mode, the slope of the luminance reduction rate becomes gentle as shown in FIG. 8, and the lifetime of the LED can be extended.

  In the third embodiment, the brightness mode is lowered by one level in the image display device that does not satisfy the second condition. However, it is not always necessary to perform control to switch the prepared brightness mode to a lower mode. Control may be performed to forcibly reduce the current supplied to the light source circuit 3. For example, the current supplied to the light source circuit 3 may be controlled to be reduced by 3A.

<Effect>
In the multi-screen display device according to the third embodiment, the storage unit further stores a second threshold value that is smaller than the first threshold value, and the image display device that is determined not to satisfy the first condition has a luminance The light source driving circuit of the image display device that determines whether or not the second condition that the luminance measured by the sensor 10 is greater than the second threshold is satisfied and that the second condition is not satisfied is Drive with lower driving ability.

  When the LED light source of the image display device that does not satisfy the first condition is left without being replaced, information cannot be displayed as the image display device due to the LED light disappearing due to the life of the LED light source. In order to prevent this, when the image display apparatus no longer satisfies the second condition, the life of the LED light source can be extended by forcibly reducing the supply current to the LED light source. Furthermore, even when the brightness of the LED light source suddenly decreases, the brightness of the image display device can be extended by automatically detecting the brightness decrease and reducing the supply current.

  In the multi-screen display device according to the third embodiment, the second threshold value is obtained by multiplying the second coefficient TH2 smaller than the first coefficient TH1 by the initial luminance of the light source measured by the luminance sensor 10. Value.

  Therefore, by setting the second coefficient TH2 to 0.3, for example, it is possible to determine whether or not the current luminance of the light source is 30% lower than the initial luminance.

<Embodiment 4>
The configuration of the multi-screen display device screen, the functional block configuration of each image display device, and the functional block configuration of the light source circuit 3 in the fourth embodiment are the same as those in the first embodiment (FIGS. 1, 2, and 3). The description is omitted.

  In the first and second embodiments, luminance correction is not performed on an image display device that does not satisfy the first condition. In this case, a luminance difference may be large between an image display device that performs luminance correction and an image display device that does not perform luminance correction.

  Even when the brightness of the entire multi-screen display device is reduced, it may be desired to make the brightness difference between the image display devices uniform. In this case, even when there is an image display device in which the luminance of the LED is equal to or lower than the first threshold (that is, the first condition is not satisfied), an image in which the luminance is not reduced by the algorithm shown in FIG. A method of correcting the luminance of the entire multi-screen display device by adjusting the video signal level of the display device can be considered. However, although the brightness of the entire multi-screen display device is greatly reduced, the current value supplied to the LED light source of the image display device in which the brightness is not reduced does not change, so the power consumption of the multi-screen display device is does not change.

  In the fourth embodiment, the luminance mode is not changed for an image display device in which the output luminance of the LED is equal to or lower than the first threshold (that is, an image display device that does not satisfy the first condition). On the other hand, for an image display device that satisfies the first condition, the luminance chromaticity adjustment is performed after the luminance mode is lowered by one step.

  9 and 10 are flowcharts showing the brightness adjustment operation of the multi-screen display device according to the fourth embodiment. The operations from step S501 to step S506 and the operations from step S601 to step S606 in FIG. 9 are the same as steps S101 to S106 and steps S201 to S206 in FIG.

  After step S506, based on the determination result YEr_i of each image display device, the master device 101 determines whether there is at least one image display device that does not satisfy the first condition (that is, an image display device with YEr_i = 1). Determine. If there is at least one image display device in which YEr_i = 1, the result YCd = 1 is set. Otherwise, YCd = 0 is set. Then, the master device 101 transmits the Ycd value to each image display device.

  The master device 101 and the slave devices 102 to 109 determine whether or not Ycd = 1 (steps S507 and S607). When Ycd = 1 is not satisfied (that is, YCd = 0), since all the image display devices satisfy the first condition, the luminance correction is performed so that the luminances of all the image display devices are equal to the target luminance Emin. (Steps S516 and S616).

  On the other hand, if YCd = 1 in steps S507 and S607, it is next determined whether or not the image display device is YEr_i = 0 (steps S508 and S608). When YEr_i = 0, all the image display devices in which YEr_i = 0 are driven with the same amount of driving ability. Specifically, the brightness mode of all the image display devices with YEr_i = 0 is lowered by one level (steps S510 and S610).

  On the other hand, if the image display device is YEr_i = 1, the brightness mode is not changed, and a warning mark is displayed on the OSD menu displayed when the image display device is adjusted (steps S509 and S609). This is to make it clear during the maintenance that the output luminance of the LED has decreased by more than the first threshold value from the initial factory setting. Instead of displaying a warning mark, a mechanism for changing a part of the color of the OSD menu displayed at the time of adjustment or displaying a warning display on the back of each image display device may be provided. That is, an image display device with reduced brightness cannot be recognized during normal operation, and there is no problem if an image display device with reduced brightness can be easily recognized during maintenance.

  Next, the master display device 101 requests the transmission of luminance information to all image display devices (step S511), and each image display device measures the luminance of the light source (steps S512 and S612), and the master display device 101 Luminance information is transmitted to the apparatus 101 (step S613). When the master device 101 receives the brightness information from each image display device (step S513), the master device 101 sets the target brightness Emin. At this time, the lowest luminance is set as the target luminance Emin regardless of the value of YEr_i.

  Then, the master device 101 transmits the target luminance Emin to each image display device (step S515). When each image display device receives the target luminance Emin (step S615), the luminance of the light source becomes equal to the target luminance Emin. Luminance correction represented by Expression 6 is performed (steps S516 and S616).

  By the above operation, automatic adjustment can be performed so that the output luminance among all the image display devices constituting the multi-screen display device becomes uniform.

  If the image display device in which the output luminance of the LED exceeds the first threshold later becomes equal to or lower than the first threshold (that is, when YEr_i = 1), the lowered luminance mode is increased by one step. Then, again, the luminance reduction rate is calculated from the luminance measurement result of each image display device at the time of initial setting of the multi-screen display device, and the same operation as that of the first embodiment is performed to configure the multi-screen display device. Automatic adjustment can be made so that the output luminance of all the image display devices is uniform.

<Effect>
In the multi-screen display device according to the fourth embodiment, when there is even one image display device that is determined not to satisfy the first condition, the master image display device 101 is determined to satisfy the first condition. Before setting the target luminance for the image display device, an instruction is issued to drive the light source with the same amount of low driving ability to all the image display devices determined to satisfy the first condition. Thereafter, the luminance information is acquired again from the image display device, and the target luminance is set based on the luminance information.

  Therefore, in the fourth embodiment, for an image display device in which the output luminance of the LED is larger than the first threshold value (that is, an image display device that satisfies the first condition), the luminance color is lowered after the luminance mode is lowered by one step. Adjust the degree. Thereby, it is possible to suppress a luminance difference between the image display device that performs luminance correction and the image display device that does not perform luminance correction. That is, uniform brightness can be maintained throughout the multi-screen display device. Further, the power consumption of the multi-screen display device can be reduced as compared with the case where the luminance correction is performed by adjusting the video signal level without lowering the luminance mode. Furthermore, in an image display device with a lowered luminance mode, the life of the LED can be extended by reducing the current supplied to the LED.

<Embodiment 5>
In the fourth embodiment, the master device 101 determines whether there is even one image display device that does not satisfy the first condition. If there is an image display device that does not satisfy the first condition, the luminance mode of all the image display devices that satisfy the first condition is lowered by one level, and then the same luminance correction as in the first embodiment is performed. went.

  In the fifth embodiment, in the fourth embodiment, the luminance of the image display device whose measured luminance is equal to or lower than the first threshold (that is, the image display device that does not satisfy the first condition) is the second luminance. When the voltage falls below the threshold value (that is, when the second condition is not satisfied), the current mode of the LED is lowered by one step in the image display device (for example, switching from the normal mode to the low luminance mode). At the same time, the image display apparatus that satisfies the first condition raises the brightness mode that has been lowered by one step and restores it to the original state (for example, switches from the low luminance mode to the normal mode).

  Then, the master device 101 sets the target luminance Emin based on the luminance information of only the image display device that satisfies the first condition. The light source driving circuit of the image display device that satisfies the first condition drives the light source so that the luminance of the light source approaches the target luminance Emin.

<Effect>
In the multi-screen display device according to the fifth embodiment, the storage unit 9 further stores a second threshold value that is smaller than the first threshold value, and the image display device that is determined not to satisfy the first condition is The light source driving circuit of the image display apparatus that determines whether or not the second condition that the luminance measured by the luminance sensor 10 is greater than the second threshold is satisfied, and that the second condition is not satisfied, When there is an image display device that drives the light source with a lower driving capability and is determined not to satisfy the second condition, the master image display device 101 displays all the images that are determined to satisfy the first condition. After instructing the device to drive the light source with the same amount of high driving capability, the luminance information is obtained from the image display device determined to satisfy the first condition, and the target luminance is obtained based on the luminance information. Emin A constant.

  In the fifth embodiment, when the light source of the image display device whose luminance has decreased below the first threshold is further deteriorated and the luminance is below the second threshold, the supply current to the LED is forcibly reduced. Reduce. Thereby, it is possible to suppress the light source shortage due to the lifetime of the LED light source. That is, information can be continuously displayed as the entire multi-screen display device.

  In the fifth embodiment, the brightness of the entire multi-screen display device is kept uniform in a state where the brightness of the image display device whose brightness has decreased satisfies the second condition (that is, exceeds the second threshold). To control. Furthermore, when the output brightness of some image display apparatuses does not satisfy the second condition (that is, when the output brightness is less than or equal to the second threshold), the image display apparatus that satisfies the first condition is lowered by one step. The brightness mode is returned to the original mode, and the brightness correction is performed so that the brightness is uniform only for the image display apparatus that has returned to the original brightness mode. This is because when the brightness of the entire multi-screen display device is adjusted to be uniform according to the brightness of the image display device that does not satisfy the second condition, the overall brightness of the multi-screen display device is reduced. This is because it gets worse.

  In the fifth embodiment, when there is even one image display device that does not satisfy the second condition, the luminance mode of the image display device that has been lowered in luminance mode is returned to the original luminance mode, and the original luminance is restored. The luminance is corrected again for the image display device that has been returned to the mode. By this control, it is possible to prevent the display of the image display device that has not been reduced in luminance from becoming dark in accordance with the luminance of the display device that has been greatly reduced in luminance.

  It should be noted that the present invention can be freely combined with each other within the scope of the invention, and each embodiment can be appropriately modified or omitted.

  DESCRIPTION OF SYMBOLS 1 Transmission / reception part, 2 Control part, 3 Light source circuit, 4 Light valve, 5 Projection lens, 6 Screen, 7 Signal processing part, 8 Image input part, 9 Storage part, 10 Brightness sensor, 11 Red light source drive circuit, 12 Green light source Drive circuit, 13 Blue light source drive circuit, 14 Red LED, 15 Green LED, 16 Blue LED, 101 Master image display device, 102, 103, 104, 105, 106, 107, 108, 109 Slave image display device, 110 Communication cable .

Claims (6)

A multi-screen display device configured by combining a plurality of image display devices to form one screen,
Any one of the plurality of image display devices is a master image display device,
The master image display device is connected to the plurality of image display devices other than the master image display device via communication means,
Each of the plurality of image display devices includes:
At least one light source;
A luminance sensor for measuring the luminance of light emitted from the light source;
A light source driving circuit for driving the light source;
A storage unit storing a first threshold;
With
Each of the plurality of image display devices determines whether or not a first condition that the luminance measured by the luminance sensor is greater than the first threshold is satisfied,
The master image display device has a common target for an image display device determined to satisfy the first condition based on luminance information received from the image display device and based on luminance measured by the luminance sensor. Set the brightness
The light source driving circuit of the image display device determined to satisfy the first condition drives the light source so that the luminance of the light source approaches the target luminance,
The image display device determined not to satisfy the first condition does not perform luminance correction based on the target luminance, and the adjustment menu displayed at the time of adjustment is displayed in the initial state when the output luminance of the light source is the factory default. modified as it can be seen that falls below the first threshold value from,
The storage unit further stores a second threshold value smaller than the first threshold value,
The image display device that is determined not to satisfy the first condition determines whether or not a second condition that the luminance measured by the luminance sensor is greater than the second threshold is satisfied,
The light source driving circuit of the image display device determined not to satisfy the second condition drives the light source with a lower driving capability;
Multi-screen display device. The master image display device receives a determination result whether the first condition is satisfied and the luminance information from each of the plurality of image display devices including the master image display device;
The multi-screen display device according to claim 1. Only the image display device determined to satisfy the first condition transmits the luminance information to the master image display device,
The master image display device determines that the image display device that has transmitted the luminance information satisfies the first condition;
The multi-screen display device according to claim 1. A multi-screen display device configured by combining a plurality of image display devices to form one screen,
Any one of the plurality of image display devices is a master image display device,
The master image display device is connected to the plurality of image display devices other than the master image display device via communication means,
Each of the plurality of image display devices includes:
At least one light source;
A luminance sensor for measuring the luminance of light emitted from the light source;
A light source driving circuit for driving the light source;
A storage unit storing a first threshold;
With
Each of the plurality of image display devices determines whether or not a first condition that the luminance measured by the luminance sensor is greater than the first threshold is satisfied,
The master image display device has a common target for an image display device determined to satisfy the first condition based on luminance information received from the image display device and based on luminance measured by the luminance sensor. Set the brightness
The light source driving circuit of the image display device determined to satisfy the first condition drives the light source so that the luminance of the light source approaches the target luminance,
The image display device determined not to satisfy the first condition does not perform luminance correction based on the target luminance, and the adjustment menu displayed at the time of adjustment is displayed in the initial state when the output luminance of the light source is the factory default. modified as it can be seen that falls below the first threshold value from,
When there is at least one image display device determined not to satisfy the first condition, the master image display device performs the target luminance with respect to the image display device determined to satisfy the first condition. From the image display device, after instructing all the image display devices determined to satisfy the first condition to drive the light source by the same amount of low driving capability. Acquiring the luminance information again, setting the target luminance based on the luminance information,
The storage unit further stores a second threshold value smaller than the first threshold value,
The image display device that is determined not to satisfy the first condition determines whether or not a second condition that the luminance measured by the luminance sensor is greater than the second threshold value is satisfied,
The light source driving circuit of the image display device determined not to satisfy the second condition drives the light source with a lower driving capability,
When there is an image display device that is determined not to satisfy the second condition, the master image display device uses the same light source for all image display devices that are determined to satisfy the first condition. After issuing an instruction to drive with a drive capability that is higher by the amount, the luminance information is acquired from the image display device determined to satisfy the first condition, and the target luminance is set based on the luminance information ,
Multi-screen display device. The first threshold is a value obtained by multiplying the first coefficient by the initial luminance of the light source measured by the luminance sensor.
The multi-screen display device according to any one of claims 1 to 4 . The second threshold is a value obtained by multiplying the second coefficient smaller than the first coefficient by the initial luminance of the light source measured by the luminance sensor.
The multi-screen display device according to claim 5 .

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