JP2017204341A - Illuminating device, and display device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an illuminating device which can appropriately control a quantity of light emission of a backlight unit even if a light-emitting block of the illuminating device changes in the degree of operation stability.SOLUTION: An illuminating device 100 according to the present invention comprises: a plurality of light-emitting blocks 121 of which the quantities of light emission can be controlled individually; and a backlight control section 111 which periodically executes a process to make determination about whether one or more light-emitting blocks 121 including a targeted light-emitting block are in an initial activation state where the operation stability is relatively low, or a stable state where the operation stability is relatively high and to correct a quantity of light emission of the targeted light-emitting block. The backlight control section 111 periodically executes a temperature sensor use correction process to correct the quantity of light emission of the targeted light-emitting block when the light-emitting block is determined to be in the initial activation state. The backlight control section executes a luminance sensor use correction process to correct the quantity of light emission of the targeted light-emitting block in a longer cycle than a cycle to execute the temperature sensor use correction process when the light-emitting block is determined to be in the stable state.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an illuminating device capable of correcting a light emission amount and a display device using the illuminating device.

  A display device using a transmissive display panel includes an illumination device (backlight device) that irradiates light to the display panel from the back side of the display panel. There is a lighting device that includes a plurality of light-emitting blocks each including a light source, and that can individually control the light emission amount of each light-emitting block. In recent years, the number of light-emitting blocks provided in the lighting device has increased in order to cope with the increase in size and thickness required for the display device, or to improve the luminance distribution of light emitted from the lighting device to the display panel. There is a tendency.

  In addition, the light emission amount of each light-emitting block may change depending on the stability of the operation of the light-emitting block such as individual differences of light sources provided in the light-emitting block, aging deterioration, or temperature change. For example, if the temperature of the light source changes abruptly due to heat generated from the drive circuit or the light source immediately after the lighting device starts driving (the operational stability is low), each light-emitting block may be controlled under the same driving conditions. In some cases, the light emission amount of each light-emitting block changes.

  In response to such a variation in light emission amount, Patent Document 1 discloses a display device that measures the luminance of light emitted from each light emission block of the backlight device and feedback-controls the light emission amount of each light emission block. Has been. In the display device disclosed in Patent Document 1, in order to accurately measure the luminance of each light emitting block, another light emitting block that affects the measurement of luminance during the period in which the luminance of the light emitting block to be measured is measured. Stops (turns off) lighting of (non-measurement light emitting block).

  If feedback control using a luminance sensor is performed continuously in a short time, the luminance of the light emitted from the lighting device to the display panel may be reduced or flicker may occur due to the extinction of the light emitting block that is not the measurement target. It was. In order to suppress the influence on the light emitted from the lighting device by the feedback control, turning off some of the light-emitting blocks by the feedback control using the luminance sensor may be executed with a period longer than a predetermined correction interval. Conceivable. In that case, in order to perform feedback control using a luminance sensor for a plurality of light emitting blocks, a measurement period proportional to the number of light emitting blocks and the predetermined correction interval is required.

JP 2005-157316 A

  However, in the conventional technique described above, when the number of light emitting blocks included in the lighting device increases, the measurement period required to complete the feedback control of all the light emitting blocks increases. By increasing the measurement period, for example, when the temperature change per unit time of each light emitting block is large (operation stability is low) immediately after the start of driving of the illumination device, the light emission amount of the light emitting block changes. May grow. At this time, the amount of light emitted from the lighting device to the display panel becomes unstable.

  Therefore, in view of the above problems, the present invention provides a lighting device capable of suitably controlling the light emission amount of each light-emitting block even when the stability of the operation of the light-emitting block of the lighting device changes. Objective.

  In order to solve the above-described problems, one embodiment of the lighting device according to the present invention relates to a plurality of light emitting units capable of individually controlling the light emission amount and one or a plurality of light emitting units including a target light emitting unit. Determining means for determining whether the first state is relatively low in operational stability or the second state in which the operational stability is relatively higher than that in the first state; And a correction unit that periodically executes a process of correcting the light emission amount of the target light emission unit. When the determination unit determines that the determination unit is in the first state, A first correction process for correcting the light emission amount of the light emitting means is executed in a first period, and when it is determined that the determination means is in the second state, a second correction process for correcting the light emission amount of the target light emission means. Is executed in a second period longer than the first period. And wherein the door.

  According to the illumination device of the present invention, an appropriate correction process is selected according to the operational stability of the target light emitting unit, and the light emission amount correction process of the target light emitting unit is performed. Therefore, even if the stability of the operation of the light emitting block of the lighting device changes, the light emission amount of the backlight device can be suitably controlled.

It is an apparatus block diagram of a display apparatus. It is a functional block diagram which shows the functional block of a display apparatus provided with an illuminating device. It is the schematic diagram which showed the apparatus structure of the backlight unit. It is a 1st flowchart which shows 1 cycle of the brightness | luminance correction process of a backlight control part. It is the sub-flowchart which showed the flow of the brightness | luminance sensor use correction process and the temperature sensor use correction process. It is the graph which showed the temperature change of the light emission block with respect to elapsed time. It is the schematic diagram which showed the temperature characteristic of the luminous efficiency of a light source. It is the graph which showed the change of the emitted light quantity of one light emission block with respect to elapsed time. It is the 2nd flowchart which showed the flow of the brightness correction processing cycle in the illuminating device which concerns on a 2nd Example. It is the subflowchart which showed the flow of the hybrid correction process. It is the schematic diagram which showed the time change of the emitted light amount at the time of performing the brightness | luminance correction process in a 2nd Example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The technical scope of the present invention is determined by the scope of claims, and is not limited by the examples illustrated below. Further, not all the combinations of features described in the embodiments are essential to the present invention. The contents described in this specification and drawings are illustrative and should not be construed as limiting the present invention. Various modifications (including combinations of the embodiments) are possible based on the spirit of the present invention, and they are not excluded from the scope of the present invention. That is, all configurations in which the embodiments and their modifications are combined are also included in the present invention.

(First embodiment)
The lighting device 100 described in the first embodiment determines the state indicating the operational stability of the light emitting block 121 included in the lighting device 100 based on the acquired determination parameter, and determines the light emission amount based on the state of each light emitting block 121. Switch the correction method. Specifically, the lighting device 100 corrects the light emission amount of the light emission block 121 using the luminance of the light emission block 121 when the operation stability of the light emission block 121 is relatively high. Furthermore, the lighting device 100 corrects the light emission amount of the light emission block 121 using a parameter other than the luminance of the light emission block 121 when the operational stability of the light emission block 121 is relatively low.

  Here, it is assumed that the operational stability of the light emission block 121 is an index indicating the stability of the light emission amount of the light emission block 121 with respect to time. The relatively high operational stability means that the change of the light emission amount of the light-emitting block 121 with respect to time can be regarded as relatively small. The relatively low operational stability means that the change of the light emission amount of the light emission block 121 with respect to time can be regarded as relatively large.

  In other words, the lighting device 100 described in the first embodiment uses the luminance of the light-emitting block 121 when the change in the light emission amount of the light-emitting block 121 included in the lighting device 100 can be regarded as small. The light emission amount of the light emission block 121 is corrected. Further, when the light emission amount of the light emission block 121 included in the illumination device 100 is in a state that can be considered to be large, the light emission amount of the light emission block 121 is corrected using parameters other than the luminance of the light emission block 121. It can also be said.

  FIG. 1 is a device configuration diagram of the display device 1. The display device 1 includes an input unit 10, a lighting device 100, a liquid crystal control circuit 210, and a liquid crystal panel 220. The lighting device 100 includes a backlight control circuit 110 and a backlight unit 120. FIG. 2 is a functional block diagram illustrating functional blocks of the display device 1 including the illumination device 100.

  The input unit 10 inputs control information to the backlight control circuit 110 and the liquid crystal control circuit 210. The control information is information relating to the image signal displayed on the display device 1 and the maximum display luminance of the display device 1. The input unit 10 is a recording medium such as a hard disk that can record and output control information. The input unit 10 may be an input terminal that can acquire control information from an external device.

  The illumination device 100 is a backlight device that irradiates the liquid crystal panel 220 with light. The backlight control circuit 110 is a control circuit that controls the light emission amount of each light emission block of the backlight unit 120. The operation of the backlight control circuit 110 will be described later.

  The backlight unit 120 includes a light emitting block 121, a luminance sensor 122, and a temperature sensor 123. FIG. 3 is a schematic diagram showing a device configuration of the backlight unit 120. The backlight unit 120 includes a plurality of light emitting blocks 121a to 121f whose brightness can be individually controlled. The light emitting block 121a includes a luminance sensor 122a that detects the luminance of light emitted from the light emitting block 121a, and a temperature sensor 123a that detects the temperature of the light emitting block 121a. The light emitting block 121a includes a plurality of light sources 124a. The light emission blocks 121b to 121f also include corresponding luminance sensors 122b to 122f, temperature sensors 123b to 123f, and light sources 124b to 124f, respectively.

  The light emission efficiency of the light source 124, which is the ratio of the light emission amount with respect to the drive current, varies depending on the temperature of the light source 124. For example, it is assumed that the light source 124 is an LED (Light Emitting Diode) whose luminous efficiency decreases as the temperature increases.

  The backlight control circuit 110 is a control circuit board capable of controlling the light emission amount of each light emission block. The backlight control circuit 110 includes a backlight control unit 111, an elapsed time acquisition unit 112, a backlight drive unit 113, a drive current acquisition unit 114, a luminance acquisition unit 115, a temperature acquisition unit 116, and a memory 117.

  The backlight control unit 111 is an arithmetic processing device (processor) that determines the drive current value of each light emitting block 121 and outputs the drive current value to the backlight drive unit 113. Note that the backlight control unit 111 may be configured using two or more processors. Furthermore, the backlight control unit 111 may include hardware such as one or more electronic circuits that can execute a part of functions executed by the backlight control unit 111 described later.

  Based on the image signal acquired from the input unit 10, the backlight control unit 111 determines the amount of light emitted from each light-emitting block 121, and the light is emitted from each light-emitting block 121 with the determined light amount. Next, the drive current value of each light emitting block 121 is determined. Note that the backlight control unit 111 may determine the light emission amount of each light emission block in accordance with the setting of the maximum luminance value displayed on the display device 1.

  The backlight control unit 111 acquires the elapsed time t1 from the elapsed time acquisition unit 112 as a determination parameter, and determines the state of each light-emitting block 121. Details of the elapsed time t1 will be described later. For example, when the backlight control unit 111 determines whether each light-emitting block 121 is in a stable state with relatively high operation stability or a drive initial state with relatively low operation stability using the determination parameter. To do. As described above, the operational stability of the light emission block is an index indicating the stability of the light emission amount of the light emission block 121 with respect to time.

  The backlight control unit 111 can determine the state of each light emitting block 121 individually or can determine the state of each of the plurality of light emitting blocks 121. For example, it is assumed that the backlight control unit 111 determines the state of all the light emission blocks 121 included in the lighting device 100.

  The backlight control unit 111 periodically executes a process of correcting the light emission amount of each light emission block. Based on the state of each light emission block, the backlight control unit 111 executes a process for correcting the light emission amount using the luminance measurement value for each light emission block, or corrects the light emission amount using the temperature measurement value. Decide whether to execute the process. Here, the cycle in which the backlight control unit 111 executes the process of correcting the light emission amount using the temperature measurement value is longer than the cycle of executing the process of correcting the light emission amount using the brightness measurement value.

  Specifically, the backlight control unit 111 corrects the light emission amount using the luminance measurement value when the operation stability of the light emission block (target light emission block) for correcting the light emission amount is relatively high. . Furthermore, the backlight control unit 111 corrects the light emission amount using the temperature measurement value when the operation stability of the target light emission block is relatively low.

  When the backlight control unit 111 determines to execute the correction process using the luminance measurement value, the backlight control unit 111 outputs a luminance detection instruction to the backlight driving unit 113 and the luminance acquisition unit 115. When the backlight control unit 111 determines to execute the correction process using the temperature measurement value, the backlight control unit 111 outputs a temperature detection instruction to the temperature acquisition unit 116.

  The backlight control unit 111 corrects the drive current value of each light emission block using the luminance measurement value or the temperature measurement value of each light emission block, and controls the light emission amount of each light emission block.

  The backlight control unit 111 periodically executes a series of processes including a determination process of the operation stability of each light-emitting block and a correction process of the drive current value as one correction cycle. While the lighting apparatus 100 is being driven, the backlight control unit 111 repeatedly executes the correction cycle. Each light emission block is subjected to the light emission amount correction process at least once in one correction cycle.

  The cycle of the correction cycle executed by the backlight control unit 111 for each light-emitting block is a correction cycle. Whether the correction process executed for each light-emitting block is a correction process using a luminance measurement value, or temperature It differs depending on whether the correction process uses the measured value.

  The elapsed time acquisition unit 112 measures an elapsed time t1 after the lighting device 100 starts driving, and outputs the measured time to the backlight control unit 111. For example, it is assumed that the elapsed time t1 is an elapsed time after at least one of the plurality of light emitting blocks 121 starts to emit light.

  Based on the drive current value of each light emission block 121 acquired from the backlight control unit 111, the backlight drive unit 113 controls the light emission of the light source of each light emission block 121 by pulse width modulation (PWM: Pulse Width Modulation). It is a drive circuit. In addition, when the backlight driving unit 113 acquires a luminance detection instruction from the backlight control unit 111, the backlight driving unit 113 lights the light-emitting block to be detected in a predetermined driving condition and detects the luminance during a predetermined measurement period. Control to turn off non-target light-emitting blocks.

  Further, when the light emitting block 121 is driven, the backlight driving unit 113 outputs information on the driving current value that has flowed to each light emitting block 121 to the driving current acquisition unit 114.

  The drive current acquisition unit 114 is a current value sensor that acquires the drive current value that has flowed to each light emitting block 121 acquired from the backlight drive unit 113 and outputs the drive current value to the backlight control unit 111. The drive current acquisition unit 114 can also acquire the amount of change in the drive current value for each light emitting block 121 and output it to the backlight control unit 111.

  When the luminance acquisition unit 115 acquires a luminance detection instruction from the backlight control unit 111, the luminance acquisition unit 115 acquires a luminance measurement value from the luminance sensor 122 corresponding to the light emission block to be measured for luminance. The luminance acquisition unit 115 integrates the values output from the luminance sensor 122 corresponding to the luminance detection target light emission block at the timing when the luminance detection target light emission block is turned on and the light emission block that is not the luminance detection target is turned off. Thus, the luminance measurement value of the light emission block to be subjected to luminance detection is acquired. The luminance acquisition unit 115 outputs the acquired luminance measurement value to the backlight control unit 111.

  When the temperature acquisition unit 116 acquires a temperature detection instruction from the backlight control unit 111, the temperature acquisition unit 116 acquires a temperature measurement value from the temperature sensor 123 corresponding to the light emission block to be temperature measured. The temperature acquisition unit 116 outputs the acquired temperature measurement value to the backlight control unit 111. It can be said that the measured temperature value of each light emitting block 121 is operation information indicating the operating environment of each light emitting block 121.

  The memory 117 is a storage medium in which parameters and programs used by the backlight control unit 111 are stored, and the backlight control unit 111 can read and write information. The memory 117 includes a threshold value Th <b> 1 used by the backlight control unit 111 to determine the operational stability of each light-emitting block 121, temperature characteristic information indicating the relationship between the light-emitting efficiency and temperature of the light source, and the luminance target of each light-emitting block 121. The value is stored and output to the backlight control unit 111.

  The liquid crystal control circuit 210 is a control circuit board that controls the liquid crystal panel 220 using an image signal acquired from the input unit 10. The liquid crystal control circuit 210 includes an image processing unit 211 and a liquid crystal panel driving unit 212.

  The image processing unit 211 performs image processing such as γ conversion processing and sharpness on the image signal acquired from the input unit 10 to generate an output image signal. The image processing unit 211 outputs an output image signal to the liquid crystal panel driving unit 212. The liquid crystal panel driving unit 212 controls the transmittance of the liquid crystal panel 220 based on the acquired output image signal.

  The liquid crystal panel 220 is a transmissive display panel including a plurality of liquid crystal elements arranged in a matrix and a color filter corresponding to each liquid crystal element. The transmittance of each liquid crystal element is controlled by the liquid crystal panel driving unit 212 in accordance with the output image signal. The liquid crystal panel 220 transmits the light emitted from the lighting device 100 and displays an image on the screen.

  Note that the liquid crystal panel 220 may be a transmissive display panel, and may be a display panel using a MEMS (Micro Electro Mechanical Systems) element as an element for controlling the transmittance.

  The brightness correction processing of the backlight control unit 111 will be described with reference to the flowcharts of FIGS. 4 and 5. FIG. 4 is a flowchart showing one cycle of the luminance correction processing of the backlight control unit 111.

  When the brightness correction processing cycle is started, the backlight control unit 111 executes acquisition processing for acquiring the elapsed time t1 from the elapsed time acquisition unit 112 in S100. The process proceeds to S101.

  In S <b> 101, the backlight control unit 111 determines the state of each light-emitting block 121 of the lighting device 100 using the elapsed time t <b> 1 acquired from the elapsed time acquisition unit 112. The backlight control unit 111 determines whether the elapsed time t1 is greater than the threshold value Th1. Specifically, when the elapsed time t1 is larger than the predetermined threshold Th1, the backlight control unit 111 determines that the operation stability of each light-emitting block 121 is relatively high. Further, when the elapsed time t1 is equal to or less than the predetermined threshold Th1, the backlight control unit 111 determines that the operation stability of each light-emitting block 121 is in a driving initial state that is relatively low.

  The threshold Th1 is a parameter read from the memory 117. The threshold value Th1 is a parameter determined based on a temperature change of the light emitting block 121 with respect to the elapsed time t1 acquired in advance. FIG. 6 is a graph showing the temperature change of the light emitting block 121 with respect to the elapsed time t1 acquired in advance. When the lighting device 100 starts driving, heat is generated from the backlight control circuit 110 and the light emitting block 121, and the temperature of the light emitting block 121 rises.

  For example, the threshold value Th1 is an elapsed time t1 when the temperature of the light emitting block 121 reaches a predetermined temperature threshold value. As shown in FIG. 6, it is assumed that the initial temperature T0 before starting the driving of the lighting device 100 is 20 ° C. and the saturation temperature Ts is 50 ° C. Assuming that the temperature threshold is 80% of the saturation temperature Ts of the light emitting block 121, 60 seconds when the temperature of the light emitting block 121 is about 80% of the saturation temperature Ts is set as the threshold Th1. In the initial stage of driving (elapsed time t1 ≦ Th1), the gradient of the temperature change of the light emitting block 121 is large.

  Note that the threshold Th1 can also be an elapsed time during which the temperature change per unit time of the light emitting block 121 is equal to or less than a predetermined threshold. The predetermined threshold value is equal to or less than a value in which the change amount of the light emission amount of the light emission block 121 due to the temperature change is allowed as the luminance change of the lighting device 100 in the time interval in which the correction process using the luminance sensor can be executed. It may be a temperature change per unit time.

  If the elapsed time t1 is greater than the threshold Th1 in S101, the backlight control unit 111 determines that the operational stability of each light-emitting block 121 is relatively high and proceeds to the processing of S110. If the elapsed time t1 is equal to or less than the threshold Th1, the backlight control unit 111 determines that the operation stability of each light-emitting block 121 is low and is in an initial driving state, and proceeds to the process of S120.

  Each correction process of S110 or S120 is executed, and one cycle of the brightness correction process is completed. The backlight control unit 111 repeatedly executes the above-described cycle.

  FIG. 5 is a flowchart showing a flow of the brightness sensor use correction process executed in S110 and the temperature sensor use correction process executed in S120. Each correction process will be described with reference to FIG.

  FIG. 5A is a flowchart showing a flow of luminance sensor use correction processing. S110 is luminance sensor use correction processing for executing processing for correcting the drive current value for each light emitting block 121 based on the luminance measurement value acquired by the corresponding luminance sensor 122.

  When the luminance sensor use correction process is started, in S111, the backlight control unit 111 determines a target light emission block to be subjected to the correction process. For example, it is assumed that the target light emission block is determined so as to be sequentially selected from the upper left 121a with respect to the plurality of light emission blocks 121a to 121f included in the backlight unit 120 illustrated in FIG. For example, it is assumed that the backlight control unit 111 selects the light emission block 121a as the target light emission block. The process proceeds to S112.

  In S112, the backlight control unit 111 acquires the luminance measurement value of the target light emission block. Specifically, a luminance acquisition instruction for acquiring a luminance measurement value of the light emission block 121a is output to the backlight driving unit 113 and the luminance acquisition unit 115. The backlight drive unit 113 controls the light emitting block 121a to be turned on under a predetermined driving condition during the measurement period, and the other light emitting blocks 121b to 121f are turned off. In addition, the luminance acquisition unit 115 acquires the luminance measurement value of the light emission block 121a from the value output from the luminance sensor 122a during the measurement period, and outputs the luminance measurement value to the backlight control unit 111.

  The luminance acquisition process of the target light emission block involves turning off the light emission blocks other than the target light emission block when measuring the luminance of the target light emission block. Therefore, the luminance measurement processing in the luminance sensor usage correction processing is executed after a certain period of time in order to prevent the user from feeling a disturbance due to the lighting block being turned off when the user is viewing the screen. It is desirable. For example, it is assumed that the luminance measurement process is executed once every 4 seconds. The process proceeds to S113.

  In S113, the backlight control unit 111 determines the drive current value based on the luminance change rate R of the light emission block 121a acquired using the acquired luminance measurement value of the light emission block 121a and the luminance target value acquired from the memory 117. Correct.

  The luminance target value is a luminance measurement value acquired by the luminance acquisition unit 115 when the light emitting block 121a is driven under a predetermined driving condition in the reference state. The luminance change rate R is a value obtained by dividing the acquired luminance measurement value by the target luminance value. That is, the luminance change rate R is the luminance change rate of the light emitting block 121a from the reference state at the time when the luminance measurement value is acquired. The reference state is a state used as a reference for driving the light-emitting block 121a. For example, it is assumed that the light-emitting block is in the initial driving state where the temperature of the light-emitting block is 20 ° C. and the deterioration with time is small.

  The backlight control unit 111 corrects the drive current value based on the luminance change rate R. When the light emission amount has a linear relationship with the drive current value, the backlight control unit 111 corrects the drive current value of the light emission block 121a by dividing it by the luminance change rate R. For example, it is assumed that the time for which the backlight control unit 111 executes the process of correcting the light emission amount of the target light emission block based on the luminance measurement value is 1 second. The process proceeds to S114.

  In step S114, the backlight control unit 111 determines whether correction processing has been completed for all light-emitting blocks that are to be corrected. When the backlight control unit 111 determines that the correction process has not been completed for all the light emission blocks to be corrected, the process returns to S111. In S111, the backlight control unit 111 determines the next light emission block 121b as the target light emission block. When the backlight control unit 111 determines that the correction process has been completed for all the light-emitting blocks that are the target of the correction process, the luminance sensor use correction process is terminated.

  A series of luminance sensor use correction processing is a total period of a period for acquiring the luminance of all the target light emitting blocks 121 and a period for correcting the light emission amounts of all the target light emitting blocks 121. A certain luminance correction period is required. When the backlight control unit 111 determines in S101 that each light-emitting block 121 is in a stable state, the backlight control unit 111 periodically executes the luminance sensor use correction process at a cycle equal to or longer than the luminance correction period. For example, when it takes 4 seconds to acquire the luminance of one light emitting block 121 and 1 second to correct the light emission amount of one light emitting block 121, a luminance sensor is used for six light emitting blocks 121. In order to execute the correction process, the luminance correction period is 30 seconds.

  FIG. 5B is a flowchart showing a flow of temperature sensor use correction processing. S120 is a temperature sensor use correction process for executing a process of correcting the drive current value based on the temperature measurement value acquired by the corresponding temperature sensor 123 for each light emitting block 121.

  When the temperature sensor use correction process is started, in S121, the backlight control unit 111 determines a target light emission block to be subjected to the correction process. It is assumed that the target light emission block is determined similarly to S111. The process proceeds to S122.

  In S122, the backlight control unit 111 acquires a temperature measurement value of the light emission block 121a. The temperature acquisition unit 116 acquires the temperature measurement value of the light emitting block 121a from the value output from the temperature sensor 123a, and outputs it to the backlight control unit 111. In addition, when the temperature acquisition part 116 performs the process which acquires the temperature measurement value of each light emission block 121, the process which turns off the light emission block which is not an object light emission block like S112 is not performed. The period during which the temperature acquisition unit 116 executes the temperature acquisition process for the target light emission block is shorter than the period during which the luminance acquisition unit 115 executes the luminance acquisition process for the target light emission block. For example, it is assumed that the temperature acquisition process is executed once every 0.5 seconds. The process proceeds to S123.

  In S123, the backlight control unit 111 drives based on the light emission efficiency Ea of the light emission block 121a acquired using the acquired temperature measurement value of the light emission block 121a and the temperature characteristic of the light emission block 121a acquired from the memory 117. Correct the current value.

  The temperature characteristic is a characteristic showing the relationship between the temperature of the light emitting block 121a and the light emission efficiency Ea. FIG. 7 is a schematic diagram showing temperature characteristics stored in the memory 117. For example, the temperature characteristic is obtained from the result of measuring the light emission amounts at a plurality of measurement temperatures when the light emission block 121a is driven under a predetermined driving condition. The temperature characteristics shown in FIG. 7 indicate that light emission from the light emission block 121a when the measurement temperature is 0 ° C., 20 ° C., 40 ° C., and 60 ° C. is taken as 100%. The result which calculated | required efficiency Ea is shown.

  The temperature characteristics may be acquired individually for each light emitting block 121 in advance. Further, the same temperature characteristic may be used for each light emitting block 121.

  The backlight control unit 111 corrects the drive current value based on the light emission efficiency Ea. When the light emission amount has a linear relationship with the drive current value, the backlight control unit 111 corrects the drive current value of the light emission block 121a by dividing it by the light emission efficiency Ea. When the temperature characteristic indicates the measured value of the luminous efficiency Ea acquired with respect to the discrete measured temperatures as shown in FIG. 6, the backlight control unit 111 emits the luminous efficiency for the measured temperature values other than the measured temperatures. Ea is determined by linear interpolation using each measured value. The interpolation method may be nonlinear interpolation. For example, it is assumed that the time for the backlight control unit 111 to execute the process of correcting the light emission amount of the target light emission block based on the temperature measurement value is 1 second. The process proceeds to S124.

  Note that the luminance correction using the light emission efficiency Ea obtained from the temperature characteristics includes an error because it is corrected using the temperature characteristics measured in advance. Accordingly, the correction process using the luminance sensor that directly measures and corrects the light emission amount at the time of correction has higher correction accuracy than the correction process that uses the temperature sensor.

  In S124, the backlight control unit 111 determines whether or not the correction process has been completed for all the light-emitting blocks to be corrected. When the backlight control unit 111 determines that the correction process has not been completed for all the light-emitting blocks that are the target of the correction process, the process returns to S121. In step S121, the backlight control unit 111 determines the next light emission block 121b as the target light emission block. When the backlight control unit 111 determines that the correction process has been completed for all the light-emitting blocks that are the target of the correction process, the temperature sensor use correction process ends.

  The series of temperature sensor use correction processing is a total period of a period for acquiring the temperatures of all target light emitting blocks 121 and a period for correcting the light emission amounts of all target light emitting blocks 121. A certain temperature correction period is required. When the backlight control unit 111 determines in S101 that each light-emitting block 121 is in the initial driving state, the backlight control unit 111 periodically executes the temperature sensor use correction process at a period equal to or higher than the temperature correction period. For example, when it takes 0.5 seconds to acquire the temperature of one light-emitting block 121 and 1 second to correct the light-emission amount of one light-emitting block 121, the luminance of the six light-emitting blocks 121 is increased. The temperature correction period for executing the sensor use correction process is 9 seconds.

  Unlike the brightness sensor use correction process, the temperature sensor use correction process does not need to be accompanied by turning off the light emission blocks other than the target light emission block when measuring the temperature of the target light emission block. Therefore, the temperature sensor use correction process can be executed in a shorter period than the luminance sensor use correction process. The backlight control unit 111 executes the temperature sensor use correction process at a cycle shorter than the cycle at which the luminance sensor use correction process is executed.

  Note that the period at which the backlight control unit 111 executes the luminance sensor use correction process and the period at which the temperature sensor use correction process is executed may not be constant. If the interval at which the plurality of brightness sensor use correction processes are executed is equal to or longer than the brightness correction period, the period for executing the brightness sensor use correction process may be a non-uniform period. Similarly, if the interval at which the plurality of temperature sensor use correction processes are executed is equal to or less than the luminance correction period and is equal to or greater than the temperature correction period, the period for executing the temperature sensor use correction process is an uneven period. Also good.

  The backlight control unit 111 can also provide a temperature correction period shorter than the luminance correction period between the plurality of temperature sensor use correction processes.

  With the above-described processing, the light emission amount correction processing is executed once for each light emission block in the correction cycle shown in FIG. Therefore, the light emission amount of each light emission block 121 is corrected at a cycle in which the correction cycle is executed. The cycle (9 seconds) of the correction cycle for executing the temperature sensor use correction process is shorter than the cycle (30 seconds) of the correction cycle for executing the brightness sensor use correction process. That is, the period in which the light emission amount of each light emission block 121 is corrected when each light emission block 121 is in the initial driving state is the light emission amount of each light emission block 121 is corrected when each light emission block 121 is in a stable state. Shorter than the period.

  Next, the effect when the brightness correction process in the present embodiment is executed will be described.

  FIG. 8A is a graph showing a change in the light emission amount of one light emission block 121 (for example, 121a) with respect to the elapsed time t1 when the luminance correction processing in the present embodiment is executed. FIG. 8B shows, for comparison, the elapsed time t1 of the light emission amount of one light emission block 121 (for example, 121a) when the brightness correction process is executed using only the brightness sensor use correction process. It is the graph which showed the change.

  When the brightness correction process is executed only by the brightness sensor use correction process, the correction process is executed once every 30 seconds. Therefore, as shown in FIG. 8B, in the initial stage of driving, the change in the light emission amount due to the rapid temperature change becomes large while the correction process is being fed back.

  In the lighting device 100 according to the present embodiment, when the operation stability of each light-emitting block 121 is relatively low, the temperature sensor use correction process is executed. For example, the temperature sensor use correction process is executed at a cycle of 9 seconds. Therefore, as shown in FIG. 8A, it is possible to suppress a change in the light emission amount due to a rapid temperature change in the initial stage of driving. Further, when the operational stability of each light-emitting block 121 is in a relatively high stability state, it is possible to execute a correction process with higher accuracy by executing the brightness sensor use correction process.

  In other words, it can be said that the illumination device 100 according to the present embodiment selects and executes a correction process that requires a short period of luminance correction when it can be considered that the temperature change per unit time is large.

  According to the lighting device 100 according to the present invention, when the operational stability of the light emission block 121 is relatively low, the process of correcting the light emission amount using the temperature sensor use correction process is periodically executed. Further, when the operation stability of the light emission block 121 is relatively high, the process of correcting the light emission amount using the brightness sensor use correction process is performed at a period longer than the period at which the temperature sensor use correction process is executed. Run. Thereby, when the operational stability is low and the luminance fluctuation with respect to the time of the light emitting block 121 is large, it is possible to perform a lot of luminance correction processing in a short time. Furthermore, when the operational stability is high and the luminance variation with respect to the time of the light emitting block 121 is small, it is possible to perform a more accurate luminance correction process. Therefore, when the operation stability of the light emitting block of the lighting device is low, fluctuations in the light emission amount can be suppressed, and the light emission amount of the backlight device can be suitably controlled.

(Second embodiment)
In the lighting device 100 according to the second embodiment, the state of each light-emitting block 121 is an unstable state in which the operational stability is relatively higher than the initial driving state and the operational stability is relatively lower than the stable state. The determination is made in three stages in addition to the initial driving state and the stable state, and the content of the correction process is switched. And when the state of each light emission block 121 of the illuminating device 100 is an unstable state, the brightness | luminance correction process of the light emission block 121 is performed using a some correction process.

  Since the device configuration diagram and the functional block diagram of the illumination device 100 according to the second embodiment are the same as those in the first embodiment, description thereof will be omitted. The illumination device 100 of the second embodiment is different from the first embodiment in part of the luminance correction processing of the backlight control unit 111.

  FIG. 9 is a flowchart illustrating a flow of a luminance correction processing cycle in the illumination device 100 according to the second embodiment. When the luminance correction processing cycle is started and executed, the backlight control unit 111 acquires the elapsed time t1 from the elapsed time acquisition unit 112 in S100. The process proceeds to S201.

  In step S <b> 201, the backlight control unit 111 determines whether the elapsed time t <b> 1 is greater than the threshold value Th <b> 2 acquired from the memory 117. The threshold value Th2 is a value larger than the threshold value Th1. For example, the threshold value Th2 is a value corresponding to the elapsed time t1 at which the temperature of the light emitting block 121 is about 95% of the saturation temperature Ts. If the elapsed time t1 is greater than the threshold Th2 in S201, the backlight control unit 111 determines that each light-emitting block 121 is in a stable state, and proceeds to the process of S110. S110 is luminance sensor usage correction processing. The luminance sensor usage correction process is the same as the process with the same name described in the first embodiment, and thus the description thereof is omitted. If the elapsed time t1 is less than or equal to the threshold Th2, the process proceeds to S101.

  In S101, the backlight control unit 111 determines whether or not the elapsed time t1 is greater than the threshold value Th2 acquired from the memory 117. For example, the threshold Th1 is assumed to be the same value as in the first embodiment. In S101, when the elapsed time t1 is larger than the threshold value Th1, the backlight control unit 111 causes each light-emitting block 121 to have an operation stability relatively higher than the driving initial state and relatively lower than the stable state. It determines with it being in an unstable state, and progresses to a hybrid correction process (S130).

  If the elapsed time t1 is equal to or less than the threshold Th1, the backlight control unit 111 determines that each light-emitting block 121 is in the initial driving state, and proceeds to the processing of S120. S120 is a temperature sensor use correction process. Since the temperature sensor use correction process is the same as the process of the same name described in the first embodiment, the description thereof is omitted.

  The backlight control unit 111 executes the correction process selected based on the elapsed time t1, the threshold value Th1, and the threshold value Th2 for all the light-emitting blocks 121, and the luminance correction process cycle ends. The backlight control unit 111 repeatedly executes the luminance correction processing cycle.

  S130 is a hybrid correction process that switches between the light emission block to which the luminance correction process using the luminance sensor is applied and the light emission block to which the correction process using the temperature sensor is applied every luminance correction processing cycle. FIG. 10 is a flowchart showing the flow of the hybrid correction process.

  When the hybrid correction process is started, the backlight control unit 111 executes a process of determining a specific light emission block for executing the luminance sensor use correction process in S131. The backlight control unit 111 acquires information indicating the specific light emission block selected for the luminance correction processing cycle from the memory 117, and determines the specific light emission block. For example, it is assumed that the backlight control unit 111 determines the light emission block 121b and the light emission block 121f as the specific light emission blocks. Note that the specific light emission block may be a single light emission block 121, or may be three or more light emission blocks 121. The backlight control unit 111 switches the light emission block 121 to be selected as the specific light emission block for each luminance correction processing cycle. The process proceeds to S132.

  In step S132, the backlight control unit 111 determines a target light emission block to be subjected to correction processing. For example, it is assumed that the target light emission block is determined so as to be sequentially selected from the upper left 121a with respect to the plurality of light emission blocks 121a to 121f included in the backlight unit 120 illustrated in FIG. For example, it is assumed that the backlight control unit 111 selects the light emission block 121a as the target light emission block. The process proceeds to S133.

  In S133, the backlight control unit 111 determines whether or not the target light emission block is the same as the specific light emission block. If the target light emission block is the same as the specific light emission block, the process proceeds to S134.

  In S134, the backlight control unit 111 acquires the luminance measurement value of the target light emission block. Since the process executed in S134 is the same as the process executed in S112 in the first embodiment, a description thereof will be omitted. In S135, the backlight control unit 111 corrects the driving current value based on the luminance change rate R of the target light emission block acquired using the luminance measurement value of the target light emission block and the luminance target value acquired from the memory 117. To do. Since the process executed in S134 is the same as the process executed in S113 in the first embodiment, the description thereof is omitted. The process proceeds to S138.

  If the backlight control unit 111 is different from the specific light emission block in S133, the process proceeds to 136.

  In S136, the backlight control unit 111 acquires a temperature measurement value of the target light emission block. Since the process executed in S136 is the same as the process executed in S122 in the first embodiment, the description thereof is omitted. In S137, the backlight control unit 111 performs driving based on the light emission efficiency Ea of the target light emission block acquired using the acquired temperature measurement value of the target light emission block and the temperature characteristic of the target light emission block acquired from the memory 117. Correct the current value. Since the process executed in S137 is the same as the process executed in S123 in the first embodiment, the description thereof is omitted. The process proceeds to S138.

  In step S138, the backlight control unit 111 determines whether correction processing has been completed for all light-emitting blocks that are to be corrected. When the backlight control unit 111 determines that the correction process has not been completed for all the light emission blocks to be corrected, the process returns to S132. In step S132, the backlight control unit 111 determines the next light emission block 121 as the target light emission block. For example, it is assumed that the backlight control unit 111 selects the light emission block 121b as the target light emission block. When the backlight control unit 111 determines that the correction process has been completed for all the light-emitting blocks that are the targets of the correction process, the hybrid correction process ends.

  In a series of hybrid correction processes (S130), the correction process using the brightness sensor 122 is executed only for the specific light emission block among the plurality of light emission blocks 121. Therefore, the correction process can be executed a plurality of times in a shorter time than the luminance sensor correction process (S110). For example, suppose that two light emission blocks 121 are selected as a specific light emission block for one luminance correction processing cycle.

  In the hybrid correction process, the luminance sensor use correction process is performed on the specific light emission block among the light emission blocks 121 to be corrected, and the temperature sensor use correction process is performed on the light emission block 121 that is not the specific light emission block. For example, a period of 5 seconds is required to perform the luminance sensor use correction process on one light emitting block 121, and a period of 1.5 seconds to perform the temperature sensor use correction process on one light emitting block 121 Is required. As described above, when two light-emitting blocks 121 are selected, the period required for performing the hybrid correction process requires a period of 16 seconds.

  That is, the correction period required to execute the hybrid correction process is longer than the temperature correction period and shorter than the luminance correction period. Therefore, the backlight control unit 111 executes the hybrid correction process at a cycle shorter than the cycle at which the brightness sensor use correction process is executed and longer than the cycle at which the temperature sensor use correction process is executed.

  Further, since the backlight control unit 111 switches the specific light emission block for each correction cycle, the luminance of each light emission block is corrected using the luminance sensor at least once for a plurality of correction cycles. . Therefore, a plurality of correction processes can be executed in a short time while improving the correction accuracy.

  FIG. 11 is a schematic diagram showing a temporal change in the light emission amount when the luminance correction processing in the second embodiment is executed. The horizontal axis indicates the elapsed time t1, and the vertical axis indicates the light emission amount ratio. Similar to the first embodiment, the temperature sensor use correction process is executed in the driving initial state (t1 ≦ Th1) in which the operational stability of each light-emitting block 121 of the lighting device 100 is relatively low. For example, it is assumed that the temperature sensor use correction process is executed once every 9 seconds as in the first embodiment. By performing many brightness correction processes in a short period of time, it is possible to suppress a change in the amount of light emission due to a rapid temperature change.

  Further, the hybrid correction process is executed in an unstable state (Th1 <t1 ≦ Th2) in which the operational stability of each light-emitting block 121 of the lighting device 100 is relatively medium. For example, it is assumed that the hybrid correction process is executed once every 16 seconds. In addition, the luminance sensor use correction process is executed in a stable state (Th2 <t1) in which the operation stability of each light emitting block 121 of the lighting device 100 is relatively high. For example, it is assumed that the luminance sensor use correction process is executed once every 30 seconds.

  The backlight control unit 111 performs control so that the frequency with which correction processing is performed on each light-emitting block 121 increases as the operational stability of each light-emitting block 121 of the lighting device 100 decreases. In addition, the backlight control unit 111 is configured such that the higher the operational stability of each light emitting block 121 of the lighting device 100 is, the higher the frequency with which correction processing using a luminance sensor is executed on each light emitting block 121. Control. Accordingly, the greater the temperature change of the light emitting block 121, the higher the frequency of the correction process, and it is possible to correct a sudden luminance change due to the temperature change. Therefore, even if the stability of the operation of the light emitting block of the lighting device changes, the light emission amount of the backlight device can be suitably controlled.

(Other examples)
Note that when the operational stability is low and the luminance variation with respect to the time of the light-emitting block 121 is large, the correction process to be performed is not limited to the correction process using the temperature sensor. Using the operation information other than the temperature measurement value, it is also possible to execute a correction process that can perform many correction processes in a short period of time using the luminance sensor correction process.

  The backlight control unit 111 can also correct the luminance of each light emission block 121 using the drive current value that has flowed to each light emission block 121 acquired by the drive current acquisition unit 114. When the current value flowing through the light source 124 depends on the temperature, the drive current value can be handled in the same manner as the temperature measurement value. In this case, the backlight control unit 111 acquires information that associates the drive current value, the temperature, and the light emission efficiency from the memory 117, and executes the luminance correction process.

  Like the temperature sensor luminance correction process, the correction process using the drive current value does not need to be accompanied by turning off the light-emitting blocks other than the target light-emitting block, so that a lot of correction processes can be executed in a short time. Become. In this case, it is not necessary to install the temperature sensor 123, and it can be performed at a lower cost.

  In addition, as the determination parameter for determining the operational stability of the lighting device 100, a value other than the elapsed time t1 can be used. It is also possible to use the elapsed time t2 from the timing when the control method of each light emitting block 121 of the lighting device 100 is switched as a determination parameter.

  It is also possible to use the elapsed time from the timing when the upper limit value of the control range of the light emission amount of each light emission block 121 has changed significantly as a determination parameter. For example, when the display mode of the display device 1 is switched from a mode that expresses an image in the conventional luminance range (Standard Dynamic Range (SDR)) to a High Dynamic Range (HDR) mode that expresses a higher luminance image, The upper limit value of the light emission amount control range of the light emission block 121 is increased.

  In this case, the temperature of each light-emitting block 121 changes from the operating temperature during the SDR mode operation to the saturation temperature during the HDR mode operation. Therefore, by using the elapsed time t2 from the timing when the display mode is switched, it is possible to suitably control the light emission amount of the backlight device by determining the operation stability and switching the luminance correction processing method. . Note that the measurement timing of the elapsed time t2 may be a timing at which the display mode of the display device 1 is changed from the HDR mode to the SDR mode.

  Also, the elapsed time t3 from the timing when the standard control mode for controlling each light emission block 121 with the same light emission amount and the local dimming control mode for controlling the light emission amount for each light emission block 121 is set as a determination parameter. Is also possible.

  The backlight control unit 111 can also determine the operational stability using a value other than the elapsed time from a predetermined timing as a determination parameter. For example, the backlight control unit 111 may determine that the driving is initial when the change in the temperature measurement value per unit time of the light emitting block 121 acquired by the temperature sensor 123 is equal to or greater than a predetermined threshold.

  Further, the backlight control unit 111 can also determine the operation stable state based on the drive current value of each light emitting block 121. Specifically, when the time change of the average value of the driving current value of each light emitting block 121 is larger than a predetermined value, it is determined as the driving initial state or the unstable state.

  Further, the backlight control unit 111 can determine the operational stability for each light emission block 121 and switch the correction process. In this case, every time the target light emission block changes, the backlight control unit 111 determines the operation stability of the target light emission block and switches the correction processing method. Thereby, it becomes possible to correct | amend a brightness | luminance suitably for every light emission block 121. FIG.

  Further, it is conceivable to use a plurality of types of light sources, for example, three primary color backlights, as the backlight, but the temperature characteristics may differ depending on the type of light source. At this time, the determination condition and correction processing of the stable state of the backlight luminance may be changed for each type of light source.

DESCRIPTION OF SYMBOLS 100 Illuminating device 111 Backlight control part 121 Light emission block 122 Luminance sensor 123 Temperature sensor

Claims (24)

A plurality of light emitting means capable of individually controlling the light emission amount;
For one or more light-emitting means including the target light-emitting means, it is determined whether the first state has a relatively low operational stability or the second state has a relatively high operational stability than the first state Determination means to perform,
Correction means for periodically executing a process of correcting the light emission amount of the target light emitting means according to the state of one or a plurality of light emitting means including the target light emitting means;
With
When the determination unit determines that the determination unit is in the first state, the correction unit executes a first correction process for correcting the light emission amount of the target light emission unit in a first period, and the determination unit performs the second process. When it determines with it being a state of this, the 2nd correction process which correct | amends the light-emission quantity of the said object light emission means is performed with a 2nd period longer than the said 1st period. Of the plurality of light emitting means, a first detecting means for obtaining the luminance of light emitted from the target light emitting means;
A second detection means for obtaining a temperature of the target light emission means among the plurality of light emission means;
Further comprising
The first correction process is a correction process for correcting the light emission amount of the target light emitting unit based on the luminance of the target light emitting unit acquired by the first detection unit;
The said 2nd correction process is a correction process which correct | amends the light emission amount of the said object light emission means based on the temperature of the said object light emission means which the said 2nd detection means acquired. Lighting device.   When the first detection means acquires the luminance of the target light emitting means, the target light emitting means is caused to emit light among the plurality of light emitting means and the other light emitting means among the plurality of light emitting means for a predetermined period. The lighting device according to claim 2, further comprising a control unit that controls the lamp so as not to emit light.   The lighting device according to claim 2, wherein the second detection unit is a temperature sensor that acquires a temperature of the target light emitting unit.   4. The lighting device according to claim 2, wherein the second detection unit is a current value sensor that acquires a value of a current flowing through a drive circuit of the target light emitting unit.   When the first elapsed time that has elapsed since the lighting device has started driving is one or more light-emitting means including the target light-emitting means, the determination means is less than or equal to a first threshold value. 6. The device according to claim 1, wherein if the first elapsed time is longer than the first threshold value, the second state is determined. The lighting device according to item 1.   When the second elapsed time that has elapsed since the driving condition of the illumination device is changed is one or more light emitting means including the target light emitting means is less than or equal to a second threshold, 6. The method according to claim 1, wherein the state is determined to be the first state, and if the second elapsed time is longer than the second threshold, the second state is determined. The lighting device according to claim 1. Comprising first acquisition means for detecting a temperature change of each light emitting means;
For the one or more light emitting means including the target light emitting means, the determination means has a temperature change of the one or more light emitting means including the target light emitting means acquired by the first acquisition means equal to or greater than a third threshold value. The case is determined to be the first state, and when the temperature change is smaller than the third threshold, it is determined to be the second state. The lighting device according to any one of the above. Comprising a second acquisition means for detecting a change in drive current of each light emitting means;
When the change in the drive current of the target light emitting unit acquired by the second acquisition unit is greater than or equal to a fourth threshold with respect to one or a plurality of light emitting units including the target light emitting unit, 6. The device according to claim 1, wherein the state is determined to be the second state when the change in the driving current is smaller than the fourth threshold value. The lighting device described in 1.   10. The method according to claim 1, wherein when a plurality of types of light sources are used for the light emitting unit, the determination condition of the determination unit is changed for each type of light source. 11. Lighting device.   11. The illumination according to claim 1, wherein the light emission amount correction process by the first correction process has higher accuracy than the light emission amount correction process by the second correction process. apparatus.   The lighting device according to claim 1, wherein the correction unit repeats a cycle of performing correction processing on the plurality of light emitting units.   For the one or more light emitting means including the target light emitting means, the determination means has a relatively higher operational stability than the first state and a relatively higher operational stability than the second state. When it is determined that the third state is low, the correction means performs the light emission amount correction process of the target light emission means in the first correction process in the first cycle, and is executed after the first cycle. The lighting device according to claim 12, wherein in the second cycle, a correction process of the light emission amount of the target light emitting unit is performed in the second correction process. The lighting device according to any one of claims 1 to 13,
Display means for transmitting light emitted from the illumination device and displaying an image;
A display device comprising: A plurality of light emitting means capable of individually controlling the light emission amount;
Luminance acquisition means for acquiring the luminance of each light emitting means;
Temperature acquisition means for acquiring the temperature of each light emitting means;
For one or more light-emitting means including the target light-emitting means, it is determined whether the first state has a relatively low operational stability or the second state has a relatively high operational stability than the first state Determination means to perform,
When it is determined that the determination unit is in the first state, a first correction process for correcting a light emission amount of the target light emitting unit is performed based on a temperature of the target light emitting unit, and the determination unit performs the second process. A correction unit that performs a second correction process on the light emission amount of the target light emitting unit based on the luminance of the target light emitting unit,
A lighting device comprising:   When the luminance acquisition means acquires the luminance of the target light emitting means, the target light emitting means is caused to emit light among the plurality of light emitting means and another light emitting means is selected from among the plurality of light emitting means for a predetermined period. The illumination device according to claim 15, further comprising a control unit that performs control so as not to emit light.   When the first elapsed time that has elapsed since the lighting device has started driving is one or more light-emitting means including the target light-emitting means, the determination means is less than or equal to a first threshold value. The state according to claim 15 is determined, and when the first elapsed time is longer than the first threshold, it is determined that the state is the second state. Lighting device.   When the second elapsed time that has elapsed since the driving condition of the illumination device is changed is one or more light emitting means including the target light emitting means is less than or equal to a second threshold, The state is determined to be 1, and if the second elapsed time is longer than the second threshold, it is determined to be the second state. Lighting equipment. Comprising first acquisition means for detecting a temperature change of each light emitting means;
For the one or more light emitting means including the target light emitting means, the determination means has a temperature change of the one or more light emitting means including the target light emitting means acquired by the first acquisition means equal to or greater than a third threshold value. The case is determined to be the first state, and when the temperature change is smaller than the third threshold, it is determined to be the second state. The lighting device described. Comprising a second acquisition means for detecting a change in drive current of each light emitting means;
When the change in the drive current of the target light emitting unit acquired by the second acquisition unit is greater than or equal to a fourth threshold with respect to one or a plurality of light emitting units including the target light emitting unit, The lighting device according to claim 15 or 16, wherein the lighting device is determined to be in the state, and when the change in the driving current is smaller than the fourth threshold value, it is determined as the second state. .   21. The determination method according to any one of claims 15 to 20, wherein when a plurality of types of light sources are used for the light emitting unit, the determination condition of the determination unit is changed for each type of light source. Lighting device.   The lighting device according to any one of claims 15 to 21, wherein the correction unit repeats a cycle of performing a correction process on the plurality of light emitting units.   For the one or more light emitting means including the target light emitting means, the determination means has a relatively higher operational stability than the first state and a relatively higher operational stability than the second state. When it is determined that the third state is low, the correction means performs the light emission amount correction process of the target light emission means in the first correction process in the first cycle, and is executed after the first cycle. 23. The lighting device according to claim 22, wherein in the second cycle, the light emission amount correction process of the target light emitting unit is performed in the second correction process. The lighting device according to any one of claims 15 to 23;
Display means for transmitting light emitted from the illumination device and displaying an image;
A display device comprising:

Images