WO2016157494A1 - Circuit de réglage automatique de luminance destiné à un dispositif d'affichage numérique - Google Patents

Circuit de réglage automatique de luminance destiné à un dispositif d'affichage numérique Download PDF

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Publication number
WO2016157494A1
WO2016157494A1 PCT/JP2015/060462 JP2015060462W WO2016157494A1 WO 2016157494 A1 WO2016157494 A1 WO 2016157494A1 JP 2015060462 W JP2015060462 W JP 2015060462W WO 2016157494 A1 WO2016157494 A1 WO 2016157494A1
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Prior art keywords
unit
display unit
display
period
display units
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PCT/JP2015/060462
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English (en)
Japanese (ja)
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隆一 小池
渉 西岡
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理化工業株式会社
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Priority to PCT/JP2015/060462 priority Critical patent/WO2016157494A1/fr
Priority to JP2017509104A priority patent/JPWO2016157494A1/ja
Publication of WO2016157494A1 publication Critical patent/WO2016157494A1/fr

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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/04—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of a single character by selection from a plurality of characters, or by composing the character by combination of individual elements, e.g. segments using a combination of such display devices for composing words, rows or the like, in a frame with fixed character positions
    • G09G3/06—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of a single character by selection from a plurality of characters, or by composing the character by combination of individual elements, e.g. segments using a combination of such display devices for composing words, rows or the like, in a frame with fixed character positions using controlled light sources
    • G09G3/12—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of a single character by selection from a plurality of characters, or by composing the character by combination of individual elements, e.g. segments using a combination of such display devices for composing words, rows or the like, in a frame with fixed character positions using controlled light sources using electroluminescent elements
    • G09G3/14—Semiconductor devices, e.g. diodes
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
    • G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
    • G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]

Definitions

  • the present invention relates to an automatic luminance adjustment circuit for a digital display device including a plurality of display units including a plurality of light emitting elements, and more particularly, to an automatic luminance adjustment circuit for a digital display device in a temperature controller including a plurality of display units including a plurality of LED segments. It is about.
  • a plurality of display units each including a plurality of segment LEDs such as a 7-segment LED and a 16-segment LED as a light emitting element are used.
  • the display unit is provided with 7 segment LED.
  • As an electrical characteristic of the segment LED constituting the 7 segment LED there is a “forward voltage” which is a voltage drop generated when a forward current is passed between the anode and the cathode of the segment LED. This forward voltage generally has a certain degree of variation due to differences in raw materials and production processes of each segment LED, and is regarded as an element specification.
  • the forward current flowing through the plurality of segment LEDs also varies accordingly. This variation becomes more conspicuous as the drive voltage is lowered, which is an obstacle to power saving. Since the brightness of the segment LEDs is proportional to the forward current, if the forward current flowing through the plurality of segment LEDs varies, the brightness of the plurality of segment LEDs also varies. Therefore, the display unit manufacturer generally suppresses variations in luminance between the segment LEDs constituting the display unit by performing rank designation by luminance selection or using segment LEDs of the same lot. I am doing so. Alternatively, there is a method of keeping the forward current constant by adding a constant current circuit, but there is a tendency that the components are expensive or the circuit becomes complicated.
  • Patent Document 1 discloses a luminance adjustment circuit that varies the luminance of a plurality of light emitting elements so that the number of pulses commonly applied to the electrodes of the plurality of light emitting elements within a predetermined period can be changed. It is disclosed.
  • the electrical characteristics of the plurality of segment LEDs constituting the display unit are substantially uniform, the variation in the brightness of the plurality of segment LEDs constituting the display unit is suppressed within a certain range.
  • a plurality of segment LEDs are required for each display unit constituting the display device, and as a result, a large number of segment LEDs must be prepared.
  • the manufacturing restriction that the segment LED of the same lot is used and the rank by luminance selection are designated. It is necessary to impose restrictions, which makes it practically difficult to operate within limited manufacturing costs.
  • the variation in electrical characteristics of the segment LEDs mounted on each display unit is not always small between the plurality of display units constituting the display device, and thus, variation in luminance occurs between the display units.
  • the luminance adjustment circuit disclosed in Patent Document 1 is applied to a display device in which N display units are arranged, the display unit is composed of 8 segment LEDs including a segment LED representing a decimal point. If it is segment LED, the brightness
  • the present invention has been made to solve the above-described problems, and provides an automatic luminance adjustment circuit for a digital display device capable of making the luminance uniform among a plurality of display units constituting the digital display device. With the goal.
  • An automatic brightness adjustment circuit for a digital display device includes a voltage application unit that applies a power supply voltage to a plurality of segment LEDs in a plurality of display units each composed of a plurality of segment LEDs, and a plurality of displays.
  • a display unit to be lit is sequentially selected from the units, and among the plurality of segment LEDs constituting the selected display unit, the segment LED to which the power supply voltage is applied by the voltage application unit is set to the ground.
  • a selection switch that allows forward current to flow through the segment LED
  • a current measurement unit that measures forward current flowing through the segment LED connected to the ground by the selection switch for each display unit
  • a plurality of displays In order to keep the brightness of the unit within a certain range, the forward current measured by the current measurement unit and multiple A period calculation unit that calculates a period in which a forward current flows to the segment LED that constitutes the display unit from a common luminance setting value for the display unit, and the selection switch control unit is provided for each display unit.
  • the connection with the ground by the selection switch is controlled so that the forward current flows through the segment LED constituting the display unit.
  • the automatic luminance adjusting circuit of the digital display device includes a lighting pattern storage unit that stores lighting patterns indicating periods in which a plurality of display units can be lit, and the period calculation unit includes the luminances of the plurality of display units.
  • the display unit indicated by the lighting pattern can be turned on.
  • a period during which a forward current is supplied to the segment LED constituting the display unit is calculated.
  • the lighting pattern stored in the lighting pattern storage unit indicates that the turn-off period of all the display units is before and after the turn-on period of each display unit.
  • the selection switch control unit controls the connection with the ground by the selection switch so that forward current does not flow due to interference with the segment LEDs constituting the plurality of display units during the extinguishing period indicated by the lighting pattern. It is what you do.
  • FIG. 1 is a block diagram showing a digital display device according to Embodiment 1 of the present invention.
  • the display 1 which is a digital display device has three display units 11, 12, and 13 arranged.
  • the display unit 11 is a seven-segment LED including eight segment LEDs 11a, 11b, 11c, 11d, 11e, 11f, 11g, and 11h including a segment LED 11h that represents a decimal point.
  • the display unit 12 is a seven-segment LED including eight segment LEDs 12a, 12b, 12c, 12d, 12e, 12f, 12g, and 12h, including a segment LED 12h that represents a decimal point.
  • the display unit 13 is a seven-segment LED including eight segment LEDs 13a, 13b, 13c, 13d, 13e, 13f, 13g, and 13h including a segment LED 13h that represents a decimal point.
  • the display units 11, 12, and 13 are 7-segment LEDs, but are not limited to 7-segment LEDs. For example, 17 segment LEDs including a segment LED that represents a decimal point are included. 16 segment LED comprised from these may be sufficient.
  • the display device 1 includes three display units. However, this is only an example, and it is only necessary to include two or more display units. It is assumed that the electrical characteristics of the eight segment LEDs constituting each display unit are aligned in advance. Therefore, if attention is paid to one display unit, the variation in luminance of the eight segment LEDs is suppressed within a certain range. However, since the electrical characteristics of the mounted segment LEDs are not necessarily the same between the display units 11, 12, and 13, there may be variations in luminance.
  • a power supply voltage Vdd output from a power supply device (not shown) is applied to the power supply voltage line 21. Since the forward voltage of the segment LEDs 11a to 11h, 12a to 12h, and 13a to 13h constituting the display units 11, 12, and 13 is 1.7 to 2.5V, the power supply voltage Vdd is a voltage that can be driven at a higher voltage. It is.
  • the transistor 22 that is a switching element switches the connection state between the power supply voltage line 21 and the resistor 23 in accordance with a control signal Seg output from a controller 30 described later.
  • the power supply voltage line 21 and the transistor 22 constitute a voltage application unit.
  • the resistor 23 is a current measuring resistor inserted between the transistor 22 and the display 1.
  • the transistor 22 and resistor 23 are connected to each segment LED constituting the display units 11, 12, and 13. ing.
  • the display units 11, 12, and 13 are each composed of eight segment LEDs, so that eight transistors 22 and eight resistors 23 are mounted. Therefore, the control signal Seg output from the controller 30 instructs to apply the power supply voltage Vdd to the anodes of the segment LEDs 11a, 12a, 13a constituting the display units 11, 12, 13, for example.
  • the ON state is a state where the power supply voltage line 21 and the resistor 23 are connected
  • the OFF state is a state where the power supply voltage line 21 and the resistor 23 are disconnected.
  • a FET (Field Effect Transistor) 24 selects a display unit to be lit in order from the three display units 11, 12, and 13 in accordance with the control signal Drv output from the controller 30.
  • the FET 24 is connected to the ground LED 25 by connecting the cathode of the segment LED to which the power supply voltage Vdd is applied by the transistor 22 among the segment LEDs constituting the selected display unit. It is a selection switch that allows current to flow.
  • the controller 30 includes, for example, an MCU (Micro Control Unit) that is a micro control unit, a semiconductor integrated circuit on which a CPU (Central Processing Unit) is mounted, and the like.
  • the controller 30 identifies the lighting period and the extinguishing period with reference to the dynamic lighting pattern of FIG. 3 in which the lighting period and the extinguishing period are repeated.
  • the controller 30 controls the transistor 22 to be in an ON state during the lighting period so that the power supply voltage Vdd is applied to the anodes of the segment LEDs constituting the display units 11, 12, and 13.
  • the controller 30 controls the transistor 22 to be in an OFF state during the extinguishing period so that the power supply voltage Vdd is not applied to the anodes of the segment LEDs constituting the display units 11, 12, and 13.
  • the controller 30 controls the segment LEDs 11a to 11h and 12a to constitute the display unit for each of the display units 11, 12, and 13 in order to keep the luminance of the display units 11, 12, and 13 within a certain range. 12h and 13a to 13h, the period during which the forward current flows is calculated. Then, the controller 30 causes each of the display units 11, 12, and 13 so that forward current flows through the segment LEDs 11a to 11h, 12a to 12h, and 13a to 13h constituting the display unit during the calculated period. The connection to the ground 25 by the FET 24 is controlled.
  • FIG. 2 is a block diagram showing the controller 30 of the digital display device according to Embodiment 1 of the present invention.
  • the lighting pattern storage unit 31 is a storage medium such as a RAM that stores a dynamic lighting pattern indicating the lighting order and lighting periods of the display units 11, 12, and 13.
  • the transistor control unit 32 turns on the transistor 22 during the time of each drive, and lights up the plurality of segment LEDs 11a to 11h, 12a to 12h, and 13a to 13h in each of the display units 11, 12, and 13. Control is performed so that the power supply voltage Vdd is applied to the anode of the segment LED that is desired to be generated.
  • the transistor control unit 32 turns off the transistor 22 during the extinguishing period, and the power supply voltage Vdd is the anode of all the segment LEDs 11a to 11h, 12a to 12h, and 13a to 13h constituting the display units 11, 12, and 13. It controls so that it may not be applied to.
  • the current measuring unit 33 is a voltage V applied to both ends of the resistor 23 connected to the segment LED (for example, 11a, 12a, 13a) connected to the ground 25 by the FET 24 for each of the display units 11, 12, 13. 1 and V 2 are measured, and the potential difference ⁇ V between the voltage V 1 and the voltage V 2 is divided by the resistance value R of the resistor 23, whereby the segment LED connected to the ground 25 by the FET 24 (for example, 11a, 12a, 13a ) To calculate the forward current I (I D1 , I D2 , I D3 ).
  • the period calculation unit 34 sets the forward current I measured by the current measurement unit 33 and the common luminance setting value L for the display units 11, 12, 13 in order to keep the luminance of the display units 11, 12, 13 within a certain range. From each of the display units 11, 12, and 13, the forward current is supplied to the segment LEDs 11 a to 11 h, 12 a to 12 h, and 13 a to 13 h constituting the display unit during the lighting period of the display unit indicated by the lighting pattern. A lighting period T (T D1 , T D2 , T D3 ) is calculated.
  • the period storage unit 35 is a storage medium such as a non-volatile memory that stores a lighting period T in which a forward current is supplied to the segment LEDs 11a to 11h, 12a to 12h, and 13a to 13h calculated by the period calculation unit 34.
  • the selection switch control unit 36 refers to the dynamic lighting pattern stored in the lighting pattern storage unit 31 and identifies the lighting period and the extinguishing period. Further, the selection switch control unit 36 is provided for each of the display units 11, 12, 13 during the lighting period T stored in the period storage unit 35, and the segment LEDs 11 a to 11 h, 12 a to 12 h, constituting the display unit. The connection of the FET 24 to the ground 25 is controlled so that a forward current flows through 13a to 13h.
  • the period storage unit 35 is provided.
  • the segment LEDs 11a to 11h and 12a calculated by the period calculation unit 34 by the selection switch control unit 36 are shown. It is also possible to acquire and hold a lighting period T in which a forward current is passed through to 12h and 13a to 13h.
  • FIG. 3 is an explanatory diagram illustrating an example of a dynamic lighting pattern stored in the lighting pattern storage unit 31.
  • a dynamic lighting pattern with a lighting cycle of 16 msec is shown, and Drv0 is a period during which the display units 11, 12, and 13 are turned off for 2 msec.
  • Drv1 indicates a period during which the display unit 11 can be turned on (4 msec), and indicates that the display unit 11 is lit for 1 to 4 msec and the display unit 11 is turned off for 3 to 0 msec.
  • Drv2 indicates a period during which the display unit 12 can be turned on (4 msec). The display unit 12 is turned on for 1 to 4 msec and the display unit 12 is turned off for 3 to 0 msec.
  • Drv3 indicates a period during which the display unit 13 can be turned on (4 msec), and indicates that the display unit 13 is lit for 1 to 4 msec and the display unit 13 is turned off for 3 to 0 msec.
  • “turn off” before and after Drv1, Drv2, and Drv3 means that the display units 11, 12, and 13 are turned off during a period of 0.5 msec.
  • the lighting cycle of the dynamic lighting pattern is 16 msec.
  • the lighting of the display units 11, 12, and 13 is intermittent when the lighting cycle is 20 msec or less.
  • the lighting cycle of the dynamic lighting pattern is set to 16 msec from a value lower than that and the number of display units.
  • the luminance of any one of the eight segment LEDs 11a to 11h (for example, 11a) It can be seen that the luminance of the other seven segment LEDs (for example, 11b to 11h) is the same.
  • the display units 12 and 13 if the luminance of any one segment LED is known, the luminance of the other seven segment LEDs is the same.
  • the segment LED is repeatedly turned on and off in a short cycle, the human eye feels that the lighting state continues, and the brightness of the segment LED is proportional to the time and amount of current that the forward current flows. If the amount of current converted per unit time is the same, the brightness of the LEDs is the same.
  • each of the forward currents flowing through any one of the segment LEDs is measured in the display units 11, 12, and 13, and based on the measurement result, per unit time flowing through each segment LED.
  • the luminance variation between the display units 11, 12, and 13 is suppressed. Specifically, it is as follows.
  • the transistor control unit 32 of the controller 30 refers to the dynamic lighting pattern stored in the lighting pattern storage unit 31 and turns on the transistor 22 during the periods of Drv1, Drv2, and Drv3 that are lighting possible periods.
  • the power supply voltage Vdd is controlled to be applied to the anodes of the segment LEDs constituting the display units 11, 12, and 13.
  • the electrical characteristics of the eight segment LEDs constituting the individual display units 11, 12, and 13 are aligned in advance by the manufacturer. For this reason, if the luminance of any one segment LED (for example, 11a) is known in each of the display units 11, 12, and 13, it is determined that the luminance of the other segment LEDs (for example, 11b to 11h) is comparable.
  • the transistor control unit 32 selects the segment LEDs 11a, 11a, 11a, 13a, 13a, 13a, 13h, 13a, 13h, 13a, 13a, 13h, 13a, 13h, 13h, 13h, 13h, 13h, 13h, 13h, 13h, 13h, 13h, 13h, 13h, 13h, 13h, 13h, 13h, 13h, 13h, 13h, 13h, 13h, 13h, Control is performed so that the power supply voltage Vdd is applied to the anodes of 12a and 13a. Further, the transistor control unit 32 turns off the transistor 22 during periods other than Drv1, Drv2, and Drv3, which are extinguishing periods, and the segment LEDs 11a to 11h in which the power supply voltage Vdd constitutes the display units 11, 12, and 13 are displayed. , 12a to 12h and 13a to 13h are controlled so as not to be applied.
  • the selection switch control unit 36 of the controller 30 refers to the dynamic lighting pattern stored in the lighting pattern storage unit 31, and during the lighting period (1 to 4 msec) in Drv1, the display unit 11, 12, 13 Then, the display unit 11 is selected.
  • the selection switch control unit 36 grounds the cathode of the segment LED 11a that constitutes the selected display unit 11.
  • a control signal Drv indicating connection to 25 is output to the FET 24.
  • the selection switch control unit 36 of the controller 30 selects the display unit 12 from the display units 11, 12, and 13 during the lighting period (1 to 4 msec) in Drv2, and configures the selected display unit 12.
  • a control signal Drv indicating that the cathode of the segment LED 12 a connected to the ground 25 is connected is output to the FET 24.
  • the selection switch control unit 36 of the controller 30 selects the display unit 13 from the display units 11, 12, and 13 during the lighting period (1 to 4 msec) in Drv 3, and configures the selected display unit 13.
  • a control signal Drv indicating that the cathode of the segmented LED 13 a is connected to the ground 25 is output to the FET 24.
  • the current measurement unit 33 of the controller 30 controls the cathode of the segment LED 11a that constitutes the display unit 11 according to the control signal Drv output from the selection switch control unit 36 by the FET 24.
  • the voltages V 1 -D1 and V 2-D1 applied to both ends of the resistor 23 connected to the segment LED 11a are measured.
  • the current measuring unit 33 of the controller 30 controls the cathode of the segment LED 12a constituting the display unit 12 according to the control signal Drv output from the selection switch control unit 36 by the FET 24.
  • the voltages V 1 -D2 and V 2-D2 applied to both ends of the resistor 23 connected to the segment LED 12a are measured.
  • Current measuring unit 33 during the lighting periods within Drv2, when measuring the voltage V 1-D2, V 2- D2, the resistance value of the voltage V 1-D2 and the voltage V 2-D2 of the potential difference [Delta] V D2 and resistor 23 R The forward current ID2 flowing in the segment LED 12a constituting the display unit 12 is calculated by dividing by.
  • the current measuring unit 33 of the controller 30 controls the cathode of the segment LED 13a constituting the display unit 13 according to the control signal Drv output from the selection switch control unit 36 by the FET 24 during the lighting period (4 msec) in Drv3.
  • Drv the control signal
  • the voltages V 1 -D3 and V 2-D3 applied to both ends of the resistor 23 connected to the segment LED 13a are measured.
  • the period calculation unit 34 of the controller 30 includes the segment LEDs 11a to 11h, 12a to 12h, which constitute the display units 11, 12, and 13; In order to make the amount of current converted per unit time flowing through 13a to 13h constant, as shown in the following formulas (1) to (3), the forward current I D1 , The display units 11, 12, and 13 are configured during the lighting period (1 to 4 msec) in Drv1, Drv2, and Drv3 from the common luminance setting value L for I D2 and I D3 and the display units 11, 12, and 13.
  • the lighting periods T D1 , T D2 , and T D3 for flowing a forward current to the segment LEDs 11a to 11h, 12a to 12h, and 13a to 13h are calculated.
  • T D1 , T D2 , and T D3 are as follows.
  • the lighting periods T D1 , T D2 , and T D3 through which the forward current calculated by the period calculation unit 34 flows are stored in the period storage unit 35. Since the period storage unit 35 is composed of a nonvolatile memory, the storage of the lighting periods T D1 , T D2 , and T D3 is retained even when the digital display device of FIG. 1 is turned off. This completes the process for shipping the digital display device of FIG.
  • the selection switch control unit 36 of the controller 30 acquires the lighting periods T D1 , T D2 , and T D3 stored in the period storage unit 35.
  • the selection switch control unit 36 refers to the dynamic lighting patterns stored in the lighting pattern storage unit 31 and sets the periods of Drv1, Drv2, and Drv3 (lighting and extinguishing) The total duration).
  • the time-up time of the internal clock is set to the lighting cycle (16 msec) indicated by the dynamic lighting pattern, and every time the internal clock times up, the Drv0 turn-off time (2 msec) ⁇ light-off time ( 0.5 msec) ⁇ Drv1 time (4 msec) ⁇ light-out time (0.5 msec) ⁇ Drv2 time (4 msec) ⁇ light-out time (0.5 msec) ⁇ Drv3 time (4 msec) ⁇ light-out time (0. 5msec), the period of Drv1, Drv2, Drv3 is specified.
  • the selection switch control unit 36 specifies that the 4 msec period between 2.5 and 6.5 msec is the period of Drv1, and after the internal clock times up, A period of 4 msec between ⁇ 11 msec is specified as a period of Drv2. Further, after the internal clock times out, the selection switch control unit 36 specifies that the 4 msec period between 11.5 and 15.5 msec is the Drv3 period.
  • the selection switch control unit 36 between the T D1 is the lighting periods within the period of Drv1 identified as forward current flows through the segment LED constituting the display unit 11, to constitute a display unit 11
  • a control signal Drv D1 indicating that the segment LED is connected to the ground 25 is output to the FET 24.
  • the segment LED connected to the ground 25 varies depending on the characters displayed on the display unit 11. Specifically, if the character displayed on the display unit 11 is the numeral “8”, the segment LEDs 11a to 11g are connected to the ground 25 so that forward current flows through the segment LEDs 11a to 11g constituting the display unit 11.
  • a control signal Drv D1 indicating connection is output to the FET 24.
  • a control signal Drv D1 indicating that the two segment LEDs 11b and 11c constituting the rightmost vertical line are connected to the ground 25 is output to the FET 24 so that a forward current flows through the FET 24.
  • the selection switch control unit 36 between the T D2 is a lighting period in the period Drv2 identified as forward current flows through the segment LED constituting the display unit 12, to constitute a display unit 12 A control signal Drv D2 indicating that the segment LED connected to the ground 25 is connected is output to the FET 24.
  • the selection switch control unit 36, between the T D3 is a lighting period in the period Drv3 identified as forward current flows through the segment LED constituting the display unit 13, to constitute a display unit 13
  • a control signal Drv D3 indicating that the segment LED is connected to the ground 25 is output to the FET 24.
  • the segment LED connected to the ground 25 varies depending on the characters displayed on the display units 12 and 13.
  • FET24 receives the signal Drv D1 from the selection switch control unit 36 of the controller 30, during the lighting period T D1 of Drv1, ground 25 segment LED display unit 11 to which the control signal Drv D1 is instructed to connect Connect with.
  • T D1 for lighting period T D1 is 2.5 msec, in the period Drv1 (4 msec), while the 2.5 msec, connect segment LED display unit 11 and the ground 25, the remainder of 1.5msec In the meantime, the segment LED of the display unit 11 and the ground 25 are disconnected.
  • FET 24 receives a signal Drv D2 from the selection switch control unit 36 of the controller 30, during the lighting period T D2 of Drv2, segment LED display unit 12 to which the control signal Drv D2 is instructed to connect Connect to ground 25.
  • the segment LED of the display unit 12 is connected to the ground 25 for 2.77 msec in the Drv2 period (4 msec), and the remaining 1.23 msec
  • the segment LED of the display unit 12 and the ground 25 are disconnected.
  • FET 24 receives a signal Drv D3 from the selection switch control unit 36 of the controller 30, during the lighting period T D3 of Drv3, segment LED display unit 13 to which the control signal Drv D3 is instructed to connect Connect to ground 25.
  • T D3 is 3.12Msec
  • Drv3 4 msec
  • connect segment LED display unit 13 and the ground 25 the remainder of 0.88msec
  • the segment LED of display unit 13 and ground 25 are not connected.
  • the display unit 11 , 12 and 13 since the forward current flows through each segment LED constituting the display units 11, 12, and 13 only during the lighting periods T D1 , T D2 , and T D3 calculated by the period calculation unit 34, the display unit 11 , 12 and 13, the amount of current converted per unit time flowing to each segment LED becomes constant, and the luminance between the display units 11, 12 and 13 becomes uniform.
  • the display units to be turned on are sequentially selected from the three display units 11, 12, and 13 in accordance with the control signal Drv output from the controller 30.
  • the segment LED to which the power supply voltage Vdd is applied by the transistor 22 is connected to the ground 25 among the segment LEDs constituting the selected display unit, so that a forward current flows through the segment LED.
  • the controller 30, the segment LED 11 a constituting the display unit is provided for each display unit 11, 12, 13.
  • the luminance of the display units 11, 12, and 13 can be made uniform. Further, when a plurality of display devices 1 including the display units 11, 12, and 13 are arranged, the luminance of the plurality of display devices 1 can be made uniform.
  • control is performed so that the amount of current converted per unit time flowing through the plurality of segment LEDs 11a to 11h, 12a to 12h, and 13a to 13h constituting the display units 11, 12, and 13 is constant.
  • the variation in luminance of the plurality of segment LEDs 11a to 11h, 12a to 12h, and 13a to 13h becomes obvious. Even in this case, it is possible to suppress variations in luminance of the plurality of segment LEDs 11a to 11h, 12a to 12h, and 13a to 13h.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
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  • Control Of El Displays (AREA)

Abstract

L'objectif de la présente invention est d'obtenir un circuit de réglage automatique de luminance destiné à un dispositif d'affichage, qui permette d'égaliser la luminance parmi une pluralité d'unités d'affichage. L'invention concerne un circuit de réglage automatique de luminance destiné à un dispositif d'affichage, comprenant un FET (24) qui sélectionne de manière séquentielle une unité d'affichage devant être éclairée parmi trois unités d'affichage (11, 12, 13), conformément à un signal de commande Drv produit à partir d'un dispositif de commande (30), et relie à la terre (25), parmi des DEL de segments (11a - 11h, 12a - 12h, 13a - 13h) constituant l'unité d'affichage sélectionnée, une DEL de segment à laquelle une tension d'alimentation Vdd est appliquée par un transistor (22), de telle manière qu'un courant direct circule à travers la DEL de segment. Le dispositif de commande calcule une période d'éclairage (TD1, TD2, TD3), pour chaque unité d'affichage, durant laquelle un courant direct est amené à circuler à travers les DEL de segments constituant l'unité d'affichage, de manière à régler la luminance dans l'unité d'affichage à l'intérieur d'une plage prescrite. Pour chaque unité d'affichage, le dispositif de commande commande le raccordement à la terre par l'intermédiaire du FET, de manière que le courant direct circule à travers les LED de segments constituant l'unité d'affichage pendant la période d'éclairage calculée.
PCT/JP2015/060462 2015-04-02 2015-04-02 Circuit de réglage automatique de luminance destiné à un dispositif d'affichage numérique WO2016157494A1 (fr)

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PCT/JP2015/060462 WO2016157494A1 (fr) 2015-04-02 2015-04-02 Circuit de réglage automatique de luminance destiné à un dispositif d'affichage numérique
JP2017509104A JPWO2016157494A1 (ja) 2015-04-02 2015-04-02 デジタル表示装置の自動輝度調整回路

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PCT/JP2015/060462 WO2016157494A1 (fr) 2015-04-02 2015-04-02 Circuit de réglage automatique de luminance destiné à un dispositif d'affichage numérique

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KR20220053849A (ko) 2020-10-23 2022-05-02 주식회사 엘엑스세미콘 엘이디 구동장치

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JPS60168291A (ja) * 1984-02-13 1985-08-31 小糸工業株式会社 情報表示装置
JPH03237484A (ja) * 1990-02-15 1991-10-23 Fujitsu Ltd 多桁型７セグメント式ｌｅｄ数字表示装置
JPH06186922A (ja) * 1992-12-21 1994-07-08 Toshiba Corp 輝度調整装置
JPH06282239A (ja) * 1993-03-26 1994-10-07 Pfu Ltd 発光素子の輝度／色調調整方法
JP2000187467A (ja) * 1998-12-24 2000-07-04 Stanley Electric Co Ltd 有機ｅｌ素子の点灯制御装置及び点灯制御方法
JP2001013904A (ja) * 1999-07-02 2001-01-19 Seiko Instruments Inc 発光表示器駆動回路
JP2011237517A (ja) * 2010-05-07 2011-11-24 Tokai Ec Co Ltd ７セグメント表示装置及び表示機器。

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4474701B2 (ja) * 1998-09-16 2010-06-09 ソニー株式会社 表示装置

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60168291A (ja) * 1984-02-13 1985-08-31 小糸工業株式会社 情報表示装置
JPH03237484A (ja) * 1990-02-15 1991-10-23 Fujitsu Ltd 多桁型７セグメント式ｌｅｄ数字表示装置
JPH06186922A (ja) * 1992-12-21 1994-07-08 Toshiba Corp 輝度調整装置
JPH06282239A (ja) * 1993-03-26 1994-10-07 Pfu Ltd 発光素子の輝度／色調調整方法
JP2000187467A (ja) * 1998-12-24 2000-07-04 Stanley Electric Co Ltd 有機ｅｌ素子の点灯制御装置及び点灯制御方法
JP2001013904A (ja) * 1999-07-02 2001-01-19 Seiko Instruments Inc 発光表示器駆動回路
JP2011237517A (ja) * 2010-05-07 2011-11-24 Tokai Ec Co Ltd ７セグメント表示装置及び表示機器。

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