JP2005070081A - Light emitting diode module using multiplication slot system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem in a conventional full color light-emitting diode (LED) display system wherein, since an independent control circuit is required for each of three primary color LED lamps, many signal lines are required and lighting efficiency is low also. <P>SOLUTION: The lighting efficiency is optimized by sharing signal lines between a shift register for sending out lighting control data to each LED lamp and a shift register for realizing time division drive, and by optimizing time division lighting control among three primary color LED lamps. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
[Industrial application fields]
The present invention relates to a large-sized video display system using LEDs and a configuration and control method of an LED module constituting an electrical decoration system.
[0002]
[Prior art]
In general, the digital control of the brightness of LED lamps provides a plurality of time zones within a frame cycle by dividing the frame cycle, and selectively assigns these time zones to each LED lamp. It is done by adjusting the lighting / non-lighting time ratio based on the luminance data given for each frame period (hereinafter, set by determining the time position and time width within the frame period, for luminance adjustment) The time zone assigned to each LED lamp is called a “lighting control slot”). A first method for adjusting the lighting time ratio within each frame period is to assign one lighting control slot to each LED lamp, and within the assigned lighting control slot, a time width proportional to given luminance data. In this method, pulses are generated to drive an LED lamp. The difficulty of this method is that it basically requires a pulse width conversion circuit for each LED lamp. The second method is a method of assigning a plurality of lighting control slots such that the time width is doubled for each LED lamp, and controlling lighting and non-lighting in each slot. In this method, the number of lighting control slots to be assigned is the same as the number of bits of luminance data, so that each lighting control slot and each bit of luminance data can be made to correspond one-to-one. Thus, it is sufficient to control lighting and non-lighting in the corresponding lighting control slot. Hereinafter, the first driving method is referred to as a pulse width modulation method, and the second driving method is referred to as a multiplication slot method. 1 and 2 illustrate the difference between the above two systems. In both figures, the luminance data is set to 4 bits, and accordingly, the luminance is controlled over 0 to 15 stages. In FIG. 1, which is a pulse width modulation method, a pulse having a time width of 10 is generated in a lighting control slot having a time width of 15 corresponding to a luminance data value of 10 (binary display / 1010). On the other hand, in FIG. 2 of the multiplying slot method, four lighting control slots S0 to S3 having time widths 1, 2, 4, and 8 are set, respectively, and the same luminance data 10 (binary display / 1010) is set. A pulse that is turned on in the lighting control slots S1 and S3 is generated.
[0003]
The multiplying slot method is used as a configuration method of a continuous bead-shaped LED module called a non-uniform slot type LED module (Patent Reference 1). This continuous bead-shaped LED module uses a display unit in which LED lamps are arranged in a single bead instead of an LED module having a display unit in which LED lamps are arranged in a matrix. (2D) wiring and three-dimensional wiring are eliminated, only linear (1D) wiring is used, the configuration of various large display systems using LED lamps is simplified, costs are reduced, and maintainability is improved. It is an LED module aiming at ultra-large size, flat screen, and screen shapes other than rectangles, and weight reduction. In this tandem LED module, as shown in FIG. 3, a very simple control circuit (lamp unit) is arranged for each LED lamp, and adjacent lamp units are connected by a necessary signal line. These lamp units are connected in a single string, and one end of the lamp units is connected to the control unit to achieve this goal. By adopting the multiplying slot method for the LED array modules, the lamp unit circuit can be simplified and made uniform, and at the same time, the amount of data transferred on the signal lines connecting the lamp units can be greatly reduced. it can. Since the tandem LED module adopting this multiplying slot method is positioned as the predecessor of the LED module according to the present invention, the LED module will be simply referred to as a conventional module, and its circuit configuration and operating principle will be described below. .
[0004]
The conventional module to be described is composed of 256 LED lamps, and can control the luminance of each lamp in 256 steps (8 bits). In this conventional module, as shown in FIG. 4, 256 LED lamps connected in a tandem shape, and 16 lamp units added to each LED lamp are 16 pieces from the end to which the control unit is connected. Are divided into groups (called unit groups), i is a unit group number, j is a number indicating the order of arrangement within the unit group, and L_{i, j}, LM_{i, j}(I = 0... 15, j = 0... 15) unit numbering is performed (hereinafter, when it is necessary to indicate unit numbers on signal lines and circuit elements of individual lamp units, PD_{i, j}, PCO_{i, j}... Etc., and the lamp unit number is added to the symbols representing circuit elements and signal lines. In general, the luminance control of the LED lamp is performed by setting the ratio of the lighting time in each frame period based on the luminance data (8 bits) supplied to each lamp every frame period (1/30 second) from an image generation device or the like. It is done by controlling. In general, in order to increase luminous efficiency, a plurality of LED lamps to be controlled are divided into groups each composed of several equal numbers of LED lamps, and each group is driven in a time-sharing manner (this group is divided into two groups). Called a time-sharing group).
[0005]
As will be described later, in the conventional module, LED lamps (16 each) having the same arrangement sequence number in each unit group form one time division group and are driven simultaneously. Also, each time division group is numbered 0, 1,... 15 which is the same as the arrangement order number. That is, each time division group configuration is as follows.
Time division group 0 L_0,0    L_{1, 0}L_2,0  ・ ・ ・ ・ ・ ・ L_15.0
Time division group 1 L_{0, 1}    L_1,1L_2,1  ・ ・ ・ ・ ・ ・ L_15,1
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・
Time division group 15 L_0,15  L_1,15L_2,15  ・ ・ ・ ・ ・ ・ L_{15, 15}
[0006]
FIG. 5 shows a circuit diagram of the lamp unit. In FIG. 5, the signal line on the right side of the unit is an input signal line for the lamp unit, and the signal line on the left side of the unit is an output line corresponding to each input line. In adjacent lamp units, each output line is connected to a corresponding input line adjacent thereto, and an input signal line of the outermost lamp unit is connected to a corresponding output line of the control unit. The main circuit elements of the lamp unit (see FIG. 5) are an LED lamp L, a lighting control register P, a register Q (hereinafter referred to as a lighting control data holding register) that latches the output of the lighting control register, and a selection register S. All of these three latch registers latch the input d as an internal state at the rising edge of the clock c, and the new internal state is reflected in the output q.
[0007]
As described above, since the input and output of the lighting control register P and the selection register S are connected to each other, they are shifted by the clock signals PC and SC from the control unit as shown in FIG. Two sets of shift registers, that is, the above-described lighting control shift register and selection control shift register are configured. The output signals PD and SD of the control unit are data input signals to the respective shift registers. The two shift registers are synchronized with the respective clocks PC and SC, and necessary data is shifted in from the control unit. Latch register P of each lamp unit_{i, j}Or S_{i, j}It serves to set the internal state of the to a predetermined value.
[0008]
Next, the luminance control operation of this circuit will be described. FIG. 7 is a time chart for one frame of the conventional module. Within one frame period, eight lighting control cycles of Nos. 0 to 7 having a minimum time width of 60 μsec and sequentially multiplying the time width are set. That is, the time width of the lighting control cycle k is t_kIf so:
t_k= 60x2^kμsec.
The lighting control cycle k (k = 0, 1,... 7) further includes 16 equally spaced lighting control slots R._{k, 0}, R_{k, 1}, ... R_{k, 15}And a lighting control slot R within each lighting control cycle k._{k, i}Then, the time division group i is selected and the time division driving is performed. The circuit operation in each lighting control cycle is divided into (1) lighting control data update operation and (2) time-division driving operation that are synchronized in time and operate in parallel.
[0009]
(1) Lighting control data update operation
In each lighting control cycle, the content of the lighting control shift register is updated. A feature of the multiplication slot type LED module is that each lighting control slot having a different time width corresponds to the bit position of the luminance data, and in the lighting control cycle k, the bit at the bit position k of the luminance data of each LED lamp. As a result, the lighting control shift register is updated. That is, 256 LED lamps L in one frame period_{i, j}8-bit luminance data;
c_{i, j, 0}, C_{i, j, 1}, C_{i, j, 2}  ... c_{i, j, 7}
(I = 0 ... 15, j = 0 ... 15, c_{i, j, 0}Is the least significant bit, c_{i, j, 7}Is the most significant bit)
, The lighting control data (256 bits each) shifted into the lighting control shift register in the lighting control cycles 0, 1,..., 7 can be expressed as follows.
Cycle 0 (c_{15, 15, 0}, C_{15, 14, 0}, ... c_{0, 1, 0}, C_{0, 0, 0})
Cycle 1 (c_{15, 15, 1}, C_{15, 14, 1}, ... c_{0, 1, 1}, C_{0, 0, 1})
...
Cycle 7 (c_{15, 15, 7}, C_{15, 14, 7}, ... c_{0, 1, 7}, C_{0, 0, 7})
Each of the lighting control data is generated by decomposing luminance data in bit units, rearranging and editing the data in bit units in the order of lighting control cycles (= bit position order) and the order of LED lamp arrangement. FIG. 8 shows the structure of the lighting control data for one frame period, and it is continuously shifted into the lighting control shift register over one frame period. FIG. 9 is a time chart in one lighting control cycle (number k). As shown in the figure, in the lighting control cycle k, the lighting control data; c_{15, 15, k}  ... c_{0,2, k}  , C_{0,1, k}, C_{0, 0, k}  Are successively shifted into the lighting control shift register in synchronization with the clock signal PC from the control unit output signal PD. As a result, at the end of the lighting control cycle k, 256 all lighting control registers P_{i, j}(I = 0 ... 15, j = 0 ... 15) is the corresponding lighting control data c_{i, j, k}Will be updated. The lighting control register P updated as shown in FIG._{i, j}Is stored in the lighting control data holding register Q by the QC signal at the start of each lighting control cycle._{i, j}And is held until the end of the lighting control cycle. The time width t of the lighting control cycle k_kIs t_k= 60x2^kThe period of the clock signal PC in each lighting control cycle is t._k  Therefore, the period of the clock PC of each lighting control cycle is also set to be a multiple of the minimum period 60/256 μsec.
[0010]
(2) Time-division drive operation
In each lighting control cycle, a time division group is selected in order, and time division driving is performed. On the circuit, the selection of the time division group is realized by selectively turning on the corresponding selection register. Therefore, at the time of system startup, the selection control shift register is the 15th selection register of each unit group, that is, the 16 selection registers S of the time division group 15._{k, 15}Only (k = 0, 1,... 15) is on, and all other selection registers are initially set to an off state (hereinafter referred to as an initial setting state). This initial setting is realized by shifting a predetermined bit pattern into the selection control shift register when the system starts up. FIG. 10 shows a time chart in the lighting control cycle k of one unit group (unit group number i) composed of 16 LED lamps and lamp units. . The shift clock signal SC is a signal obtained by dividing the clock signal PC by 1/16, and plays a role of substantially dividing each lighting control cycle into 16 lighting control slots. The input data signal SD to the selection control shift register is turned on in the control unit every 16 clocks of the clock SC, that is, at the start of each lighting control cycle. As a result, the selection control shift register always returns to the initial setting state after 16 clock cycles, that is, at the start of the next lighting control cycle. Further, as described above in (1) lighting control data update operation, each lighting control data holding register Q_{i, 15}, Q_{i, 14}... Q_{i, 0}Holds the lighting control data of the LED lamp corresponding to each from the lighting control cycle start point to the end point. On the other hand, the selection register S of the unit group i shown here reflects the operation of the selection control shift register described above._{i, 0}, S_{i, 1}... S_{i, 15}Also, the on-data is shifted in synchronization with the clock SC. That is, a mechanism is realized in which the selection register of each LED lamp is turned on by one cycle of the shift clock SC within the lighting control cycle. On the other hand, the selection register S_{i, j}In the period when is on, the corresponding LED lamp L_{i, j}Is the holding register Q_{i, j}The lighting is controlled according to the contents of the selection register S_{i, j}When LED is off, the corresponding LED lamp L_{i, j}Is turned off. As a result, a lighting control slot having a time width obtained by dividing each lighting control cycle by 1/16 is sequentially assigned to each LED lamp. In the LED module as a whole, the selection register works in the same way for all unit groups, so that time-division driving with 1/16 duty is realized for each lighting control slot.
By the circuit operation described above, each LED lamp L_{i, j}Is the corresponding luminance data (c_{i, j, 0}, C_{i, j, 1}, C_{i, j, 2}  ... c_{i, j, 7}  ) Per frame
(C_{i, j, 0}・ 2⁰+ C_{i, j, 1}・ 2¹+ ... + c_{i, j, 7}・ 2⁷) A mechanism for lighting and luminance control in a time width of x60 / 16 μsec is realized.
[0011]
[Patent Document 1] Japanese Patent Application No. 2002-232188 (page 16)
[0012]
[Problems to be solved by the present invention]
The problems to be solved by the present invention are as follows.
[00013]
{Circle around (1)} When a conventional system is used to realize a full color of a tan LED module, basically three sets of conventional module circuits corresponding to the three primary colors are used. Therefore, in the case of a full color display system using a conventional system, three sets of lamp units and control units are required. Further, in order to control the luminance of the three primary color LED lamps as a full-color display system, it is necessary to ensure a so-called white balance of the luminance of each color. This Hawaiian balance is ensured by maintaining the effective lighting time width of each of the green, red, and blue LED lamps at a ratio of about 3: 2: 1 for the same luminance data value (the exact ratio is Depending on the characteristics of each color LED lamp actually employed, luminous efficiency, etc.). The lighting time width ratio among the three primary colors is realized by compressing the time width of the red and blue lighting control slots to 2/3 and 1/3 of the green lighting control slot, respectively. In the conventional system, with the reduction of the time width of the lighting control slot, the lighting control shift register of the red and blue modules, the shift clock of the selection control shift register, or the period of the latch signal QC is 2/3 of the case where each is green, It will be shortened to 1/3. Therefore, in the conventional system, the period of the timing signal such as a clock is required to be different for each color, and the function to adjust to the characteristics of each color lamp to be used is actually required. When trying to achieve full color using it, it is difficult to share signals such as clocks among the three primary color modules, and as a result, the number of signal lines crossing between the lamp units also increases three times. It will be. From the viewpoint of cost reduction, simplification, and weight reduction of the display system, it is desirable to reduce the number of signal lines that cross between the lamp units as much as possible.
[0014]
(2) In the conventional module, it is assumed that the transfer of lighting control data to all LED lamps is completed in each lighting control cycle. In the case of the multiplying slot method, the minimum time width of this lighting control cycle is about 60 μsec in the green module in which the entire frame period is the effective lighting control time width, but in order to ensure white balance as described above. In the blue module, it becomes 1/3 of that, approximately 20 μsec, and the required transfer clock frequency of the lighting control data exceeds 10 MHz. In order to construct a display system having a more complicated shape, the more LED lamps that can be accommodated in the module, the more advantageous and the cost can be reduced. However, in the conventional module, the number of LED lamps increases to 256 or more. As a result, higher transfer rates are required.
[0015]
(3) In order to ensure white balance, the red and blue lighting control data update slot widths are compressed, so that the effective lighting control time width remains 2/3 and 1/3 of the entire frame period. Therefore, a luminance control method that can secure white balance and has less time zone to be ineffective is desired.
[0016]
[Means for solving problems]
The problem solving means of the present invention corresponding to the above-described problems will be described.
[0017]
The main means for solving the problems of the conventional LED module are as follows.
(1) Each pixel is composed of three lamps of green, red, and blue. On the circuit side, all three primary color lamps (3 × 256 = 768) are connected in series to form one module. In other words, a lighting control register and a selection register are provided for all three primary color LED lamps, and the lighting control shift register and the selection control shift register are configured by mutually connecting the input and output of these registers. Control by unit.
[0018]
(2) A lighting control data update slot that is temporally independent (not superimposed on the lighting control slot) is provided in each lighting control cycle. This eliminates the need to increase the lighting control data transfer rate resulting from connecting all three primary color lamps (768) in series, and at the same time, a lighting control shift register between the three primary color LEDs. The sharing of clock signals and data input / output signals of the two shift registers of the division control shift register is planned.
[0019]
(3) Like the conventional module, a time division group is formed, and each lighting control slot is time-division driven for each time division group. On the other hand, in order to ensure white balance, one time division group is composed only of lamps of the same color. Are grouped so that the time width of each lighting control slot is divided at a ratio necessary for ensuring white balance and assigned to each color.
[0020]
【Example】
Examples in the case where a full-color tandem LED module is configured using the circuit and operation method according to the present invention are shown below. In the LED module of this embodiment, each pixel (pixel) is composed of three lamps of green, red, and blue, and a pixel unit is assigned to each of the 256 pixels (FIG. 11). FIG. 12 shows a circuit of the pixel unit. Like the conventional system, the three primary color LED lamps constituting the pixel: L_g, L_r, L_bLighting control register for each; P_g, P_r, G_b, Selection register; S_g, S_r, S_bIs provided. The output signals DSO, CLO, DDO of each pixel unit make a pair with the corresponding input signals DSI, CLI, DDI, and these input / output signals are connected to a lighting control register and a selection register in each pixel unit. Each of the adjacent 768-bit shift registers for shifting the shared data input signal DD by the shared clock signal CL in accordance with the display selection signal DS, ie, a lighting control shift register and a selection control shift register. The corresponding input / output signals are connected between the pixel units.
[0021]
In FIG. 11, the display control signal DS (and the DSI of each pixel) is a signal for controlling the selection of the two shift registers and the lighting and non-lighting of all the lamps. That is, the input signal, output signal, and clock of the two shift registers are shared, but they are selectively driven by the display control signal DS. When the display control signal DS is on, When the selection control shift register is selected, the input data from the shared data input signal DD is shifted according to the shared clock signal CL, and when the display control signal is OFF, all the lamps are AND gates G_g, G_r, G_bAt the same time, the lighting control shift register is selected and the input data is shifted according to the shared clock signal CL.
[0022]
As shown in FIG. 11, as in the conventional system, these LED lamps are divided into unit groups of 12 units (4 pixel units) from the end to which the control unit is connected. Group number, j is a number indicating the arrangement order in the unit group L_{i, j}  A serial number is assigned as follows. In this numbering, the arrangement of the three primary color lamps is reflected. In each unit group, j = 0, 3, 6, and 9 are green LED lamps, j = 1, 4, 7, and 10 are red LED lamps, and j = 2. , 5, 8 and 11 are blue LED lamps. Further, as will be described later, in this module, 12 time-division groups are formed by LED lamps having the same arrangement number (768/12 = 64) in each unit group. That is, the lamp configuration of each time division group is as follows.
Time division group 0 L_0,0    L_{1, 0}L_2,0  ・ ・ ・ ・ ・ ・ L_64,0
Time division group 1 L_{0, 1}    L_1,1L_2,1  ・ ・ ・ ・ ・ ・ L_64,1
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・
Time division group 11 L_0,11  L_1,11L_2,11  ・ ・ ・ ・ ・ ・ L_64,11
This time division group configuration reflects that the number of LED lamps included in one unit group is a multiple of 3 (green, red, blue), and only the same color LED lamps belong to the same time division group. The time division groups 0, 3, 6, and 9 are green LED lamp groups, the time division groups 1, 4, 7, and 10 are red LED lamp groups, and the time division groups 2, 5, 8, and 11 are blue LED lamp groups. It becomes.
[0023]
As shown in FIG. 13, one frame period of the LED module is divided into eight lighting control cycles having different time widths and numbered 0, 1,. Each lighting control cycle is composed of one lighting control data update slot and twelve lighting control slots each corresponding to each time division group. The time widths of these lighting control slots are set so that the time widths of the lighting control slots included in the lighting control cycle 0 are set to the minimum time width and are sequentially multiplied for each lighting control cycle.
[0024]
The operation of the entire module in each lighting control cycle is divided into two basic operations: (1) the above-mentioned lighting control data update operation and (2) time-division driving operation in 12 lighting control slots.
In the conventional system, these two operations are parallel operations that are temporally superimposed, but in this module, they are set as operations that are temporally independent. Each basic operation will be described below.
[0025]
(1) Lighting control data update operation
FIG. 14 is a time chart in one lighting control cycle (lighting control cycle i). As shown in the figure, during the lighting control data update operation period, the display control signal DS is kept off and all the lamps of the module are turned off. At the same time, the lighting control shift register is selected from the two shift registers, and the control unit synchronizes with the clock CL, shifts the lighting control data into the shift register, and updates all the lighting control registers. Like the lighting control data of the conventional system shown in FIG. 10, the lighting control shift register is updated by lighting control data obtained by rearranging and editing the luminance data for each LED lamp in the order of bit position and LED lamp arrangement. That is, 768 LED lamps L in one frame period_{i, j}8-bit luminance data
(C_{i, j, 0}, C_{i, j, 1}, C_{i, j, 2}  ... c_{i, j, 7}  )
(I = 0 ... 63, j = 0 ... 11, c_{i, j, 0}Is the least significant bit, c_{i, j, 7}, Is the most significant bit)
In the lighting control cycles 0, 1,..., The lighting control data (768 bits each) shifted into the shift register in the lighting control data update slot is as follows.
Lighting control cycle 0 (c_{63, 11, 0}, C_{63, 10, 0}, ... c_{0, 1, 0}  , C_{0, 0, 0})
Lighting control cycle 1 (c_{63, 11, 1}, C_{63, 10, 1}, ... c_{0, 1, 1}  , C_{0, 0, 1})
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・
Lighting control cycle 7 (c_{63, 11, 7}, C_{63, 10, 7}, ... c_{0, 1, 7}  , C_{0, 0, 7})
As in the conventional system, in the lighting control data update slot in the lighting control cycle k, the lighting control data in the order of the numbers of the corresponding LED lamps;
c_{63, 11, k}  ... c_{0,2, k}  , C_{0,1, k}, C_{0, 0, k}
Are continuously shifted into the lighting control shift register in synchronization with the clock signal CL from the control unit output signal DD. As a result, at the end of the lighting control data update slot, 768 all lighting control registers P_{i, j}  (I = 0... 64, j = 0... 11) is the corresponding lighting control data c._{i, j, k}Will be updated. The lighting control data shifted in in one update is the number of all LED lamps, that is, 768 bits, and the time required for the update is 76.8 μsec when the clock frequency is 10 MHz.
[0026]
(2) Time-division drive operation
As described above, each lighting control cycle is provided with twelve lighting control slots corresponding to each time division group, and the time division group k is selectively driven in the lighting control slot k. The basic operation of the time-division driving circuit in each lighting control slot is almost the same as that of the conventional system. In each lighting control slot, the display control signal DS is held on, whereby the selection control shift register is selected as the shift register, and the time-division group is selected by selectively turning on the selection register corresponding to each time-division group. Are sequentially selected and time-division driven. Ie;
At the start of the system, the selection control shift register has 64 selection registers S corresponding to the LED lamps of the time division group 11_{k, 11}Only (k = 0, 1,... 63) is on, and all other selection registers are initially set to an off state.
In each lighting control cycle, the input data signal DD is turned on in the control unit prior to the rise of the first clock signal CL to the selected shift register, and this on signal is sent to the selected shift register at the first rise of the clock signal CL. Is set off after is shifted in.
The ON signal of the selected shift register that has been shifted in is sequentially shifted in the selected shift register over 11 cycles of the clock signal CL.
On the other hand, since the display control signal DS is set to ON, each lamp is lit according to the contents of the corresponding lighting control register and selection register.
[0027]
Each time division group is configured to include only lamps of the same color, and the time width of the lighting control slot corresponding to each time division group varies depending on the lamp color of the time division group to ensure white balance. The width is set. The time width of the lighting control slot to be set is set to three types corresponding to the three primary colors. The ratio of each time width is about 3: 2: 1 (green: red: blue).
[0028]
The time width of each lighting control slot is set by adjusting the time width of one cycle of the clock signal to the selection control shift register. That is, as shown in FIG. 14, the period of the selection control shift register clock cycle j is set to τ_jIf so, select register S_{i, j}(I = 0, 1, 2,... 63) is τ_j  The time-division group j is selectively driven only during the time period. Therefore, in order to ensure white balance, the selection control shift register / clock cycle is divided into three time width cycles, ie, a green cycle, a red cycle, and a blue cycle, in which the ratio of the respective time widths is approximately 3: 2: 1. As shown above, among 0-11 time division groups, 0, 3, 6, and 9 are green, 1, 4, 7, and 10 are red, and 2, 5, 8, and 11 are blue Reflecting that it is a time-sharing group, j = 0, 3, 6, and 9 are green cycles, 1, 4, 7, and 10 are red cycles 2, 5, 8, and 11 are blue cycles. The width is set.
[0029]
When the control unit receives video data from a video generation system such as a personal computer and displays the video, an editing function in units of bits from luminance data to lighting control data is indispensable. ) Etc., and when the same display contents are repeatedly displayed, the data edited in advance in the lighting control bit stream format is stored in the ROM, so that the memory contents are read in the order of addresses and serialized. The above bit editing function can be omitted with only the simplified function.
[0030]
In this embodiment, lighting control data for each LED lamp is transferred from the control unit to the lighting control register every lighting control cycle. For example, lighting control for one frame is performed for each pixel unit. By providing a buffer register that holds data (= luminance data), it is also possible to transfer lighting control data for one frame from the control unit for each frame in a batch (by the shift and latch method) to the buffer register. It is. Even in this case, each LED lamp reads the lighting control data in the lighting control cycle from the buffer register to the corresponding lighting control register at the start of the lighting control cycle, thereby realizing the same brightness control as in this embodiment. be able to. The provision of the buffer register in each pixel leads to an increase in the pixel unit circuit, but there is an advantage that the bit editing function in the control unit described above can be omitted and the control unit circuit can be simplified.
[0031]
The advantages of the LED module according to the present invention described above are as follows.
(1) A full color tandem LED module can be realized with a simple pixel unit circuit and three signal lines connecting them. Accordingly, the system can be greatly simplified and reduced in weight, and the flexibility can be increased, so that the display surface can be easily processed into various three-dimensional shapes.
(2) In each frame period, only the lighting control data update slot (eight) is the time zone (non-lighting time zone) that is not subject to lighting control. Since the time width of each lighting control data update slot is 76.8 μsec (10 MHz) as described above, the total time width of the non-lighting time zone is 8 × 76.8 = 614.4 μsec, which is the frame period. It is only about 2%. That is, high luminous efficiency is achieved while maintaining white balance. Furthermore, even if the number of LED lamps housed in one module is increased, it is a great advantage that the problem related to the clock speed of the lighting control shift register update as in the conventional system does not occur. For example, even in a module accommodating 1024 pixels (the number of lamps 3072), the non-lighting time zone is slightly increased to 8%, but the module is realized with the same control method and circuit as described in this embodiment. Is possible.
[Brief description of the drawings]
FIG. 1 illustrates a pulse width modulation method.
FIG. 2 illustrates a multiplication slot method.
FIG. 3 illustrates the configuration of a continuous bead-shaped LED module.
FIG. 4 illustrates a unit numbering method for a conventional module.
FIG. 5 illustrates a lamp unit circuit of a conventional module.
FIG. 6 illustrates a lighting control shift register and a selection control shift register of a conventional module.
FIG. 7 is a time chart for one frame period of a conventional module.
FIG. 8 illustrates a lighting control data configuration of a conventional module.
FIG. 9 illustrates a lighting control data update operation of a conventional module.
FIG. 10 illustrates a time-division driving operation of a conventional module.
FIG. 11 illustrates a system configuration of an embodiment.
FIG. 12 is a circuit diagram of a pixel unit according to an embodiment.
FIG. 13 is a time chart for one frame period of the embodiment.
FIG. 14 illustrates a lighting control data update operation and a time-division driving operation according to the embodiment.

Claims (3)

A plurality of lighting control slots are provided in the frame period, and each of the LED lamps is assigned a plurality of lighting control slots preselected from the lighting control slots,
For each LED lamp, lighting control data for controlling the lighting time width in each lighting control slot assigned is generated based on the luminance data given for each frame period,
A lighting control register is provided for each LED lamp,
The lighting control registers are connected to each other and connected to each other, and each lighting control data is transferred to a lighting control register associated with the corresponding LED lamp via a shift register operating with a common shift clock. With a circuit,
A selection register is provided with each LED lamp,
By connecting the inputs and outputs of these selection registers to each other, a shift register that operates with a common shift clock is configured, and each LED lamp is associated with each lighting control slot set within the frame period. The input data to the shift register and the common shift clock are controlled so that it can be determined whether or not it is a lighting control slot pre-assigned to itself according to the internal state of the selection register,
Each LED lamp is lit in a time width based on the corresponding lighting control data in response to the internal state of the selection register and lighting control register associated with each LED lamp for each lighting control slot in the frame period. Or controlled to be off,
In addition, in both shift registers of the shift register configured by the lighting control register and the shift register configured by the selection register, the lighting control register configuring the respective shift registers, the input of the selection register, the output signal line, and the common An LED module characterized in that all or part of a shift clock signal line is shared by using both in a time-sharing manner. Each pixel constituting the display screen is composed of three primary color LED lamps of red, blue, and green, and a plurality of lighting control slots that are divided into three groups corresponding to the three primary colors are provided in the frame period. ,
Each LED lamp is assigned a plurality of lighting control slots selected from among the lighting control slots of the group corresponding to the emission color of the LED lamp, and the luminance given to each LED lamp for each frame period. Based on the data, in each assigned lighting control slot, lighting control data for controlling the ratio of the lighting time width to the respective lighting control slot time width is generated,
Each of the LED lamps is provided with a lighting control register, and is configured by connecting the input and output of these lighting control registers to each other, and each of the lighting control data via a shift register that operates with a common shift clock. And a circuit for transferring the light to the lighting control register associated with the corresponding LED lamp,
Each LED lamp receives lighting control data transferred to a lighting control register associated with the LED lamp for each lighting control slot assigned within the frame period, and the lighting time width is controlled.
In addition, the white balance in each pixel is ensured by adjusting the time width of the lighting control slot for each group of lighting control slots corresponding to the three primary colors according to the light emission characteristics of each color LED lamp. LED module. A selection register is provided with each LED lamp,
Operate with a common shift clock by connecting the input and output of these selection registers to each other so that the connection of the selection registers associated with each of the three primary color lamps constituting each pixel is in the same connection order through all the pixels. Configure the shift register
In addition, by controlling the input data to the shift register and the common shift clock, for each LED lamp, the associated selection register is turned on in the assigned lighting control slot, and is turned off otherwise. The LED module according to claim 2, wherein

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