CN114708823A

CN114708823A - LED display screen driving system and LED display screen

Info

Publication number: CN114708823A
Application number: CN202210395898.1A
Authority: CN
Inventors: 王朝; 朱卫强
Original assignee: Shenzhen Zhouming Technology Co Ltd
Current assignee: Shenzhen Zhouming Technology Co Ltd
Priority date: 2022-04-15
Filing date: 2022-04-15
Publication date: 2022-07-05
Anticipated expiration: 2042-04-15
Also published as: CN114708823B

Abstract

The invention discloses an LED display screen driving system and an LED display screen, belonging to the technical field of display control, wherein the LED display screen driving system comprises: the display control subsystem is used for receiving the gray weight of the display data and generating a refreshing data stream for driving the lamp beads according to a preset gray weight refreshing sequence based on the gray weight; the programmable voltage generator is used for generating corresponding dynamic voltage according to the dynamic current control signal corresponding to the sub-frame to be refreshed; and the constant current chip is used for driving the lamp beads to refresh display data according to the refresh data stream and the dynamic voltage corresponding to the sub-frame to be refreshed when receiving the row tube conduction signal corresponding to the lamp beads. According to the embodiment of the invention, the gray scale of the lamp bead is defined in two dimensions of instantaneous driving current corresponding to dynamic voltage and refreshing PWM, so that the driving efficiency of the lamp bead is greatly improved, the time required for realizing the corresponding gray scale is reduced, and the load of driving data volume is reduced.

Description

LED display screen driving system and LED display screen

Technical Field

The invention relates to the technical field of display control, in particular to an LED display screen driving system and an LED display screen.

Background

The LED display screen displays contents by utilizing direct light emission of the LED lamp beads, and each pixel point on the screen comprises a red lamp bead, a green lamp bead and a blue lamp bead. Different brightness and color display of the pixel points needs to be realized, and the three lamp beads need to have different brightness ratios. For each lamp bead, different brightness is realized through gray level refreshing, and the method is also a working basis of the constant current driving chip for driving the LED lamp beads to emit light.

With the increasing pixel density of the LED display screen, the loading capacity of the constant current chip can not keep up with the development speed of the LED display screen gradually. Usually, 512 lamp pearls (typical value) can be carried to a constant current chip, and along with the development of pixel density, this quantity is not enough to let the chip drive the lamp pearl of complete module. I.e., the area on the module is not enough to put down so many driver chips. And then the refresh rate of the driving chip has to be increased, and on the other hand, the driving time of a single lamp bead has to be reduced. Thereby reducing the display effect.

Meanwhile, the amount of driving data is also increased along with the increase of the number of lamp beads, and in a display screen with higher density, the refreshing rate of a video has to be reduced to ensure that the whole driving system can bear huge amount of data. Originally, 1080P, 240HZ video stream can be played, and after the screen quality is improved to 4K, only 60HZ or even 24HZ video stream can be played. And many grey scale details of the screen are lost while the refresh frequency is reduced.

Disclosure of Invention

In view of this, an embodiment of the present invention provides an LED display panel driving system and an LED display panel, so as to solve the technical problem that the existing LED display panel driving system cannot meet the requirements of higher and higher pixel density and driving data amount.

The technical scheme adopted by the invention for solving the technical problems is as follows:

according to a first aspect of the embodiments of the present invention, there is provided an LED display screen driving system, including:

the display control subsystem is used for receiving gray weight values of display data and generating a refreshing data stream for driving the lamp beads according to a preset gray weight value refreshing sequence based on the gray weight values, wherein the refreshing data stream is divided into a plurality of gray weight value bits according to different gray weight values, and each gray weight value bit corresponds to more than one subframe;

the programmable voltage generator is used for generating corresponding dynamic voltage according to the dynamic current control signal corresponding to the sub-frame to be refreshed;

and the constant current chip is used for driving the lamp beads to refresh display data according to the refresh data stream and the dynamic voltage corresponding to the sub-frame to be refreshed when receiving the row tube conduction signal corresponding to the lamp beads.

According to a second aspect of the embodiments of the present invention, there is provided an LED display screen, which includes the LED display screen driving system of the first aspect.

The LED display screen driving system and the LED display screen provided by the embodiment of the invention comprise: the display control subsystem is used for receiving gray weight values of display data and generating a refreshing data stream for driving the lamp beads according to a preset gray weight value refreshing sequence based on the gray weight values, wherein the refreshing data stream is divided into a plurality of gray weight value bits according to different gray weight values, and each gray weight value bit corresponds to more than one subframe; the programmable voltage generator is used for generating corresponding dynamic voltage according to the dynamic current control signal corresponding to the sub-frame to be refreshed; and the constant current chip is used for driving the lamp beads to refresh display data according to the refresh data stream and the dynamic voltage corresponding to the sub-frame to be refreshed when receiving the row tube conduction signal corresponding to the lamp beads. Therefore, the method for expressing the gray level of the lamp bead is changed from the original method of only relying on a string of binary numbers into the form of adding the binary numbers to the instantaneous driving current corresponding to the dynamic voltage, and the gray level of the lamp bead is defined from two dimensions, so that the driving efficiency of the lamp bead is greatly improved, the time required for realizing the corresponding gray level is reduced, and the load of the driving data volume is reduced. The transmission rate of the display data can be increased to several times of the original rate under the condition of ensuring the same display effect; or, under the condition of not increasing the transmission rate, the gray scale of the display screen is greatly improved; or, under the same display data quantity, more lamp beads are driven to display the content.

Drawings

The invention will be further described with reference to the accompanying drawings and examples, in which:

FIG. 1 shows a conventional LED display screen driving system driving control lamp bead mode;

FIG. 2 is a constant current chip internal register architecture;

FIG. 3 is a schematic diagram of a control loop provided by an embodiment of the present invention;

FIG. 4 is a current-period relationship of a conventional LED display screen driving system;

FIG. 5 illustrates a dynamic current driving relationship provided by an embodiment of the present invention;

FIG. 6 is a graph of volt-ampere characteristics of an LED lamp bead;

FIG. 7 shows the brightness variation of the lamp beads under different current driving conditions;

FIG. 8 is a schematic diagram of an LED display driving system according to an embodiment of the present invention;

FIG. 9 illustrates a dynamic current flag signaling format according to an embodiment of the present invention;

FIG. 10 is a schematic diagram of a dynamic current signature signal in data transmission according to an embodiment of the present invention;

FIG. 11 is a schematic diagram of a programmable voltage generator according to an embodiment of the present invention;

fig. 12 is a schematic diagram of another LED display panel driving system according to an embodiment of the present invention.

Detailed Description

It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the following description, suffixes such as "module", "component", or "unit" used to denote elements are used only for facilitating the explanation of the present invention, and have no specific meaning in itself. Thus, "module", "component" or "unit" may be used mixedly.

Example one

In order to solve the technical problem that the existing LED display screen driving system cannot meet the requirements of higher and higher pixel density and driving data amount, the embodiment provides an LED display screen driving system. The system comprises:

the display control subsystem 1 is used for receiving gray weight values of display data, generating refreshing data flow for driving lamp beads according to a preset gray weight value refreshing sequence based on the gray weight values, dividing the refreshing data flow into a plurality of gray weight value bits according to different gray weight values, wherein each gray weight value bit corresponds to more than one subframe;

the programmable voltage generator 2 is used for generating a corresponding dynamic voltage according to a dynamic current control signal corresponding to a subframe to be refreshed;

and the constant current chip 3 is used for driving the lamp beads 4 to refresh display data according to the refresh data stream and the dynamic voltage corresponding to the sub-frame to be refreshed when receiving the row tube conduction signal corresponding to the lamp beads.

In the embodiment of the present invention, it should be noted that, in the process of developing LED panel driving, the inventor finds that, when the current LED panel driving control faces a huge driving problem, a 4k video resolution is 4096 × 2160, each pixel is represented by 256 color (8bit) data of red, blue and green, the number of video frames is 60fps, and then the data amount of one-second picture is: 4096x2160x3x8x60 ≈ 11.9 Gbps. Further, the sound is approximately one tenth of the video data amount, and thus the data amount of 4k video for one second is approximately 13Gb ≈ 1.6 Gb. The data amount is audio and video data, and the transmission redundancy and gamma correction are included, and the bandwidth requirement of transmission of a 4K LED display screen is 16Gbps, namely at least 16 network lines are needed to transmit the data to the screen.

The main content of the transmitted data is the gray information of the lamp beads. The pixel of the LED display screen is composed of three beads of red, green and blue, each bead has 256-level gray scale, and the pixel point can show 16.77M colors according to different gray scale ratios, which is the basis for realizing content display on the screen.

For a single lamp bead, the gray scale is recorded by an 8-bit binary number, each bit of the 8-bit binary number can be 0 or 1, so that 256 types are provided, and the gray scale is exactly corresponding to the 256 gray scales one by one. The binary number records the gray information of the lamp beads, but the lamp beads cannot be directly driven to display. The lamp pearl is the current sensitive device, and slight current change all can lead to direct luminance change promptly. The brightness of the lamp beads needs to be accurately controlled to maintain normal display of the lamp beads. The current commonly adopted strategy is constant current driving, namely, the constant of control current is maintained to control the brightness of the lamp beads. The specific constant current mode is to modulate the current of the driving lamp bead through PWM, the lamp bead can flash in the dark and light with high frequency under the PWM signal, the pulse width is adjusted, the lighting time of the lamp bead can be adjusted, and the duty ratio is adjusted.

The constant current driving mode needs to convert sent lamp bead gray data into PWM signals for driving the lamp beads by means of a constant current chip. Specifically, one constant current chip comprises 16 paths of PWM output channels, namely, the chip can simultaneously drive 16 lamp beads to be lightened at the same time. In order to reduce the number of chips and save cost, the constant current chip can also carry out alternate current circulating drive on the lamp bead area array in a dynamic scanning mode. Usually, the constant current chip controls a 16 × N LED array (in practice, N is generally 8, 16, 32, etc. and is configurable), that is, one OUT channel drives N LEDs. When displaying, N rows of round-robin display modes are adopted for working, and the round-robin selection logic of the N rows is realized by an off-chip row management circuit.

The gray scale of one lamp bead is described through an 8-bit binary number, 16 paths of PWM (pulse-width modulation) signals are output on a chip, and 16 PWM signals can be output at the same moment to drive and light 16 lamp beads.

The 8-bit binary number has different weights according to the height of the bit number. The basic logic of driving the lamp beads is that in the time of one frame, the lamp beads can be refreshed 256 times, and the brightness of each lighting is the same. The number of times the lamp beads are lit within the frame time corresponds to the gray scale of the lamp beads.

And the constant current chip works, namely, after the weight value number of the 8-bit binary number is received, the driving lamp bead is lightened according to specific times. In order to improve the processing capacity of the chip, the constant current chip is also controlled by the enable signal, so that the lamp bead does not need to be refreshed 256 times, and can achieve the same effect as the above effect only by refreshing 64 times (enabling work).

The basic working logic of the enabling signal is to cut a PWM signal for driving the lamp bead to be lightened, and to invalidate part of the PWM signal, namely, to lighten the lamp bead.

Based on this, the specific way of driving the control lamp bead is as shown in fig. 1. In the time of a frame, the lamp beads can be refreshed 64 times, and each time the lamp beads are refreshed, the lamp beads are a subframe.

And after the constant current chip receives the 8-bit gray scale weight, the bead is driven to be lightened according to the specific weight. In FIG. 1, the 8-bit gray scale weights are sorted from the highest bit to the lowest bit according to a [7] to a [0 ]. When the constant current chip receives the weight a [7], the lamp bead is driven to light 32 subframes, when the constant current chip receives the weight a [6], the lamp bead is driven to light 16 subframes, and the like, until the lamp bead receives the weight a [1], only half subframes of the lamp bead need to be lightened, at the moment, the enable signal can work, the chip is in an invalid state under the half subframes, and therefore the lamp bead is not lightened, and the lamp bead is only lightened in the half subframes.

Under the simplest driving mode, the constant current chip uniformly drives the lamp beads to be lightened according to the same current weight. The constant current chip has the following structure: taking the constant current chip 2038 as an example, the 2038 constant current driving chip includes 32 registers, which are divided into two types, the first type includes 16 shift registers, and the second type includes 16 latch registers. The shift registers are connected in series, and data are transmitted in series on the shift registers. Each latch register is connected in parallel to each shift register, and data can be latched in the form shown in fig. 2. The chip can light 16 lamp beads at the same time, and the transmission form of internal data is that data is written from the 16-path shift register. That is, 160 s or 1 s are written, and after the 16 shift registers are filled up, the latch signal operates to store the 16 signals in the latch register. The constant current chip can drive the lamp bead to refresh according to the data stored in the latch register.

The 16 latched signals can be distinguished according to the transmission sequence, and it should be noted that the 16 signals latched at one time are under the same weight value, and the data of different weight values are sorted and refreshed according to time sequence. That is, 16 a [7] data are latched first, then 16 a [6] data are latched, and so on. The chip latches the gray data of 16 lamp beads at the same time, and for a single lamp bead, the chip latches 8 times (shifts 8 times) in one output path to clearly display the gray data of one frame.

The simplest mode is that the data are transmitted to a constant current chip for latching one by one according to the weight of 8-bit lamp beads, display data with 16 a [7] weights are transmitted first, the lamp beads are refreshed for 32 times, and some lamp beads need to be refreshed and some lamp beads do not (depend on display content). Then transmit the display data of 16 a 6 weights, the lamp bead refreshes 16 times, only display the necessary refreshing, later transmit step by step, shift 8 times, make 8bit gray can all reflect on the lamp bead.

In fact, in the form of dynamic scanning, the constant current chip sends PWM signals to the lamp beads under the high-speed conduction of the row tube, taking 32 scanning as an example, the lamp beads first illuminate the lamp beads in the first row, then illuminate the second row and the third row, and then return to illuminate the first row after illuminating the 32 th row, under such polling scanning, the registers in the constant current chip first register the gray data of the first row, then latch the gray data of the second row, and thus register the gray data of the 32 rows. Within a frame time, such polling is performed 8 times, so that the whole gray data of the current 16 × 32 area array of lamp beads can be displayed. Polling requires 512 bits to be latched once, and a total of 4096 bits to be stored for 8 rounds. Each lamp bead is written with 8-bit gray data, thereby completing the driving of the lamp bead.

Based on this, the lamp bead driving and the display data are corresponded, and in fact, the lamp bead driving and the display data can be understood as the gray scale data of all the lamp beads in a certain time and a certain area. Under a single lamp bead lighted at a single time, the brightness of the lamp beads is consistent, namely the current magnitude for driving the lamp beads is also consistent. Specifically, because the current is constant, theoretically, the magnitude of the driving current applied to the lamp bead at each conducting time is fixed, which means that the brightness of the lamp bead is fixed at each time. The lamp beads need to display different contents, the light and shade of pixel points are changed, different colors are achieved, and the core idea is that the lamp beads are driven to work through PWM. The duty ratio of the lamp beads in unit time is adjusted by adjusting the pulse width, so that the red, green and blue lamp beads on the pixel points can have different gray levels and show different pixels and colors. This is the basic method of current drive control for LED displays.

Based on the method, the gray scale of the lamp bead is described by an 8-bit binary number, and finally the gray scale is displayed on the lamp bead, and 256 gray scale representations are realized by matching 64 times of refreshing with an enabling signal.

With the continuous development of packaging technology, higher requirements are put forward on the driving of the constant current chip, and the chip can carry more lamp beads simultaneously. For example, assuming that the gray scale of each lamp bead is 8bit, 64 lamp beads can be lighted by one chip within one frame time, which means that the chip can output all the gray scale data of 64 lamp beads to the lamp beads within one frame time, and 512 bits are transmitted in total. A 60 frame, 30720 bits, is transmitted one second.

At present, a chip is required to light 512 lamp beads according to the same time of one frame under the condition of ensuring the same gray effect, the gray data of the 512 lamp beads are required to be completely transmitted to the 512 lamp beads within one frame time, the chip still keeps 16 paths of output, 4096 bits of data are output within one frame time, namely 245.76Kb of data within one second, and the data is increased to 8 times of the original data compared with the original data.

The above is a simplification for convenience of explanation, and in practical application, the contents of loading on a board, line width of a channel, and the like need to be considered.

In fact, the amount of information that can be expressed by the binary number describing the information on the grey scale of the lamp bead is limited, since the bead can only be lit at a constant current each time. Therefore, the key lies in the luminance of lamp pearl, if there are multiple mode can adjust the luminance of lamp pearl, the grey information of expression lamp pearl that just can be better to promote the drive efficiency of lamp pearl. Particularly, the most intuitive way of changing the brightness information of the lamp beads is to adjust the current. The foregoing describes a current driving method for a lamp bead of an LED display screen, where the magnitude of the current is constant, and thus the current of the lamp bead is constant in each subframe. The current of the lamp bead is changed within a controllable range, so that the better display content of the lamp bead is facilitated, and the gray information of the lamp bead can be displayed in more modes. Of course, the control of the current is realized on the premise of maintaining the total brightness value of the lamp bead in a frame time unchanged.

Specifically, the LED display screen is formed by the LED lamp beads, and the LED lamp beads belong to current sensitive devices, namely different brightness changes can be shown for the change of the current. The volt-ampere characteristic of the LED lamp bead is determined. The volt-ampere characteristic curve of the LED lamp bead is shown in FIG. 6. As can be seen from fig. 6, the lamp bead does not generate an induced current immediately after being connected to the forward voltage, because the external voltage is less than the internal barrier voltage of the PN junction, i.e., the on voltage, it is impossible to generate a current in the direction of the external voltage. When the voltage continuously increases and reaches the point A, the internal balance is broken, the lamp bead is conducted, the current starts to be generated, and then the current exponentially increases along with the increase of the voltage. Just because when the lamp pearl switches on the back, the current change can be the exponential increase along with the continuous increase of voltage, so voltage can not infinitely increase, otherwise will make the current become infinitely great, and then cause the short circuit, burn out the lamp pearl. In order to fully ensure the consistency of the driving current of the lamp beads, the existing driving control mode of the LED display screen is realized by adopting constant current driving. In other words, in the working interval, a specific current is selected as the calibration current of the driving lamp bead, and the current of the driving lamp bead is controlled to be the calibration current, which is called constant current driving.

Further, as shown in fig. 7, the lamp bead is a current sensitive device, and the brightness of the lamp bead is different under different driving currents, and the brightness variation range of the lamp bead changes along with the increase of the driving current. Under the drive of large current, a series of factors including junction temperature can cause the color temperature of the lamp bead to shift. The event is through the voltage that the maximum current that interception lamp pearl 4 normal work can bear corresponds to A point voltage, and on this interval, is LED lamp pearl 4's forward workspace, and in this interval, lamp pearl 4 can be normally worked on specific voltage.

Based on the above analysis, in order to improve the loading capacity of the constant current chip, improve the driving efficiency of the lamp bead, and reduce the time and the driving data amount burden required for realizing the corresponding gray scale, the embodiment of the invention provides an LED display screen driving system.

Specifically, the display control subsystem 1 receives a gray weight of display data, and generates a refresh data stream for driving the lamp bead 4 according to a preset gray weight refresh sequence based on the gray weight, wherein the refresh data stream is divided into a plurality of gray weight bits according to different gray weights, and each gray weight bit corresponds to more than one sub-frame; the programmable voltage generator 2 generates a corresponding dynamic voltage according to a dynamic current control signal corresponding to a subframe to be refreshed; and when receiving a row tube conduction signal corresponding to the lamp bead 4, the constant current chip 3 drives the lamp bead 4 to refresh display data according to the refresh data stream and the dynamic voltage corresponding to the sub-frame to be refreshed. According to the LED display screen driving system disclosed by the embodiment of the invention, for a single lamp bead 4, the relation of the whole control loop is shown in FIG. 3. When the lamp beads 4 are switched on by the row tube, for the current row lamp beads 4, the current row lamp beads are controlled by two parameters of dynamic current corresponding to the refresh data stream and the dynamic voltage. Therefore, the lamp beads 4 can display gray scale with dynamic current. The refreshing data stream is used for determining which lamp beads 4 in the current row are lighted, and which lamp beads 4 are not lighted; the dynamic voltage output of the programmable voltage generator 2 determines at what current the constant current chip 3 is outputting. Optionally, the calibration current pins of all the constant current chips 3 are connected together on one display module, the module is lit according to the same current magnitude when lit each time, and the module can be lit according to different currents in the two adjacent lighting processes, so that a dynamic current pulse width modulation driving mode is realized. It will be understood by those skilled in the art that the values between the different dynamic currents are not limited to integer multiples, and the graphs and associated values shown in the embodiments of the present invention are only integer multiples for convenience of illustration. In fact, the difference between two adjacent dynamic currents depends on the brightness of the lamp bead and the gamma distribution curve, that is, the value is taken according to the sensitivity of human eyes to the current brightness.

Optionally, there are more than two kinds of dynamic voltages, each of the sub-frames corresponds to a different dynamic voltage, or some of the sub-frames correspond to the same dynamic voltage.

Specifically, it should be noted that, in the existing driving method, the gray scale expression of the lamp bead can be regarded as the accumulation of brightness over a time length, the brightness corresponds to the current, and the current corresponds to the control voltage (calibration voltage) of the constant current chip. Taking 8-bit gray scale weights as an example, there is a conventional current-period relationship as shown in fig. 4. Fig. 4 shows the periodic distribution of 8-bit grayscale weights refreshed by one lamp bead in one frame time. Specifically, the gray scale of the lamp bead in one frame time is the sum of the brightness in the frame time, the lamp bead maintains constant current, different time lengths are refreshed (on/off of PWM high frequency) according to different weights, and the lamp bead can be turned on for half of the time at most when the highest position is refreshed. And sequentially reducing gradually until all the gray levels are refreshed. The 8-bit gray scale weight value corresponds to the grid region according to the refreshing sequence from the highest bit to the lowest bit, the highest bit corresponds to the grid with the largest leftmost area, the brightness of the lamp beads required in the region is the highest, and therefore the more time is taken for lighting the lamp beads.

At each lighting moment of the frame, the brightness of the lamp bead corresponds to the current, the brightness is the same, the current is also the same, and the difference is the lighting time of the lamp bead. The lamp beads are different in time length for refreshing and lighting, and the gray scales are naturally different.

Specifically, when the high-order weight is refreshed, the lamp beads are required to be highlighted, so that the lighting time of the lamp beads has to be prolonged, the more the lamp beads are lighted in unit time, the brighter the lamp beads are, and the longer the same required time is.

In fact, the refresh has a certain weight and period correspondence table as shown in table 1, which is based on fig. 4.

Weight value

a[7]

a[6]

a[5]

a[4]

a[3]

a[2]

a[1]

a[0]

Period of time

32T

16T

8T

4T

2T

T

T(1/2)

T(1/4)

Table 1 weight and period corresponding table of existing LED display screen driving system

The highest bit refresh is specified to occupy 32T time, namely the lamp bead refreshes 32 times. By analogy, the cooperation needs to be enabled until the refreshed brightness does not meet the brightness of lighting the lamp bead once, namely the later T (1/2), namely the sub-frame is enabled to work in a sub-frame of lighting the lamp bead by half, so that the lighting time of the lamp bead is only half of the original time. The whole working period is 65T, and the 65T time is refreshed within one frame time.

The LED display screen driving system provided by the invention means that the current for driving the lamp beads 4 to be lightened can be different at each refreshing time of the lamp beads 4. Under the condition of current change, 8-bit gray scale weights are refreshed similarly, and the time for refreshing the high-weight current can be shortened by increasing the current value of the high weight.

Specifically, continue to use foretell 8 bits grey level weight as an example, when refreshing the most significant weight before, lamp pearl 4 needs 32T just can accumulate the luminance that the most significant weight required, just can promote original 8 times (supposing that the luminance change of lamp pearl 4 is directly proportional with the current change) through the electric current size that drives lamp pearl 4 now, so when lighting lamp pearl 4 at every turn, the luminance of lamp pearl 4 is exactly 8 times originally, lamp pearl 4 just need not light 32 times like this, only need light 4 times and just can realize aforementioned luminance, there are 4 subframes to correspond the same dynamic current this moment. Specifically, the currents I1, I2, I3, and I4 described in fig. 5 correspond to 8 times, 4 times, 2 times, and 1 time of the brightness corresponding to the current I in fig. 4, respectively.

Based on this, a weight mapping table based on dynamic current pulse width modulation can be obtained, as shown in table 2.

Weight value

a[7]

a[6]

a[5]

a[4]

a[3]

a[2]

a[1]

a[0]

Period of time

4T

2T

T

T(1/2)

T(1/4)

TABLE 2 dynamic current weight and period mapping table

Based on the above refresh example, the refresh period can be reduced from the original 65T to 21T, and the time for refreshing a gray scale of the lamp bead 4 is reduced to less than half of the original time. And in the same time, the lamp beads 4 can refresh the gray scales twice.

For another example, the driving circuit can drive the lamp beads 4 to display with 8 different currents, each corresponding to an accurate gray value, so that the control system can write 8-bit gray data into the constant current chip 3 through 8T and refresh the data, and at the moment, each sub-frame corresponds to different dynamic currents. So, in same time, lamp pearl 4 can refresh 8 times of greyscales, very big improvement refresh efficiency, reduce the screen scintillation condition.

Optionally, the brightness value of the lamp bead 4 generated by controlling the dynamic voltage corresponding to all the sub-frames in one frame time corresponds to the gray value of the lamp bead 4 in the frame. That is, with the LED display driving system of this embodiment, the total brightness value of the lamp bead 4 in one frame time corresponds to the gray scale value of the lamp bead 4 in the frame, so that the lamp bead 4 just completes the refreshing of the corresponding gray scale value in one frame time.

Optionally, the preset grayscale weight refreshing sequence includes: refreshing according to the sequence of the gray weight values from high to low, or refreshing according to the sequence of the gray weight values from low to high, or refreshing according to a non-monotone ascending and descending sequence.

Specifically, refreshing according to the sequence of the gray scale weight from high to low or from low to high is more convenient to realize; refreshing according to a non-monotone ascending and descending sequence can enable the brightness of the lamp beads 4 to be more uniform and constant, and the influence of color temperature drift on display is reduced, for example, the lamp beads are refreshed in a staggered mode according to the rule of the highest gray scale weight value, the lowest gray scale weight value, the next highest gray scale weight value and the next lowest gray scale weight value, or the lamp beads are refreshed in a staggered mode according to the rule of the lowest gray scale weight value, the highest gray scale weight value, the next lowest gray scale weight value and the next highest gray scale weight value. Those skilled in the art can understand that other gray scale weight refreshing sequences can also be preset, and the embodiment does not limit the specifically adopted gray scale weight refreshing sequence.

In one embodiment, the programmable voltage generator 2 is a first programmable voltage generator 21, the first programmable voltage generator 21 is respectively connected with the display control subsystem 1 and the constant current chip 3, and the constant current chip 3 is connected with the lamp bead 4.

In this embodiment, please refer to fig. 8, and fig. 8 is a schematic diagram of a driving system for an LED display screen according to an embodiment of the present invention. The LED display screen driving system comprises a display control subsystem 1, a first programmable voltage generator 21, a constant current chip 3 and a lamp bead 4. Specifically, the gray scale weight of the display data is transmitted from the outside to the display control subsystem 1. The display control subsystem 1 converts the external gray scale weight into a refreshing data stream for the constant current chip 3 to drive the lamp bead 4 to refresh. The purpose of the dynamic current mark is to distinguish different dynamic currents, so that the constant current chip 3 can drive the lamp beads 4 according to different currents. The first programmable voltage generator 21 is used for generating a dynamic voltage for controlling the current output of the constant current chip 3, so that the current output of the constant current chip 3 can be changed in real time according to the refresh requirement.

In one embodiment, the refresh data stream includes a dynamic current flag signal corresponding to a subframe to be refreshed, and the dynamic current flag signal is used as the corresponding dynamic current control signal.

In this embodiment, the dynamic current flag signal as the dynamic current control signal is included in the refresh data stream, and the first programmable voltage generator 21 may generate a dynamic voltage corresponding to a subframe to be refreshed according to the dynamic current flag signal, so as to control the constant current chip 3 to drive the lamp bead 4 with a corresponding dynamic current.

Optionally, the dynamic current marking signal marks before or after the starting point of the row display data stream of the row where the lamp bead 4 is located.

Specifically, for example, the data format is shown in fig. 9, where the dynamic current flag signal corresponding to the sub-frame to be refreshed is marked after the data stream is displayed in the row of the row where the lamp bead 4 is located.

Further optionally, the dynamic current flag signal flag before or after the starting point of the row display data stream of the row where the lamp bead 4 is located includes: in the sub-frame to be refreshed, marking the dynamic current marking signal corresponding to the sub-frame to be refreshed of the module only before, during or after the data stream is displayed in the row of the first row of the module in which the lamp bead 4 is positioned.

Specifically, a schematic diagram of the transmission logic is shown in fig. 10. The calibration current pins of all the constant current chips 3 on one display module are connected together, and in one subframe, the driving currents of all the lamp beads 4 on the display module are the same, so that the dynamic current corresponding to the subframe to be refreshed of the module can be marked before, during or after the data stream is displayed on the first row of the module where the lamp beads 4 are located, and the data volume is reduced.

In one embodiment, the dynamic current flag signal is generated according to the position of the corresponding sub-frame to be refreshed in the frame where the sub-frame is located.

In this embodiment, the corresponding dynamic current is configured for the sub-frame to be refreshed according to the arrangement order of the sub-frame in the frame where the sub-frame is located. For example, one dynamic current is configured for subframes 1 through 4, another dynamic current is configured for subframes 5-8, and so on. Of course, a different current may be configured for each subframe in the order of the permutation. The present embodiment does not limit the specific dynamic current configuration manner.

In another embodiment, the dynamic current flag signal is generated according to a gray scale weight bit to be refreshed corresponding to the dynamic current flag signal.

In this embodiment, a corresponding dynamic current is configured for the sub-frame to be refreshed according to the gray-scale weight corresponding to the gray-scale weight bit to be refreshed. That is, the dynamic currents of the sub-frames corresponding to the same gray-scale weight bits to be refreshed are the same. When one gray weight bit to be refreshed corresponds to only one subframe, the dynamic current corresponding to the subframe is used for driving the lamp bead 4, and the refreshing of the gray weight corresponding to the gray weight bit to be refreshed can be completed through one subframe.

Specifically, based on the existing LED display screen driving system, the constant current chip drives the lamp beads to display a picture, namely, display data of a frame, and the method is realized through high-speed scanning and refreshing. Taking the example that the constant current chip has 16 paths of output, it means that 16 lamp beads can be lighted by one constant current chip at the same time. Continuing to take 16 constant current chips as a group as an example, on a group of chips, the constant current chips are connected in series, and display data streams for lighting the lamp beads are shifted in series on the constant current chips, so that 256 clocks need to be shifted, display data of all 256 paths of output corresponding lamp beads can be written into each path of output of the 16 constant current chips, at the moment, a latch signal is reset, data is latched and output, and thus a row of 256 lamp beads are lighted.

After 256 lamp beads in a row are lightened, an 8-bit clock refreshing line-changing signal is reserved, the row tube can shift the transmission line to the next row, the lamp beads are continuously lightened, 32 rows are lightened in this way, a round of scanning refreshing is completed, and at the moment, when viewed from the module, a picture of a subframe can be displayed in the area of 256x32 lamp beads.

Further, to display a complete frame of picture, such a sub-frame of picture needs to be refreshed 65 cycles, that is, 65 times, so as to realize the picture display of one frame. If a 60 frame video is played, it is refreshed 60 times in one second. A video stream is played with a data capacity up to (256+8) × 32 × 65 × 60 ═ 32.94 Mb.

In the LED display screen driving system according to the embodiment of the present invention, for a single lamp bead 4, the relationship of the whole control loop is shown in fig. 3. When the lamp beads 4 are switched on by the row tube, the current row lamp beads 4 are controlled by two parameters of a refresh data stream and a dynamic current. Therefore, the lamp beads 4 can display gray scale with dynamic current. The dynamic voltage of the constant current chip 3 is determined by the programmable voltage generator 21. On one display module, all the calibration current pins of the constant current chip 3 are connected together, the module is lightened according to the same current during each lightening, and the module can be lightened according to different currents during the adjacent lightening process, so that a dynamic current pulse width modulation driving mode is realized.

The LED display driving system according to the embodiment of the present invention may add several bits of data for marking dynamic current, that is, between the line feed signal and the line display data stream, the data are transmitted to the first programmable voltage generator 21 step by step to generate the required lighting current.

Then, based on the LED display screen driving system of the embodiment of the present invention, the lamp bead 4 only needs to display one gray scale after 8 cycles (the cycle is the same as the cycle in duration). The constant current chip 3 can output different currents based on different current size marks. The bead 4 can be driven to realize 256-level gray scale in the shortest period according to 8-bit gray scale weight interpretation, namely, 256 gray scale displays of the bead 4 can be realized in 8 periods through 8 different driving currents.

Further, the first programmable voltage generator 21 may be in the form as shown in fig. 11, and its input terminal includes 3 signal pins, which can be set to high and low respectively, and is corresponding to a specific resistance by a 3-bit binary code. The specific resistance of the first programmable voltage generator 21 corresponds to a specific voltage, and the voltage output by the output end of the first programmable voltage generator 21 after passing through the corresponding specific resistance is the calibration voltage of the on-board constant current chip 3. The specific correspondence is shown in table 3.

Binary current signature	Resistance (RC)	Output of the calibration voltage
			000	R1	U1
001	R2	U2
			010	R3	U3
011	R4	U4
			100	R5	U5
101	R6	U6
			110	R7	U7
111	R8	U8

TABLE 3 first programmable Voltage Generator 21 mapping Table

The first programmable voltage generator 21 outputs different voltages according to the different marking currents. The first programmable voltage generator 21 is directly connected with the calibration current control pins of all the constant current chips 3 on the board, and inputs the calibration voltage into the constant current chips 3 so as to output the calibration voltage according to the set calibration current. The magnitude of the driving current is calibrated in each output, and then the lamp beads 4 can be lightened according to different currents.

Based on this, only 3 bits of data for marking the magnitude of the current are sufficient to drive the first programmable voltage generator 21 to control the current output of the constant current chip 3 in accordance with eight different calibration voltages.

The total data capacity, i.e., (256+3+8) × 32 × 8 × 60 ═ 4.1Mb, reduces the data size to 12.45% of the original size, and reduces the transmission time to 12.3% of the original size. The method can realize the same gray scale effect expression in a faster time and less data flow, and improves the gray scale expression efficiency of the system.

In one embodiment, the LED display screen driving system further includes an accumulator 5, the programmable voltage generator 2 is a second programmable voltage generator 22, the accumulator 5 is connected to the display control subsystem 1 and the second programmable voltage generator 22 respectively, and the constant current chip 3 is connected to the second programmable voltage generator 22, the display control subsystem 1 and the lamp bead 4 respectively; the accumulator 5 is used for generating a corresponding dynamic current control signal according to the position of the sub-frame to be refreshed in the frame where the sub-frame is located.

In this embodiment, referring to fig. 12, fig. 12 is a schematic diagram of another LED display panel driving system according to an embodiment of the present invention. The LED display screen driving system comprises a display control subsystem 1, an accumulator 5, a second programmable voltage generator 22, a constant current chip 3 and a lamp bead 4. The display control subsystem 1 receives gray weight values of display data, and generates a refreshing data stream for driving the lamp beads 4 according to a preset gray weight value refreshing sequence based on the gray weight values, wherein the refreshing data stream is divided into a plurality of gray weight value bits according to different gray weight values, and each gray weight value bit corresponds to more than one subframe; the accumulator 5 generates a corresponding dynamic current control signal according to the position of the sub-frame to be refreshed in the frame in which the sub-frame is positioned; the second programmable voltage generator 22 generates a corresponding dynamic voltage according to the dynamic current control signal; and when receiving a row tube conduction signal corresponding to the lamp bead 4, the constant current chip 3 drives the lamp bead 4 to refresh display data according to the refresh data stream and the dynamic voltage corresponding to the sub-frame to be refreshed. According to the LED display screen driving system disclosed by the embodiment of the invention, for a single lamp bead 4, the relation of the whole control loop is shown in FIG. 3. When the lamp beads 4 are switched on by the row tube, for the current row lamp beads 4, the current row lamp beads are controlled by two parameters of dynamic current corresponding to the refresh data stream and the dynamic voltage. Therefore, the lamp beads 4 can display gray scale with dynamic current. The refreshing data stream is used for determining which lamp beads 4 in the current row are lighted, and which lamp beads 4 are not lighted; the dynamic voltage output of the programmable voltage generator 2 determines at what current the constant current chip 3 is outputting. Optionally, the calibration current pins of all the constant current chips 3 are connected together on one display module, the module is lit according to the same current magnitude when lit each time, and the module can be lit according to different currents in the two adjacent lighting processes, so that a dynamic current pulse width modulation driving mode is realized. The step of generating the corresponding dynamic current control signal by the accumulator 5 according to the position of the sub-frame to be refreshed in the frame where the sub-frame is located includes: and configuring corresponding dynamic currents for the subframes to be refreshed according to the arrangement sequence of the subframes in the frame where the subframes are located, for example, configuring one dynamic current for the 1 st to 4 th subframes, configuring another dynamic current for the 5 th to 8 th subframes, and the like. Of course, a different current may be configured for each subframe in the order of the permutation. The present embodiment does not limit the specific dynamic current configuration manner.

In one embodiment, the second programmable voltage generator 22 includes a second control signal input pin connected to the accumulation signal output pin of the accumulator 5 and a plurality of second output pins, each of which is connected to a voltage regulating resistor corresponding to the position of the second output pin.

Specifically, referring to fig. 12, the second programmable voltage generator 22 has a second control signal input pin and a plurality of second output pins, and each time it receives a second accumulation signal, the output terminal moves down by one cell, and correspondingly jumps from one second output pin to another output pin, and thus to another voltage regulating resistor. And returning to the first grid voltage regulating resistor after jumping to the last grid voltage regulating resistor, and repeating the steps. Each second output pin of the output end of the second programmable voltage generator 22 is connected with the current calibration pin of the constant current chip 3 after passing through the corresponding voltage regulating resistor, and is used for controlling the output current of the constant current chip 3. Optionally, the number of the voltage-regulating resistors is less than or equal to the number of subframes in one frame time, when the number of the voltage-regulating resistors is less than the number of subframes in one frame time, one voltage-regulating resistor corresponds to multiple subframes, and when the number of the voltage-regulating resistors is equal to the number of subframes in one frame time, one voltage-regulating resistor corresponds to one subframe, so that a corresponding dynamic voltage and a corresponding dynamic current are configured for each subframe.

In one embodiment, the accumulator 5 is configured to generate a corresponding dynamic current control signal according to a position of a sub-frame to be refreshed in a frame in which the sub-frame is located, and includes:

after the display control subsystem 1 is started, refreshing data stream to the constant current chip 3 for the first time, and then activating the accumulator 5;

the accumulator 5 starts to sample the clock of the display control subsystem 1 after being activated and outputs a first accumulation signal to the second programmable voltage generator 22, so that the second programmable voltage generator outputs a dynamic voltage corresponding to a first subframe to be refreshed to the constant current chip 3 after receiving the first accumulation signal;

the accumulator 5 outputs a second accumulation signal to the second programmable voltage generator 22 every other preset number of clocks of the display control subsystem 1, so that the second programmable voltage generator 22 moves a second output pin of the second accumulation signal downwards by one bit each time the second accumulation signal is received, and is connected with another voltage-regulating resistor, and then outputs a dynamic voltage corresponding to a current subframe to be refreshed to the constant current chip 3;

the first and second accumulation signals are used as the dynamic current control signal.

In this embodiment, the preset number is the number of clocks of the display control subsystem 1 required for refreshing one sub-frame by one module. The switching sequence of the voltage regulating resistors corresponds to the refreshing sequence of the corresponding sub-frames. Referring to fig. 12, the display control subsystem 1 receives the gray-scale weight of the display data, converts the gray-scale weight into a refresh data stream for the constant current chip 3 to refresh and output, and sends the refresh data stream to the constant current chip 3. One clock is output to the accumulator 5 for sampling. The accumulator 5 is activated after the display control subsystem 1 refreshes the data stream to the constant current chip 3, starts to sample the working clock of the display control subsystem 1 and outputs a first accumulation signal to the second programmable voltage generator 22, and then outputs an accumulation signal to the second programmable voltage generator 22 every other specific clock. The constant current chip 3 drives the lamp bead 4 to work, and received digital signals are converted into analog signals (PWM). The working current output depends on the current calibration pin. The lamp bead 4 is driven to display content, and the driving method comprises the following steps: taking an example that an 8-bit gray scale weight corresponds to 8-level current drive, and a full-page module comprises 16 constant current chips 3 with 32 sweeps, after the display control subsystem 1 is started, a data stream is refreshed on the constant current chip 3 for the first time, an accumulator 5 is activated, so that the accumulator starts to sample a clock of the display control subsystem 1 and outputs a first accumulation signal to a second programmable voltage generator 22; after receiving the first accumulation signal, the second programmable voltage generator 22 outputs a dynamic voltage corresponding to a first subframe to be refreshed to the constant current chip 3, so that the dynamic voltage outputs a dynamic current corresponding to the first subframe to be refreshed; the accumulator 5 outputs a second accumulation signal to the second programmable voltage generator 22 every 256 × 32, i.e., 8192 clocks of the display control subsystem 1; when the second programmable voltage generator 22 receives the second accumulated signal each time, the output pin moves down by one bit and is connected with another voltage-regulating resistor, so as to output a dynamic voltage corresponding to the current sub-frame to be refreshed to the constant current chip 3, and enable the dynamic voltage to output a dynamic current corresponding to the current sub-frame to be refreshed.

In one embodiment, the second programmable voltage generator 22 shifts its output pin down by one bit each time it receives the second accumulation signal, connecting to another voltage regulation resistor comprises:

if the output pin of the second programmable voltage generator 22 is already connected to the last voltage regulating resistor before receiving the second accumulation signal, it is returned to the connection to the first voltage regulating resistor after receiving the second accumulation signal.

Specifically, the second programmable voltage generator 22 has only one signal pin, and the output terminal moves down one grid to jump to another voltage regulating resistor each time it receives a second accumulated signal. And the process is repeated until the last voltage-regulating resistor is jumped and the first voltage-regulating resistor is returned again.

The LED display screen driving system of the embodiment of the invention comprises: the display control subsystem 1 is used for receiving gray weight values of display data, and generating a refreshing data stream for driving the lamp beads 4 according to a preset gray weight value refreshing sequence based on the gray weight values, wherein the refreshing data stream is divided into a plurality of gray weight value bits according to different gray weight values, and each gray weight value bit corresponds to more than one subframe; the programmable voltage generator 2 is used for generating corresponding dynamic voltage according to the dynamic current control signal corresponding to the sub-frame to be refreshed; and the constant current chip 3 is used for driving the lamp beads 4 to refresh display data according to the refresh data stream and the dynamic voltage corresponding to the sub-frame to be refreshed when receiving the row tube conduction signal corresponding to the lamp beads 4. Therefore, the method for expressing the gray scale of the lamp bead 4 is changed from the original method of only relying on a string of binary numbers into the form of adding the binary numbers to the instantaneous driving current corresponding to the dynamic voltage, and the gray scale of the lamp bead 4 is defined from two dimensions, so that the driving efficiency of the lamp bead 4 is greatly improved, the time for driving the lamp bead 4 is shortened, and the burden of the driving data volume is reduced. The transmission rate of the display data can be increased to several times of the original rate under the condition of ensuring the same display effect; or, under the condition of not increasing the transmission rate, the gray scale of the display screen is greatly improved; or, under the same display data quantity, more lamp beads 4 are driven to display the content.

Example two

The embodiment of the invention also provides an LED display screen, which comprises the LED display screen driving system in the first embodiment.

The LED display screen of the embodiment of the present invention and the system of the first embodiment belong to the same concept, and the specific implementation process is described in detail in the corresponding system embodiment, and the technical features in the system embodiment are all applicable in the embodiment of the LED display screen, which is not described herein again.

The corresponding technical features in the above embodiments may be used with each other without causing contradiction in the schemes or without being implementable.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.

While the present invention has been described with reference to the particular illustrative embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but is intended to cover various modifications, equivalent arrangements, and equivalents thereof, which may be made by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. An LED display screen driving system, comprising:

2. The LED display screen driving system according to claim 1, wherein the programmable voltage generator is a first programmable voltage generator, the first programmable voltage generator is respectively connected with the display control subsystem and the constant current chip, and the constant current chip is connected with the lamp bead.

3. The LED display screen driving system of claim 2, wherein the refresh data stream includes a dynamic current flag signal corresponding to a sub-frame to be refreshed, the dynamic current flag signal being the corresponding dynamic current control signal.

4. The LED display screen driving system according to claim 3, wherein the dynamic current marking signal marks before or after a starting point of a row display data stream of a row in which the lamp bead is located.

5. The LED display screen driving system according to claim 4, wherein the dynamic current marking signal marking before or after the starting point of the row display data stream of the row where the lamp bead is located comprises:

and in the sub-frame to be refreshed, marking the dynamic current marking signal corresponding to the sub-frame to be refreshed of the module only before, during or after the data stream is displayed in the row of the first row of the module in which the lamp bead is positioned.

6. The LED display screen driving system according to claim 3, wherein the dynamic current flag signal is generated according to the position of the sub-frame to be refreshed corresponding to the dynamic current flag signal in the frame in which the dynamic current flag signal is located.

7. The LED display screen driving system according to claim 3, wherein the dynamic current flag signal is generated according to the corresponding gray scale weight bits to be refreshed.

8. The LED display screen driving system according to claim 1, further comprising an accumulator, wherein the programmable voltage generator is a second programmable voltage generator, the accumulator is connected to the display control subsystem and the second programmable voltage generator, respectively, and the constant current chip is connected to the second programmable voltage generator, the display control subsystem and the lamp bead, respectively;

the accumulator is used for generating a corresponding dynamic current control signal according to the position of the sub-frame to be refreshed in the frame where the sub-frame is located.

9. The LED display screen driving system of claim 8, wherein the second programmable voltage generator comprises a second control signal input pin and a plurality of second output pins, the second control signal input pin is connected to the accumulation signal output pin of the accumulator, and each of the second output pins is connected to a voltage regulating resistor corresponding to the position of the second output pin.

10. The LED display screen driving system of claim 9, wherein the number of voltage regulating resistors is less than or equal to the number of sub-frames in a frame time.

11. The LED display screen driving system according to claim 9 or 10, wherein the accumulator is configured to generate the corresponding dynamic current control signal according to the position of the sub-frame to be refreshed in the frame thereof, and comprises:

the display control subsystem refreshes the data stream to the constant current chip for the first time after starting and then activates the accumulator;

the accumulator starts to sample a clock of the display control subsystem after being activated and outputs a first accumulation signal to the second programmable voltage generator, so that the accumulator outputs a dynamic voltage corresponding to a first sub-frame to be refreshed to the constant current chip after receiving the first accumulation signal;

the accumulator outputs second accumulation signals to the second programmable voltage generator every other preset number of clocks of the display control subsystem, so that the second programmable voltage generator moves a second output pin of the second programmable voltage generator downwards by one bit when receiving the second accumulation signals each time, and is connected with another voltage regulating resistor, and further dynamic voltage corresponding to the current subframe to be refreshed is output to the constant current chip;

12. The LED display screen driving system of claim 11, wherein the second programmable voltage generator shifts its output pin down by one bit each time it receives the second accumulation signal, and the connection with the further voltage regulating resistor comprises:

and if the output pin of the second programmable voltage generator is connected with the last regulating resistor before the second accumulated signal is received, returning to be connected with the first regulating resistor after the second accumulated signal is received.

13. The LED display screen driving system of claim 11, wherein the predetermined number is the number of clocks of the display control subsystem required for a module to refresh a sub-frame.

14. The LED display screen driving system according to claim 11, wherein the switching sequence of the voltage-regulating resistors corresponds to the refreshing sequence of the sub-frames corresponding thereto.

15. The LED panel driver system of claim 1, wherein the plurality of dynamic voltages are different for each of the sub-frames or different for some of the sub-frames.

16. The LED display screen driving system according to claim 1, wherein the brightness value of the lamp bead generated by the dynamic voltage control corresponding to all sub-frames in a frame time corresponds to the gray value of the lamp bead in the frame.

17. The LED display screen driving system according to claim 1, wherein the preset gray scale weight refresh sequence comprises: refreshing according to the sequence of the gray weight values from high to low, or refreshing according to the sequence of the gray weight values from low to high, or refreshing according to a non-monotone ascending and descending sequence.

18. LED display screen, characterized in that it comprises a LED display screen driving system according to any one of claims 1-17.