KR102417623B1 - Automatic correction device for analog deviation of LCoS drive board - Google Patents

Abstract

A device for automatic compensation of analog deviation of LCoS drive board is disclosed. The device for automatically correcting analog deviation of an LCoS drive board according to the present invention is an automatic analog deviation compensation device for an LCoS drive board that includes an analog circuit including a D/A converter and an amplifier on the LCoS drive board outside the panel. The LCoS drive board 20 and A half VCOM voltage for determining a center reference voltage that separates a positive field from a negative field using the ADC jig board 22 separately installed, the VCOM voltage measured by the ADC jig board 22, and the first Positive field driving voltage and negative field based on VCOM, the reference common voltage of the panel actually measured based on the output slope corresponding to the actual amplification characteristics of the amplifier using the offset value, the second offset value, and the output voltage for deriving the output slope A computer 24 that matches the driving voltage and derives a gain and an offset for each channel to obtain the same output voltage level for each channel with respect to the same input, and applies the gain and offset values derived by the computer 24 to each channel and an LCoS drive board 20 that drives the LCoS panel 21 with the same driving voltage with respect to the same input by correcting deviations in amplification characteristics of each amplifier. The analog deviation automatic correction device of the LCoS drive board as described above produces a driving voltage of a different output level for each channel even when the same input signal is input due to the characteristic deviation of the elements constituting the electronic circuit when manufacturing a silicon liquid crystal display (LCoS). By solving the output problem, the contrast expression for each channel is consistent, the flicker phenomenon and afterimage phenomenon are minimized, and the same color and accurate gamma expression as the input can be obtained.

Description

Automatic correction device for analog deviation of LCoS drive board

The present invention relates to an automatic analog deviation correction device for an LCoS drive board, and more particularly, to an LCoS drive board that is outside of a panel including analog circuits such as a D/A converter and an amplifier, and including such analog circuits inside the panel In the driving type LCoS drive board, which has a relatively high driving voltage swing width compared to the driving method, the positive field driving voltage and the negative field driving voltage are matched based on VCOM, the reference common voltage of the panel, and the output level deviation for each channel is corrected. It is about the analog deviation automatic compensation device of the LCoS drive board.

LCoS is an abbreviation for a silicon liquid crystal display device, which is a microdisplay made by placing liquid crystal on a silicon (Si) wafer. In general, liquid crystal is injected between two pieces of glass. The light reflected from the substrate gives color, and the brightness is controlled by the alignment of the liquid crystal. In LCoS, colors are created by sequentially flashing RGB in a single pixel, not in red, green, and blue (RGB) sub-pixels. The DLP method is the same as the LCoS method in that it reflects light to produce color, but the difference is that it uses a microelectromechanical system (MEMS) rather than liquid crystal to produce contrast and color. see.

The LCoS method is evaluated to be useful for manufacturing high-resolution and high-definition easily and inexpensively large-screen TVs. Transmissive liquid crystal panels currently widely used in projectors and the like have a problem in that an aperture ratio indicating a rate of light transmission is lowered because a driving circuit is wired between the pixels. However, in the LCoS panel, since the driving circuit is designed behind the reflective film, there is almost no part that blocks the light, so it is possible to project a smooth image. In addition, since the aperture ratio is high, high luminance is realized at the same time.

The LCoS panel driving method can be divided into an analog driving method and a digital driving method depending on the driving method of TR (transistor) in the LCOS panel. It can be divided into a first driving type including analog circuits such as A converter and amplifier, and a second driving type including analog circuits such as D/A converter and amplifier on an LCoS drive board outside the panel. The most representative difference between the first driving type and the second driving type is that the voltage level for driving the liquid crystal is different. The first driving type has a driving voltage swing range of 0 to 3.3V, whereas the second driving type is the first driving type Compared to that, it has a wide 0 ~ 6V driving voltage swing range.

Compared to the first driving type in the driving voltage swing range of 0 to 3.3V, the second driving type has advantages in that it has relatively high luminance, high color depth of 12 bits, and excellent gamma characteristics in driving the liquid crystal. Since the voltage swing width is large, the analog signal of the same level must be output for each VCOM reference channel, and the positive field driving voltage and the negative field driving voltage must be accurately matched to achieve clear contrast expression, minimize flicker, and prevent afterimage. In addition, the same color as the input may be expressed and accurate gamma expression may be possible. It is worth noting that the device for automatically correcting analog deviation of the LCoS drive board described in this specification is related to the LCoS drive board of the second drive type including analog circuits such as a D/A converter and an amplifier in the LCoS drive board outside the panel. have.

1 is a block diagram showing a conventional general structure of an LCoS drive board to which a UHD method of 4K resolution is applied, which is equipped with a D/A converter and an OP amplifier to drive an LCoS panel. Referring to FIG. 1, when the FPGA stage 100 of the LCoS drive board 10 to which the UHD method of 4K resolution is applied outputs a digital image signal expressing 0 to 4096 in 12 bits, a 32-channel D/A conversion unit 102 ) to an analog signal of 0 ~ 1.9V, for example, 32 channels (#0 ~ The analog signal of #31) is input to the LCoS panel 12 to display an image.

However, the conventional LCoS drive board as described above includes an analog circuit (D/A converter and OP amplifier). Due to the characteristics of the electronic circuit element, even if the same input signal is input, it is output at a slightly different level for each channel. There is a problem in that the contrast expression is different, and a flicker phenomenon, an afterimage phenomenon, and a color different from the input and an inaccurate gamma expression are generated. There is a problem that the deviation is markedly displayed.

The present invention has been developed to solve the above problems, and the technical problem to be achieved in the present invention is

In order to express clear contrast, minimize flicker, and prevent image retention, it is necessary to match the positive field driving voltage and the negative field driving voltage based on VCOM, which is the reference common voltage of the LCos panel.

An apparatus for automatically correcting analog deviation of an LCoS drive board according to the present invention for achieving the above technical problem,

It is an analog deviation automatic compensation device of LCoS drive board that includes analog circuit including D/A converter and amplifier on LCoS drive board outside the panel,

LCoS drive by measuring the VCOM voltage, which is the reference common voltage of the LCos panel, the output voltage for each channel of the LCoS drive board 20, and the output voltage for deriving the output slope with output values for any first and second offsets ADC jig board 22 installed separately from the board 20;

Using the VCOM voltage measured by the ADC jig board 22, a half VCOM voltage for determining a central reference voltage that separates the positive field and the negative field, the first offset value, the second offset value, and the output slope are derived Based on the output slope corresponding to the actual amplification characteristics of the amplifier, the positive field driving voltage and the negative field driving voltage are matched based on VCOM, which is the reference common voltage of the actually measured panel, and for the same input, each channel a computer 24 for deriving per-channel gains and offsets to achieve the same output voltage level; and

an LCoS drive board 20 for driving the LCoS panel 21 with the same driving voltage for the same input by applying the gain and offset values derived by the computer 24 to correct the deviations in the amplification characteristics of the amplifier for each channel; It is characterized in that it includes.

In addition, it is preferable that the apparatus for automatically correcting analog deviation of the LCoS drive board divides the positive field or the negative field based on the half VCOM voltage corresponding to 1/2 of the VCOM which is the reference common voltage of the actually measured panel.

In addition, the LCoS drive board includes an analog circuit including a D/A converter and an amplifier on the LCoS drive board outside the panel, and has a relatively high drive voltage swing width compared to a drive method including the analog circuit inside the panel. It is preferable to be type-based.

In addition, the computer 24,

Considering the offset range of the full scale, it is more preferable to apply the full gray scale.

In addition, the computer 24,

The driving offset Igap, defined as the difference between the offset corresponding to the full gray scale and the offset corresponding to the gray scale of the half VCOM,

rescued by

output slope Slop,

After obtaining by

gain and offset to achieve the same output voltage level per channel;

gain is,

derived by

Offset is,

derived by

The LCoS drive board 20,

LCoS panel 21 as a driving voltage obtained by computer 24 using the data measured by the ADC jig board 22 and corrected for deviation by applying gain and offset values to obtain the same output for each channel. It is more preferable to drive

In addition, the LCoS drive board is based on 4K UHD,

The computer 24 obtains gain and offset values for obtaining the same output for each channel,

The driving offset Igap, defined as the difference between the offset corresponding to the full gray scale and the offset corresponding to the gray scale of the half VCOM,

rescued by

output slope Slop,

obtained by

gain and offset to achieve the same output voltage level per channel;

gain is,

derived by

Offset is,

derived by

The LCoS drive board 20 may output a driving voltage using the derived gain and offset.

As described above, the apparatus for automatically correcting analog deviation of an LCoS drive board according to the present invention includes analog circuits such as a D/A converter and an amplifier in an LCoS drive board outside the panel, and includes the analog circuit inside the panel. In the driving type LCoS drive board having a relatively high driving voltage swing width compared to the above, the positive field driving voltage and the negative field driving voltage are matched based on VCOM, which is the reference common voltage of the panel, and the output level deviation for each channel is corrected. Therefore, when manufacturing a silicon liquid crystal display (LCoS), the problem of outputting driving voltages of different output levels for each channel even when the same input signal is input due to the characteristic deviation of elements constituting the electronic circuit is solved, so that the contrast expression is consistent and minimizes the flicker and afterimage, and obtains the same color and accurate gamma expression as the input.

1 is a block diagram showing a conventional general structure of an LCoS drive board to which a UHD method of 4K resolution is applied, which is equipped with a D/A converter and an OP amplifier to drive an LCoS panel;
2 is a block diagram showing the structure of an automatic analog deviation correction device of an LCoS drive board according to a preferred embodiment of the present invention;
3 is a flowchart for explaining an algorithm performed in the apparatus for automatically correcting analog deviation of the LCoS drive board according to the embodiment of the present invention shown in FIG.
4 is a graph for explaining a process of obtaining an output slope (Slop) defined as a proportional relationship of an output voltage with respect to an offset at a DAC stage when a channel is driven at full scale within the reference common voltage VCOM range;
5 is a view for comparing and explaining the output level of each channel before and after correction for the same input signal in order to explain the effect of the automatic analog deviation correction device of the LCoS drive board according to the present invention;
6 is an output voltage, an output slope, and half VCOM measured in real time for each offset measured in real time in order to explain the effect of an automatic analog deviation correction device for an LCoS drive board according to the present invention, and a gain and offset for each channel with respect to the half VCOM An example of a GUI displayed on a computer screen to explain the process of obtaining a flat output by applying .

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

2 is a block diagram showing the structure of an automatic analog deviation correction device of an LCoS drive board according to a preferred embodiment of the present invention. Referring to FIG. 2 , an apparatus for automatically correcting analog deviation of an LCoS drive board according to the present invention includes an LCoS drive board 20 , an ADC jig board 22 , and a computer 24 .

The LCoS drive board 20 includes an analog circuit including a D/A converter and an amplifier on an LCoS drive board outside the panel, and has a relatively high driving voltage swing width compared to a driving method including the analog circuit inside the panel. The branches are made based on the drive type.

The ADC jig board 22 is installed separately from the LCoS drive board 20 and includes the VCOM voltage that is the reference common voltage of the LCos panel, the output voltage for each channel of the LCoS drive board 20, and any first offset and second As an output value for the offset, the output voltage for deriving the output slope is measured in real time. In this embodiment, voltage values are measured with respect to offset 512 (reference number 310 in FIG. 4), offset 2048 (reference number 312 in FIG. 4), and offset 3,584 (reference number 314 in FIG. 4), which will be described later. As shown, the output slope is derived using the output voltage measurement value at the offset 512 (reference numeral 310 in FIG. 4 ) and the offset 3,584. It can be understood that the output slope corresponds to the actual amplification characteristic of the amplifier.

The computer 24 uses the VCOM voltage measured by the ADC jig board 22 to determine a half VCOM voltage for determining a central reference voltage that separates the positive field from the negative field, the first offset value and the second offset Using the output voltage for deriving the value and output slope, the positive field driving voltage and the negative field driving voltage are matched based on the VCOM, the reference common voltage of the panel actually measured based on the output slope corresponding to the actual amplification characteristics of the amplifier, and the same For the input, the gain and offset for each channel are derived to obtain the same output voltage level for each channel.

The LCoS drive board 20 applies the gain and offset values derived by the computer 24 to correct deviations in the amplification characteristics of the amplifier for each channel to drive the LCoS panel 21 with the same driving voltage for the same input. do.

3 is a flowchart for explaining an algorithm performed in the apparatus for automatically correcting analog deviation of the LCoS drive board according to the embodiment of the present invention shown in FIG. 2 . In the embodiment of FIG. 3, a case applied to the 32-channel 4K UHD method will be described as an example. That is, the Full Gray Scale is 4,095 and the Half Gray Scale is 2,047.

First, the 32-channel ADC jig board 22 measures the VCOM voltage, which is the reference common voltage of the panel (step S300). Since the reference common voltage VCOM of the panel is slightly different for each manufactured liquid crystal panel, the VCOM voltage referred to as '302' in FIG. 4 herein is defined as the reference common voltage actually measured by the 32-channel ADC jig board 22 do. Next, a half VCOM value 304 that is an intermediate value of the VCOM voltage may be derived from the measured VCOM value (step S302).

LCD controls the color that comes out through backlight-color filter-liquid crystal by polarization effect by twisting liquid crystal. Therefore, by inverting VCOM for each field, the twist direction of the liquid crystal is reversed for each field displaying the screen. That is, the direction is reversed by making VCOM high with respect to half VCOM, and making VCOM low with respect to half VCOM in the next field. For this purpose, in the present invention, half VCOM is obtained as a reference common voltage that distinguishes the negative field from the positive field.

Next, the 32-channel ADC jigboard 22 has three arbitrary offset points for 32 channels in which each channel is divided by 4,095 scales, in this embodiment offset 512, offset 2048, and offset 3,584 points 310, 312, 314) to measure the voltage value (step S310). The plurality of measured voltage values measured in step S310 are for deriving the output slope (Slop) and are related to the amplification characteristics that determine the output voltage value according to the offset in the op amp, so the output slope (Slop) is the actual measured It is calculated based on the voltage value.

4 shows a graph for explaining a process of obtaining an output slope (Slop) defined as a proportional relationship of an output voltage with respect to an offset at the DAC stage when a channel is driven at full scale within the reference common voltage VCOM range.

In this embodiment, the output slope (Slop) is calculated using the measured voltage value at the offset 512 and the offset 3,584,

By obtaining as shown in FIG. 4 , an output slope (Slop: 320) for each 32 channels is obtained, and when the output slope (Slop: 320) for each channel is obtained, a driving voltage (power) graph for each offset is obtained as shown in FIG. 4 .

Next, the offset value corresponding to the gray scale of the full scale, for example, 3,939, and the half VCOM value from the slope (Slop) and the graph obtained above, for example, the half VCOM of the VCOM of 5,500, the half VCOM 2,750 (304), the offset value 2,248 ( Drive offset Igap 340 from 330,

is obtained by (step S320). In this embodiment, calculation is performed based on a gray scale signal.

을 하프 그레이스케일의 중심값인 1,024에 대한 단위 게인이라 할 때, 출력 기울기(Slop), 구동 오프셋 Igap, 및 하프 VCOM값을 사용하여 32 채널별 DAC 단에서의 동일한 출력을 얻기 위한 게인 및 오프셋값을,now,

Assuming that is the unit gain for 1,024, the center value of half grayscale, the gain and offset values for obtaining the same output at the DAC stage for each 32 channels using the output slope (Slop), the driving offset Igap, and the half VCOM value second,

It can be derived as (step S330), and the D/A conversion unit 202 and the amplifier 204 of the LLoS drive board 20 are referred to as “A” in FIG. 2 and are derived by the computer 24 By driving the LCoS panel 21 with the driving voltage (power) corrected for the deviation by applying the gain and offset values, the analog output is automatically corrected (step S340).

Since one correction may not correct to the desired degree, measure the output of 32 channels again through the ADC jig board 20 (step S350) to check whether the analog output corrected in the above step is correct. It is finally confirmed whether the corrected output data is obtained (step S360).

5 is a diagram for comparing and explaining the output level of each channel before and after correction for the same input signal in order to explain the effect of the automatic analog deviation correction device of the LCoS drive board according to the present invention. Referring to (a) of FIG. 5 , there is a significant deviation in the driving voltage for each channel with respect to the same input signal before automatic adjustment. As shown in (b), for the same input signal, the driving voltage for each channel is obtained at a constant output level without deviation.

6 shows the output voltage, output slope, and half VCOM for each offset measured in real time in order to explain the effect of the automatic analog deviation correction device of the LCoS drive board according to the present invention, and the gain and offset for each channel with respect to the half VCOM. A screen example of a GUI displayed on a computer screen is shown to explain the process of obtaining a flat output by applying . Referring to FIG. 6 , the output levels at offsets 512, 2,048, and 3,584 are measured by the ADC jig board 22 and the output slope and half VCOM are derived by the computer 24, and the derived output slope and Igap and The gain and offset are derived from the half VCOM value.

First, the output slope Slop = (V_3584 - V_512) / (3584 - 512) is determined from the voltage measurement value made with respect to the offset 512 and the offset 3584 by the ADC jig board 22 and Equation 1, and the determined output slope Slop is Based on this, Gray scale of Full Scale = Full Scale / Slop is determined, and Gray scale of Half Vcom = Half Vcom / Slop is determined.

Afterwards, when Half Vcom = Vcom / 2 = 2835, by Equations 3 and 4,

Igap = gray scale of full scale - gray scale of Half Vcom

Gain = (Igap) * 1Gain(1024) / Half gray scale(2048.0)

Offset = gray scale of Half Vcom - Igap

This is derived

When explaining the process of finding the gain and offset for channel 1,

Slop = (4789.4 - 734.6) / (3584 - 512) = 1.319921875

gray scale of Full Scale = 5200 / 1.319921875 = 3939.627… = 3940

gray scale of Half Scale = 2835 / 1.319921875 = 2,147.854… = 2148

Igap = gray scale of Full Scale - gray scale of Half Scale = 1792

is obtained as

Gain = 1992(Gap) * 1024 / 2048 = 896

Offset = 2148 (gray scale of Half Scale) - 1792 (Igap) = 356

Gain and offset are derived as

When explaining the process of finding the gain and offset for channel 2,

Slop = (4733.4 - 725.1) / (3584 - 512) = 1.30478515625

gray scale of Full Scale = 5200 / 1.30478515625 = 3,985.330… = 3985

gray scale of Half Scale = 2835 / 1.30478515625 = 2,172.771… = 2173

Igap = gray scale of Full Scale - gray scale of Half Scale = 1,812

is obtained as

Gain = 1812 (Igap) * 1024 / 2048 = 906

Offset = 2148 (gray scale of Half Scale) - 1812 (Igap) = 361

Gain and offset are derived as

It can be seen that the LCoS drive board 20 is derived for each channel and obtains a flat output for each channel by applying a gain and an offset to obtain a flat output value to convert the input signal into a channel driving voltage and output it. That is, in FIG. 6 , it can be seen that the output voltages V_512, V_2048, and V_3584 for each channel before correction have significant deviation, whereas the output V-output for each channel corrected by applying the derived gain and offset is flat.

The apparatus for automatically correcting analog deviation of the LCoS drive board according to the present invention as described above continuously measures the voltage level for each channel through feedback, derives and applies a gain and an offset for matching, and applies the same for each channel. The same output is obtained by correcting the deviation for each channel with respect to the input signal. That is, the positive field driving voltage and the negative field driving voltage are matched based on VCOM by applying the gain/offset values derived by applying the algorithm.

Therefore, when manufacturing a silicon liquid crystal display (LCoS), it solves the problem that the driving voltage of different output level is output for each channel even when the same input signal is input due to the characteristic deviation of the elements constituting the electronic circuit. For LCoS panels that swing and display at high voltage, the contrast expression for each channel is consistent, and the flicker and afterimage effects are minimized. can be implemented as much as possible.

As described above, the analog deviation automatic correction device of the LCoS drive board according to the present invention can be applied to both the 8-channel analog output full HD (Full-HD) LCoS drive board and the 32-channel analog output UHD LCoS drive board. If applied to UHD LCOS drive board with 32-channel analog output consisting of output lines, a more pronounced effect can be exhibited.

20: LCoS drive board 21: LCoS panel
22: ADC jig board 24: computer

Claims (6)

A device for automatically correcting analog deviation of an LCoS drive board comprising an analog circuit including a D/A converter and an amplifier on the LCoS drive board outside the panel,
LCoS drive by measuring the VCOM voltage, which is the reference common voltage of the LCos panel, the output voltage for each channel of the LCoS drive board 20, and the output voltage for deriving the output slope with output values for any first and second offsets ADC jig board 22 installed separately from the board 20;
Using the VCOM voltage measured by the ADC jig board 22, a half VCOM voltage for determining a central reference voltage that separates the positive field and the negative field, the first offset value, the second offset value, and the output slope are derived Based on the output slope corresponding to the actual amplification characteristics of the amplifier, the positive field driving voltage and the negative field driving voltage are matched based on the VCOM, the reference common voltage of the actually measured panel, and for the same input, each channel a computer 24 for deriving per-channel gains and offsets to achieve the same output voltage level; and
an LCoS drive board 20 for driving the LCoS panel 21 with the same driving voltage for the same input by applying the gain and offset values derived by the computer 24 to correct deviations in the amplification characteristics of the amplifier for each channel; Analog deviation automatic compensation device of the LCoS drive board, characterized in that it comprises a. According to claim 1, wherein the analog deviation automatic correction device of the LCoS drive board,
Analog deviation automatic compensation device for LCoS drive board, characterized in that it distinguishes positive field or negative field based on half VCOM voltage corresponding to 1/2 of VCOM, which is the reference common voltage of the actually measured panel. According to claim 1, wherein the LCoS drive board,
It is based on a driving type that includes an analog circuit including a D/A converter and an amplifier on the LCoS drive board outside the panel, and has a relatively high driving voltage swing width compared to a driving method that includes the analog circuit inside the panel Analog deviation automatic compensation device of LCoS drive board. The method of claim 1, wherein the computer (24) comprises:
When considering the offset range of the full scale, the analog deviation automatic compensation device of the LCoS drive board, characterized in that the full gray scale is applied. 5. The method of claim 4,
The computer 24,
The driving offset Igap, defined as the difference between the offset corresponding to the full gray scale and the offset corresponding to the gray scale of the half VCOM,

rescued by
output slope Slop,

After obtaining by

Assuming that is the unit gain for 1,024, the center value of half grayscale, the gain and offset to obtain the same output voltage level for each channel,
gain is,

derived by
Offset is,

derived by
The LCoS drive board 20,
The LCoS panel 21 is a driving voltage obtained by the computer 24 using the data measured by the ADC jig board 22 and corrected for the deviation by applying the gain and offset values to obtain the same output for each channel. Analog deviation automatic compensation device of the LCoS drive board, characterized in that it drives. The method of claim 5, wherein the LCoS drive board is based on 4K UHD,
The computer 24 obtains the gain and offset values for obtaining the same output for each channel,
The driving offset Igap, defined as the difference between the offset corresponding to the full gray scale and the offset corresponding to the gray scale of the half VCOM,

rescued by
output slope Slop,

obtained by
gain and offset to achieve the same output voltage level per channel;
gain is,

derived by
Offset is,

derived by
The LCoS drive board 20 uses the derived gain and offset to output a driving voltage, an automatic analog deviation correction device for the LCoS drive board.

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