JP2004361444A - Liquid crystal display system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To automate the initial adjustment of luminance and contrast. <P>SOLUTION: A display output control section 13 outputs video data for testing generated by a test pattern generating section 12 to an LCD controller 3 and an adjustment value correcting section 14 captures the voltage value of a video signal V 2 detected by an A/D converter 7 for the outputted video data for testing. The adjustment value correcting section 14 determines the relations between the luminance operation value CNtB of a user and contrast operation value CntC inputted from an input device 2 and the luminance adjustment signal B and contrast adjustment signal C to be outputted from a TFT controller 4 from the relation between the video data for testing and the voltage value of the video signal V 2 so as to satisfy the standards of the LCD module and sets the same at an adjustment table 15. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a technique for adjusting display brightness and contrast in a display device such as a liquid crystal display device.
[0002]
[Prior art]
As a technique for adjusting display brightness and contrast in a liquid crystal display device, a display controller that controls display of a liquid crystal display module adjusts an offset and a gain of a video signal output to the liquid crystal display module according to an input video signal. A technique is known (for example, Japanese Patent Application Laid-Open No. 10-161600). Here, the offset of the video signal controls the brightness of the black level, which is a reference for the brightness of the video, and the gain of the video signal indicates the magnitude of the difference between the white and black levels of the video. It is controlled and corresponds to the contrast of an image.
[0003]
Prior art document information related to the invention of this application includes the following.
[0004]
[Patent Document 1]
Japanese Patent Application Laid-Open No. H10-161600
[Problems to be solved by the invention]
By the way, even if the same video is output under the same adjustment conditions, the video signal voltage output to the liquid crystal display module varies due to the accuracy error of the components of each component constituting the liquid crystal display device.
In a liquid crystal display device, it is general that the user can adjust the brightness and contrast of the liquid crystal display module to some extent. The luminance and contrast ranges that can be adjusted by the user are such that the voltage of the video signal representing white falls within the voltage range of the white level defined by the standard of the liquid crystal display module itself, and the voltage of the video signal representing black falls on the liquid crystal display module. It is necessary to limit the voltage to be within a black level voltage range defined by its own standard.
[0006]
Therefore, it is necessary to individually set the standard brightness and contrast adjustment amounts and how to limit the user-adjustable brightness and contrast ranges for each liquid crystal display device.
Therefore, it is an object of the present invention to automate setting of a standard brightness and contrast adjustment amount and a user adjustable range of brightness and contrast.
[0007]
[Means for Solving the Problems]
In order to achieve the object, the present invention provides a liquid crystal display module, and a video output signal that is a voltage signal for displaying an image on the liquid crystal display module based on an input video signal and outputs the generated voltage to the liquid crystal display module. And a liquid crystal display system including a display controller having a contrast adjustment function, an output voltage detection unit that detects a voltage of the video output signal, and an adjustment reception unit that receives an input of a luminance and contrast adjustment value from a user. A brightness adjustment unit that controls an adjustment amount of brightness adjustment in the display controller according to the brightness adjustment value received by the adjustment reception unit, and supplies a predetermined test signal to the display controller as the input video signal; The relation between the supplied test signal and the voltage detected by the output voltage detecting means with respect to the test signal is determined. The adjustment amount definition that defines the adjustment amount of the contrast adjustment in the display controller, the adjustment amount of the contrast adjustment in the display controller is such that the voltage range of the video output signal is within the standard of the liquid crystal module, and the adjustment receiving means is An adjustment amount correction unit configured to change according to the received brightness and contrast adjustment values; and an adjustment amount of contrast adjustment in the display controller according to the brightness and contrast adjustment values received by the adjustment reception unit. And a contrast adjusting means for controlling the adjustment amount to be an adjustment amount defined by the adjustment amount definition.
[0008]
According to such a liquid crystal display system, since the output voltage detecting means for detecting the voltage of the video output signal is provided, a predetermined test signal is supplied to the display controller as the input video signal, and the supplied test signal is supplied. And the voltage of the video output signal with respect to the test signal. Then, from the relationship obtained in this manner, the relationship between the contrast adjustment value received by the adjustment receiving unit and the contrast adjustment amount in the display controller is automatically changed to the contrast adjustment amount in the display controller. However, it is possible to appropriately set the voltage range of the video output signal within the standard of the liquid crystal module so as to change according to the brightness and contrast adjustment values received by the adjustment receiving unit.
[0009]
Here, in such a liquid crystal display system, the adjustment amount definition is such that, when the contrast adjustment value received by the adjustment receiving unit is a predetermined value, the contrast adjustment amount in the display controller is It is preferable to define the adjustment amount to be a linear function of the adjustment amount of the brightness adjustment in the display controller.
[0010]
Since the voltage range of the video output signal changes depending on both the adjustment amount of the contrast adjustment and the adjustment amount of the luminance adjustment in the display controller, by defining the adjustment amount of the contrast adjustment in the display controller in this manner. A case where the adjustment range of the contrast adjustment performed in accordance with the contrast adjustment value input by the user is fixed so that the voltage range of the video output signal is within the standard of the liquid crystal module regardless of the brightness adjustment amount. This makes it possible to set a wider adjustment range for contrast adjustment.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a configuration of a liquid crystal display system according to the present embodiment.
As shown in the figure, the present liquid crystal display system includes a control unit 1, an input device 2, an LCD controller 3, a TFT controller 4, an LCD module 5, a D / A converter 6, and an A / D converter 7.
The control unit 1 performs predetermined processing and outputs video data to the LCD controller 3. The LCD controller 3 reads the video data in accordance with the synchronization timing of the LCD module 5, converts the video data into, for example, a 1 Vpp RGB video signal V 1 and outputs the RGB video signal V 1 to the TFT controller 4. The TFT controller 4 generates an RGB video signal V2 of, for example, 5 Vpp, which is obtained by amplifying a video signal input from the LCD controller 3, drives the LCD module 5, and displays a video.
[0012]
Further, the control unit 1 converts the luminance adjustment signal B and the contrast adjustment signal C according to the user's luminance operation value CntB and contrast operation value CntC input from the input device 2 via the D / A converter 6 into a TFT controller. 4 is output. The TFT controller 4 adjusts the voltage offset of the video signal V2, that is, the voltage value of the black level according to the input luminance adjustment signal B, and adjusts the voltage gain based on the black level of the video signal V2, that is, the black level, according to the input contrast adjustment signal C. Adjust the difference between the level and the white level.
[0013]
Further, in such a configuration, the control unit 1 takes in the voltage level of the video signal V2 output from the TFT controller 4 to the LCD module 5 via the A / D converter 7.
Next, FIG. 2 shows an internal functional configuration of the control unit 1.
As shown in the figure, the control unit 1 functionally includes a display data generation unit 11 that performs a predetermined process according to an input from the input device 2 and generates display data to be displayed on the LCD module 5, It comprises a unit 12, a display output control unit 13, an adjustment value correction unit 14, and an adjustment table 15.
[0014]
In such a configuration of the liquid crystal display system, the control unit 1 executes a correction process when instructed to execute the correction via the input device 2 or the like. In the correction process, the display output control unit 13 outputs the test video data generated by the test pattern generation unit 12 to the LCD controller 3, and the adjustment value correction unit 14 outputs, for example, the brightness adjustment signal B and the contrast adjustment signal. While changing the signal C, the voltage value of the video signal V2 detected by the A / D converter 7 is taken into the output test video data. Then, the adjustment value correction unit 14 outputs the user's luminance operation value CntB and contrast operation value CntC input from the input device 2 to the TFT controller 4 based on the relationship between the test video data and the voltage value of the video signal V2. The relationship between the brightness adjustment signal B and the contrast adjustment signal C is determined and set in the adjustment table 15.
[0015]
Then, when such correction is completed, the display output control unit 13 of the control unit 1 outputs the video data generated by the display data generation unit to the LCD controller 3 thereafter. In addition, the adjustment value correction unit 14 outputs a luminance adjustment signal B and a luminance adjustment signal B to be output to the TFT controller 4 from the user's luminance operation value CntB and contrast operation value CntC input from the input device 2 in accordance with the relationship set in the adjustment table 15. A contrast adjustment signal C is obtained and output to the TFT controller 4 via the D / A converter 6.
[0016]
Hereinafter, details of the above-described correction processing will be described.
FIG. 3 shows the relationship between the brightness adjustment signal B and the contrast adjustment signal C that can be adjusted by the user, and the inside of the parallelogram in the figure indicates the range that can be adjusted by the user.
In the correction process, first, four vertices of the parallelogram in the figure are obtained.
That is, for example, the value Bmin of the brightness adjustment signal B at the left vertex of the parallelogram is the brightness at which the voltage of the video signal V2 corresponding to the black level is the minimum voltage possible as the black level determined by the standard of the LCD module 5. It is obtained as the value of the adjustment signal B. Similarly, the value Bmax of the brightness adjustment signal B at the right vertex of the parallelogram is a brightness adjustment value at which the voltage of the video signal V2 corresponding to the black level becomes the maximum voltage possible as the black level determined by the standard of the LCD module 5. It is obtained as the value of signal B.
[0017]
The value CminS of the contrast adjustment signal C at the lower left vertex of the parallelogram is a video signal corresponding to the white level when the value of the brightness adjustment signal B is fixed at Bmin and the contrast adjustment signal C is changed. The voltage of V2 is obtained as the value of the contrast adjustment signal C which is the minimum voltage possible as a white level determined by the standard of the LCD module 5, and the value CmaxS of the contrast adjustment signal C at the upper left vertex of the parallelogram is the brightness adjustment signal. When the value of B is fixed at Bmin and the contrast adjustment signal C is changed, the voltage of the video signal V2 corresponding to the white level becomes the maximum possible voltage as the white level determined by the standard of the LCD module 5. It is obtained as the value of the adjustment signal C. Similarly, the value CminE of the contrast adjustment signal C at the lower right vertex of the parallelogram corresponds to the white level when the value of the brightness adjustment signal B is fixed to Bmax and the contrast adjustment signal C is changed. The voltage of the video signal V2 is determined as the value of the contrast adjustment signal C that is the minimum voltage possible as the white level determined by the standard of the LCD module 5, and the value CmaxE of the contrast adjustment signal C at the upper left vertex of the parallelogram is the luminance. When the value of the adjustment signal B is fixed to Bmax and the contrast adjustment signal C is changed, the voltage of the video signal V2 corresponding to the white level is set to the maximum voltage possible as the white level determined by the standard of the LCD module 5. Is obtained as the value of the contrast adjustment signal C.
[0018]
Now, if the brightness adjustment signal B and the contrast adjustment signal C are swept in an appropriate sequence using an appropriate test pattern in this way, and the four vertices of the parallelogram in the adjustment range are obtained, then the user Is mapped to a combination of the brightness adjustment signal B and the contrast adjustment signal C output to the TFT controller 4. However, without changing the brightness adjustment signal B and the contrast adjustment signal C, four vertices of the parallelogram of the adjustment range may be obtained by calculation from the voltage pattern of the video signal V2 with respect to an appropriate test pattern. .
[0019]
Now, as an example, it is assumed that both the luminance operation value CntB and the contrast operation value CntC of the user take values from 0 to 100.
In this case, the brightness adjustment signal B may be set so that the range from Bmin to Bmax is assigned from 0 to 100.
B = ((Bmax−Bmin) CntB / 100) + Bmin
The luminance operation value CntB of the user is mapped to the luminance adjustment signal B.
[0020]
On the other hand, as understood from FIG. 3, the contrast adjustment signal C needs to change not only the contrast operation value CntC but also the change of the luminance adjustment signal B (therefore, the luminance operation value CntB). When only B is increased without changing C from the state where the position corresponding to a specific combination of C and B is within the parallelogram in the figure, the combination of C and B after the increase corresponds to the combination. This is because the position may be outside the parallelogram. Also, even if the position corresponding to the combination of C and B after the increase does not become a position outside the parallelogram, the amount by which the contrast operation can be performed in the vertical direction after the increase is different from that before the increase. There is also a problem that. That is, for example, from the state where the contrast operation value CntC is 50 and the contrast operation value can be equally changed by 50 in terms of the contrast operation value above and below, if only B is increased, the amount by which the contrast operation is possible is increased Is smaller than the amount by which the contrast operation can be performed on the lower side.
[0021]
Now, assuming that the contrast adjustment signal C is Cs when the luminance adjustment signal B is fixed at Bmin, Cs is only required to divide CminS to CmaxS from 0 to 100.
Cs = ((CmaxS-CminS) CntC / 100) + CminS
The contrast operation value CntC of the user is mapped.
[0022]
When the brightness adjustment signal B is not Bmin, the amount dC by which C is to be changed from Cs in accordance with the deviation of the brightness adjustment signal B from Bmin is obtained from the inclination of the upper and lower sides of the parallelogram,
dc =
(CmaxE-CmaxS) (B-Bmin) / (Bmax-Bmin)
It becomes.
[0023]
Therefore,
C = Cs + dc
By substituting the above equation for Cs and dc, and replacing the brightness adjustment signal B with the function of the brightness operation value CntB described above, the combination of the contrast operation value CntC and the brightness operation value CntB becomes the contrast adjustment signal C Is mapped to
[0024]
Then, the adjustment value correction unit 14 converts the function of mapping the luminance operation value CntB to the luminance adjustment signal B and the combination of the contrast operation value CntC and the luminance operation value CntB obtained by such correction processing into the contrast adjustment signal C. The function to be mapped is stored in the adjustment table 15.
[0025]
The embodiments of the present invention have been described above.
[0026]
【The invention's effect】
As described above, according to the present invention, the present invention can automate the setting of the standard adjustment amount of brightness and contrast and the setting of the user adjustable range of brightness and contrast.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of a liquid crystal display system according to an embodiment of the present invention.
FIG. 2 is a block diagram illustrating a functional configuration of a control unit according to the embodiment of the present invention.
FIG. 3 is a diagram illustrating an outline of a correction process according to the embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Control part, 2 ... Input device, 3 ... LCD controller, 4 ... TFT controller, 5 ... LCD module, 6 ... D / A converter, 7 ... A / D converter, 11 ... Display data generation part, 12 ... Test pattern generation unit, 13: display output control unit, 14: adjustment value correction unit, 15: adjustment table.

Claims (2)

A liquid crystal display module, and a display controller having a brightness and contrast adjustment function that generates a video output signal that is a voltage signal for displaying an image on the liquid crystal display module based on an input video signal and outputs the video output signal to the liquid crystal display module. A liquid crystal display system comprising:
Output voltage detection means for detecting the voltage of the video output signal,
An adjustment receiving unit that receives an input of an adjustment value of brightness and contrast from a user;
A brightness adjustment unit that controls an adjustment amount of brightness adjustment in the display controller in accordance with the brightness adjustment value received by the adjustment reception unit;
A predetermined test signal is supplied to the display controller as the input video signal, and adjustment of contrast adjustment in the display controller is performed based on a relationship between the supplied test signal and a voltage detected by the output voltage detection unit with respect to the test signal. The adjustment amount definition that defines the amount, the adjustment amount of the contrast adjustment in the display controller, the voltage range of the video output signal is within the standard of the liquid crystal module, the brightness and contrast adjustment values received by the adjustment receiving means An adjustment amount correction unit that is set to change according to
Contrast adjusting means for controlling an adjustment amount of contrast adjustment in the display controller in accordance with the brightness and contrast adjustment values received by the adjustment receiving means such that the adjustment amount is an adjustment amount defined by the adjustment amount definition. A liquid crystal display system comprising: The liquid crystal display system according to claim 1, wherein
The adjustment amount definition, when the adjustment value of the contrast received by the adjustment receiving means is a predetermined value, the adjustment amount of the contrast adjustment in the display controller is a linear function of the adjustment amount of the brightness adjustment in the display controller. A liquid crystal display system characterized by the following:

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