JP2005070799A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device which suppresses degradation in quality of display images by stopping overshoot drive or varying the degree of emphasis of overshoot drive in the case that improper images are displayed in response to execution of overshoot drive because of a fault of the device, an installation state of the device, an environment of viewing, properties of an input image, or the like. <P>SOLUTION: The liquid crystal display device is provided with; a means which obtains an emphasized and converted signal by emphasizing and converting an input image signal in accordance with a combination of tone transitions of one vertical period before and after of the input image signal; a means which displays a setting picture for selecting and setting the emphasized and converted signal or the input image signal as a signal to be supplied to a liquid crystal display panel; and a means which selectively switches one of the emphasized and converted signal and the input image signal on the basis of user's setting indication and supplies the switched signal to the liquid crystal display panel. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display device that displays an image using a liquid crystal display panel, and more particularly to a liquid crystal display device that can improve the optical response characteristics of the liquid crystal display panel.

  In recent years, display devices have also been required to be lighter and thinner due to lighter and thinner personal computers and television receivers. In accordance with such demands, liquid crystal display devices (LCDs) instead of cathode ray tubes (CRTs) have been demanded. ) Flat panel displays have been developed.

  The LCD applies an electric field to a liquid crystal layer having an anisotropic dielectric constant injected between two substrates, and adjusts the amount of light transmitted through the substrate by adjusting the strength of the electric field. A display device that obtains an image signal. Such LCDs are representative of portable and simple flat panel displays. Among these, TFT LCDs using thin film transistors (TFTs) as switching elements are mainly used.

  Recently, since the LCD is widely used not only as a display device of a computer but also as a display device of a television receiver, the necessity of implementing a moving image has increased. However, the conventional LCD has a drawback that it is difficult to implement a moving image because of a slow response speed.

  In order to improve such a response speed problem of the liquid crystal, a predetermined gradation voltage for the input image signal of the current frame is determined according to the combination of the input image signal of the previous frame and the input image signal of the current frame. There is known a liquid crystal driving method for supplying a high (overshooted) driving voltage or a lower (undershooted) driving voltage to a liquid crystal display panel. Hereinafter, in this specification, this driving method is defined as overshoot (OS) driving.

  A schematic configuration of a conventional overshoot drive circuit is shown in FIG. That is, the input image data (Current Data) of the Nth frame to be displayed and the input image data (Previous Data) of the (N−1) th frame stored in the frame memory 1 are read out to the emphasis conversion unit 2. The applied voltage data (emphasis conversion) found by comparing the gradation transition pattern of the data and the input image data of the Nth frame with the additional voltage data list stored in the OS table memory (ROM) 3 Based on the parameter), a writing gradation signal (enhancement conversion signal) required for image display of the Nth frame is determined and applied to the liquid crystal display panel 4. Here, the emphasis conversion unit 2 and the OS table memory 3 constitute a writing gradation determination means.

  Here, the applied voltage data (emphasis conversion parameter) stored in the OS table memory 3 is obtained in advance from the actual measurement value of the optical response characteristic of the liquid crystal display panel 4, and for example, the number of display signal levels, that is, the display When the number of data is 256 gradations of 8 bits, as shown in FIG. 13, it may have applied voltage data for all 256 gradations, for example, 5 representative gradations for every 64 gradations, Alternatively, only actual measurement values for nine representative gradations for every 32 gradations may be stored, and the other applied voltage data may be obtained from the actual measurement values by calculation such as linear interpolation.

  Generally, in a liquid crystal display panel, it takes a long time to change from one halftone to another halftone, and the halftone cannot be displayed within one frame period (for example, 16.7 msec for 60 Hz progressive scan). In addition to the occurrence of afterimages, there is a problem that halftones cannot be displayed correctly. However, by using the above-described overshoot drive circuit, the target halftone can be reduced for a short time as shown in FIG. Can be displayed.

  Furthermore, it is known that the response speed of the liquid crystal is very temperature-dependent, and even if the temperature of the liquid crystal panel changes, the response speed of the gradation change is always adjusted without compromising the display quality. A liquid crystal panel driving device for controlling to an optimum state is described in, for example, Japanese Patent Laid-Open No. 4-318516.

  This compares the RAM for storing the digital image data for display for one frame, the temperature sensor for detecting the temperature of the liquid crystal panel, the digital image data and the image data read from the RAM with a delay of one frame, A data conversion circuit for emphasizing and converting the current image data in the direction of change according to the temperature detected by the temperature sensor when the current image data changes compared to the image data of the previous frame; The liquid crystal panel is driven to display based on image data output from the circuit.

That is, the temperature of the liquid crystal panel detected by the temperature sensor is, for example, a three-stage value Th, Tm, Tl (Th>Tm> Tl), and the A / D converter outputs a mode signal to the data conversion circuit corresponding to this. Mh, Mm, Ml, and the ROM of the data conversion circuit stores in advance a table of image data having the current image data and the image data delayed by one frame as a designated address for the number of mode signals “3”. By setting, a table corresponding to the input mode signal is selected, and the image data written in the address position with the current image data and the image data delayed by one frame in the table as the designated address Is output to the drive circuit of the liquid crystal panel.

  Next, FIG. 15 shows a schematic configuration example viewed from the back of a direct-type backlight type liquid crystal display device. In FIG. 15, 4 is a liquid crystal display panel, 11 is a fluorescent lamp for irradiating the liquid crystal display panel 4 from the back surface, 12 is an inverter transformer for driving the fluorescent lamp 11 to light, 13 is a power supply unit, and 14 is a video processing circuit. A substrate, 15 is an audio processing circuit substrate, and 16 is a temperature sensor.

  Here, the inverter transformer 12 and the power supply unit 13 have a heat generating effect that greatly affects the response speed characteristics of the liquid crystal display panel 4. On the other hand, it is desirable to provide the temperature sensor 16 in the liquid crystal display panel 4 for its original purpose. However, since this is difficult, it is necessary to attach the temperature sensor 16 to another member such as a circuit board.

Therefore, when each of the structural members 11 to 15 is arranged as shown in FIG. The detection output of the temperature sensor 16 is used in an overshoot drive circuit provided on the video processing circuit board 14.
Japanese Patent Laid-Open No. 4-365094 JP-A-4-318516 JP 2002-318516 A

  However, the conventional liquid crystal display device described above has the following problems.

  (1) For example, when the applied voltage data (emphasis conversion parameter) stored in the OS table memory 3 itself is destroyed or an arithmetic algorithm such as linear interpolation in the enhancement conversion unit 2 is destroyed due to a device failure The correct applied voltage data (enhanced conversion signal) corresponding to the image signal cannot be supplied to the liquid crystal display panel 4, and the image quality of the display image is significantly deteriorated, which hinders viewing of the image.

  (2) Also, as described above, the temperature sensor 16 is provided in a place where it is least susceptible to heat generation by other members such as the inverter transformer 12 and the power supply unit 13 in the normal installation state (stand installation state) shown in FIG. However, for example, in the case of a vertically inverted installation state (ceiling suspended state) as shown in FIG. 16B or a 90-degree rotational installation state (screen vertical / horizontal switching state) as shown in FIG. 16C, Since the path of the hot airflow is changed, the temperature sensor 16 is greatly affected by the heat generation action by other members, and the temperature of the liquid crystal display panel 4 cannot be accurately detected.

  As a result, the correct applied voltage data (enhanced conversion signal) corresponding to the temperature of the liquid crystal display panel 4 cannot be supplied to the liquid crystal display panel 4, and too little applied voltage data (enhanced conversion signal) is supplied to the liquid crystal display panel 4. The image quality of the display image is significantly deteriorated, such as black tailing occurs, excessive applied voltage data (enhanced conversion signal) is supplied to the liquid crystal display panel 4 and pixel whitening occurs. End up.

  Further, when the liquid crystal display device is installed, for example, in a place exposed to air blow from an air conditioner or in a place exposed to direct sunlight, the temperature of only a part of the liquid crystal display panel 4 is decreased or increased. An in-plane temperature distribution of the panel 4 occurs, an error in temperature detected by the temperature sensor 16 increases, and excessive applied voltage data (emphasis conversion signal) is supplied to the liquid crystal display panel 4 in a part of the area, and a white point is generated. The image quality of the display image is significantly deteriorated, for example, when the applied voltage data (enhanced conversion signal) is supplied to the liquid crystal display panel 4 and black tailing occurs. The problem of the in-plane temperature distribution of the liquid crystal display panel 4 due to the installation location (viewing environment) becomes prominent particularly when the display screen size is increased.

  (3) Also, for example, when image display is performed by inputting / decoding image encoded data encoded using an encoding method that performs orthogonal transform in units of M × N pixels, image encoded data Depending on the compression ratio, block distortion in which the boundary of the processing block can be seen at the flat part of the decoded image, and mosquito noise that is moire around the edges of characters and outlines may occur. However, when overshoot driving is performed, noise is emphasized and the quality of the display image is deteriorated.

  Similarly, when an image signal with a poor S / N is input, if overshoot driving is performed, noise is emphasized and the image quality of the display image is deteriorated. In this way, depending on the nature of the input image, the adverse effect of overshoot drive occurs and the image quality of the display image is impaired.

  The present invention has been made in view of the above problems, and an inappropriate image is displayed when overshoot driving is performed depending on the failure of the device, the installation state of the device, the viewing environment, or the nature of the input image. In such a case, the present invention provides a liquid crystal display device capable of suppressing deterioration in image quality of a display image by stopping overshoot driving or changing the degree of overshoot driving enhancement.

  A first invention of the present application is a liquid crystal display device that displays an image using a liquid crystal display panel, and emphasizes the input image signal according to a combination of gradation transitions before and after one vertical period of the input image signal. Means for converting and obtaining an enhanced conversion signal; and means for displaying a setting screen for selecting and setting either the enhanced conversion signal or the input image signal as a signal to be supplied to the liquid crystal display panel; And a means for selectively switching one of the enhancement conversion signal and the input image signal based on a setting instruction by a user and supplying the signal to the liquid crystal display panel.

  A second invention of the present application is a liquid crystal display device that displays an image using a liquid crystal display panel, and emphasizes the input image signal according to a combination of gradation transitions before and after one vertical period of the input image signal. Means for converting and obtaining an enhanced conversion signal; means for displaying a setting screen for variably setting the degree of enhancement conversion with respect to the input image signal as a signal to be supplied to the liquid crystal display panel; and a setting instruction by a user And a means for changing the degree of enhancement conversion with respect to the input image signal and supplying it to the liquid crystal display panel.

  Since the liquid crystal display device of the present invention is configured as described above, an inappropriate image is displayed when overshoot drive is performed due to device failure, device installation state, viewing environment, or input image properties. Even in such a case, the overshoot drive can be stopped by the user's instruction, and the emphasis conversion degree of the overshoot drive can be changed, so that an appropriate writing gradation signal is always supplied to the liquid crystal display panel. As a result, it is possible to prevent image quality deterioration of the display image.

  Hereinafter, the first embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2, but the same parts as those in the conventional example are given the same reference numerals, and the description thereof will be omitted. Here, FIG. 1 is a block diagram showing a schematic configuration of a main part of the liquid crystal display device of the present embodiment, and FIG. 2 is a schematic explanatory diagram showing table contents of an OS table memory used in the liquid crystal display device of the present embodiment.

  In the liquid crystal display device of the present embodiment, as shown in FIG. 1, the OS table storing emphasis conversion parameters LEVEL 0 and LEVEL 1 corresponding to each temperature range of the liquid crystal display panel 4 as writing gradation determination means. Referring to one of the memories (ROM) 3a and 3b and the OS table memory (ROM) 3a and 3b, the image signal (Previous Data) of the previous frame stored in the frame memory 1 and the image of the current frame An enhancement conversion unit for reading an enhancement conversion parameter corresponding to a combination (tone transition) with a signal (Current Data) and determining an enhancement conversion signal for compensating an optical response characteristic of the liquid crystal display panel 4 with respect to an input image signal. 22 and based on a user instruction input, the enhancement conversion signal and the input image signal are selectively switched and output as a writing gradation signal to be supplied to the liquid crystal display panel 4 And a selector switch (selector) 19 that.

  In the present embodiment, in order to simplify the explanation, as shown in FIG. 2, the emphasis conversion parameter LEVEL used when the temperature detected by the temperature sensor 16 is lower than a predetermined threshold temperature as an OS table memory (ROM). Two types of ROM are provided: an OS table memory 3a storing 0 and an OS table memory 3b storing an emphasis conversion parameter LEVEL 1 used when the temperature detected by the temperature sensor 16 is higher than a predetermined threshold temperature. However, it is needless to say that three or more types of ROM corresponding to each of three or more predetermined temperature ranges may be provided. .

  2 shows the emphasis conversion parameters (measured values) for representative gradation transition patterns for every 32 gradations when the number of display signal levels, that is, the number of display data is 256 gradations of 8 bits. For an image signal stored in a 9 × 9 matrix and having gradations other than the representative gradation, an enhancement conversion signal is obtained by performing interpolation using the enhancement conversion parameter (actual measurement value). However, it is clear that this is not a limitation.

  Further, the temperature sensor 16 for detecting the temperature of the liquid crystal display panel 4 is preferably provided so as to be able to detect the temperature of the liquid crystal display panel 4 as much as possible for that purpose. Each may be provided at a different position in the apparatus.

  In the present embodiment, a control CPU 17 that switches and selects the OS table memories 3a and 3b as appropriate based on the temperature of the liquid crystal display panel 4 detected by the temperature sensor 16 is provided. Furthermore, a remote control light receiving unit 18 that receives an instruction signal input by a user using a remote controller (remote controller) (not shown) is provided. The control CPU 17 analyzes the instruction signal received by the remote control light receiving unit 18 and performs each processing. Control part.

  Here, the changeover switch 19 for selectively switching and outputting either the emphasis conversion signal by the emphasis conversion unit 22 or the input image signal as the writing gradation signal supplied to the liquid crystal display panel 4 is displayed by the user on the menu. The control CPU 17 performs switching control based on an “overshoot drive stop” instruction signal input using a remote controller (not shown) while referring to the setting screen.

  That is, during normal use, the overshoot drive operates, and the OS table memories 3a and 3b are switched and selected according to the detected temperature detected by the temperature sensor 16, and the selected OS is selected. By referring to the table memories 3a and 3b, an enhancement conversion parameter corresponding to a combination of gradation transitions before and after one frame period of the input image signal is read, and an operation such as linear interpolation is performed using the enhancement conversion parameter. An enhancement conversion signal for the input image signal is obtained for all gradation transition patterns, and this is supplied to the liquid crystal display panel 4 as a writing gradation signal.

  If the display image deteriorates due to undesired white spots, noise enhancement, black tailing, etc. due to device failure, device installation status, viewing environment or input image properties, the user Use the remote control to input “Stop overshoot drive”. This instruction signal is received by the remote control light-receiving unit 18, and the control CPU 17 analyzes it and controls the changeover switch 19 to change the input image signal not subjected to emphasis conversion as a writing gradation signal as it is as a liquid crystal display panel. 4 is supplied.

  Therefore, even if the overshoot drive is adversely affected by the failure of the device, the installation state of the device, the viewing environment or the nature of the input image, the overshoot drive is stopped by the user's judgment. It is possible to cancel the adverse effect of the shoot drive and prevent the deterioration of the image quality of the display image.

  In the first embodiment described above, the emphasis conversion unit 22 and the OS table memories (ROMs) 3a and 3b constitute the writing gradation determination means, but instead of providing the OS table memory (ROM). For example, an emphasis conversion signal (writing gradation signal) that compensates for the optical response characteristics of the liquid crystal display panel 4 by a two-dimensional function f (pre, cur) having the gradation before transition and the gradation after transition as variables. It is good also as composition which asks for.

  Next, the second embodiment of the present invention will be described in detail with reference to FIG. 3, but the same parts as those of the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted. Here, FIG. 3 is a block diagram showing the writing gradation determining means in the liquid crystal display device of the present embodiment.

  As shown in FIG. 3, the liquid crystal display device according to the present embodiment is an emphasis conversion unit 2 that obtains an emphasis conversion signal based on an emphasis conversion parameter read from, for example, an OS table memory (ROM) 3 as a writing gradation determination unit. A subtracter 20 that subtracts the input image signal from the enhancement conversion signal obtained by the enhancement conversion unit 2, a multiplier 21 that adds a weighting factor k to the output signal of the subtractor 20, and an output of the multiplier 21 An adder 22 for obtaining a writing gradation signal to be supplied to the liquid crystal display panel 4 by adding the signal to the input image signal is provided. Based on the control signal from the control CPU 17, the weight coefficient k By switching and controlling the value of, the writing gradation signal supplied to the liquid crystal display panel 4 can be variably controlled.

  That is, during normal use (overshoot driving operation), the control CPU 17 variably controls the weighting factor of the multiplier 21 to k = 1 ± α according to the temperature detected by the temperature sensor 16, whereby the liquid crystal display panel. In addition to being able to perform appropriate enhancement conversion according to the temperature of 4 on the input image signal, the control CPU 17 sets a weighting factor when an instruction of “stop overshoot driving” is input by the user. By setting k = 0, the input image signal can be supplied as it is to the liquid crystal display panel 4 without performing enhancement conversion.

  Alternatively, when the adverse effect of overshoot drive is visually recognized due to the installation state of the device, viewing environment, or the nature of the input image, the weight coefficient is variably controlled to k = 1 ± α ± β according to a user instruction. Therefore, it is possible to supply the liquid crystal display panel 4 with a writing gradation signal that can improve the optical response characteristics (response speed) of the liquid crystal while suppressing the adverse effects of overshoot driving.

  As described above, the document supplied to the liquid crystal display panel 4 at the discretion of the user even if the overshoot drive is adversely affected by the failure of the device, the installation state of the device, the viewing environment or the nature of the input image. By outputting the input image signal as it is, or by changing the enhancement degree of the enhancement conversion signal as the embedded gradation signal, the adverse effects of the overshoot drive can be canceled and image quality deterioration of the display image can be prevented. Is possible.

  Next, the third embodiment of the present invention will be described in detail with reference to FIG. 4, but the same parts as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted. Here, FIG. 4 is a block diagram showing a schematic configuration of the main part of the liquid crystal display device of the present embodiment.

  As shown in FIG. 4, the liquid crystal display device according to the present embodiment is provided with a multiplier 31 that integrates the weighting coefficient k into the enhancement conversion signal by the enhancement conversion unit 22 instead of the changeover switch 19 in the first embodiment. The write gradation signal supplied to the liquid crystal display panel 4 can be variably controlled by switching and controlling the value of the weight coefficient k based on a control signal from the control CPU 17. .

  That is, when the adverse effect of overshoot drive is visually recognized due to the installation state of the device, viewing environment or the nature of the input image, the weight coefficient is variably controlled to k = 1 ± β according to a user instruction. It is possible to supply the liquid crystal display panel 4 with a writing gradation signal that can improve the optical response characteristic (response speed) of the liquid crystal while suppressing the harmful effects of the chute drive.

  Instead of the multiplier 31, an adder / subtracter for adding / subtracting a predetermined value to / from the enhancement conversion signal by the enhancement conversion unit 22 based on a control signal from the control CPU 17 may be provided. For example, when the occurrence of noise due to over-emphasis of the input image signal is visually recognized and the user gives an instruction to reduce the degree of enhancement conversion, the control CPU 17 performs control so as to subtract a predetermined value from the enhancement conversion signal by the enhancement conversion unit 22. As a result, the generation of noise due to the adverse effects of overshoot driving can be suppressed.

  As described above, the document supplied to the liquid crystal display panel 4 at the discretion of the user even if the overshoot drive is adversely affected by the failure of the device, the installation state of the device, the viewing environment or the nature of the input image. By outputting the emphasis conversion signal with the emphasis conversion signal varied as a grayscale signal, it is possible to cancel the adverse effects of the overshoot drive and prevent the image quality of the display image from deteriorating.

  Next, the fourth embodiment of the present invention will be described in detail with reference to FIGS. 5 and 6. The same reference numerals are given to the same parts as those of the above-described first embodiment, and the description thereof will be omitted. Here, FIG. 5 is a block diagram showing a schematic configuration of the main part of the liquid crystal display device of the present embodiment, and FIG. 6 is a schematic explanatory diagram showing table contents of a non-conversion table memory used in the liquid crystal display device of the present embodiment.

  As shown in FIG. 5, the liquid crystal display device according to the present embodiment is added with a non-conversion table memory (ROM) 3c storing non-conversion parameters in the writing gradation determination means, as compared with the first embodiment. The changeover switch 19 is abolished. That is, by referring to any one of the table memories (ROM) 3 a to 3 c, the emphasis conversion unit (write tone determination unit) 32 determines a write tone signal to be supplied to the liquid crystal display panel 4.

  Here, the table memory (ROM) 3a to 3c and the table memory (ROM) 3a to 3c are switched and referred to based on the control signal from the control CPU 17, and the writing gradation signal to be supplied to the liquid crystal display panel 4 is obtained. The enhancement conversion unit (writing gradation determination unit) 32 constitutes a writing gradation determination unit.

  As shown in FIG. 6, the non-conversion table memory (ROM) 3c stores non-conversion parameters for outputting the input image signal as it is without performing emphasis conversion. The non-conversion table memory 3c is selected. In this case, the input image signal is output as it is. Further, the conversion table memories 3a and 3b and the non-conversion table memory 3c are selectively switched based on a user instruction input for reference.

  That is, during normal use (during overshoot drive operation), either one of the OS table memories 3a and 3b is switched and selected according to the temperature detected by the temperature sensor 16, and the emphasis conversion unit 32 selects the selected OS table memory 3a. 3b, by reading out enhancement conversion parameters corresponding to combinations of gradation transitions before and after one frame period of the input image signal, and performing operations such as linear interpolation using the enhancement conversion parameters The enhancement conversion signal for the input image signal is obtained for all gradation transition patterns, and this is supplied to the liquid crystal display panel 4 as a writing gradation signal.

  On the other hand, if the display image deteriorates due to the occurrence of white spots, noise enhancement, black tailing, etc. due to device failure, device installation status, viewing environment or input image properties, etc. Use the remote control to input “Stop overshoot drive”. This instruction signal is received by the remote control light receiving unit 18, and the control CPU 17 analyzes this and selects and controls the non-conversion table memory 3 c, so that the emphasis conversion unit 32 refers to the non-conversion table memory 3 c and does not convert the non-conversion parameters. , And the input image signal is supplied to the liquid crystal display panel 4 as a writing gradation signal without being emphasized and converted (through output).

  Therefore, even if the trouble of overshoot drive occurs due to the failure of the device, the installation state of the device, the viewing environment or the nature of the input image, the overshoot drive can be stopped at the user's judgment, It is possible to cancel the adverse effects of the overshoot drive and prevent image quality deterioration of the display image.

  Next, the fifth embodiment of the present invention will be described in detail with reference to FIGS. 7 and 8, but the same parts as those in the above-described fourth embodiment are denoted by the same reference numerals, and the description thereof is omitted. Here, FIG. 7 is a block diagram showing a schematic configuration of a main part of the liquid crystal display device of the present embodiment, and FIG. 8 is an explanatory diagram showing emphasis conversion parameter levels referred to in each state in the liquid crystal display device of the present embodiment.

  The liquid crystal display device according to the present embodiment does not include the non-conversion table memory (ROM) 3c as in the fourth embodiment described above, but as shown in FIG. In addition to the emphasis conversion table memories (ROM) 3a and 3b for time, the emphasis conversion table memories (ROM) 3d and 3e for low temperature and high temperature that are referred to when the user gives an instruction to reduce the degree of emphasis conversion. , And the emphasis conversion table memories (ROM) 3f and 3g for low temperature and high temperature, which are referred to when the user gives an instruction to increase the degree of emphasis conversion.

  Here, the OS table memories (ROM) 3a, 3b, 3d to 3g and the OS table memories (ROM) 3a, 3b, 3d to 3g are switched and referred to based on a control signal from the control CPU 17, and the liquid crystal display panel 4 is switched. A writing gradation determining means is constituted by an emphasis conversion unit (writing gradation determining unit) 42 for obtaining a writing gradation signal to be supplied to. Further, as shown in FIG. 8, the OS table memories (ROM) 3d to 3g store enhancement conversion parameters LEVEL 2 to LEVEL 5 corresponding to the respective temperature ranges of the liquid crystal display panel 4 for each instruction setting state. ing. Here, it is assumed that the emphasis degree of each emphasis conversion parameter has a relationship of LEVEL 3 <LEVEL 1 <LEVEL 5 ≦ LEVEL 2 <LEVEL 0 <LEVEL 4.

  In other words, during use in the normal setting (standard setting), one of the OS table memories (ROM) 3a and 3b is selected according to the temperature detected by the temperature sensor 16, and the emphasis conversion unit 42 selects the selected emphasis. With reference to one of the conversion table memories (ROM) 3a and 3b, an enhancement conversion parameter corresponding to a combination of gradation transitions before and after one frame period of the input image signal is read, and linear interpolation or the like is performed using this enhancement conversion parameter. By performing this calculation, an enhancement conversion signal for the input image signal is obtained for all gradation transition patterns, and this is supplied to the liquid crystal display panel 4 as a writing gradation signal.

  On the other hand, when the generation of white spot noise is recognized depending on the installation state of the apparatus, the viewing environment or the nature of the input image, and the user gives a setting instruction to reduce the degree of enhancement conversion, this is received by the remote control light receiving unit 18. The control CPU 17 selects and controls one of the OS table memories (ROM) 3d and 3e according to the temperature detected by the temperature sensor 16. The enhancement conversion unit 42 reads out enhancement conversion parameters corresponding to combinations of gradation transitions before and after one frame period of the input image signal with reference to any of the selected enhancement conversion table memories (ROM) 3d and 3e. By performing operations such as linear interpolation using the enhancement conversion parameter, an enhancement conversion signal for the input image signal is obtained in all gradation transition patterns, and this is supplied to the liquid crystal display panel 4 as a writing gradation signal.

  In addition, when the occurrence of black tailing is recognized depending on the installation state of the apparatus, the viewing environment or the nature of the input image, and the user gives a setting instruction to further increase the degree of enhancement conversion, this is received by the remote control light receiving unit 18. The control CPU 17 selects and controls one of the OS table memories (ROM) 3f and 3g according to the temperature detected by the temperature sensor 16. The enhancement conversion unit 42 reads out enhancement conversion parameters corresponding to combinations of gradation transitions before and after one frame period of the input image signal with reference to any of the selected enhancement conversion table memories (ROM) 3f and 3g. By performing operations such as linear interpolation using the enhancement conversion parameter, an enhancement conversion signal for the input image signal is obtained in all gradation transition patterns, and this is supplied to the liquid crystal display panel 4 as a writing gradation signal.

  As described above, a plurality of emphasis conversion table memories (ROM) storing emphasis conversion parameters LEVEL 2 to LEVEL 5 selectable by the user in addition to the emphasis conversion parameters LEVEL 0 and LEVEL 1 that are optimized during standard use. 3a, 3b, 3d to 3g are provided, and the plurality of enhancement conversion table memories 3a, 3b, 3d to 3g are switched and referred to according to the user instruction and the temperature detection result, thereby performing optimum enhancement conversion for the user. The emphasized conversion signal can be supplied to the liquid crystal display panel 4 as a writing gradation signal, so that the adverse effects of overshoot driving caused by the installation state of the device, the viewing environment or the nature of the input image are cancelled. As a result, it is possible to prevent image quality deterioration of the display image.

  In the above embodiment, the emphasis conversion parameters LEVEL 0 to LEVEL 5 corresponding to each temperature range are individually provided for each user instruction setting. However, the threshold temperature for switching the emphasis conversion parameters is changed for each user instruction setting. Thus, the emphasis conversion process may be performed using the same emphasis conversion parameter at the detection temperatures T1 to T2 in a certain setting state A and at the detection temperatures T3 to T4 in another setting state B. As described above, by sharing the emphasis conversion parameters used under different setting conditions, it is possible to suppress an increase in the capacity of the table memory (ROM).

  Next, the sixth embodiment of the present invention will be described in detail with reference to FIG. 9 and FIG. 10, but the same parts as those of the above-described fourth embodiment will be denoted by the same reference numerals, and the description thereof will be omitted. Here, FIG. 9 is a block diagram showing a schematic configuration of the main part of the liquid crystal display device of the present embodiment, and FIG. 10 is a schematic explanatory diagram showing table contents in a table memory used in the liquid crystal display device of the present embodiment.

  As shown in FIG. 9, the liquid crystal display device of the present embodiment includes a single ROM 3h as a table memory. By referring to this table memory (ROM) 3h, an emphasis conversion unit (determining writing gradation) Part) 52 is configured to determine a writing gradation signal to be supplied to the liquid crystal display panel 4. Here, the table gradation (ROM) 3h and the reference table area in the table memory (ROM) 3h are switched and referenced based on the control signal from the control CPU 17, and the writing gradation signal supplied to the liquid crystal display panel 4 is obtained. A writing gradation determination means is constituted by the desired enhancement conversion section (writing gradation determination section) 52.

  In this table memory (ROM) 3h, as shown in FIG. 10, the low-temperature emphasis conversion parameter LEVEL 0, the high-temperature emphasis conversion parameter LEVEL 1, and the non-conversion parameter are stored in separate table areas. The conversion table area in which the emphasis conversion parameters LEVEL 0 and LEVEL 1 are stored and the non-conversion table area in which no conversion parameters are stored are selectively switched based on the user's instruction input and referred to. Yes.

  That is, the reference table area in the table memory (ROM) 3h is switched and controlled based on a control signal from the control CPU 17, and the correspondence between each table area is determined in accordance with the gradation transition around one frame period of the input image signal. By referring to the address to be read, the emphasis conversion parameters LEVEL 0, LEVEL 1 and no conversion parameter can be selectively switched and read.

  Therefore, during normal use (during overshoot drive operation), one of the conversion table areas in which the emphasis conversion parameters LEVEL 0 and LEVEL 1 of the table memory (ROM) 3h are stored is selected according to the temperature detected by the temperature sensor 16. Then, the enhancement conversion unit 52 reads out the enhancement conversion parameter corresponding to the combination of gradation transitions before and after one frame period of the input image signal with reference to any of the selected conversion table regions, By performing operations such as linear interpolation, an enhancement conversion signal for the input image signal is obtained in all gradation transition patterns, and this is supplied to the liquid crystal display panel 4 as a writing gradation signal.

  In addition, if the display image deteriorates undesirably due to the occurrence of white spots, noise enhancement, black tailing, etc. due to device failure, device installation status, or the nature of the input image, the user can use the remote control. Use to input “Stop overshoot drive”. This instruction signal is received by the remote control light receiving unit 18, and the control CPU 17 analyzes this and selects and controls the non-conversion table area of the table memory (ROM) 3 h, whereby the emphasis conversion unit 42 selects the selected non-conversion table. The non-conversion parameter is read with reference to the area, and the input image signal is used as it is (through-output) without being subjected to the emphasis conversion using this, and is supplied to the liquid crystal display panel 4 as a writing gradation signal.

  As described above, even when the trouble of the overshoot drive such as generation of an undesired white spot or black tailing occurs due to the failure of the device, the installation state of the device, the viewing environment or the nature of the input image, the user By stopping the overshoot drive based on this determination, it is possible to cancel the adverse effects of the overshoot drive and prevent the image quality of the display image from deteriorating.

  Next, the seventh embodiment of the present invention will be described in detail with reference to FIG. 11. However, the same parts as those in the above-described sixth embodiment are denoted by the same reference numerals, and the description thereof is omitted. Here, FIG. 11 is a schematic explanatory diagram showing the table contents of the table memory used in the liquid crystal display device of the present embodiment.

  In the sixth embodiment, the liquid crystal display device according to the present embodiment stores a plurality of emphasis conversion parameters LEVEL 0 to LEVEL 5 used for each instruction setting instead of the table memory (ROM) 3h having a non-conversion table area. Table memory (ROM) 3i having a reference table area. Here, the table gradation in the table memory (ROM) 3i and the table area in the table memory (ROM) 3i are switched and referred to based on the control signal from the control CPU 17, and the writing gradation signal to be supplied to the liquid crystal display panel 4 is obtained. The emphasis conversion unit (writing tone determination unit) constitutes writing tone determination means.

  In this table memory (ROM) 3i, as shown in FIG. 11, when low-temperature and high-temperature enhancement conversion parameters LEVEL 0 and LEVEL 1 used in the normal setting state are instructed by the user to reduce the degree of enhancement conversion. The low-temperature and high-temperature emphasis conversion parameters LEVEL 2 and LEVEL 3 used, and the low-temperature and high-temperature emphasis conversion parameters LEVEL 4 and LEVEL 5 used when the user gives an instruction to increase the degree of emphasis conversion are separate tables. The table area stored in the area and storing the emphasis conversion parameters LEVEL 0 to LEVEL 5 is selectively switched based on a user instruction and referred to.

  That is, at the time of use in the normal setting (standard setting), one of the conversion table areas in which the emphasis conversion parameters LEVEL 0 and LEVEL 1 of the table memory 3i are stored is selected depending on the temperature detected by the temperature sensor 16. The enhancement conversion unit refers to one of the selected conversion table areas, reads out an enhancement conversion parameter corresponding to a combination of gradation transitions before and after one frame period of the input image signal, and performs linear interpolation using the enhancement conversion parameter. By performing operations such as these, an enhancement conversion signal for the input image signal is obtained for all gradation transition patterns, and this is supplied to the liquid crystal display panel 4 as a writing gradation signal.

  Further, when the occurrence of white spot noise is recognized depending on the installation state of the apparatus, viewing environment or the nature of the input image, and the user gives a setting instruction to reduce the degree of enhancement conversion, this is received by the remote control light receiving unit 18. The control CPU 17 selects and controls one of the conversion table areas in which the emphasis conversion parameters LEVEL 2 and LEVEL 3 of the table memory 3i are stored in accordance with the temperature detected by the temperature sensor 16. The enhancement conversion unit refers to one of the selected conversion table areas, reads out an enhancement conversion parameter corresponding to a combination of gradation transitions before and after one frame period of the input image signal, and performs linear interpolation using the enhancement conversion parameter. By performing operations such as these, an enhancement conversion signal for the input image signal is obtained for all gradation transition patterns, and this is supplied to the liquid crystal display panel 4 as a writing gradation signal.

  Further, when the occurrence of black tailing is recognized depending on the installation state of the device, the viewing environment or the nature of the input image, and the user gives a setting instruction to further increase the degree of enhancement conversion, this is received by the remote control light receiving unit 18. Then, the control CPU 17 selects and controls one of the conversion table areas in which the emphasis conversion parameters LEVEL 4 and LEVEL 5 of the table memory 3 i are stored in accordance with the temperature detected by the temperature sensor 16. The enhancement conversion unit refers to any of the selected conversion table areas, reads one of the enhancement conversion parameters corresponding to the combination of gradation transitions before and after one frame period of the input image signal, and uses this enhancement conversion parameter. By performing operations such as linear interpolation, an enhancement conversion signal for the input image signal is obtained in all gradation transition patterns, and this is supplied to the liquid crystal display panel 4 as a writing gradation signal.

  As described above, in addition to the emphasis parameters LEVEL 0 and LEVEL 1 optimized during standard use, multiple reference table areas that store user selectable LEVEL 2 to LEVEL 5 are stored in a single table memory. An emphasis conversion signal that has been subjected to emphasis conversion optimum for the user by switching and referring to the plurality of table areas according to a user instruction and a temperature detection result is provided as a writing gradation signal on the liquid crystal display panel. 4, it is possible to cancel the adverse effects of overshoot driving caused by the installation state of the device, viewing environment, or the nature of the input image, and prevent deterioration in the image quality of the display image. .

  In the above embodiment, the emphasis conversion parameters LEVEL 0 to LEVEL 5 corresponding to each temperature range are individually provided for each user instruction setting. However, the threshold temperature for switching the emphasis conversion parameters is changed for each user instruction setting. Thus, the emphasis conversion process may be performed using the same emphasis conversion parameter when the temperature T1 to T2 is detected in a certain setting state A and when the temperature T3 to T4 is detected in another setting state B. As described above, by sharing the emphasis conversion parameters used under different setting conditions, it is possible to suppress an increase in the capacity of the table memory (ROM).

  Further, in each of the embodiments of the present invention, the description has been given of the case where the user inputs the instruction regarding the overshoot drive on / off or the overshoot drive enhancement conversion degree by using the remote controller while referring to the menu setting screen. It goes without saying that a user instruction input may be performed using an operation unit provided in the apparatus main body.

  Further, the menu setting screen is not limited to the one that allows the user to directly select “overshoot drive ... strong / weak / none”. For example, by causing the user to select “noise clean… on / off”, the overshoot is performed. The on / off control of driving may be performed, or the “noise clean level” and “afterimage cancellation level” may be selected to variably control the enhancement conversion degree of overshoot driving.

  As described above, in the embodiment of the present invention, a liquid crystal display device that displays an image using a liquid crystal display panel, the input image signal corresponding to a combination of gradation transitions before and after one vertical period. An enhancement conversion signal that compensates for the optical response characteristics of the liquid crystal display panel is obtained by enhancement conversion of the image signal, and either the enhancement conversion signal or the input image signal is selectively selected based on a user instruction. And a writing gradation determining means for supplying to the liquid crystal display panel.

  In addition, the writing gradation determining means may convert the input image signal into an optical response of the liquid crystal display panel according to a combination of gradation transitions before and after one vertical period of the input image signal. A conversion table memory storing an enhancement conversion parameter for conversion to an enhancement conversion signal that compensates for characteristics; a subtractor that subtracts the input image signal from the enhancement conversion signal obtained using the enhancement conversion parameter; and a user instruction A multiplier that integrates a weighting coefficient that is controlled to switch to the output signal of the subtractor, and a document that is supplied to the liquid crystal display panel by adding the output signal of the multiplier to the input image signal. And an adder for determining a grayscale signal.

  Further, the writing gradation determining means converts the input image signal into an enhanced conversion signal that compensates for the optical response characteristic of the liquid crystal display panel according to a combination of gradation transitions before and after one vertical period of the input image signal. A conversion table memory storing emphasis conversion parameters, a non-conversion table memory storing non-conversion parameters for outputting the input image signal as it is, and the conversion table memory and the non-conversion based on a user instruction A switching unit that selectively switches between table memories and a writing unit that determines a writing gradation signal to be supplied to the liquid crystal display panel by referring to the conversion table memory or the non-conversion table memory switched by the switching unit And a gradation determining unit.

  Further, the writing gradation determining means converts the input image signal into an enhanced conversion signal that compensates for the optical response characteristic of the liquid crystal display panel according to a combination of gradation transitions before and after one vertical period of the input image signal. A table memory storing emphasis conversion parameters for conversion and a non-conversion parameter for outputting the input image signal as it is; a reference table area storing the emphasis conversion parameters based on a user instruction; A switching unit that selectively switches between reference table areas in which no-conversion parameters are stored, and a writing floor that is supplied to the liquid crystal display panel by referring to the reference table area of the table memory switched by the switching unit. And a writing gradation determining unit that determines a tone signal.

  Further, a liquid crystal display device that displays an image using a liquid crystal display panel, wherein the input image signal is emphasized and converted according to a combination of gradation transitions before and after one vertical period of the input image signal. An enhancement conversion signal that compensates for an optical response characteristic of the liquid crystal display panel is obtained, and a writing gradation determination unit that varies the enhancement conversion signal based on a user instruction and supplies the enhancement conversion signal to the liquid crystal display panel is provided. And

  Further, the writing gradation determining means converts the input image signal into an enhanced conversion signal that compensates for the optical response characteristic of the liquid crystal display panel according to a combination of gradation transitions before and after one vertical period of the input image signal. Conversion table memory for storing enhancement conversion parameters, a subtractor for subtracting the input image signal from the enhancement conversion signal obtained using the enhancement conversion parameter, and a weighting coefficient variably controlled based on a user instruction Are added to the output signal of the subtractor, and an adder that determines a writing gradation signal to be supplied to the liquid crystal display panel by adding the output signal of the multiplier to the input image signal. It is characterized by having.

  Further, the writing gradation determining means converts the input image signal into an enhanced conversion signal that compensates for the optical response characteristic of the liquid crystal display panel according to a combination of gradation transitions before and after one vertical period of the input image signal. A plurality of conversion table memories storing different emphasis conversion parameters for conversion, a switching unit for selectively switching one of the plurality of conversion table memories based on a user instruction, and switching by the switching unit And a writing gradation determining unit that determines a writing gradation signal to be supplied to the liquid crystal display panel by referring to the conversion table memory.

  Further, the writing gradation determining means converts the input image signal into an enhanced conversion signal that compensates for the optical response characteristic of the liquid crystal display panel according to a combination of gradation transitions before and after one vertical period of the input image signal. A table memory storing different emphasis conversion parameters for each of a plurality of reference table areas, a switching section for selectively switching one of the plurality of reference table areas based on a user instruction, and the switching section And a writing gradation determination unit that determines a writing gradation signal to be supplied to the liquid crystal display panel by referring to the reference table area of the table memory switched by the above.

  That is, according to the liquid crystal display device according to the embodiment of the present invention, the emphasis conversion signal and the input image signal are selectively switched based on a user instruction and supplied to the liquid crystal display panel as a writing gradation signal. Therefore, an appropriate display image can be obtained even in the case where the trouble of overshoot drive occurs due to the failure of the device, the installation state of the device, the viewing environment or the nature of the input image.

  Further, according to the liquid crystal display device according to the embodiment of the present invention, the writing gradation signal to be supplied to the liquid crystal display panel can be obtained by changing the enhancement degree of the input image signal based on the user instruction. Therefore, an appropriate display image can be obtained even if the overshoot drive is adversely affected by the installation state, viewing environment, or the nature of the input image.

It is a block diagram which shows the principal part schematic structure in 1st Embodiment of the liquid crystal display device of this invention. It is a schematic explanatory drawing which shows the table content of OS table memory used for 1st Embodiment of the liquid crystal display device of this invention. It is a block diagram which shows the other structural example of the writing gradation determination means in 2nd Embodiment of the liquid crystal display device of this invention. It is a block diagram which shows the principal part schematic structure in 3rd Embodiment of the liquid crystal display device of this invention. It is a block diagram which shows the principal part schematic structure in 4th Embodiment of the liquid crystal display device of this invention. It is a schematic explanatory drawing which shows the table content of the non-conversion table memory used for 4th Embodiment of the liquid crystal display device of this invention. It is a block diagram which shows the principal part schematic structure in 5th Embodiment of the liquid crystal display device of this invention. It is explanatory drawing which shows the emphasis conversion parameter level referred in each state in 5th Embodiment of the liquid crystal display device of this invention. It is a block diagram which shows the principal part schematic structure in 6th Embodiment of the liquid crystal display device of this invention. It is a schematic explanatory drawing which shows the table content of the table memory used for 6th Embodiment of the liquid crystal display device of this invention. It is a schematic explanatory drawing which shows the table content of the table memory used for 7th Embodiment of the liquid crystal display device of this invention. It is a block diagram which shows schematic structure of the overshoot drive circuit in the conventional liquid crystal display device. It is a schematic explanatory drawing which shows an example of the table content in OS table memory used for an overshoot drive circuit. It is explanatory drawing which shows the relationship between the voltage applied to a liquid crystal, and the response of a liquid crystal. It is explanatory drawing which shows the schematic structural example seen from the back surface of the liquid crystal display device of a direct type backlight system. It is explanatory drawing which shows (a) normal installation state, (b) upside down installation state, and (c) 90 degree rotation installation state of a liquid crystal display device.

Explanation of symbols

1 frame memory 2, 22, 32, 42, 52 enhancement conversion unit 3a conversion table memory for low temperature 3b conversion table memory for high temperature 3c non-conversion table memory 3d conversion table memory for low temperature 3e conversion table memory for high temperature 3f conversion table memory for low temperature 3g Conversion table memory for high temperature 3h Table memory 3i Table memory 4 Liquid crystal display panel 16 Temperature sensor 17 Control CPU
18 Remote control light receiving portion 19 Changeover switch 20 Subtractor 21, 31 Multiplier 23 Adder

Claims (2)

A liquid crystal display device that displays an image using a liquid crystal display panel,
Means for emphasizing the input image signal in accordance with a combination of gradation transitions before and after one vertical period of the input image signal to obtain an emphasis conversion signal;
Means for displaying a setting screen for selecting and setting either the enhancement conversion signal or the input image signal as a signal to be supplied to the liquid crystal display panel;
A liquid crystal display device comprising: means for selectively switching one of the enhancement conversion signal and the input image signal based on a setting instruction by a user and supplying the signal to the liquid crystal display panel. A liquid crystal display device that displays an image using a liquid crystal display panel,
Means for emphasizing the input image signal in accordance with a combination of gradation transitions before and after one vertical period of the input image signal to obtain an emphasis conversion signal;
Means for displaying a setting screen for variably setting the degree of enhancement conversion for the input image signal;
A liquid crystal display device comprising: means for changing an enhancement conversion degree with respect to the input image signal based on a setting instruction by a user and supplying the degree of enhancement conversion to the liquid crystal display panel.

Images