JP2004118179A - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display for displaying proper images by stopping over-shooting drive and varying an intensity degree of the over-shooting drive even in the case that an improper image is displayed in the case of performing the over-shooting drive by failure of a device, an installation state of the device, a watching environment or a property of an input image or the like. <P>SOLUTION: The liquid crystal display is provided with an emphatic conversion part 2 finding a stress conversion signal compensating optical response characteristics of a liquid crystal display panel 4 by stress-converting an input image signal in response to combination of gradation transition in before and after one vertical display period of the input image signal, and a changeover switch 19 for selectively changing over any one of the emphatic conversion signal and the input image signal, and supplying to the liquid crystal display panel as a write gradation signal on the basis of an user instruction in the liquid crystal display for displaying an image by using the liquid crystal display panel 4. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a liquid crystal display device for displaying an image using a liquid crystal display panel, and more particularly to a liquid crystal display device capable of improving the optical response characteristics of the liquid crystal display panel.

In recent years, lighter and thinner display devices have been required to reduce the weight and thickness of personal computers and television receivers. In response to such demands, liquid crystal displays (LCDs) have been used instead of cathode ray tubes (CRTs). ) Has been developed.

An LCD applies a desired electric field to a liquid crystal layer having an anisotropic dielectric constant injected between two substrates, and controls the intensity of the electric field to control the amount of light transmitted through the substrates to achieve a desired level. This is a display device for obtaining an image signal. Such LCDs are typical of portable simple flat panel displays. Among them, TFT LCDs using thin film transistors (TFTs) as switching elements are mainly used.

Recently, LCDs have been widely used not only as display devices for computers but also as display devices for television receivers, and thus the need to implement moving images has increased. However, the conventional LCD has a shortcoming that it is difficult to realize a moving image due to a low response speed.

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

FIG. 12 shows a schematic configuration of a conventional overshoot drive circuit. That is, the input image data (Current Data) of the N-th 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 gradation transition pattern of the data and the input image data of the Nth frame are compared with a list of additional voltage data stored in the OS table memory (ROM) 3, and the applied voltage data (emphasis conversion) found by the comparison. Based on the parameters, a write gradation signal (emphasis conversion signal) required for displaying an image of the Nth frame is determined and applied to the liquid crystal display panel 4. Here, the writing gradation determining means is constituted by the emphasis conversion unit 2 and the OS table memory 3.

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 is, 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 is possible to have applied voltage data for all 256 gradations, for example, five representative gradations for every 64 gradations, Alternatively, only the measured values of nine representative gradations for every 32 gradations may be stored, and the other applied voltage data may be obtained from the measured values by an operation such as linear interpolation.

Generally, in a liquid crystal display panel, the time required to change from one halftone to another halftone is long, and the halftone cannot be displayed within one frame period (for example, 16.7 msec in the case of 60 Hz progressive scan). In addition, there is a problem that not only an afterimage is generated but also a halftone cannot be displayed correctly. However, by using the above-described overshoot driving circuit, as shown in FIG. Can be displayed.

Furthermore, it is known that the response speed of the liquid crystal has a very large temperature dependency, so that even if the temperature of the liquid crystal panel changes, the response speed of the gradation change can always be adjusted without deteriorating the display quality. A liquid crystal panel driving device for controlling the liquid crystal panel to an optimum state is described in, for example, Japanese Patent Application Laid-Open No. 4-318516.

This is because a RAM that stores display digital image data for one frame, a temperature sensor that detects the temperature of a liquid crystal panel, and the digital image data are compared with image data that is read from the RAM one frame later, A data conversion circuit for enhancing the current image data in the direction of the change in accordance with the temperature detected by the temperature sensor when the current image data changes compared to the image data of one frame before; The liquid crystal panel is driven for display based on image data output from the circuit.

That is, the temperature of the liquid crystal panel detected by the temperature sensor is set to, for example, three-step values Th, Tm, Tl (Th> Tm> Tl), and the mode signal output from the A / D converter to the data conversion circuit correspondingly. As Mh, Mm, and Ml, and in the ROM of the data conversion circuit, a table of image data having the current image data and the image data delayed by one frame as designated addresses is stored in advance by the number of mode signals “3”. By setting, the table corresponding to the input mode signal is selected, and the image data written in the address position where the current image data and the image data delayed by one frame in the table are designated addresses. And outputs it to the drive circuit of the liquid crystal panel.

Next, FIG. 15 shows a schematic configuration example as viewed from the back surface of the direct type backlight type liquid crystal display device. In FIG. 15, reference numeral 4 denotes a liquid crystal display panel, 11 denotes a fluorescent lamp for irradiating the liquid crystal display panel 4 from the back, 12 denotes an inverter transformer for driving and driving the fluorescent lamp 11, 13 denotes a power supply unit, and 14 denotes a video processing circuit. The board, 15 is a voice processing circuit board, and 16 is a temperature sensor.

(4) 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, the temperature sensor 16 is desirably provided 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 the components 11 to 15 are arranged as shown in FIG. 15, for example, the temperature sensor 16 is attached to the audio processing circuit board 15 which is least affected by the heat generating action of the inverter transformer 12 and the power supply unit 13, The detection output of the temperature sensor 16 is used by an overshoot drive circuit provided on the video processing circuit board 14.
JP-A-4-365094 JP-A-4-318516 JP-A-2002-318516

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

(1) If, for example, 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 input is performed. 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 displayed image is significantly deteriorated, which hinders the viewing of the image.

(2) Further, as described above, the temperature sensor 16 is provided in a place where the heat generation by the other members such as the inverter transformer 12 and the power supply unit 13 is least likely to occur in the normal installation state (stand installation state) shown in FIG. However, for example, in a vertically inverted installation state (ceiling suspended state) as shown in FIG. 16B or a 90-degree rotated installation state (screen vertical and horizontal switching state) as shown in FIG. Since the path of the hot air flow changes, the temperature sensor 16 is greatly affected by the heat generated by other members, and the temperature of the liquid crystal display panel 4 cannot be accurately detected.

As a result, correct applied voltage data (emphasized 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 small applied voltage data (emphasized conversion signal) is supplied to the liquid crystal display panel 4. When supplied, black tailing occurs, or excessive applied voltage data (emphasized conversion signal) is supplied to the liquid crystal display panel 4 to cause white spots of pixels, thereby significantly deteriorating the image quality of the displayed image. I will.

Further, when the liquid crystal display device is installed in a place where, for example, air blown by an air conditioner or a place where direct sunlight of a sunshine shines, the temperature of only a part of the liquid crystal display panel 4 falls or rises, and the liquid crystal display An in-plane temperature distribution of the panel 4 occurs, an error in the temperature detected by the temperature sensor 16 increases, and excessive applied voltage data (emphasized conversion signal) is supplied to the liquid crystal display panel 4 in a part of the area. When the applied voltage data (emphasized conversion signal) is generated or supplied to the liquid crystal display panel 4, the image quality of a displayed image is significantly deteriorated, for example, 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 particularly noticeable when the display screen size is increased.

(3) For example, when image display is performed by inputting / decoding image encoded data that is encoded using an encoding method that performs orthogonal transformation in units of blocks of M × N pixels, the image encoded data Depending on the compression ratio, block distortion in which the boundary of the processing block is visible in the flat part of the decoded image and mosquito noise that makes the noise around the edges of characters and contours may occur. Also, if the overshoot drive is performed, noise is emphasized, and the image quality of the displayed image is deteriorated.

Similarly, even 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 displayed image is degraded. As described above, depending on the properties of the input image, an adverse effect of the overshoot driving occurs, thereby deteriorating the image quality of the display image.

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

A first invention of the present application is a liquid crystal display device that displays an image using a liquid crystal display panel, and converts the input image signal according to a combination of gradation transitions before and after one vertical display period of the input image signal. By performing the emphasis conversion, an emphasis conversion signal for compensating the optical response characteristics of the liquid crystal display panel is obtained, and one of the emphasis conversion signal and the input image signal is selectively switched based on a user instruction, The image processing apparatus further comprises a write gradation determining means for supplying a write gradation signal to the liquid crystal display panel.

According to a second aspect of the present invention, the write gradation determining means converts the input image signal to an optical response characteristic of the liquid crystal display panel according to a combination of gradation transitions before and after one vertical display period of the input image signal. A conversion table memory storing an enhancement conversion parameter for converting to an enhancement conversion signal to be compensated, a subtractor for subtracting the input image signal from the enhancement conversion signal obtained by using the enhancement conversion parameter, and A multiplier that integrates the weighting coefficient k, which is switched and controlled by the output signal of the subtractor, and the output signal of the multiplier is added to the input image signal to determine the write gradation signal. And an adder.

According to a third aspect of the present invention, the writing gradation determining means converts the input image signal into an optical response characteristic of the liquid crystal display panel according to a combination of gradation transitions before and after one vertical display period of the input image signal. A conversion table memory storing an enhancement conversion parameter for converting to an enhanced conversion signal to be compensated, a non-conversion table memory storing a non-conversion parameter for outputting the input image signal as it is, and A switching unit for selectively switching between the conversion table memory and the non-conversion table memory; and a document for determining the write gradation signal by referring to the conversion table memory or the non-conversion table memory switched by the switching unit. And a gradation determining unit.

According to a fourth aspect of the present invention, the writing gradation determining means converts the input image signal into an optical response characteristic of the liquid crystal display panel according to a combination of gradation transitions before and after one vertical display period of the input image signal. The emphasis conversion parameter is stored on the basis of a table memory that stores an emphasis conversion parameter for converting the input image signal into an emphasis conversion parameter for converting the input image signal as it is, and a user instruction. A switching section for selectively switching between a reference table area and a reference table area in which the non-conversion parameter is stored; and a reference table area of the table memory switched by the switching section, thereby obtaining the write floor. A write gradation determining unit for determining a tone signal.

The fifth invention of the present application is a liquid crystal display device that displays an image using a liquid crystal display panel, and converts the input image signal according to a combination of gradation transitions before and after one vertical display period of the input image signal. The emphasis conversion obtains an emphasis conversion signal for compensating the optical response characteristics of the liquid crystal display panel, and varies the emphasis conversion signal based on a user's instruction, and supplies it to the liquid crystal display panel as a write gradation signal. A writing gradation determining means for performing the writing.

According to a sixth aspect of the present invention, the writing gradation determining means converts the input image signal to an optical response characteristic of the liquid crystal display panel according to a combination of gradation transitions before and after one vertical display period of the input image signal. A conversion table memory storing an enhancement conversion parameter for converting to an enhancement conversion signal to be compensated, a subtractor for subtracting the input image signal from the enhancement conversion signal obtained by using the enhancement conversion parameter, and A multiplier that integrates the weighting coefficient k variably controlled by the subtractor with the output signal of the subtractor; and adding the output signal of the multiplier to the input image signal to determine the write gradation signal. And an adder.

According to a seventh aspect of the present invention, the writing gradation determining means converts the input image signal into an optical response characteristic of the liquid crystal display panel according to a combination of gradation transitions before and after one vertical display period of the input image signal. A plurality of conversion table memories storing different enhancement conversion parameters for converting to an enhanced conversion signal to be compensated, and a switching unit for selectively switching one of the plurality of conversion table memories based on a user instruction; A writing gradation determining unit that determines the writing gradation signal by referring to the conversion table memory switched by the switching unit.

According to an eighth aspect of the present invention, the writing gradation determining means converts the input image signal into an optical response characteristic of the liquid crystal display panel according to a combination of gradation transitions before and after one vertical display period of the input image signal. One of the plurality of reference table areas is selectively switched based on a table memory in which different enhancement conversion parameters for converting to an enhanced conversion signal to be compensated are stored for each of a plurality of reference table areas and a user instruction. A switching unit; and a write gradation determining unit that determines the write gradation signal by referring to a reference table area of the table memory switched by the switching unit.

That is, according to the liquid crystal display device of the present invention, it is possible to selectively switch between the enhanced conversion signal and the input image signal based on the user's instruction, and to supply this as a write gradation signal to the liquid crystal display panel. Even if a failure of the overshoot drive occurs due to a failure of the device, an installation state of the device, a viewing environment, or a property of the input image, an appropriate display image can be obtained.

Further, according to the liquid crystal display device of the present invention, the write gradation signal to be supplied to the liquid crystal display panel can be obtained by changing the degree of enhancement of the input image signal based on the user's instruction. Even if a problem of overshoot driving occurs due to the viewing environment or the characteristics of the input image, it is possible to obtain an appropriate display image.

Since the liquid crystal display device of the present invention has the above-described configuration, an improper image is displayed when overshoot drive is performed due to a failure of the device, an installation state of the device, a viewing environment, or a property of an input image. Even in such a case, the overshoot drive can be stopped by the user's instruction or the degree of overshoot drive enhancement conversion can be varied, so that an appropriate write gradation signal is always supplied to the liquid crystal display panel. As a result, it is possible to prevent the image quality of the displayed image from deteriorating.

Hereinafter, the first embodiment of the present invention will be described in detail with reference to FIG. 1 and FIG. 2, but the same parts as those in the above-described conventional example will be denoted by 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 in 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, an OS table in which emphasis conversion parameters LEVEL 0 and LEVEL 1 corresponding to each temperature range of the liquid crystal display panel 4 are stored as write gradation determining means. With reference to one of the memories (ROM) 3a, 3b and the OS table memory (ROM) 3a, 3b, the image signal (Previous Data) of the previous frame stored in the frame memory 1 and the image of the current frame are referred to. An emphasis conversion unit for reading out a corresponding emphasis conversion parameter from a combination (gradation transition) with a signal (Current Data) and determining an emphasis conversion signal for compensating an optical response characteristic of the liquid crystal display panel 4 for an input image signal. 22 and selectively switch between the emphasized conversion signal and the input image signal based on a user instruction input and output as a write gradation signal to be supplied to the liquid crystal display panel 4. And a selector switch (selector) 19.

In the present embodiment, in order to simplify the description, an emphasis conversion parameter LEVEL used as an OS table memory (ROM) when the temperature detected by the temperature sensor 16 is lower than a predetermined threshold temperature as shown in FIG. Two types of ROMs are provided: an OS table memory 3a storing 0 and an OS table memory 3b storing an enhancement conversion parameter LEVEL 1 used when the temperature detected by the temperature sensor 16 is higher than a predetermined threshold temperature. The overshoot drive will be described by switching and referring to FIG. 3. However, it goes without saying that three or more types of ROMs corresponding to three or more predetermined temperature ranges may be provided. .

In the case shown in FIG. 2, when the number of display signal levels, that is, the number of display data is 256 gradations of 8 bits, the emphasis conversion parameter (measured value) for the representative gradation transition pattern for every 32 gradations is set. An image signal that is stored in a 9 × 9 matrix and has an image signal having a gradation other than the representative gradation is obtained by performing an interpolation operation using the emphasized conversion parameter (actually measured value) to obtain the emphasized converted signal. However, it is clear that the present invention is not limited to this.

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

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

Here, as a write gradation signal to be supplied to the liquid crystal display panel 4, a switch 19 for selectively switching and outputting one of the emphasized conversion signal by the emphasizing conversion unit 22 and the input image signal is provided by a user. Switching is controlled by the control CPU 17 based on an instruction signal of “stop overshoot driving” input using a remote controller (not shown) while referring to the setting screen.

That is, during normal use, the overshoot drive is operating, and 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 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 emphasis 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 is degraded due to the occurrence of undesired white spots, the emphasis of noise, the occurrence of black tailing, etc. due to the failure of the device, the installation state of the device, the viewing environment or the nature of the input image, etc. An instruction to stop overshoot driving is input using a remote controller. The instruction signal is received by the remote control light receiving section 18 and analyzed by the control CPU 17, and the changeover switch 19 is controlled so that the input image signal which is not subjected to the enhancement conversion is directly used as a write gradation signal as a liquid crystal display panel. 4

Therefore, even if the overshoot drive is adversely affected due to a failure of the device, the installation state of the device, the viewing environment, the nature of the input image, or the like, the overshoot drive is stopped by the user's judgment. It is possible to cancel the adverse effects of the shoot drive and prevent the image quality of the displayed image from deteriorating.

In the first embodiment described above, the writing gradation determining means is constituted by the emphasis conversion unit 22 and the OS table memories (ROM) 3a and 3b. Instead of providing the OS table memory (ROM), For example, an emphasis conversion signal (writing gradation signal) for compensating the optical response characteristics of the liquid crystal display panel 4 by a two-dimensional function f (pre, cur) using the gradation before transition and the gradation after transition as variables. May be obtained.

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

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

That is, during normal use (during the overshoot driving operation), the control CPU 17 variably controls the weight coefficient of the multiplier 21 to k = 1 ± α in accordance with the temperature detected by the temperature sensor 16, so that the liquid crystal display panel In addition to not only applying appropriate enhancement conversion to the input image signal in accordance with the temperature of step 4 above, when the user inputs an instruction to "stop overshoot driving", the control CPU 17 sets the weight coefficient to By setting k = 0, the input image signal can be directly supplied to the liquid crystal display panel 4 without being subjected to enhancement conversion.

Alternatively, when the adverse effect of the overshoot drive is visually recognized due to the installation state of the apparatus, the viewing environment, the nature of the input image, or the like, the weight coefficient is variably controlled to k = 1 ± α ± β according to a user instruction. In addition, it is possible to supply the liquid crystal display panel 4 with a write gradation signal capable of improving the optical response characteristic (response speed) of the liquid crystal while suppressing the adverse effect of the overshoot drive.

As described above, even when the overshoot drive is adversely affected due to the failure of the device, the installation state of the device, the viewing environment, the nature of the input image, or the like, the document supplied to the liquid crystal display panel 4 is determined by the user. By outputting the input image signal as it is as the embedded gradation signal, or by changing the degree of enhancement of the enhanced conversion signal and outputting the same, it is possible to cancel the adverse effects of the overshoot drive and prevent the image quality of the displayed image from deteriorating. Becomes possible.

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

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

In other words, when the adverse effect of the overshoot drive is visually recognized due to the installation state of the apparatus, the viewing environment, the nature of the input image, or the like, the weight coefficient is variably controlled to k = 1 ± β in accordance with the user's instruction. It is possible to supply the liquid crystal display panel 4 with a write gradation signal capable of improving the optical response characteristics (response speed) of the liquid crystal while suppressing the adverse effects of the shoot drive.

Note that, instead of the multiplier 31, an adder / subtracter for adding / subtracting a predetermined value to / from the enhanced conversion signal by the enhancement converter 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 the enhancement conversion, the control CPU 17 controls the enhancement conversion unit 22 to subtract a predetermined value from the enhancement conversion signal. This can suppress the generation of noise due to the adverse effect of the overshoot drive.

As described above, even when the overshoot drive is adversely affected due to the failure of the device, the installation state of the device, the viewing environment, the nature of the input image, or the like, the document supplied to the liquid crystal display panel 4 is determined by the user. By variably outputting the emphasis conversion signal as the embedded gradation signal and outputting it, it is possible to cancel the adverse effects of the overshoot drive and prevent the image quality of the display image from deteriorating.

Next, a fourth embodiment of the present invention will be described in detail with reference to FIGS. 5 and 6, but the same parts as those in the above-described first embodiment will be denoted by the same reference numerals, and description thereof will be omitted. Here, FIG. 5 is a block diagram showing a schematic configuration of a main part in 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, in the liquid crystal display device of the present embodiment, a non-conversion table memory (ROM) 3c in which non-conversion parameters are stored is added to the write gradation determining means as compared with the first embodiment. And the changeover switch 19 is eliminated. That is, by referring to any of the table memories (ROM) 3 a to 3 c, the emphasis conversion unit (write gradation determination unit) 32 determines a write gradation signal to be supplied to the liquid crystal display panel 4.

Here, the table memories (ROM) 3a to 3c and the table memories (ROM) 3a to 3c are switched and referred to based on a control signal from the control CPU 17 to obtain a write gradation signal to be supplied to the liquid crystal display panel 4. The emphasis conversion section (writing gradation determination section) 32 constitutes a writing gradation determination section.

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

That is, during normal use (at the time of overshoot driving operation), 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, an enhancement conversion parameter corresponding to a combination of gradation transitions before and after one frame period of the input image signal is read out, and an operation such as linear interpolation is performed using the enhancement conversion parameter. In each of the gradation transition patterns, an emphasis conversion signal for the input image signal is obtained and supplied to the liquid crystal display panel 4 as a writing gradation signal.

On the other hand, if the display image is undesirably deteriorated due to the occurrence of white spots, the enhancement of noise, the occurrence of black tailing, etc. due to the failure of the device, the installation state of the device, the viewing environment, the nature of the input image, etc. An instruction to stop overshoot driving is input using a remote controller. The instruction signal is received by the remote control light-receiving unit 18, and the control CPU 17 analyzes the instruction signal and selects and controls the non-conversion table memory 3 c. Is read, and the input image signal is supplied to the liquid crystal display panel 4 as a write gradation signal as it is (through output) without emphasizing conversion.

Therefore, even when the overshoot drive is adversely affected due to a failure of the device, the installation state of the device, the viewing environment, the nature of the input image, or the like, the overshoot drive can be stopped by the user's determination. It is possible to cancel the adverse effects of the overshoot drive and prevent the image quality of the displayed image from deteriorating.

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

The liquid crystal display device of the present embodiment does not include the non-conversion table memory (ROM) 3c as in the above-described fourth embodiment, but, as shown in FIG. Low-temperature and high-temperature enhancement conversion table memories (ROM) 3d and 3e that are referred to when the user gives an instruction to reduce the degree of enhancement conversion, in addition to the enhancement conversion table memories (ROM) 3a and 3b for time. , And low-temperature and high-temperature enhancement conversion table memories (ROM) 3f and 3g which are referred to when the user gives an instruction to increase the degree of enhancement 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 referenced based on a control signal from the control CPU 17, and the liquid crystal display panel 4 is referred to. The writing gradation determining means is composed of an emphasis conversion unit (writing gradation determining unit) 42 for obtaining a writing gradation signal to be supplied to the CPU. As shown in FIG. 8, the OS table memories (ROM) 3d to 3g store enhancement conversion parameters LEVEL 2 to LEVEL 5 corresponding to each temperature range of the liquid crystal display panel 4 for each instruction setting state. ing. Here, it is assumed that the degree of emphasis of each emphasis conversion parameter has a relationship of LEVEL3 <LEVEL1 <LEVEL5 ≦ LEVEL2 <LEVEL0 <LEVEL4.

That is, 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 highlight conversion unit 42 selects the highlight. 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 out, and linear interpolation or the like is performed using the enhancement conversion parameter. By performing the above calculation, an enhanced conversion signal for the input image signal is obtained in all the gradation transition patterns, and this is supplied to the liquid crystal display panel 4 as a writing gradation signal.

On the other hand, the occurrence of white spot noise is recognized depending on the installation state of the apparatus, the viewing environment, the nature of the input image, and the like. If the user gives a setting instruction to reduce the degree of enhancement conversion, this is received by the remote control light receiving unit 18. Then, the control CPU 17 selectively controls one of the OS table memories (ROM) 3d and 3e according to the temperature detected by the temperature sensor 16. The emphasis conversion section 42 refers to one of the selected emphasis conversion table memories (ROM) 3d and 3e and reads out an emphasis conversion parameter corresponding to a combination of gradation transitions before and after one frame period of the input image signal. By performing an operation such as linear interpolation using the emphasis conversion parameter, an emphasis 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 write gradation signal.

The occurrence of black tailing is recognized depending on the installation state of the apparatus, the viewing environment, the nature of the input image, and the like. If a setting instruction to further increase the degree of enhancement conversion is given by the user, this is received by the remote control light receiving unit 18. Then, the control CPU 17 selectively controls one of the OS table memories (ROM) 3f and 3g according to the temperature detected by the temperature sensor 16. The emphasis conversion section 42 refers to one of the selected emphasis conversion table memories (ROM) 3f and 3g and reads out an emphasis conversion parameter corresponding to a combination of gradation transitions before and after one frame period of the input image signal. By performing an operation such as linear interpolation using the emphasis conversion parameter, an emphasis 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 write gradation signal.

As described above, a plurality of emphasis conversion table memories (ROM) storing emphasis conversion parameters LEVEL 2 to LEVEL 5 that can be selected by the user in addition to the emphasis conversion parameters LEVEL 0 and LEVEL 1 optimized at the time of standard use. 3a, 3b, 3d to 3g are provided, and the plurality of emphasis conversion table memories 3a, 3b, 3d to 3g are switched and referred to in accordance with a user's instruction and a temperature detection result, so that an emphasis conversion optimum for the user is performed. It is possible to supply the emphasized converted signal as a write gradation signal to the liquid crystal display panel 4, thereby canceling the adverse effect of overshoot driving due to the installation state of the apparatus, the viewing environment, or the characteristics of the input image. As a result, it is possible to prevent the image quality of the displayed image from deteriorating.

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, but the threshold temperature for switching the emphasis conversion parameter is changed for each user instruction setting. Thus, the emphasis conversion processing may be performed using the same emphasis conversion parameter between the detected temperatures T _{1 and} T ₂ in a certain setting state A and the detected temperatures T _{3 and} T ₄ in another setting state B. good. As described above, by sharing the enhancement conversion parameters used under different setting conditions, it is possible to suppress an increase in the capacity of the table memory (ROM).

Next, a sixth embodiment of the present invention will be described in detail with reference to FIGS. 9 and 10. The same reference numerals are given to the same portions as those in the above-described fourth embodiment, and the description thereof will be omitted. Here, FIG. 9 is a block diagram showing a schematic configuration of a main part in 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 according to the present embodiment includes a single ROM 3h as a table memory, and refers to the table memory (ROM) 3h to enable the enhancement conversion unit (write gradation determination). The unit 52 determines the write gradation signal to be supplied to the liquid crystal display panel 4. Here, the table memory (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 to write the write gradation signal to be supplied to the liquid crystal display panel 4. A writing gradation determining unit is constituted by the required enhancement conversion unit (writing gradation determining unit) 52.

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

That is, based on the control signal from the control CPU 17, the switching control of the reference table area in the table memory (ROM) 3h is performed, and the correspondence of each table area is changed according to the gradation transition around one frame period of the input image signal. By referring to the address to be converted, the emphasis conversion parameters LEVEL 0 and LEVEL 1 and the non-conversion parameter can be selectively switched and read.

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

In addition, when a display image is undesirably deteriorated due to a white spot, noise enhancement, black tailing, or the like due to a failure of the device, an installation state of the device, or a property of the input image, the user operates the remote controller. The instruction input of "stop overshoot drive" is performed using the command. The instruction signal is received by the remote control light-receiving unit 18, the control CPU 17 analyzes the signal, and selects and controls the non-conversion table area of the table memory (ROM) 3 h. The non-conversion parameter is read out with reference to the area, and the input image signal is supplied to the liquid crystal display panel 4 as a write gradation signal as it is (through output) without emphasizing conversion using this parameter.

As described above, even if an undesired white spot or an adverse effect of overshoot driving such as black tailing occurs due to a failure of the device, an installation state of the device, a viewing environment, or a property of an input image, the user can perform the operation. By stopping the overshoot drive according to the determination of the above, it is possible to cancel the adverse effects of the overshoot drive and prevent the image quality of the displayed image from deteriorating.

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

The liquid crystal display device of this embodiment is different from the sixth embodiment in that a plurality of emphasis conversion parameters LEVEL 0 to LEVEL 5 used for each instruction setting are stored in place of the table memory (ROM) 3 h having a non-conversion table area. Is provided with a table memory (ROM) 3i having a reference table area. Here, the table memory (ROM) 3i and the table area in the table memory (ROM) 3i are switched and referenced based on a control signal from the control CPU 17 to obtain a write gradation signal to be supplied to the liquid crystal display panel 4. The writing gradation determining means is constituted by the emphasis conversion section (writing gradation determining section).

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

That is, during use in the normal setting (standard setting), one of the conversion table areas storing the emphasis conversion parameters LEVEL 0 and LEVEL 1 of the table memory 3 i is selected according to the temperature detected by the temperature sensor 16. The enhancement conversion unit refers to any one of the selected conversion table areas, reads 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 such an operation as above, an emphasis 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.

The occurrence of white spot noise is recognized depending on the installation state of the apparatus, the viewing environment, the nature of the input image, and the like. If the user gives a setting instruction to reduce 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 the table memory 3i in which the enhancement conversion parameters LEVEL 2 and LEVEL 3 are stored in accordance with the temperature detected by the temperature sensor 16. The enhancement conversion unit refers to any one of the selected conversion table areas, reads 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 such an operation as above, an emphasis 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, the occurrence of black tailing is recognized depending on the installation state of the apparatus, the viewing environment, the nature of the input image, and the like, and when a setting instruction to further increase the degree of enhancement conversion is given by the user, 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 the table memory 3i in which the enhancement conversion parameters LEVEL 4 and LEVEL 5 are stored in accordance with the temperature detected by the temperature sensor 16. The enhancement conversion unit refers to any one of the selected conversion table areas, reads any enhancement conversion parameter corresponding to a combination of gradation transitions before and after one frame period of the input image signal, and uses the enhancement conversion parameter. By performing an operation such as linear interpolation, an emphasis 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.

As described above, in addition to the emphasis parameters LEVEL 0 and LEVEL 1 optimized at the time of standard use, a plurality of reference table areas storing LEVEL 2 to LEVEL 5 which can be selected by the user are stored in a single table memory. A plurality of table areas that are switched and referred to in accordance with a user's instruction and a temperature detection result, so that an enhanced conversion signal that has been subjected to optimum enhancement conversion for the user can be used as a write gradation signal as a write gradation signal. 4, it is possible to cancel the adverse effect of the overshoot drive caused by the installation state of the apparatus, the viewing environment, the nature of the input image, and the like, thereby preventing the image quality of the display image from deteriorating. .

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, but the threshold temperature for switching the emphasis conversion parameter is changed for each user instruction setting. Thus, the emphasis conversion process may be performed using the same emphasis conversion parameter when detecting temperatures T _{1 to} T ₂ in a certain setting state A and when detecting temperatures T _{3 to} T ₄ in another setting state B. good. As described above, by sharing the enhancement conversion parameters used under different setting conditions, it is possible to suppress an increase in the capacity of the table memory (ROM).

Also, in each of the embodiments of the present invention described above, the user inputs a user instruction regarding ON / OFF of overshoot drive or the degree of enhancement conversion of overshoot drive using the remote controller with reference to the menu setting screen. Needless to say, a configuration may be employed in which a user's instruction is input using an operation unit provided in the apparatus main body.

Further, the user is not limited to directly selecting "overshoot drive ... strong / weak / none" on the menu setting screen. For example, the user is allowed to select "noise clean ... on / off" to overshoot. The degree of overshoot drive enhancement conversion may be variably controlled by performing drive on / off control or by allowing the user to select a “noise clean level” or a “afterimage cancel level”.

FIG. 1 is a block diagram illustrating a schematic configuration of a main part of a liquid crystal display device according to a first embodiment of the present invention. FIG. 3 is a schematic explanatory diagram showing table contents of an OS table memory used in the first embodiment of the liquid crystal display device of the present invention. FIG. 13 is a block diagram illustrating another configuration example of the write gradation determining unit in the second embodiment of the liquid crystal display device of the present invention. FIG. 11 is a block diagram illustrating a schematic configuration of a main part of a liquid crystal display device according to a third embodiment of the present invention. FIG. 14 is a block diagram illustrating a schematic configuration of a main part of a liquid crystal display device according to a fourth embodiment of the present invention. FIG. 14 is a schematic explanatory diagram showing table contents of a non-conversion table memory used in a fourth embodiment of the liquid crystal display device of the present invention. FIG. 14 is a block diagram illustrating a schematic configuration of a main part of a liquid crystal display device according to a fifth embodiment of the present invention. It is an explanatory view showing an emphasis conversion parameter level referred in each state in a 5th embodiment of a liquid crystal display device of the present invention. FIG. 16 is a block diagram illustrating a schematic configuration of a main part of a liquid crystal display device according to a sixth embodiment of the present invention. It is a schematic explanatory view showing the contents of the table of the table memory used for the sixth embodiment of the liquid crystal display device of the present invention. It is a schematic explanatory view showing the contents of a table of a table memory used for a 7th embodiment of a liquid crystal display of the present invention. FIG. 11 is a block diagram illustrating a schematic configuration of an overshoot drive circuit in a conventional liquid crystal display device. FIG. 4 is a schematic explanatory diagram showing an example of table contents in an OS table memory used for an overshoot drive circuit. FIG. 4 is an explanatory diagram illustrating a relationship between a voltage applied to the liquid crystal and a response of the liquid crystal. It is an explanatory view showing a schematic configuration example viewed from the back of a liquid crystal display device of a direct backlight type. It is explanatory drawing which shows the (a) normal installation state, (b) upside down installation state, and (c) 90 degree rotation installation state of a liquid crystal display device.

Explanation of reference numerals

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

Claims (8)

A liquid crystal display device that displays an image using a liquid crystal display panel,
According to a combination of gradation transitions before and after one vertical display period of the input image signal, the input image signal is emphasized and converted to obtain an emphasized conversion signal for compensating the optical response characteristic of the liquid crystal display panel.
A write gradation determining means for selectively switching one of the emphasized conversion signal and the input image signal based on a user instruction and supplying the selected signal to the liquid crystal display panel as a write gradation signal. Characteristic liquid crystal display device. The liquid crystal display device according to claim 1,
The write gradation determining means converts the input image signal into an emphasized conversion signal for compensating optical response characteristics of the liquid crystal display panel in accordance with a combination of gradation transitions before and after one vertical display period of the input image signal. A conversion table memory storing enhancement conversion parameters for
A subtractor for subtracting the input image signal from the enhanced conversion signal determined using the enhancement conversion parameter,
A multiplier for integrating a weighting factor k, which is switched and controlled based on a user instruction, to an output signal of the subtractor;
A liquid crystal display device comprising: an adder that determines the write gradation signal by adding an output signal of the multiplier to the input image signal. The liquid crystal display device according to claim 1,
The write gradation determining means converts the input image signal into an emphasized conversion signal for compensating optical response characteristics of the liquid crystal display panel in accordance with a combination of gradation transitions before and after one vertical display period of the input image signal. A conversion table memory storing enhancement conversion parameters for
A non-conversion table memory storing non-conversion parameters for directly outputting the input image signal,
A switching unit that selectively switches between the conversion table memory and the non-conversion table memory based on a user instruction;
A liquid crystal display device comprising: a write gradation determining unit that determines the write gradation signal by referring to the conversion table memory or the non-conversion table memory switched by the switching unit. The liquid crystal display device according to claim 1,
The write gradation determining means converts the input image signal into an emphasized conversion signal for compensating optical response characteristics of the liquid crystal display panel in accordance with a combination of gradation transitions before and after one vertical display period of the input image signal. A table memory storing an enhancement conversion parameter for and a non-conversion parameter for outputting the input image signal as it is,
A switching unit configured to selectively switch between a reference table area in which the enhancement conversion parameter is stored and a reference table area in which the non-conversion parameter is stored, based on a user instruction;
A liquid crystal display device comprising: a write gradation determining unit that determines the write gradation signal by referring to a reference table area of the table memory switched by the switching unit. A liquid crystal display device that displays an image using a liquid crystal display panel,
According to a combination of gradation transitions before and after one vertical display period of the input image signal, the input image signal is emphasized and converted to obtain an emphasized conversion signal for compensating the optical response characteristic of the liquid crystal display panel.
A liquid crystal display device comprising: a write gradation determining unit that varies the emphasized conversion signal based on a user instruction and supplies the emphasized conversion signal to the liquid crystal display panel as a write gradation signal. The liquid crystal display device according to claim 5,
The write gradation determining means converts the input image signal into an emphasized conversion signal for compensating optical response characteristics of the liquid crystal display panel in accordance with a combination of gradation transitions before and after one vertical display period of the input image signal. A conversion table memory storing enhancement conversion parameters for
A subtractor for subtracting the input image signal from the enhanced conversion signal determined using the enhancement conversion parameter,
A multiplier for integrating a weighting coefficient k variably controlled based on a user instruction into an output signal of the subtractor;
A liquid crystal display device comprising: an adder that determines the write gradation signal by adding an output signal of the multiplier to the input image signal. The liquid crystal display device according to claim 5,
The write gradation determining means converts the input image signal into an emphasized conversion signal for compensating optical response characteristics of the liquid crystal display panel in accordance with a combination of gradation transitions before and after one vertical display period of the input image signal. A plurality of conversion table memories storing different enhancement conversion parameters for
A switching unit for selectively switching one of the plurality of conversion table memories based on a user instruction;
A liquid crystal display device comprising: a write gradation determining unit that determines the write gradation signal by referring to the conversion table memory switched by the switching unit. The liquid crystal display device according to claim 5,
The write gradation determining means converts the input image signal into an emphasized conversion signal for compensating optical response characteristics of the liquid crystal display panel in accordance with a combination of gradation transitions before and after one vertical display period of the input image signal. A table memory storing different enhancement conversion parameters for each of a plurality of reference table areas,
A switching unit that selectively switches one of the plurality of reference table areas based on a user instruction;
A liquid crystal display device comprising: a write gradation determining unit that determines the write gradation signal by referring to a reference table area of the table memory switched by the switching unit.

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