JP2006323311A - Display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display apparatus capable of performing a more stable and appropriate correction without increasing the number of parts. <P>SOLUTION: All pixels are rendered into a white display mode; and not the reflected light from a document but illumination light from a backlight is detected by a light accepting element of a liquid crystal display/reading panel 20. A microcontroller 6 calculates the light quantity of the backlight based on a detected voltage outputted from a detector 23, compares the calculated light quantity with a reference light quantity, produces a correction value to correct the light quantity of the backlight to reduce the difference, and outputs the value to an inverter circuit 5. The controller calculates a deviation of luminance from an average in each pixel, generates a correction value in each pixel to compensate the calculated deviation and outputs the value to an image correcting unit 3. Further, the controller generates a correction value to correct lightness in each of RGB colors in display image data to control the luminance averages of the respective colors to be in a predetermined balance, and outputs the correction value to the image correcting unit 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention includes a display panel having a display element for displaying an image and a light receiving element for receiving light, and a light source for irradiating the display panel with light. The present invention relates to a display device capable of reading a document image.

  A display device typified by a liquid crystal display device realizes not only a display function for displaying still images and moving images but also a high-performance display device for various purposes by adding other functions. .

  Functions added to the display device include an input interface function using a touch panel as a coordinate input device and an image scanner function using an image sensor as an image reading device.

  The display input integrated device with an image sensor described in Patent Document 1 has a structure in which a transparent and flat image sensor is superimposed on a display input integrated device in which a coordinate input device and a flat display device are integrated. Yes. This apparatus can read paper information with an image sensor and display it on a screen, and can draw a line or take notes on an image with a coordinate input device. In the reading procedure by the image sensor, the paper to be read is placed on the screen of the apparatus, all the liquid crystal displays are turned on so that light can be transmitted, the backlight is turned on, and the reflected light from the paper is detected.

  Furthermore, a liquid crystal display device has been developed that incorporates an optical sensor (image sensor) in a liquid crystal panel by SOG (system on glass) and can capture an image without separately superimposing the image sensors.

  In a display device having such an image scanner function, it is necessary to correct image display such as luminance and color tone unevenness caused by a built-in light source such as a backlight and ambient light in both display and reading of an image.

  Conventionally, a backlight light amount detection sensor and an ambient light amount detection sensor are individually provided, and correction by feedback control is performed according to detection results from these sensors.

JP-A-5-173709

  When correction is performed by separately providing a light amount detection sensor, the number of parts increases, so that many problems remain, such as a complicated manufacturing process, an increase in device scale, and an increase in manufacturing cost.

  Further, depending on the position and number of the light amount detection sensors, a stable detection result cannot be obtained, and there is a possibility that appropriate correction cannot be performed.

  An object of the present invention is to provide a display device that can perform more stable and appropriate correction without increasing the number of parts.

The present invention includes a display panel having a display element for displaying an image and a light receiving element for receiving light, and a light source for irradiating the display panel with light. A display device capable of reading a document image,
Light source driving means for driving the light source;
Display control means for displaying an image on the display panel based on the input display image data;
A light amount detection means for detecting the amount of light emitted from the light source by the light receiving element receiving light emitted from the light source;
A display device comprising: control means for controlling operations of the light source driving means and the display control means based on a detection result of the light quantity detection means.

The present invention also includes a display panel having a display element for displaying an image and a light receiving element for receiving light, and a light source for irradiating the display panel with light, and displaying input display image data And a display device capable of reading a document image,
Light source driving means for driving the light source;
Display control means for displaying an image on the display panel based on the input display image data;
A light amount detecting means for detecting the amount of light emitted from the external light by receiving the external light applied to the display panel from outside the display device;
A display device comprising: control means for controlling operations of the light source driving means and the display control means based on a detection result of the light quantity detection means.

  Further, the present invention is characterized in that the control means controls the operation of the light source driving means so that the luminance of each pixel of the display panel is constant based on the detection result of the light quantity detection means.

In the present invention, the display control unit includes a data changing unit that changes the input display image data.
The control unit causes the data change unit to change display image data based on a detection result of the light amount detection unit.

Further, according to the present invention, the display panel includes a display element and a light receiving element for each pixel,
The light amount detecting means performs detection using all light receiving elements built in the display panel.

Further, according to the present invention, the display panel includes a display element and a light receiving element for each pixel,
The light quantity detection means performs detection using a light receiving element of a pixel not involved in image display.

Further, the present invention, the light amount detection means includes a light source light detection unit that detects an irradiation light amount of the light source, or an external light detection unit that detects the irradiation light amount of the external light,
The light source light detection unit includes a light receiving element of a pixel not involved in image display, a reflective material provided on the opposite side of the light source so as to cover the light receiving element, and a light shielding provided so as to cover the reflective material. With materials,
The external light detection unit includes a light receiving element of a pixel that does not participate in image display, and a light shielding material provided between the light source and the light receiving element so as to cover the light receiving element.

In the present invention, the light amount detection means outputs output values output from a plurality of light receiving elements to the control means as detection results,
The control unit calculates the plurality of average values when controlling operations of the light source driving unit and the display control unit based on the plurality of output values input from the light amount detection unit, and calculates the average An output value whose difference from the value is equal to or greater than a predetermined value is not used for controlling operations of the light source driving unit and the display control unit.

  According to the present invention, a display panel including a display element for displaying an image and a light receiving element for receiving light, and a light source for irradiating the display panel with light, the display element is used to display the display. The display device can display display image data input to the panel and read a document image placed on the display panel using a light receiving element.

  The light source is driven by a light source driving unit, and the display control unit displays an image on the display panel based on input display image data.

  When the light receiving element receives the light emitted from the light source and the light amount detecting means detects the amount of light emitted from the light source, the control means, based on the detection result of the light amount detecting means, the light source driving means and The operation of the display control means is controlled.

  As a result, a change in the amount of light emitted from the light source to the display panel is detected using a light receiving element built in the display panel for reading a document image, so that an appropriate image can be obtained without increasing the number of parts. Display correction can be performed.

  According to the invention, there is provided a display panel having a display element for displaying an image and a light receiving element for receiving light, and a light source for irradiating the display panel with light, and the display element is used to The display device can display display image data input to the display panel and read a document image placed on the display panel using a light receiving element.

  The light source is driven by a light source driving unit, and the display control unit displays an image on the display panel based on input display image data.

  When the light receiving element detects the amount of irradiation light of the external light by receiving external light irradiated on the display panel from the outside of the display device, the control unit, based on the detection result of the light amount detection unit, The operation of the light source driving means and the display control means is controlled.

  This makes it possible to detect changes in external light radiated to the display panel from the outside of the display device using a light receiving element built in the display panel for reading a document image, thereby increasing the number of components. In addition, appropriate image display correction can be performed according to the brightness and color environment around the apparatus.

According to the invention, the control unit controls the operation of the light source driving unit so that the luminance of each pixel of the display panel is constant based on the detection result of the light amount detection unit.
Thereby, it is possible to perform correction so as to eliminate the luminance unevenness of the display panel.

According to the invention, the display control unit includes a data changing unit that changes the input display image data, and the control unit displays the data on the data changing unit based on the detection result of the light amount detecting unit. Thus, the color tone of the image displayed on the display panel can be corrected by changing the display image data.

According to the invention, the display panel includes a display element and a light receiving element for each pixel, and the light amount detection unit performs detection using all the light receiving elements built in the display panel.
This makes it possible to perform stable and appropriate correction over the entire display panel.

According to the invention, the display panel includes a display element and a light receiving element for each pixel, and the light amount detection unit performs detection using the light receiving elements of the pixels not involved in image display.
As a result, the image display can be corrected even while the image is being displayed.

  According to the invention, the light amount detection means includes a light source light detection unit that detects an irradiation light amount of the light source or an external light detection unit that detects an irradiation light amount of the external light.

  The light source light detection unit is provided with a light-receiving element and a reflective material and a light-shielding material on the opposite side of the light source so as to cover the light-receiving element, thereby eliminating the influence of the external light and irradiating from the light source. The amount of light to be detected can be detected.

  The external light detection unit is provided with a light shielding material provided so as to cover the light receiving element between the light source and a light receiving element of a pixel not involved in image display, thereby affecting the influence of light emitted from the light source. Thus, the amount of external light can be detected.

  According to the invention, the light quantity detection means outputs output values output from a plurality of light receiving elements to the control means as detection results, and the control means outputs a plurality of outputs input from the light quantity detection means. Based on the value, the operation of the light source driving means and the display control means is controlled. At this time, the control means calculates the plurality of average values, and an output value whose difference from the calculated average value is not less than a predetermined value is not used for controlling the operation of the light source driving means and the display control means. .

  Among output values output from the light receiving element, an output value whose difference from the average value is a predetermined value or more is likely to be a defective element for some reason. By eliminating the output value, more accurate image display correction can be performed.

In the present invention, for example, a TFT (Thin that can read an original image in an image display area)
This is realized by a liquid crystal display device of a film transistor type. In such a display device, a display element such as a TFT and a light receiving element for reading an image are formed on the same substrate of the display panel. In the case of displaying an image, the optical characteristics of the light emitted from the backlight as the light source are changed by operating the TFT and changing the alignment state of the liquid crystal. When reading an image, the original placed in the display area is irradiated with light from the backlight, and the reflected light is detected by the light receiving element.

  If the light emitted from the light source is uneven, or the light guide plate and the reflection plate are not uniform, the luminance of the display area is uneven, and the displayed image has a color shift. In the present invention, by using a light receiving element built in the display panel, detecting backlight light and ambient light around the device, and controlling at least the operation of the light source or the display element based on the detection result, The image display is corrected.

  FIG. 1 is a block diagram showing a configuration of a display device 1 according to the first embodiment of the present invention. The display device 1 displays an image in a display area based on input display image data, and outputs read image data based on an image read from a document. Here, the display image data and the read image data are composed of a plurality of pixels, and each pixel has a pixel value such as brightness, density, and chromaticity and a coordinate value indicating a position in the image data.

  The display device 1 includes an image display / reading module 2, an image correction unit 3, a timing generation unit 4, an inverter circuit 5, a microcontroller 6, and an operation panel 7.

  The image display / reading module 2 includes a liquid crystal display / reading panel 20, a source driver 21, a gate driver 22, a detector 23, and a backlight 24.

  The liquid crystal display / reading panel 20 is an existing TFT type liquid crystal display panel in which a light receiving element is formed in each pixel region. The source driver 21 and the gate driver 22 drive the source line and the gate line of the liquid crystal display / read panel 20 at a predetermined voltage and timing based on the display data and the line shift timing data output from the timing generation unit 4. The TFT is operated. The detector 23 is a light amount detecting unit that is connected to the source line, amplifies the photocurrent generated in each light receiving element of the liquid crystal display / reading panel 20, and outputs a detection voltage as a detection result to the microcontroller 6. An output value obtained by A / D (analog / digital) conversion of the detection voltage becomes a pixel value of the read image data and a detection value of backlight light or outside light. The backlight 24 is a surface-emitting light source that irradiates the entire liquid crystal display / reading panel 20 with light from the back side. Specifically, a combination of a fluorescent lamp (hot cathode tube or cold cathode tube) serving as a light source and a light guide plate and a diffusion plate for reflecting and diffusing light emitted from the light source to emit light in a planar shape It is.

  The image correction unit 3 is a data changing unit that corrects input display image data based on display image correction data output from the microcontroller 6. The timing generation unit 4 constitutes display control means together with the image correction unit 3, generates display data indicating the drive voltage of each source line based on the display image data corrected by the image correction unit 3, and the source driver 21. The line shift timing data indicating the timing for scanning the gate line is generated and output to the gate driver 22.

  The inverter circuit 5 is a backlight lighting circuit, and is a light source driving means that adjusts and outputs a backlight driving AC voltage based on backlight correction data output from the microcontroller 6.

  The microcontroller 6 includes a brightness / color tone correction value generation unit 60 and a luminance correction value generation unit 61, and is a control unit that generates and outputs read image data based on an output value from the detector 23. The lightness / tone correction value generation unit 60 generates a correction value for display image data correction based on the output value from the detector 23 and outputs the correction value to the image correction unit 3 as display image correction data. The luminance correction value generation unit 61 generates a correction value for correcting the backlight control data based on the output value from the detector 23 and outputs the correction value to the inverter circuit 5 as the backlight correction data.

  The operation panel 7 is an input means for inputting an instruction for the user to operate the display device 1, such as an image display and document reading start instruction, an end instruction, selection of image display data and read image data, setting, and the like. Is input by the user.

  FIG. 2 is a schematic diagram showing a circuit configuration of the image display / read module 2. A plurality of gate lines X0, X1,..., Xm, Xm + 1 are connected to the gate driver 22, and a plurality of source lines Y1 (R), Y1 (G), Y1 (B), Y2 (R), Y2 (G), Y2 (B),..., Yn (R), Yn (G), Yn (B) are connected. Here, R, G, and B indicate red, green, and blue, respectively. In the pixel region P at the intersection of the gate line X and the source line Y, a TFT, a light receiving element, and the like are provided.

  FIG. 3 is an equivalent circuit diagram of the pixel region P at the intersection of the gate line Xi and the source line Yi. A gate line Xi is connected to the gate electrode of the TFT, a source line Yi is connected to the source electrode, and a transparent pixel electrode is connected to the drain electrode. The light receiving element PD is provided between the bias electrode E1 and the drain electrode. The liquid crystal layer on the equivalent circuit functions as the capacitor C1, and the capacitance between the drain electrode and the counter electrode E2 also functions as the capacitor C2. Furthermore, drain-gate parasitic capacitances C3 and C4 are generated between the drain electrode and the gate line Xi-1 and between the drain electrode and the gate line Xi + 1, respectively.

  At the time of image display, since the drain-gate parasitic capacitance fluctuates the driving voltage, the gate line is driven in consideration of the fluctuating voltage in advance. However, since only one of the drain-gate parasitic capacitances C3 and C4 is generated for the two gate lines located at the extreme ends, the fluctuation voltage differs from the other gate lines. Therefore, the two gate lines located at the extreme ends are treated as so-called dummy lines that are not involved in image display. In the present embodiment, the two gate lines X0 and Xm + 1 located at the extreme ends are dummy lines, and an area where the dummy lines are provided is referred to as an ineffective display area. The gate lines X1 to Xm are gate lines involved in image display, and an area where these are provided is referred to as an effective display area.

  FIG. 4 is a diagram for explaining the image reading operation. A reverse bias voltage Vr = cathode side bias voltage Vb−pixel voltage Vp is applied to the light receiving element PD provided in the image region P, and when this is irradiated with light, a photocurrent Ip is generated. The generated photocurrent Ip flows to the detector 23 via the source line connected to the TFT. The detector 23 includes a plurality of inverting amplifier circuits including an input resistor Ri, an operational amplifier A, and a feedback resistor Rf, and converts the photocurrent Ip into a detection voltage Vo = −Ip × Rf and outputs the converted voltage.

The image display function of the display device 1 will be described.
FIG. 5 is a timing chart during image display. The display of the image is performed by sequentially scanning the gate lines including the dummy lines from the uppermost gate line X0, and applying a driving voltage based on display data to the source line in accordance with the scanning, and the lowermost gate line Xm + 1. After the end of scanning, it consists of a blanking period until scanning of the gate line X0 is started again.

  In the display period, first, a voltage is applied to the gate line X0 to turn it on, and after a predetermined time, it is discharged to turn it off. At the same time as the gate line X0 is turned off, a voltage is applied to the gate line X1 to turn it on. This is repeated until the gate line Xm + 1 is turned off. Simultaneously with the scanning of the gate line, a driving voltage based on display data is applied to the source line. Since the dummy line is not involved in image display, when the gate line X0 is in the ON state, a voltage based on BLANK data indicating white display or black display is applied to all source lines. When the gate line X1 is turned on, a voltage based on LINE1 data, which is display data of a pixel on the gate line X1, is applied to all the source lines in order to operate each TFT connected to the gate line X1.

  In the display period and the blanking period, the backlight 24 emits light with a predetermined light amount, and the bias voltage of the light receiving element is turned off (high impedance state).

  As described above, one screen (one frame) of the display image data is displayed.

Next, the image reading function of the display device 1 will be described.
FIG. 6 is a timing chart at the time of image reading. Image reading is performed by irradiating the original with a backlight period and an initialization period in which light is transmitted through all pixels so that the light receiving element can receive reflected light from the original. Reading period in which the reflected light from the light is received.

  In the initialization period, the same operation as the display period at the time of image display is performed using display data in which all pixels display white.

  In the reading period, all pixels are displayed in white, that is, in a state where light can be transmitted, and the backlight is irradiated with the maximum light amount. The bias voltage of the light receiving element is turned ON during the reading period. The scanning of the gate line is performed in the same manner as the initialization period (display period), and the source line is set to a high impedance state.

  The detector 23 outputs a detection voltage based on the photocurrent generated in each pixel, and the microcontroller 6 generates read image data obtained by reading a document image for one screen based on the detection voltage.

  In the present invention, based on such an image reading function, the backlight light and the amount of external light applied to the liquid crystal display / reading panel 20 from the outside of the apparatus are detected, and the operation of the backlight or TFT is controlled. Correct the image display.

Example 1
In Example 1, the light amount of the backlight is detected for each position and for each RGB color using all the light receiving elements, and the backlight light amount is corrected so as to obtain an appropriate display luminance based on the detection result. The brightness of each pixel is adjusted for each RGB color so as to correct luminance unevenness in the display effective area (due to unevenness of the light guide plate / reflector of the backlight) and color shift.

FIG. 7 is a timing chart of the first embodiment.
Since the operation of the first embodiment is almost the same as the image reading operation, it will be described as an initialization period and a reading period, which are the same expressions as in FIG.

  In the initialization period, all the pixels are displayed in white, and the backlight is irradiated with the same amount of light as in the image display. In the reading period, the light receiving element detects not the reflected light from the original but the irradiated backlight.

  The microcontroller 6 calculates the average value of the luminance for each color of RGB based on the detection voltage output from the detector 23. Note that when displaying an image, it is determined in advance which color of RGB each pixel will display. Therefore, depending on the position of the pixel that has received the backlight light, the brightness of which color I know if there is.

  The difference between the average value calculated for each color and the luminance of each pixel is calculated for each color, and the luminance for which the difference is equal to or greater than a predetermined value is excluded because the light receiving element is defective.

If a value that deviates significantly from the luminance unevenness characteristic of the display device 1 is detected, it is considered that the liquid crystal display / reading panel 20 or the light receiving element is defective, and it is necessary to exclude the luminance detection data relating to the pixel. In the cold cathode tube type backlight, the luminance variation characteristic is generally defined as follows.
δY = Max (Y1, Y2, Y3, ... Yn) / Min (Y1, Y2, Y3, ... Yn)
Y1 ~ Yn: Luminance value measured at n points on the display surface in full white display

For example, if the specification of the display device 1 is δY = 1.3, the luminance variation is considered to be within ± 15% with respect to the average value. Therefore, a value greatly exceeding this, for example, a difference from the average value is ± 25% When the above value is detected, it is determined that either the liquid crystal cell or the light receiving element is defective.
The average value for each color is calculated again based on the remaining luminance not excluded.

  The amount of backlight light is calculated from the average value of the luminances of the RGB colors thus obtained. The brightness correction value generation unit 61 compares the calculated light amount with the reference light amount, creates a correction value for correcting the light amount of the backlight light so as to reduce the difference, and outputs the correction value to the inverter circuit 5. To do.

  For each pixel, a deviation (luminance unevenness) from the average value of luminance is calculated. For pixels from which luminance is excluded, the luminance of surrounding pixels is substituted.

  The lightness / tone correction value generation unit 60 generates a correction value for each pixel so as to cancel the calculated deviation, and outputs the correction value to the image correction unit 3. Further, a correction value for correcting the brightness of each color of RGB in the display image data is generated and output to the image correction unit 3 so that the balance of the luminance average value for each color becomes a predetermined value. The ratio of R, G, and B that correctly displays white is R: G: B = 30%: 59%: 11%. Based on this ratio, the characteristics of the RGB color filters, the characteristics of the light receiving element, etc. The balance of the average brightness value for each color is set in consideration of the above.

  When performing the image display operation, the inverter circuit 5 adjusts the light amount of the backlight based on the correction value, and the image correction unit 3 corrects the display image data based on the correction value.

  FIG. 8 is a schematic diagram illustrating specific correction of luminance unevenness. If the luminance unevenness as shown in FIG. 8 (a) has occurred due to the detection result of the backlight light, in order to cancel this, as shown in FIG. Correction is not performed, and a pixel having a high luminance is corrected so that the luminance becomes dark.

(Example 2)
In the second embodiment, the brightness around the apparatus is detected for each RGB color using all the light receiving elements, and the display brightness and tone according to the brightness around the apparatus and the color environment are obtained based on the detection result. Further, the correction of the backlight light amount and the brightness of each pixel are adjusted for each RGB color.

FIG. 9 is a timing chart of the second embodiment.
Since the operation of the second embodiment is almost the same as the image reading operation, it will be described as an initialization period and a reading period which are the same expressions as in FIG.

  In the initialization period, all pixels are displayed in white. In the reading period, in order to eliminate the influence of the backlight light, the backlight is turned off, and the light irradiated from the outside, not the reflected light from the document, is detected by the light receiving element.

  The microcontroller 6 calculates the average value of the luminance for each color of RGB based on the detection voltage output from the detector 23. Note that when displaying an image, it is determined in advance which color of RGB each pixel displays, so which color depends on the position of the pixel that has received light emitted from the outside. It can be seen that the brightness.

  The difference between the average value calculated for each color and the luminance of each pixel is calculated for each color, and the luminance for which the difference is equal to or greater than a predetermined value is excluded because the light receiving element is defective. The average value for each color is calculated again based on the remaining luminance not excluded.

  The amount of light emitted from the outside is calculated from the average value of the luminances of the RGB colors thus obtained. The brightness correction value generation unit 61 creates a correction value for correcting the amount of backlight light so as to be the amount of backlight light suitable for the calculated amount of light, and outputs the correction value to the inverter circuit 5.

  The brightness / color tone correction value generation unit 60 calculates a color tone around the apparatus based on the average luminance value for each color, and corrects the brightness of each RGB color of the display image data so as to obtain a color tone suitable for this. A value is generated and output to the image correction unit 3.

  When performing the image display operation, the inverter circuit 5 adjusts the light amount of the backlight based on the correction value, and the image correction unit 3 corrects the display image data based on the correction value.

  By detecting the entire surface of the liquid crystal display / reading panel 20 as in the first and second embodiments, the luminance unevenness of the entire display area can be corrected. However, since the screen display becomes white at the time of detection, the display image becomes difficult to see if corrected frequently in real time. Therefore, in the first and second embodiments, for example, an instruction to start correction can be given by using the operation panel 7 or the like. When the user feels that correction is necessary, the instruction is input, and the correction is performed when the instruction is input. It is desirable to do.

  FIG. 10 is a perspective view showing the image display / reading module 8 of the display device according to the second embodiment of the present invention. Since the configuration other than the image display / read module 8 of the present embodiment is the same as that of the first embodiment, illustration and description thereof are omitted.

  In the present embodiment, the light receiving elements of the display / reading unit 81 that are effective display areas of the liquid crystal display / reading panel 80 are not used for image display correction, but only the light receiving elements connected to the dummy lines of the non-effective display area. Is used. By using only the light receiving elements connected to the dummy lines, it is possible to detect the backlight light and the outside light even when an image is displayed. Here, an external light detection unit 82 is provided in the ineffective display region at the upper end of the panel, and a backlight light detection unit 83 that is a light source light detection unit is provided in the ineffective display region at the lower end of the panel.

  In the outside light detection unit 82, a filter 84 covers the ineffective display area at the upper end of the liquid crystal display / reading panel 80, and a light shielding material 86 covers the ineffective display area between the backlight 85 and the ineffective display area. It is provided as follows. Since the backlight 85 is turned on during image display, the influence of the backlight light on the detection of external light can be eliminated by providing the light shielding material 86. Furthermore, by providing the external light detection unit 82 at the upper end of the liquid crystal display / reading panel 80, it is possible to eliminate the influence of the shadow of the user's hand or head.

  In the backlight light detection unit 83, a reflective material 87 is provided on the front surface of the ineffective display region at the lower end of the liquid crystal display / reading panel 80 so as to cover the ineffective display region. A light shielding material 88 is provided so as to cover the reflective material 87. The light blocking member 88 blocks external light and detects the light reflected by the reflecting member 87, thereby eliminating the influence of the external light on the detection of the backlight light.

(Example 3 and Example 4)
In the third embodiment, during the image display operation, the light amount of the backlight is detected for each position and each RGB color using the light receiving element connected to the dummy line, and an appropriate display luminance is obtained based on the detection result. In addition to correcting the amount of backlight light, the brightness of each pixel is adjusted for each RGB color so as to correct luminance unevenness in the display effective area (due to the difference in the amount of light between the center and end of the light source) and color tone deviation. Adjust to.

  In the fourth embodiment, the brightness around the apparatus is detected for each RGB color by using the light receiving element connected to the dummy line during the image display operation, and the brightness and the color environment around the apparatus are detected based on the detection result. The backlight light amount is corrected and the brightness of each pixel is adjusted for each RGB color so that the display luminance and color tone according to the above are obtained.

FIG. 11 is a timing chart of the third embodiment and the fourth embodiment.
In the display period, the pixels on the two dummy lines are displayed in white, and images are displayed on the other pixels.

  In the blanking period, first, the gate line X0, which is a dummy line, is turned on, the bias voltage of the light receiving element is turned on, and the external light detection unit 82 detects light emitted from the outside by the light receiving element.

  Subsequently, the gate line Xm + 1, which is a dummy line, is turned on, the bias voltage of the light receiving element is maintained in the on state, and the backlight light detection unit 83 detects the backlight light with the light receiving element.

  The microcontroller 6 calculates the average value of the luminance for each color of RGB based on the detection voltage output from the detector 23. Note that when displaying an image, it is determined in advance which color of RGB each pixel will display. Therefore, depending on the position of the pixel that has received the backlight light, the brightness of which color I know if there is.

  The difference between the average value calculated for each color and the luminance of each pixel is calculated for each color, and the luminance for which the difference is equal to or greater than a predetermined value is excluded because the light receiving element is defective. The average value for each color is calculated again based on the remaining luminance not excluded.

  From the average value of the luminance of each RGB color thus obtained, the amount of backlight light and the amount of light emitted from the outside are calculated. The luminance correction value generation unit 61 compares the calculated backlight light amount with the reference light amount, and the light amount of the backlight light suitable for the calculated light amount of the external light so that the difference is reduced. Then, a correction value for correcting the amount of backlight light is created and output to the inverter circuit 5.

  For each pixel, a deviation from the average luminance value (luminance unevenness in the horizontal direction) is calculated. For pixels from which luminance is excluded, the luminance of surrounding pixels is substituted.

  The brightness / color tone correction value generation unit 60 generates correction values for correcting the brightness of each RGB color of the display image data so as to cancel the calculated deviation and to obtain a color tone suitable for the color tone around the apparatus. Output to the image correction unit 3. Further, a correction value for correcting the brightness of each color of RGB in the display image data is generated and output to the image correction unit 3 so that the balance of the luminance average value for each color becomes a predetermined value.

  When performing the image display operation, the inverter circuit 5 adjusts the light amount of the backlight based on the correction value, and the image correction unit 3 corrects the display image data based on the correction value.

  FIG. 12 is a schematic diagram illustrating correction of luminance unevenness in the third embodiment. In Example 3, since the amount of backlight is detected using the light receiving element connected to the dummy line, the luminance unevenness in the horizontal direction is detected. Accordingly, when the entire surface of the liquid crystal display / reading panel 80 is corrected based on the detected horizontal luminance unevenness, the vertical luminance unevenness, that is, the horizontal luminance unevenness as shown in FIG. It is corrected as if it were translated.

  In addition, a fluorescent lamp serving as a light source uses an elongated straight tube shape, and there are a vertical arrangement and a horizontal arrangement. In the case where the backlight light amount is detected using the light receiving element connected to the dummy line as in the third embodiment, the fluorescent lamp is arranged on the dummy line, that is, the gate line in order to perform more appropriate correction. It is desirable to have a parallel lateral arrangement.

(Example 5)
The fifth embodiment has a configuration similar to that of the third and fourth embodiments. The light shielding member 86 is not provided in the external light detection unit 82, and the backlight is turned off when the brightness around the apparatus is detected. Eliminate the effects of light.

FIG. 13 is a timing chart of the fifth embodiment.
In the display period, the pixels on the two dummy lines are displayed in white, and images are displayed on the other pixels.

  In the blanking period, first, the gate line X0, which is a dummy line, is turned on, the bias voltage of the light receiving element is turned on, the backlight is turned off, and the external light detection unit 82 receives light emitted from the outside. Detect with element.

  Subsequently, the gate line Xm + 1, which is a dummy line, is turned on, the bias voltage of the light receiving element is maintained in the on state, and the backlight light detection unit 83 detects the backlight light with the light receiving element.

  The microcontroller 6 calculates the average value of the luminance for each color of RGB based on the detection voltage output from the detector 23. Note that when displaying an image, it is determined in advance which color of RGB each pixel will display. Therefore, depending on the position of the pixel that has received the backlight light, the brightness of which color I know if there is.

  The difference between the average value calculated for each color and the luminance of each pixel is calculated for each color, and the luminance for which the difference is equal to or greater than a predetermined value is excluded because the light receiving element is defective. The average value for each color is calculated again based on the remaining luminance not excluded.

  From the average value of the luminance of each RGB color thus obtained, the amount of backlight light and the amount of light emitted from the outside are calculated. The luminance correction value generation unit 61 compares the calculated backlight light amount with the reference light amount, and the light amount of the backlight light suitable for the calculated light amount of the external light so that the difference is reduced. Then, a correction value for correcting the amount of backlight light is created and output to the inverter circuit 5.

  For each pixel, a deviation from the average luminance value (luminance unevenness in the horizontal direction) is calculated. For pixels from which luminance is excluded, the luminance of surrounding pixels is substituted.

  The brightness / color tone correction value generation unit 60 generates correction values for correcting the brightness of each RGB color of the display image data so as to cancel the calculated deviation and to obtain a color tone suitable for the color tone around the apparatus. Output to the image correction unit 3. Further, a correction value for correcting the brightness of each color of RGB in the display image data is generated and output to the image correction unit 3 so that the balance of the luminance average value for each color becomes a predetermined value.

  When performing the image display operation, the inverter circuit 5 adjusts the light amount of the backlight based on the correction value, and the image correction unit 3 corrects the display image data based on the correction value.

  In the above, Example 3 and Example 4 or Example 4 and Example 5 are simultaneously performed on one display device, but the display device is only one of the external light detection unit and the backlight light detection unit. It is also possible to detect the brightness around the apparatus or only detect the backlight.

  In the third to fifth embodiments, since it is possible to detect the amount of backlight light during the image display operation, not only correction is performed when a user's instruction is input, but also in the absence of the user's instruction. It is desirable to perform the automatic correction at the timing.

  When a cold-cathode tube is used as the backlight light source, it is desirable to set the appropriate timing for automatic correction as follows.

  When lighting the cold cathode tube, in order to stably start the cold cathode tube that has not been energized in advance and is sufficiently cooled, it is necessary to apply a higher voltage than usual immediately after starting. For example, if the normal applied voltage is 700 Vrms, the applied voltage at the start of lighting needs to be 1200 Vrms. Further, since the time until the discharge is stabilized is not constant due to the variation in characteristics of the cold cathode tubes and the environmental temperature, the high voltage application time needs to be set as long as about 1 second. If the cold-cathode tube is stabilized during the high voltage application period, the luminance increases after the stabilization until it returns to the normal applied voltage. That is, it may appear brighter than usual for a moment immediately after the start of lighting. Further, when the cold cathode fluorescent lamp is continuously lit, the light amount gradually decreases as the temperature rises. The decrease in the amount of light occurs over several hours until the temperature is saturated. The degree of decrease is, for example, about 10% in 3 hours.

From these, when using a cold cathode tube,
It is desirable that automatic correction is performed every several tens to several hundreds of milliseconds for 1 second after the start of lighting, and thereafter automatic correction is performed every few minutes.

  Further, since the brightness around the apparatus can be detected during the image display operation, not only correction is performed when a user instruction is input, but also at a predetermined timing without any user instruction. It is desirable to perform automatic correction. It is desirable to automatically correct the brightness around the apparatus every few seconds. This is because it is not necessary to perform correction in response to an instantaneous change, for example, when a person crosses in front of the display device and interrupts illumination for a moment.

  When an LED (Light Emitting Diode) is used as a backlight light source instead of a fluorescent lamp, the color tone of the backlight changes when used for a long time. In order to use an LED as a backlight light source, three types of LEDs each having three colors of RGB are used. The characteristics of an LED change with the passage of time of use, and the change in this characteristic varies depending on the light emission color, so that the color tone of the backlight changes when used for a long time. Therefore, it is necessary to detect the amount of light for each RGB color and correct the amount of light for each LED.

  In addition, although the case where a backlight is used as the light source has been described above, the present invention is not limited to this, and the present invention is applied by detecting the amount of light emitted from these even when a sidelight or a frontlight is used. can do.

It is a block diagram which shows the structure of the display apparatus 1 which is the 1st Embodiment of this invention. 2 is a schematic diagram showing a circuit configuration of an image display / reading module 2. FIG. It is an equivalent circuit diagram of the pixel region P at the intersection of the gate line Xi and the source line Yi. It is a figure for demonstrating image reading operation | movement. It is a timing chart at the time of image display. It is a timing chart at the time of image reading. 3 is a timing chart of the first embodiment. It is the schematic shown about the specific correction | amendment of brightness nonuniformity. 6 is a timing chart of the second embodiment. It is a perspective view which shows the image display and reading module 8 of the display apparatus which is the 2nd Embodiment of this invention. 10 is a timing chart of Example 3 and Example 4. FIG. 10 is a schematic diagram illustrating correction of luminance unevenness in the third embodiment. 10 is a timing chart of Example 5.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Display apparatus 2 Image display / reading module 3 Image correction part 4 Timing generation part 5 Inverter circuit 6 Microcontroller 7 Operation panel 20 Liquid crystal display / reading panel 21 Source driver 22 Gate driver 23 Detector 24 Backlight 60 Lightness and color tone correction value Generator 61 Brightness correction value generator

Claims (8)

A display panel having a display element for displaying an image and a light receiving element for receiving light, and a light source for irradiating the display panel with light, displaying input display image data and reading a document image A display device capable of
Light source driving means for driving the light source;
Display control means for displaying an image on the display panel based on the input display image data;
A light amount detection means for detecting the amount of light emitted from the light source by the light receiving element receiving light emitted from the light source;
A display device comprising: control means for controlling operations of the light source driving means and the display control means based on a detection result of the light quantity detection means. A display panel having a display element for displaying an image and a light receiving element for receiving light, and a light source for irradiating the display panel with light, displaying input display image data and reading a document image A display device capable of
Light source driving means for driving the light source;
Display control means for displaying an image on the display panel based on the input display image data;
A light amount detecting means for detecting the amount of light emitted from the external light by receiving the external light applied to the display panel from outside the display device;
A display device comprising: control means for controlling operations of the light source driving means and the display control means based on a detection result of the light quantity detection means.   3. The control unit according to claim 1, wherein the control unit controls the operation of the light source driving unit based on the detection result of the light amount detection unit so that the luminance of each pixel of the display panel is constant. Display device. The display control means includes a data changing unit for changing the input display image data,
The display device according to claim 1, wherein the control unit causes the data change unit to change display image data based on a detection result of the light amount detection unit. The display panel has a display element and a light receiving element for each pixel,
The display device according to claim 1, wherein the light amount detection unit performs detection using all light receiving elements built in the display panel. The display panel has a display element and a light receiving element for each pixel,
The display device according to claim 1, wherein the light amount detection unit performs detection using a light receiving element of a pixel that is not involved in image display. The light amount detection means includes a light source light detection unit that detects an irradiation light amount of the light source, or an external light detection unit that detects an irradiation light amount of the external light,
The light source light detection unit includes a light receiving element of a pixel not involved in image display, a reflective material provided on the opposite side of the light source so as to cover the light receiving element, and a light shielding provided so as to cover the reflective material. With materials,
The external light detection unit includes a light receiving element of a pixel that is not involved in image display, and a light shielding material provided between the light source and the light receiving element so as to cover the light receiving element. The display device according to any one of 1 to 6. The light amount detection means outputs output values output from a plurality of light receiving elements to the control means as detection results,
The control unit calculates the plurality of average values when controlling operations of the light source driving unit and the display control unit based on the plurality of output values input from the light amount detection unit, and calculates the average 8. The display device according to claim 1, wherein an output value whose difference from a value is equal to or greater than a predetermined value is not used for controlling operations of the light source driving unit and the display control unit. .

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