JP2005331644A - Image display device and image display method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily calibrate the chromaticity and luminance of the screen, irrespective of the temperature changes in the vicinity of a light source and without deteriorating the image quality, in a non-selfluminous constitution in which an image is displayed on the screen by the light from the light source. <P>SOLUTION: The picture display device is driven by detecting temperature in the vicinity of the light source (Ln) of which the emission chromaticity and the emission luminance are adjustable with a temperature sensor (Tm); correcting a controlled variable of the light source, which is controlled variables of the emission chromaticity and the emission luminance of the light source, with a temperature-correcting means (28, 29) in accordance with the detected temperature; outputting a controlled variable of emission, which is controlled variables of the emission chromaticity and the emission luminance of the temperature corrected light source; and adjusting the emission chromaticity and the emission luminance of the light source with a driving means (21) on the basis of the controlled variable of emission. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image display device and an image display method, and in particular, in a non-self-luminous configuration in which an image is displayed on a screen by light from a plurality of light sources, chromaticity and brightness of the screen, and color unevenness and brightness unevenness in the screen. The present invention relates to an image display device and an image display method that can easily calibrate the image.

  As a conventional image display device with a function to correct fluctuations in chromaticity and brightness of the screen, the ambient temperature of the light source is detected by a temperature sensor, and color adjustment of image processing is corrected and controlled according to the detected temperature. (For example, refer to Patent Document 1). Further, there has been a technique in which the chromaticity and luminance of the screen are detected by a single color sensor, and the chromaticity and luminance are corrected based on the detected data (for example, see Patent Document 2). In addition, there is one in which chromaticity and luminance of a screen are detected by one color sensor, and color adjustment of image processing is corrected and controlled in accordance with a variation amount of a detected value from a logical value (for example, see Patent Document 3). .

  On the other hand, as a conventional non-self-luminous image display device that displays an image on a screen by light from a light source, a light source is composed of light emitters of a plurality of colors, and light from different color light emitters is mixed. Accordingly, there is an apparatus that functions as a light source and adjusts the chromaticity and luminance of a display screen by individually controlling the light emission amount of each color light emitter. Furthermore, there are some provided with a plurality of the light sources.

  For example, in a non-self-luminous flat panel display such as a liquid crystal display that transmits light from a light source such as a backlight and displays an image on the screen, R (red, G), B (green), B There is one in which one or a plurality of light sources are constituted by a plurality of color light emitters formed by arranging a plurality of (blue, three-color) LEDs.

Japanese Unexamined Patent Publication No. 2000-112429 (FIG. 1) Japanese Patent Laying-Open No. 2002-281531 (FIG. 1) JP 2002-64842 A (FIGS. 1 and 3)

  In the conventional non-self-luminous type image display apparatus as described above, the light emission chromaticity and light emission luminance vary depending on environmental factors such as temperature, and the chromaticity and luminance of the screen fluctuate. Is required. Variations in the light emission chromaticity and light emission luminance depending on the temperature depend on, for example, the light emission characteristics of the light emitters of a plurality of colors included in the light source depending on environmental factors such as temperature. This is because the amount of fluctuation varies.

  However, when adjusting the chromaticity and luminance by applying the conventional image display device that corrects the change in chromaticity and luminance to the non-self-luminous conventional image display device including the plurality of light sources. Had the following issues.

  The conventional image display device that detects the chromaticity and brightness of the screen using only the color sensor and corrects the chromaticity and brightness based on the detected data cannot correct the change in the characteristics of the light source due to temperature. there were. For example, the light emission characteristics of the light emitters of the respective colors included in the light source vary depending on the vicinity of the light source or the temperature of the connection portion. It will be. As a result, the correction under a situation where the temperature fluctuation is severe is performed in a situation where the accuracy is low.

  Further, in a conventional image display device that corrects and controls the color adjustment of image processing according to the temperature detected by the temperature sensor, conversion error or bit loss (data loss) occurs due to image processing, and the chromaticity of the screen In some cases, the image quality deteriorates in addition to the correction of fluctuations in brightness.

  The present invention has been made to solve such a conventional problem, and in a non-self-luminous configuration that displays an image on a screen by light from a light source, regardless of a temperature change in the vicinity of the light source, It is an object of the present invention to provide an image display device and an image display method that can easily calibrate the chromaticity and luminance of a screen without degrading the image quality.

The image display device of the present invention is
In an image display device that displays an image on a screen by light from a light source capable of adjusting emission chromaticity and emission luminance,
A temperature sensor for detecting a temperature near the light source;
A light source control amount that is a control amount of the light emission chromaticity and light emission luminance of the light source is corrected according to a detection temperature of the temperature sensor, and light emission that is a temperature-corrected light emission chromaticity and light emission luminance control amount is corrected. Temperature correction means for outputting a controlled variable;
Drive means for adjusting the light emission chromaticity and light emission luminance of the light source based on the light emission control amount from the temperature correction means is provided.

The image display method of the present invention includes:
In an image display method for displaying an image on a screen by light from a light source capable of adjusting emission chromaticity and emission luminance,
According to the detected temperature detected by the temperature sensor that detects the temperature near the light source, the light source control amount that is the control amount of the light emission chromaticity and light emission luminance of the light source is corrected,
Output the light emission control amount that is the control amount of the light emission chromaticity and light emission luminance of the light source corrected for temperature,
Based on the light emission control amount, the light source is driven by adjusting light emission chromaticity and light emission luminance.

  According to the present invention, in a non-self-luminous configuration in which an image is displayed on the screen by light from the light source, the chromaticity and brightness of the screen can be easily achieved without degrading the image quality regardless of the temperature change in the vicinity of the light source. There is an effect that it can be calibrated.

  FIG. 1 is a configuration diagram of a display panel in an image display apparatus according to an embodiment of the present invention. FIG. 2 is a diagram for explaining a configuration for light emission chromaticity and light emission luminance adjustment (light source calibration) and a light source calibration procedure in the image display apparatus according to the embodiment of the present invention. In a non-self-luminous image display device, calibrating the light source means calibrating the chromaticity and luminance of the screen.

  1 and 2, the image display apparatus according to this embodiment is a non-self-luminous image display apparatus such as a liquid crystal display, and includes a display unit 11 of a display panel, a light guide plate 12 of the display panel, and a display. Four light sources L1, L2, L3, L4 of the panel, four color sensors S1, S2, S3, S4, temperature sensors T1, T2, T3, T4, a light source control unit 20, a light source driving unit 21, A color data A / D converter 22 and a temperature data A / D converter 23 are provided. The light source control unit 20 includes a light source emission amount calculation unit 24, a correlation data memory 25, a light source reference emission amount data memory 27, a light source control amount calculation unit 26, a temperature correction expression memory 29, and a temperature correction amount. A calculation unit 28 is provided.

  The light source Ln (n is an arbitrary value of 1, 2, 3 and 4) is composed of an R (Red) light emitter, a G (Green) light emitter, and a B (Blue) light emitter. For example, an R light emitter is an array of R LEDs, a G light emitter is a G LED, and a B light emitter is a B LED. The light source Ln adjusts the light emission chromaticity and the light emission luminance by independently controlling the light emission amounts of the R light emitter, the G light emitter, and the B light emitter (R channel, G channel, B channel). It is possible.

  The R, G, B light from the three color light emitters of the light source Ln is mixed by the light guide plate 12 and diffused to the display unit 11, and the transmittance is controlled according to the size of the color component in each pixel. As a result, a color image is displayed on the display unit 11.

  The color sensor Sm (m is an arbitrary value of 1, 2, 3, and 4) is disposed around the display unit 11 and in the vicinity of a part of the area Am on the display unit 11. The light amounts of R, G, and B3 colors (R, G, and B3 channels) in the area Am of light from the light sources L1 to L4 mixed by the light guide plate 12 are detected, and the detected light amounts of these R, G, and B3 channels are defined as A. The data is output to the / D converter 22. In the example shown in the drawing, the area A1 corresponds to approximately a quarter of the upper left portion of the display unit 11, the area A2 corresponds to approximately a quarter of the upper right portion of the display unit 11, and the area A3 corresponds to the display unit. 11 corresponds to approximately a quarter of the lower left portion of area 11, and area A4 corresponds to a substantially quarter of the lower right portion of display section 11. Since the chromaticity and luminance in the area Am can be determined from the detected light amounts of the three channels, the color sensor Sm detects the chromaticity and luminance in the area Am, and converts the detected chromaticity and detected luminance into color data A / D conversion. In other words, the data is output to the unit 22.

The temperature sensor Tn (n is an arbitrary value of 1, 2, 3, 4) is installed in the vicinity of the light source Ln, and the detected temperature in the vicinity of each light source is sent to the temperature data A / D conversion unit 23. Output.
In other words, in the illustrated example, the temperature sensors Tn are provided corresponding to the light sources, respectively, and detect the temperature in the vicinity of the corresponding light sources.

  Here, each of the partial areas A1, A2, A3, and A4 on the display unit 11 is expressed as being clearly divided by dotted lines in FIG. The range actually detected by each color sensor is not clearly divided in this way.

  Further, when installing the color sensors S1 to S4, in order to eliminate detection errors other than light from the light sources L1 to L4, it is desirable to have a structure that blocks incident light other than light from the light sources L1 to L4. .

  Further, when installing the temperature sensors T1 to T4, it is desirable to install a low heat resistance such as a heat radiating plate near the corresponding light sources L1 to L4, respectively, and fix them by a method such as close contact therewith.

  The light source driving unit 21 individually drives each light emitter of each light source, and calculates the light emission amount of each light emitter according to the light emission control data output from the temperature correction amount calculation unit 28 of the light source control unit 20. Control individually. The light emission control data is data representing a light emission control amount for controlling the light emission amount of each light emitter.

  The analog value of the detected light amount output from each color sensor is output to the color data A / D conversion unit 22 and converted into a digital value, and the detected light amount data is output to the light source emission amount calculation unit 24 of the light source control unit 20. To do.

  The analog value of the detected temperature output from each temperature sensor is output to the temperature data A / D converter 23 and converted into a digital value, and these temperature data are output to the temperature correction amount calculator 28 of the light source controller 20. .

  In the light source controller 20, the correlation data memory 25 stores between the detected light amounts of the R, G, and B channels of the respective color sensors and the emitted light amounts of the R, G, and B channels of the respective light sources L 1 to L 4. Correlation data representing the correlation is stored in advance. The correlation data is also data representing color correlation that is a correlation between the detected chromaticity and detected luminance of each color sensor and the emitted chromaticity and emitted luminance of each light source. That is, the correlation data memory 25 is a means for storing color correlation.

  The light source emission amount calculation unit 24 calculates the detected emission amounts of the R, G, and B channels of the respective light sources from the detected light amounts of the respective color sensors using the correlation data stored in the correlation data memory 25. Then, the detected light emission amount data representing the detected light emission amount is output to the light source control amount calculation unit 26. Here, the detected light emission amount represents the light emission amount of the light source obtained from the light amount detected by the color sensor. In other words, the light source emission amount calculation unit 24 can be rephrased as an arithmetic unit that calculates the detection emission chromaticity and the detection emission luminance of each light source from the detection chromaticity and the detection luminance of each of the color sensors. Here, the detected light emission chromaticity and the detected light emission luminance represent the light emission chromaticity and the light emission luminance of the light source obtained from the light amount detected by the color sensor.

  The light source reference light emission amount data memory 27 stores light source reference light emission amount data composed of reference light emission amounts of the respective light emitters of the respective light sources in advance. The light source reference light emission amount data is data composed of the reference light emission chromaticity and the reference light emission luminance of each light source.

  The light source control amount calculation unit 26 compares the detected light emission amount data with the light source reference light emission amount data for the light emitter stored in the light source reference light emission amount memory 27 for each light emitter of each light source, and Light source control data representing a light source control amount for controlling the light emission amount of the light emitter is output to the temperature correction amount calculation unit 28 so that the light emission amount of the light emitter matches the reference light emission amount.

  In the temperature correction type memory 29, the data stored in the correlation data memory 25 is valid, that is, the temperature in the vicinity of the light source at the time of data measurement, which is a basis for determining the correlation data, and the light source detected by the temperature sensor. A correction formula for the change in the light emission amount with respect to the drive amount (control amount) of each light emitter of the light source due to the difference from the near temperature is stored. The content stored in the temperature correction formula memory 29 is not necessarily limited to the correction formula, and the relationship between the light emission amount of each light emitter and the given light emission control amount is stored according to the detected temperature of the temperature sensor. It is only necessary to function as temperature correction type storage means. For example, instead of the correction formula, the correction amount obtained by the correction formula may be stored in a table format.

  The temperature correction amount calculation unit 28 corrects the light source control data based on the correction formula stored in the temperature correction formula memory 29 and the temperature data converted into a digital value by the temperature data A / D conversion unit 23 to control the light emission. Calculate the data. That is, the light emission control data is data obtained by correcting the light source control data in consideration of the temperature characteristics of the light source. Therefore, the temperature correction amount calculation unit 28 and the temperature correction formula memory 29 function as temperature correction means for correcting and outputting the emission chromaticity and emission luminance control amounts of the respective light sources in accordance with the temperature detected by the temperature sensor. .

  The light emission amounts of the respective light emitters of the respective light sources are initially set so that the chromaticity and the luminance are uniform over the entire screen of the display unit 11 and there is no color unevenness or luminance unevenness. However, due to the variation with time of the light emission luminance of each light emitter and the variation with time of the light emitter, the uniformity of chromaticity and luminance within the screen is lost, resulting in color unevenness and luminance unevenness. In particular, if there is a variation in the time-dependent variation among the R, G, and B light emitters, a change in chromaticity appears remarkably, and visibility decreases. For this reason, it is necessary to calibrate the amount of light emitted from each illuminant of each light source to maintain the uniformity of chromaticity and luminance within the screen as in the initial setting.

  The light source calibration procedure in the image display apparatus of this embodiment will be further described with a specific example. The light source calibration procedure of this embodiment uses the correlation between the detected light amount of each channel of each color sensor and the emitted light amount of each light emitter of each light source, and detects the temperature near the light source. Thus, the temperature characteristic of the photogen is corrected. First, the correlation between the amount of light detected by the color sensor and the amount of light emitted from the light source will be described.

First, there is a correlation between the light emission amounts of the R, G, and B light emitters of the light source Ln and the chromaticity and luminance of the light source Ln. The light emission amount of the R light emitter of the light source Ln is R _Ln , the tristimulus value at this time is (X _RLn , Y _RLn , Z _RLn ), the light emission amount of the G light emitter of the light source Ln is G _Ln , and the tristimulus value at this time _Is (X _GLn , Y _GLn , Z _GLn ), the light emission amount of the B light emitter of the light source Ln is B _Ln , and the tristimulus values at this time are (X _BLn , Y _BLn , Z _BLn ), the tristimulus of the light source Ln The values (X _Ln , Y _Ln , Z _Ln ) are expressed as the following equation (1).

In the above equation (1), C _n is the light emission amount (R _Ln , G _Ln , B _Ln ) of the R, G, and B light emitters of the light source Ln and the tristimulus values (X _Ln , Y _Ln , Z) of the light source Ln. _Ln ) is a 3 × 3 matrix showing the correlation. This correlation matrix C _n is a matrix unique to each light source, and can be obtained in advance by actual measurement or the like.

Further, the light in the partial area Am of the display unit 11 can be considered as a mixed light of light that has reached the area Am with a specific attenuation factor from each of the four light sources L1 to L4. The tristimulus values (X _Am , Y _Am , Z _Am ) of light in such an area Am are expressed as the following equation (2).

In the above equation (2), k _mn is a coefficient representing the attenuation rate until the light from the light source Ln reaches the area Am. In the above equation (2), the attenuation factors of the X, Y, and Z light from the light source Ln are all the same value _kmn . However, when the attenuation factors of the X, Y, and Z light are different, the attenuation is performed. The rate coefficient _kmn is a value unique to each of the X, Y, and Z lights.

The n-th term on the right side of the equation (2) represents the contribution ratio of the light emission amount of the light source Ln in the area Am. When all of the light sources L1 to L4 are caused to emit light, the tristimulus values (X _Am , Y _Am , Z _Am ) of light in the area Am are obtained by adding all the first to fourth terms of the above formula (2). It becomes. Further, for example, when only the light source L1 is caused to emit light, the tristimulus values (X _Am , Y _Am , Z _Am ) of light in the area Am are the first term on the right side of the above equation (2).

The color sensor Sm detects light in the area Am. There is a correlation between the tristimulus values of light in the area Am and the R, G, B detected light amounts of the color sensor Sm. When the tristimulus values of light in the area Am are (X _Am , Y _Am , Z _Am ), when the spectral sensitivity characteristics of the color sensor Sm satisfy the router condition, the R, G, B detected light amounts (RSm, (GSm, BSm) is expressed as the following equation (3).

In the above equation (3), D _m is the correlation between the tristimulus values (X _Am , Y _Am , Z _Am ) of light in the area Am and the detected light amount (R _Sm , G _Sm , B _Sm ) of the color sensor Sm. Is a 3 × 3 matrix. The correlation matrix _Dm is a matrix unique to each area (each color sensor), for example, and can be obtained in advance by actual measurement or the like.

By combining the above formulas (1) to (3), the light emission amounts (R _L1 , G _L1 , B _L1 ) to (R _L4 , G) of the R, G, B color light emitters of the four light sources L1 to L4 are combined. _L4 , B _L4 ) and the following equation (4) representing the correlation between the detected light amount (R _Sm , G _Sm , B _Sm ) of the color sensor Sm can be derived.

In the above equation (4), E _mn is the light emission amount (R _Ln , G _Ln , B _Ln ) of the R, G, B light emitters of the light source Ln and the detected light amount (R _Sm , G _Sm , B _L ) of the color sensor Sm. _Sm ) is a 3 × 3 matrix and E _mn = D _m × k _mn × C _n .

The n-th term on the right side of the above equation (4) represents the contribution rate of the light emission amount of the light source Ln in the detected light amount (R _Sm , G _Sm , B _Sm ) of the color sensor Sm. When all the light sources L1 to L4 are caused to emit light, the detected light amount (R _Sm , G _Sm , B _Sm ) of the color sensor Sm is obtained by adding all the first to fourth terms on the right side of the above equation (4). Become. For example, when only the light source L1 is caused to emit light, the detected light amount (R _Sm , G _Sm , B _Sm ) of the color sensor Sm is the first term on the right side of the above equation (4).

Correlation matrices E _{m1 to} E _m4 indicate the amount of light emitted from only one of the R, G, and B light emitters of light source Ln among light sources L1 to L4 and the color sensor S1. ˜S4 detected light amounts (R _S1 , G _S1 , B _S1 ) to (R _S4 , G _S4 , B _S4 ) can be obtained in advance.

For example, when only the R light emitter of the light source L1 emits light, the light emission amount R _L1 of the light emitter and the detected light amounts (R _S1 , G _S1 , B _S1 ) to (R _S4 , G _S4 , B) of the color sensors S1 to _S4 . _S4) with three values of the first column of the correlation matrix _E 11 _{to E 41} can be obtained, the light emitter emitting amount _{G L1} and color sensor S1~ when light is emitted only G light emitter of the light source L1 With the detected light amounts (R _S1 , G _S1 , B _S1 ) to (R _S4 , G _S4 , B _S4 ) of _S4 , three values in the second column of the correlation matrices E _{11 to} E ₄₁ can be obtained, and the light source L1 When only the B illuminant is made to emit light, the light emission amount B _L1 of the illuminant and the detected light amounts (R _S1 , G _S1 , B _S1 ) to (R _S4 , G _S4 , B _S4 ) of the color sensors S1 to _S4 , correlation matrix _{E 11} Three values of the third column of E ₄₁ can be obtained.

By substituting previously obtained correlation matrices E _{11 to} E ₄₄ into the above equation (4), R, G of the light sources L _{1 to} L ₄ for each of the total 12 detected light amounts R _{S1 to} B _S4 of the color sensors _{S 1 to S 4.} , Correlation equations with the light emission amounts R _{L1 to} B _{L4 of} the B light emitters are obtained.

By substituting a total of twelve detected light amounts R _{S1 to} B _S4 of the color sensors S1 to S4 into the total of twelve correlation equations obtained in advance, a total of twelve R, G, and B light emitters of the light sources L1 to L4 are obtained. Simultaneous equations consisting of 12 equations with the light emission amounts R _{L1 to} B _L4 as variables are obtained, and the light emission amounts (detected light emission amounts) of the R, G and B light emitters of the light sources L1 to L4 are obtained by solving these simultaneous equations. Each of R _{L1 to} B _L4 can be calculated.

Thus, by using a total of 12 correlation equations obtained from the above equation (4), the R, G, and B light emitters of the light sources L1 to L4 are detected from the detected light amounts R _{S1 to} B _S4 of the color sensors S1 to _S4 . The light emission amount (detected light emission amount) R _{L1 to} B _L4 can be calculated.

Here, when the correlation matrix is obtained from the actual measurement values as described above, it is desirable that the temperature near the light source is constant, for example, a stable state of the light emitter, but the light source is actually turned on and corrected. In this case, the temperature near the light source changes, and the light source emission amount may change at different light source vicinity temperatures for the same light source driving amount. Here, the light source emission amounts R _Ln , G _Ln , and B _{Ln with respect} to the light source drive amounts P _Rn , P _Gn , P _Bn , and the light source vicinity temperature t given to the light source from the light source drive unit 21 are, for example, the following formula (5): It is expressed as
R _Ln = f _R (t) × P _Rn
G _Ln = f _G (t) × P _Gn (5)
B _Ln = f _B (t) × P _Bn

Here, f _R (t), f _G (t), and f _B (t) are temperature correction formulas of the light source emission amount with respect to the light source driving amount with the temperature near the light source as a variable, and are determined from the product data of the light source. Actual measurements can be made and determined in advance. As the light source vicinity temperature t, temperature data detected by a temperature sensor provided in the vicinity of each light source can be used.
In the temperature correction amount calculation unit 28, light emission control data obtained by correcting the light source control data in consideration of the above equation (5) is obtained, and the light emission control data is output to the light source driving unit 21, thereby correcting the temperature characteristics of the light source. It becomes possible to do.

  FIG. 3 is a flowchart showing a light source calibration procedure in the image display apparatus according to the embodiment of the present invention. The light source calibration procedure of the present embodiment will be described below with reference to FIG.

In the correlation data memory 25, the values of the correlation matrices E _{11 to} E _{44 in} the above equation (4) are stored in advance. The values of these correlation matrices E _{11 to} E ₄₄ are set using actual measured values and the like in the design stage and the production stage. In addition, the total of twelve correlation equations obtained from the equation (4) are also stored in the correlation data memory 25 as part of the calculation algorithm for the detected light emission amounts R _{L1 to} B _L4 .

Therefore, in the correlation data memory 25, there are a total of 12 correlation equations obtained from the equation (4), in which the values of the correlation matrices E _{11 to} E _{44 in} the equation (4) are known. Are stored in advance as correlation data. Note that the correlation data memory 25 can store only the values of the correlation matrices E _{11 to} E ₄₄ , and the calculation algorithm can be stored in the light source emission amount calculation unit 24. The correlation data memory 27 can also store the calculation results obtained by the above equation (4) in a table format. In this case, the light source emission amount calculation unit 24 reads the calculation result from the table stored in the correlation data memory 25.

  The light source reference light emission amount data memory 27 stores in advance light source reference light emission amount data composed of the reference light emission amounts of the respective light emitters of the respective light sources. This light source reference light emission amount data is the light emission amount data of each illuminant of each light source when a screen having no color unevenness or brightness unevenness is obtained in the entire region, and is in the design stage or production stage (light emission amount in the production stage). At the time of initial setting).

  Further, the light source reference light emission amount data memory 27 stores in advance an allowable range of detected light emission amount data with respect to the reference light emission amount data. This allowable range is set in a design stage, a production stage, or the like according to the display quality or purpose of use of the image display device, for example.

  Further, the temperature correction formula memory 29 stores in advance a relational expression for correcting the light emission amount of the light emitter with respect to the light source drive amount by a temperature change. This relational expression is determined by determining from product data or by actually measuring in the design stage, production stage, or the like.

  In FIG. 3, at the start of light source calibration, if the light sources L1 to L4 are emitting light, the process immediately proceeds to step 1. If the light sources L1 to L4 are not emitting light, the light source control unit 20 controls the light source driving unit 21. Then, the light source driving unit 21 causes the light sources L1 to L4 to emit light, and waits until the light source is stabilized as necessary before proceeding to Step 1. The light source calibration can be started at an arbitrary timing by the user, or can be automatically set to be performed at a predetermined time interval or a predetermined time.

  In step 1, the R, G, B light amounts in the area A1 by the color sensor S1, the R, G, B light amounts in the area A2 by the color sensor S2, the R, G, B light amounts in the area A3 by the color sensor S3, and the color sensor S4. The R, G, and B light amounts in area A4 are detected.

Then, the R, G, B detected light amounts (R _S1 , G _S1 , B _S1 ) of the color sensor S1, the R, G, B detected light amounts (R _S2 , G _S2 , B _S2 ) of the color sensor _S2 , and the color sensor S3. R, G, B detected light amounts (R _S2 , G _S2 , B _S2 ) and R, G, B detected light amounts (R _S4 , G _S4 , B _S4 ) of the color sensor S4 are color data A / D converter 22. And the color data A / D converter 22 converts it into a digital value.

In the next step 2, the detected light amount data converted into a digital value by the color data A / D conversion unit 22 is sent to the light source light emission amount calculation unit 24 of the light source control unit 20. Using the total 12 correlation equations stored in the memory 25, from the total 12 detected light amounts R _{S1 to} B _S4 , the detected light emission amounts (R _L1 , G _L1 , B _L1 ), detected light emission amounts of the R, G, and B light emitters (R _L2 , G _L2 , B _L2 ) of the light source L 2, detected light amounts of the R, G, and B light emitters of the light source L 3 (R _L3 , G _L3 , B _L3 ) and the detected light emission amounts (R _L4 , G _L4 , B _L4 ) of the R, G, and B light emitters of the light source L4 are calculated.

  In the next step 3, the detected light emission amount data calculated by the light source light emission amount calculation unit 24 is sent to the light source control amount calculation unit 26, and the light source control amount calculation unit 26 detects each light emitter of each light source. A difference between the light emission amount and the reference light emission amount stored in the light source reference light emission amount memory 27 is obtained, and the difference is compared with an allowable range stored in the light source reference light emission amount memory 27. Then, when the difference between any of the light emitters exceeds the allowable range, the process proceeds to step 4, and when the difference does not exceed the allowable range, the calibration ends.

  In Step 4, when the detected light emission amount exceeding the allowable range is smaller than the reference light emission amount, the detected light emission amount exceeding the allowable range is larger than the reference light emission amount in the direction of increasing the light emission amount of the light emitter. Calculates a light source control amount for correcting in a direction to reduce the light emission amount of the light emitter.

  In step 5, the temperature sensor T1 sets the temperature near the light source L1, the temperature sensor T2 sets the temperature near the light source L2, the temperature sensor T3 sets the temperature near the light source L3, and the temperature sensor T4 sets the temperature near the light source L4. Are detected and sent to the temperature data A / D converter 23, which converts them into digital values.

In step 6, the detected temperature data t1 to t4 converted into digital values by the temperature data A / D converter 23 are sent to the temperature correction amount calculator 28 of the light source controller 20, and the temperature correction amount calculator 28 Using the data t1 to t4 and the temperature correction data f (t ₁ ) to f (t ₄ ) stored in the temperature correction type memory, the light source control amount calculated in step 4 is corrected to obtain the light emission control data. .

  In step 7, the light source driving unit 21 re-adjusts the light emission amount of each light emitter of each light source in accordance with the light emission control data, and then executes steps 1 to 3 again.

  In this way, the respective light emission amounts of the respective light sources are adjusted, and if the difference between the detected light emission amount and the reference light emission amount is within the allowable range for all the light emitters of all the light sources in step 3 above, This light source calibration procedure is terminated.

  As described above, according to the embodiment of the present invention, the detected light emission of each light source from the detected light amount using the correlation equation between the detected light amounts of the plurality of color sensors and the light emission amounts of the plurality of light sources. By calculating the amount of light and adjusting the light emission amount of each light source based on these detected light emission amounts, the image quality can be improved in a non-self-luminous configuration in which images are displayed on the screen by light from a plurality of light sources. It is possible to easily calibrate the chromaticity and brightness of the screen and the color unevenness and brightness unevenness in the screen without deteriorating. Furthermore, a temperature sensor for detecting the temperature in the vicinity of each light source is provided, and the light emission chromaticity and light emission brightness control amount are corrected according to the temperature detected by the temperature sensor. Therefore, regardless of the temperature change in the vicinity of the light source, it is possible to easily calibrate the chromaticity and brightness of the screen and the color unevenness and brightness unevenness in the screen without deteriorating the image quality.

  Furthermore, in the conventional image display device, since there is one color sensor, it is necessary to install the color sensor in the center of the screen, and the color sensor must be installed at a position that hinders image display. However, in the image display apparatus according to this embodiment, the light amounts of different areas on the screen are detected by a plurality of color sensors, respectively. Since it can be provided in the periphery of the screen and the color sensor can be installed at a position that does not interfere with image display, light source calibration can be performed as needed.

  In the above-described embodiment, four color sensors are provided in an image display device including four light sources. However, if the number of color sensors is equal to or greater than the number of light sources, the above formula (4) is used to determine the light source. Since the detected light emission amount of the light emitter can be calculated, the number of color sensors can be the same as or more than the number of light sources.

  Further, regarding the temperature sensor, if the temperature dependency for each area is substantially uniform, it is sufficient that there is one temperature sensor in the vicinity of the light source and a low thermal resistance value, that is, one or more for the entire screen.

  In the above embodiment, it is assumed that the gradation characteristic is linear. However, if the gradation characteristic is not linear due to the characteristics of the light source or the color sensor, the gradation characteristic is obtained in advance by measurement or the like. In addition, the amount of light emitted from the light source can be calculated in the same manner by incorporating it into the correlation equation (4).

It is a block diagram of the display panel in the image display apparatus of embodiment of this invention. It is a figure explaining the structure for light source calibration in the image display apparatus of embodiment of this invention, and a light source calibration procedure. It is a flowchart which shows the light source calibration procedure in the image display apparatus of embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Display part, 12 Light-guide plate, L1, L2, L3, L4 Light source, S1, S2, S3, S4 Color sensor, T1, T2, T3, T4 Temperature sensor, 20 Light source control part, 21 Light source drive part, 22 Color data A / D conversion unit, 23 Temperature data A / D conversion unit, 24 Light source emission amount calculation unit, 25 Correlation data memory, 26 Light source control amount calculation unit, 27 Light source reference emission amount data memory, 28 Temperature correction amount calculation unit, 29 Temperature compensation type memory.

Claims (21)

In an image display device that displays an image on a screen by light from a light source capable of adjusting emission chromaticity and emission luminance,
A temperature sensor for detecting a temperature near the light source;
A light source control amount that is a control amount of the light emission chromaticity and light emission luminance of the light source is corrected according to a detection temperature of the temperature sensor, and light emission that is a temperature-corrected light emission chromaticity and light emission luminance control amount is corrected. Temperature correction means for outputting a controlled variable;
An image display apparatus comprising: a driving unit that adjusts and drives the light emission chromaticity and light emission luminance of the light source based on a light emission control amount from the temperature correction unit. A color sensor that detects the chromaticity and brightness of the screen;
Color correlation storage means for storing a color correlation indicating a correlation between the detected chromaticity and detected luminance of the color sensor and the emitted chromaticity and emitted luminance of the light source;
A light source emission amount calculating means for calculating the detected emission chromaticity and the detected emission luminance of the light source from the detected chromaticity and the detected luminance using the color correlation;
The image display apparatus according to claim 1, further comprising: a light source control amount calculation unit that calculates the light source control amount based on the detected light emission chromaticity and the detected light emission luminance. A plurality of the light sources are provided,
A plurality of the temperature sensors are provided corresponding to the light sources,
The temperature sensors detect the temperature in the vicinity of the corresponding light source,
The temperature correction unit corrects the light source control amount of the light source corresponding to the temperature sensor according to the detected temperature of the temperature sensor, and outputs the light emission control amount of the light source.
2. The image display device according to claim 1, wherein the driving unit is driven by adjusting a light emission chromaticity and a light emission luminance of each of the light sources based on a light emission control amount from the temperature correction unit. A plurality of the light sources are provided,
A plurality of the temperature sensors are provided corresponding to the light sources,
The temperature sensors detect the temperature in the vicinity of the corresponding light source,
The temperature correction unit corrects the light source control amount of the light source corresponding to the temperature sensor according to the detected temperature of the temperature sensor, and outputs the light emission control amount of the light source.
The image display apparatus according to claim 2, wherein the driving means is driven by adjusting the light emission chromaticity and light emission luminance of each of the light sources based on the light emission control amount from the temperature correction means. A plurality of the color sensors are provided,
Each color sensor detects chromaticity and brightness for some areas of the screen,
The color correlation represents the correlation between the detected chromaticity and detected luminance of each of the color sensors and the emitted chromaticity and emitted luminance of each of the light sources,
The light source emission amount calculating means calculates the detected emission chromaticity and detected emission luminance of each light source from the detected chromaticity and detected luminance using the color correlation,
The image display device according to claim 4, wherein the light source control amount calculation means calculates the light source control amount of each of the light sources based on the detected light emission chromaticity and the detected light emission luminance. The light source is configured to adjust the light emission chromaticity and the light emission luminance by individually controlling the light emission amounts of the light emitters of a plurality of colors.
The light emission control amount is a control amount for controlling the light emission amount of each of the light emitters,
The image display device according to claim 1, wherein the driving unit is driven by controlling a light emission amount of each of the light emitters according to the light emission control amount. The temperature correction means is
Temperature correction type storage means for storing the relationship between the light emission amount of the light emitters of the plurality of colors and the light emission control amount given according to the temperature near the light source;
7. A temperature correction amount calculation unit that calculates the light emission control amount by correcting the light source control amount using the detected temperature of the temperature sensor and the content of the temperature correction formula storage means. The image display device described.   7. The image display device according to claim 6, wherein the light emitters of the plurality of colors are light emitters of R, G, and B colors. The color sensor detects light amounts of a plurality of colors and outputs these detected light amounts as data of a plurality of channels.
The image display apparatus according to claim 2, wherein the plurality of channels are three channels of R, G, and B. Reference data storage means for storing light source reference emission data to be the reference emission chromaticity and reference emission luminance of each of the light sources is further provided,
3. The image according to claim 2, wherein the light source control amount calculation unit calculates the light source control amount using a difference between the detected light emission chromaticity and the detected light emission luminance and the reference light emission chromaticity and the reference light emission luminance. Display device.   6. The image display device according to claim 5, wherein the number of the color sensors is equal to or greater than the number of the light sources. In an image display method for displaying an image on a screen by light from a light source capable of adjusting emission chromaticity and emission luminance,
According to the detected temperature detected by the temperature sensor that detects the temperature near the light source, the light source control amount that is the control amount of the light emission chromaticity and light emission luminance of the light source is corrected,
Output the light emission control amount that is the control amount of the light emission chromaticity and light emission luminance of the light source corrected for temperature,
An image display method comprising: driving by adjusting light emission chromaticity and light emission luminance of the light source based on the light emission control amount. Color correlation indicating correlation between detection chromaticity and detection luminance detected by a color sensor that detects chromaticity and luminance of a screen and emission chromaticity and emission luminance of the light source, and detection chromaticity and detection luminance by the color sensor Calculate the detected emission chromaticity and detected emission luminance of the light source from
The image display method according to claim 12, wherein the light source control amount is calculated based on the detected light emission chromaticity and the detected light emission luminance. A plurality of the light sources are provided,
A plurality of the temperature sensors are provided corresponding to the light sources,
The temperature sensors detect the temperature in the vicinity of the corresponding light source,
According to the temperature detected by each temperature sensor, the light source control amount of the light source corresponding to each temperature sensor is corrected, and the light emission control amount of each light source is output,
The image display method according to claim 12, wherein the image display method is driven by adjusting light emission chromaticity and light emission luminance of each of the light sources based on the light emission control amount. A plurality of the light sources are provided,
A plurality of the temperature sensors are provided corresponding to the light sources,
The temperature sensors detect the temperature in the vicinity of the corresponding light source,
According to the temperature detected by each temperature sensor, the light source control amount of the light source corresponding to each temperature sensor is corrected, and the light emission control amount of each light source is output,
The image display method according to claim 13, wherein the image display method is driven by adjusting light emission chromaticity and light emission luminance of each of the light sources based on the light emission control amount. A plurality of the above color sensors are provided, and each color sensor detects chromaticity and luminance for each of different areas of the screen,
The color correlation represents the correlation between the detected chromaticity and detected luminance of each of the color sensors and the emitted chromaticity and emitted luminance of each of the light sources,
Using the color correlation, the detected emission chromaticity and detected emission luminance of each light source are calculated from the detected chromaticity and detected luminance,
The image display method according to claim 15, wherein the light source control amount of each of the light sources is calculated based on the detected light emission chromaticity and the detected light emission luminance. The light source is configured to adjust the light emission chromaticity and the light emission luminance by individually controlling the light emission amounts of the light emitters of a plurality of colors.
The light emission control amount is a control amount for controlling the light emission amount of each of the light emitters,
The image display method according to claim 12, wherein the light emission amount of each of the light emitters is controlled and driven by the light emission control amount. Storing the relationship between the light emission amount of the light emitters of the plurality of colors and the light emission control amount given according to the temperature in the vicinity of the light source;
18. The image display method according to claim 17, wherein the light emission control amount is calculated by correcting the light source control amount using the temperature detected by the temperature sensor.   18. The image display method according to claim 17, wherein the light emitters of the plurality of colors are light emitters of R, G, and B colors. The color sensor detects light amounts of a plurality of colors and outputs these detected light amounts as data of a plurality of channels.
The image display method according to claim 13, wherein the plurality of channels are three channels of R, G, and B. The light source control amount is calculated by using the light source reference light emission data to be the reference light emission chromaticity and the reference light emission luminance of each of the light sources, the detected light emission chromaticity and the detected light emission luminance, and the difference between the reference light emission chromaticity and the reference light emission luminance. The image display method according to claim 13.

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