JP2008046375A - Display device and display method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device where the detection of light emission intensity for each illuminant or each desired region is made possible, even when the light from a plurality of the illuminants is detected with a single detection means. <P>SOLUTION: The display device which can independently change the light emission intensity of the first and second illuminants is provided with a light emission intensity detection means, capable of detecting the light emission intensity of the first and second illuminants; a light emission time indication means for indicating the detection period of lighting either the first or the second illuminants, and making the other of either the first or the second illuminants; a light emission intensity calculation means for calculating the light emission intensity of either the first or of the second illuminants, on the basis of the detection result by light emission intensity detection means during the detection period. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a display device including a plurality of light emitters and a detection method for detecting the light emission intensity of these light emitters.

  In recent years, flat panel displays such as liquid crystal display devices have been used as display devices such as monitors for mobile phones, televisions, and various electronic devices. A backlight unit is used as a mechanism for supplying light to a display panel such as a liquid crystal display device.

  The backlight unit is a planar light source that irradiates light toward the back of the display panel. The backlight unit is a planar light source for irradiating the display panel with a light emitter such as a fluorescent lamp or a light-emitting diode and the luminous flux of the light emitter. And an optical path conversion means such as a light guide plate for converting the light beam into a light beam. Particularly in recent years, those using light-emitting diodes as light emitters have been widely used for the purpose of miniaturization, thinning, and long life.

  As a driving method of this backlight unit, R (red), G (green), and B (blue) light emitters of three colors are simultaneously turned on to synthesize white light, which is combined with R (red), G ( A color filter system that performs full color display by irradiating the front of the display panel through three color filters of green and B (blue) is common.

Here, in the display device, the chromaticity of the display panel surface needs to be kept constant or adjusted. Therefore, a technique has been proposed in which the light emission intensity of a plurality of light emitters is detected, the light emission intensity is controlled based on the detection result, and the chromaticity of the display panel surface is kept constant or adjusted. (For example, see Patent Document 1)
However, in the technique as disclosed in Patent Document 1, since a combination of light from a plurality of light emitters is detected by a single detection unit, each light emitter or each desired region is detected. It was not possible to detect the emission intensity.
JP 2005-164710 A

  The present invention provides a display device capable of detecting the light emission intensity for each light emitter or each desired region, even if light from a plurality of light emitters is detected by a single detection means, and these light emitters Provided is a detection method for detecting the emission intensity.

  According to one aspect of the present invention, there is provided a display device capable of independently changing the light emission intensities of the first and second light emitters, which can detect the light emission intensities of the first and second light emitters. A light emission intensity detecting means; a light emission time designating means for designating a detection period in which one of the first and second light emitters is turned on and the other one of the first and second light emitters is turned off; Luminescence intensity calculating means for calculating the luminescence intensity of either one of the first and second illuminants based on a detection result by the luminescence intensity detecting means in a detection period. A display device is provided.

  According to another aspect of the present invention, there is provided a detection method for detecting the light emission intensity of the light emitter in a display device capable of independently changing the light emission intensity of the first and second light emitters. Light emission capable of detecting the light emission intensity of the first and second light emitters by turning on one of the first and second light emitters and turning off the other of the first and second light emitters. A detection method is provided, wherein the intensity detection means detects the emission intensity of either one of the first and second light emitters.

  ADVANTAGE OF THE INVENTION According to this invention, even if it detects light from several light-emitting body with a single detection means, the display apparatus and detection which can detect the light emission intensity for every light-emitting body or for every desired area | region A method is provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram for explaining chromaticity / brightness adjusting means of the display device according to the first embodiment.

  As shown in FIG. 1, the chromaticity / brightness adjusting means 1 includes a light emission intensity detection means 2, an A / D (Analog / Digital) conversion means 3, a light emission time designation means 4, a light emission intensity storage means 5, and a light emission intensity calculation means. 6, an input unit 7, an RGB (red / green / blue) conversion unit 8, a light emission intensity control unit 9, and a light emission output unit 10.

  The emission intensity detecting means 2 has different spectral sensitivities for each wavelength region of R (red), G (green), and B (blue), and each wavelength component of the light irradiated to the light receiving unit. A signal (luminance R, luminance G, luminance B) corresponding to the change in the emission intensity of is output. The output signals (R luminance, G luminance, B luminance) are sent to the A / D conversion means 3. The light emission intensity detection means 2 is provided at a position where the irradiation energy from the light emitting body turned on by the light emission output means 10 can be detected. As a specific example of the emission intensity detecting means 2, a color sensor or the like can be exemplified. Further, each output from the emission intensity detecting means 2 may be amplified by a signal amplifying means (not shown) so as to obtain a desired gain.

The A / D conversion means 3 has a function of converting the analog output signal from the light emission intensity detection means 2 into a digital signal having a desired resolution. The converted digital signal (emission intensity) is sent to the emission intensity storage means 5.
The light emission time designating means 4 has a function of designating a desired light emitter lighting or extinguishing condition (timing, lighting / extinguishing time length, etc.). Here, lighting or extinguishing can be arbitrarily designated for each light emitter among a plurality of light emitters or for each desired region. It should be noted that the length and timing of the designated time may be determined uniformly in advance or may be arbitrarily set. Information from the light emission time designating means 4 (lighting / lighting off timing, length of lighting / lighting off time, designation of target light emitter and region, etc.) is sent to the light emission intensity storage means 5 and the light emission intensity control means 9. .

  The emission intensity storage unit 5 has a function of storing the emission intensity detected by the emission intensity detection unit 2 and converted by the A / D conversion unit 3. In this case, since some of the light emitters are turned off by the information from the light emission time designating unit 4, the stored light emission intensity is the light emission intensity of the remaining light emitting bodies. Therefore, together with the detected light emission intensity, which light emitter is lit is also stored. The stored information is sent to the emission intensity calculation means 6.

  The light emission intensity calculation means 6 has a function of calculating the light emission intensity for each light emitter or each desired region based on the light emission intensity stored in the light emission intensity storage means 5. The calculated emission intensity is sent to the emission intensity control means 9.

  The input means 7 is for inputting chromaticity diagram coordinates Cx, Cy and luminance Y on the chromaticity diagram as control command values in order to display desired chromaticity / luminance. The input may be performed manually by the user or may be automatically transmitted from command means (not shown). These input values are sent to the RGB (red / green / blue) conversion means 8 as a Cx control command value, a Cy control command value, and a Y control command value.

  The RGB (red / green / blue) conversion means 8 converts the control command values (chromaticity diagram coordinates Cx, Cy and luminance Y) set by the input means 7 into R (red), G (green), and B (blue). ) To each luminance command value. The converted luminance command values of R (red), G (green), and B (blue) are sent to the light emission intensity control means 9.

  At this time, conversion to R (red), G (green), and B (blue) luminance command values is performed based on the following equations (1) to (3).

  Here, Cx: command value of chromaticity diagram coordinates Cx, Cy: command value of chromaticity diagram coordinates Cy, Y: luminance command value, X, Z: remaining tristimulus values excluding Y, R, G, B: Emission intensity command value of each color illuminant, a11 to a33: conversion constants.

  The conversion constants a11 to a33 are for correcting the detection characteristic error of the light emission intensity detection means 2. Specifically, the actual tristimulus values (X, Y, Z) detected using the emission intensity detection means 2 are approximated by the matrix of the equation (3), and the error from the ideal tristimulus value is minimized. Nine conversion constants from a11 to a33 are calculated and obtained.

  The emission intensity control means 9 includes RGB luminance command values converted and sent by the RGB (red / green / blue) conversion means 8, the A / D conversion means 3 detected by the emission intensity detection means 2, and the emission intensity. It has a function of comparing the value sent via the storage means 5 and the light emission intensity calculation means 6 and controlling the output of the light emission output means 10 so that the detected value approaches the luminance command value. Further, it has a function of controlling the output of the light emission output means 10 so that the designated light emitter is turned on or off based on the information sent from the light emission time designation means 4. This control signal (R control signal, G control signal, B control signal) is sent to the light emission output means 10.

  The light emission output means 10 has a function of adjusting the light emission intensity of each light emitter and turning it on / off based on a control command from the light emission intensity control means 9.

Next, before describing the operation of the chromaticity / luminance adjusting means 1, detection of the light emission intensity for each light emitter or each desired region will be described.
FIG. 2 is a schematic diagram showing a display device that can be provided with the chromaticity / luminance adjusting means 1 illustrated in FIG. That is, the liquid crystal display device 16 of this specific example is a color filter type liquid crystal display device that performs full color display by simultaneously turning on light emitting diodes of three colors of R (red), G (green), and B (blue). .
As shown in FIG. 2, the liquid crystal display device 16 includes chromaticity / luminance adjusting means 1, a liquid crystal panel 17, and a backlight unit 18. The liquid crystal panel 17 is provided on the upper surface of the backlight unit 18.

  In general, the backlight unit includes a sidelight type in which a light emitter is provided on the end face of the light guide plate 20 and a direct type in which one or a plurality of light emitters are provided opposite to the back surface of the liquid crystal panel. The side light type is shown in.

  The backlight unit 18 includes a light guide plate 20, a light source 21, a light guide 23, a light incident prism 24, and a reflection plate 25. In the light source 21, a plurality of R (red), G (green), and B (blue) light emitting diodes (light emitters) 22 are arranged in a line. The light guide plate 20 is appropriately divided, and a light shielding material (not shown) is provided on the division surface so that light between adjacent light guide plates 20 does not interfere. Further, a light guide 23 is provided in the vicinity of the entrance of the light guide plate 20 so that light traveling toward the adjacent light guide plate 20 does not enter.

  Each light guide plate 20 is provided with emission intensity detecting means 2. The position where the emission intensity detection means 2 is provided can be selected as appropriate, such as the surface or the inside of the light guide plate 20. In consideration of the balance of the distance from the light emitting diodes (light emitting bodies) 22 at both ends, it is preferable to provide the light emission intensity detecting means 2 near the center of each light guide plate 20.

These light emitting diodes (light emitting bodies) 22 are connected to the light emitting output means 10 provided in the chromaticity / luminance adjusting means 1. Then, the light emission output means 10 is controlled by the light emission intensity control means 9, and the lighting current control and the lighting ratio control for switching between lighting and extinguishing in a cycle of about several tens Hz to several tens of kHz are performed, and R (red) , G (green), and B (blue) emission intensity can be controlled independently.
The light emitted from the light emitting diode (light emitting body) 22 is guided to the light guide plate 20 via the light incident prism 24. The light traveling while being diffused through the light guide plate 20 enters the liquid crystal panel 17 and is displayed as a color image. In the case of the color filter method, the R (red), G (green), and B (blue) light emitting diodes are simultaneously turned on and mixed in the light guide plate 20 to become white light. The white light passes through a color filter provided on the liquid crystal panel 17 and becomes R (red), G (green), and B (blue) light.
According to the present invention, it is possible to detect the light emission intensity of each light emitter at the right end and the left end of the light guide plate 20. Therefore, the left and right light emitters can be controlled, and individual adjustments can be made even if there are variations in light emission intensity due to manufacturing errors or aging of the light emitters.
That is, in each light guide plate 20 of this specific example, when the light emission intensity detection means 2 tries to detect the light emission intensity of the light emitter, the detected value is the sum of the light emission intensities of the light emitters provided at the left and right ends. .

  FIG. 3 is a schematic graph for explaining the detected value of the light emission intensity when the light emitters provided at the left and right ends are turned on simultaneously. The left and right light emitters are assumed to have the same light emission intensity. The schematic graph of FIG. 3A shows the lighting timing of the rightmost light emitter. The schematic graph of FIG.3 (b) has shown the lighting timing of the leftmost light-emitting body. The schematic graph of FIG. 3C shows the emission intensity detected by the emission intensity detection means 2. In addition, the section L in the figure indicates the lighting time section, and the section D indicates the turn-off time section. Specifically, the sum of the section L and the section D can be about 5 milliseconds to 16 milliseconds. In addition, as shown in FIG.3 (c), it is due to the temperature characteristic of a light-emitting body that emitted light intensity falls with time.

  In this way, when the left and right light emitters are simultaneously turned on, the light emission intensity for each of the left and right light emitters cannot be detected, and individual control of the left and right light emitters based on the respective detection values cannot be performed. As a result, even if the left and right light emitters have variations in emission intensity due to manufacturing errors or variations in emission intensity due to secular change, they cannot be individually adjusted, and the brightness of the display screen is distributed. The display quality is remarkably deteriorated due to the occurrence of color shift. Note that the detected value of the light emission intensity at this time is the sum of the light emission intensities of the left and right light emitters, as shown in FIG.

  For such a problem, it is also conceivable to provide a dedicated emission intensity detection means 2 for each light emitter. However, if this is done, there will be a new problem that the chromaticity / brightness adjusting means 1 becomes complicated, large and expensive.

  As a result of the study, the present inventor, even when detecting with the single light emission intensity detection means 2, if the lighting time is divided and the lighting timing of each light emitter is changed, each light emitter or a desired region The knowledge that it was possible to detect the emission intensity for each time was obtained.

  FIG. 4 is a schematic graph for illustrating a first specific example of the present embodiment. The schematic graph of FIG. 4A shows the lighting timing of the light emitter at the right end of the light guide plate 20. The schematic graph of FIG. 4B shows the lighting timing of the light emitter at the left end of the light guide plate 20. The schematic graphs of FIGS. 4C and 4D are detection values obtained by the emission intensity detection means 2. The schematic graph of FIG. 4E shows the measured value of the light emission intensity of the rightmost light emitter detected by the light emission intensity detection means 2. The schematic graph of FIG.4 (f) has shown the measured value of the emitted light intensity of the leftmost light-emitting body.

  In this specific example, as shown in FIGS. 4 (a) and 4 (b), the section L of the lighting time of the light emitter is divided into eight equal parts while one of the left and right light emitters is on. The other is turned off. Therefore, the left and right light emitters are not lit at the same time, and the light emission intensities of the left and right light emitters can be detected separately by one light intensity detecting means 2. That is, for example, when the rightmost illuminant is turned on and the leftmost illuminant is turned off, this is a detection period in which the emission intensity of the rightmost illuminant can be detected.

  As shown in FIG. 4C, if the light detection unit (light sensor or the like) of the light emission intensity detection means 2 is located at an equivalent position from the left and right light emitters, and the left and right light emitters have the same light emission intensity. The measured value of the emission intensity draws a substantially continuous single detection curve. On the other hand, when the left and right light emitters have different light emission intensities, as shown in FIG. 4D, the measured value of the light intensity increases and decreases in accordance with the timing at which the left and right light emitters light.

  In both the case shown in FIG. 4 (c) and the case shown in FIG. 4 (d), the light emission intensity of the left and right light emitters are measured alternately. If it decomposes | disassembles for every, the emitted-light-intensity detection value for every right-and-left light-emitting body as shown to FIG.4 (e) and (f) can be calculated | required. Note that the reason for detecting the entire lighting period L is to consider the variation in the light emission intensity due to the temperature characteristics described above. However, as shown in FIGS. 4A and 4B, it is considered that the temporal change in the light emission intensity in the section L in the case of lighting in pulses is often different from the case of lighting continuously. That is, when the light is continuously lit during the section L, the temperature of the light emitter continuously rises, and thus the detected value of the light emission intensity shows an attenuation characteristic as illustrated in FIG. On the other hand, when the pulse lighting is performed as shown in FIGS. 4A and 4B, it is considered that the temperature rise of the light emitter may be relatively moderate. In such a case, it is considered that the attenuation characteristic of the light emission intensity as seen in the entire section L also becomes gentle. In addition, it is considered that the light emission intensity when the light is turned on after being turned off in a pulse is higher than the light emission intensity immediately before the light is turned off. However, even in these cases, according to the present embodiment, the light emission intensity of the left and right light emitters can be detected separately.

FIG. 5 is a schematic graph illustrating the case where the emission intensity of the light emitter is not attenuated. FIGS. 5A to 5F correspond to FIGS. 4A to 4F, respectively.
When there is no attenuation of the illuminant, as shown in FIG. 5 (c) or (d), the value of the luminescence intensity detected by the luminescence intensity detecting means 2 is not attenuated. As shown in FIGS. 5E and 5F, a pulsed emission intensity detection value having a constant height is obtained for each of the left and right light emitters.

  By the way, in the specific example illustrated in FIGS. 4 and 5, half the time of the section L, which is the lighting time, is allocated to the turn-off time. As a result, as shown in FIG. 4 and FIG. 5, the total value of the light emission intensity is about 50% of the case of simultaneous lighting on the left and right (represented by the alternate long and short dash line in FIG. 4 and FIG. 5). Become. Such a problem can be solved by detecting the emission intensity in a specific period rather than constantly. For example, the detection may be performed when the influence on the dark screen is small, such as when the display device is activated or during a period specified by the user.

  As a result of further study, the present inventor has found that if the detection is performed while shifting the turn-off time over a plurality of sections L, the screen is prevented from being darkened, and the emission intensity can be detected even when the display device is used. Obtained.

6 and 7 are schematic graphs for explaining the second specific example of the present invention.
That is, the schematic graphs of FIGS. 6A and 7A show the lighting timing of the rightmost light emitter. The schematic graphs of FIGS. 6B and 7B show the lighting timing of the leftmost light emitter.

  The schematic graphs of FIGS. 6C and 6D and FIGS. 7C and 7D show the detected values of the emission intensity by the emission intensity detecting means 2. This detected light emission intensity becomes the light emission intensity of the display screen. Here, FIG. 6C and FIG. 7C show the case where the light emission intensity of the left and right light emitters is the same, and FIG. 6D and FIG. 7D are compared with the light emitter at the right end. Represents the case where the emission intensity of the leftmost light emitter is low. In any of these cases, the light emission intensities of the left and right light emitters are separately detected, and therefore the light emission intensities of the left and right light emitters can be detected by extracting the results divided by time. That is, for example, when the rightmost illuminant is turned on and the leftmost illuminant is turned off, this is a detection period in which the emission intensity of the rightmost illuminant can be detected. On the contrary, when the leftmost light emitter is turned on and the rightmost light emitter is turned off, the detection period in which the light emission intensity of the left light emitter can be detected is set.

  The schematic graph of FIG.7 (e) has shown the detected value of the emitted light intensity of the light-emitting body of the right end obtained in this way. Moreover, the schematic graph of FIG.7 (f) has shown the detected value of the emitted light intensity of the leftmost light-emitting body obtained similarly.

  In this specific example, as shown in FIGS. 6 (a), 6 (b), 7 (a), and 7 (b), one turn-off is performed while shifting the timing over the sections L1 to L4 of each lighting time. I try to set aside time. Therefore, for a single light emitter, the turn-off time is only 1/8 (12.5%) of the turn-on time. As a result, as shown in FIGS. 6 (c) and 7 (c), the combined light emission intensity is about 87.5% in the case of simultaneous lighting, and a decrease in light emission intensity can be suppressed.

  Further, in this specific example, in each of the sections L1 to L4, the left end light emitter is first turned off, and then the right end light emitter is turned off, whereby the emission intensity from each light emitter is shown in FIG. Detection is performed as shown in e) and (f). Thereafter, in each of the sections L1 to L4, the order is reversed, and first the rightmost light emitter is extinguished, and then the leftmost light emitter is extinguished, thereby measuring the light emission intensities of the leftmost light emitter and the rightmost light emitter. Then, by adding to the detection results shown in FIGS. 7E and 7F, it is possible to obtain continuous detection values for each of the right and left light emitters. Such detection value storage can be executed in the emission intensity storage means 5.

  In this specific example as well, the case where the light emission intensity of the light emitter gradually decreases due to the temperature change in each of the sections L1 to L4 is exemplified. However, the light emission intensity after the light is turned off in the middle of the section L is turned off. In some cases, it becomes higher than the light emission intensity immediately before. However, even in such a case, according to this specific example, the light emission intensities of the left and right light emitters can be detected. As described above with reference to FIG. 5, this specific example can be similarly applied even when the light emission intensity of the light emitter is not attenuated.

  Here, in the specific examples shown in FIGS. 6 and 7, the left and right light emitters are turned off for 1/8 time in each of the sections L1 to L4, but the present invention is not limited to this. . That is, if the turn-off time is shortened, the decrease in emission intensity can be further reduced. For example, if each light emitter is turned off for a time that is 1/1000 of the length of each of the sections L1 to L4, a decrease in light emission intensity can be suppressed to 1/1000. However, if the turn-off time is shortened, the light emission intensity detection time is shortened accordingly. Therefore, it is preferable to appropriately determine the time and the number of sections in which each light emitter is turned off based on the reliability of detection, the necessity of detecting light emission intensity, and the like. Further, the detection value can be stored in the light emission intensity storage means 5 and added as appropriate, whereby the detection reliability can be improved.

As described above, according to the second specific example, since it is possible to suppress a decrease in light emission intensity (darkening of the display screen) during detection, it is possible to always detect the light emission intensity. Next, returning to FIG. 1, the operation of the chromaticity / luminance adjusting means 1 will be described.
First, chromaticity diagram coordinates Cx, Cy and luminance Y are input to the input means 7 as control command values. The input control command values for the chromaticity diagram coordinates Cx, Cy and luminance Y are sent to the RGB (red / green / blue) conversion means 8.
Next, in the RGB (red / green / blue) conversion means 8, the transmitted chromaticity diagram coordinates Cx, Cy and brightness Y control command values are based on the above-described equations (1) to (3). Conversion into R (red), G (green), and B (blue) luminance command values.

  On the other hand, based on information from the light emission time designating unit 4, the light emission intensity control unit 9 turns on or off the designated light emitter. The timing of lighting or extinguishing the light emitter at this time, the length of time, and the like are as described with reference to FIGS.

  The light emission intensity of the illuminator thus lit is detected by the light emission intensity detection means 2. The detection is performed every R (red), G (green), and B (blue).

  Next, the detected detection value is sent to the A / D conversion means 3 and converted into a digital signal.

  The detection value converted into the digital signal is stored in the light emission intensity storage means 5 together with the lighting or extinguishing timing and the length of time as information on the detection target light emitter. Information other than the detected value is sent from the light emission time designating means 4.

  When one detection is completed, the information stored in the emission intensity storage unit 5 is sent to the emission intensity calculation unit 6. The light emission intensity calculation means 6 calculates the light emission intensity (detection value) for each light emitter or for each desired region by calculating by adding together the detection values stored as described above. The obtained emission intensity (detected value) is sent to the emission intensity control means 9.

  In the emission intensity control means 9, the luminance command value converted by the RGB (red / green / blue) conversion means 8 is compared with the detection value sent from the emission intensity calculation means 6, and the detection value is the luminance instruction value. The output to the light emitter is controlled so as to approach. At this time, each luminance of the light emitter can be detected again by the light emission intensity detecting means 2, and the above-described procedure can be repeated. By doing so, the accuracy of adjustment can be increased.

FIG. 8 is a configuration diagram for explaining chromaticity / luminance adjusting means of the display device according to the second embodiment of the present invention.
As shown in FIG. 8, the chromaticity / brightness adjusting means 11 includes a light emission intensity detection means 2, an A / D (Analog / Digital) conversion means 3, a light emission time designation means 4, a light emission intensity storage means 5, and a light emission intensity calculation means. 6, an input unit 7, an RGB (red / green / blue) conversion unit 8, a light emission intensity control unit 9, a light emission output unit 10, and a light emission intensity complementing unit 12. In addition, the same code | symbol is attached | subjected to the part similar to FIG. 1, and description is abbreviate | omitted.

  The emission intensity complementing means 12 has a function of complementing the detection value sent from the emission intensity storage means 5 to the emission intensity calculation means 6. Here, the supplement performed in the light emission intensity complementation means 12 is demonstrated.

  FIG. 9 is a schematic graph for explaining the complement performed in the light emission intensity complementing means 12. The schematic graph of FIG. 9A shows the lighting timing of the rightmost light emitter. The schematic graph of FIG.9 (b) has shown the lighting timing of the leftmost light-emitting body. The schematic graph of FIG. 9C is a detected value of the emission intensity by the emission intensity detecting means 2. This detection value corresponds to the sum of the emission intensities of the left and right light emitters, and corresponds to the emission intensity of the display screen. The schematic graph of FIG. 6D shows the light emission intensity of the rightmost light emitter. The schematic graph of FIG.6 (e) has shown the light emission intensity | strength of the light emitter of the right end after a complement.

  In the specific example described above with reference to FIGS. 6 and 7, four sections (L1 to L4) are detected, but in the specific example described with reference to FIG. 8, detection values in two sections (L1 and L4) are detected. Then, the detected values of the remaining two sections (L2, L3) are complemented to obtain the entire emission intensity.

  That is, the detection values of the two sections (L1, L4) shown in FIG. 9D can be connected by a straight line as shown in FIG. 9E, and the values between the detection values can be complemented. For convenience of explanation, the case of the rightmost light emitter has been described, but the same applies to the case of the leftmost light emitter. In addition, the position and number of sections to be selected can be changed as appropriate. Further, when the emission intensity attenuation of the illuminant is non-linear, the number of measurement points can be increased as appropriate and the measurement points can be supplemented with a straight line or approximated with a curve.

  In this way, since the number of sections required for detection can be reduced, a decrease in emission intensity can be further suppressed. For example, in the sections L1 to L4 described above with reference to FIGS. 6 and 7, the detection is performed as described above with reference to FIG. 9 in the sections L1 and L4, and the emission intensity is detected in the sections L2 and L3. Without causing the left and right light emitters to emit light continuously. In this way, it is possible to reduce the problem of the screen becoming dark due to the detection of the emission intensity.

  Next, returning to FIG. 8, the operation of the chromaticity / luminance adjusting means 11 will be described. First, chromaticity diagram coordinates Cx, Cy and luminance Y are input to the input means 7 as control command values. The input control command values for the chromaticity diagram coordinates Cx, Cy and luminance Y are sent to the RGB (red / green / blue) conversion means 8.

  Next, in the RGB (red / green / blue) conversion means 8, the transmitted chromaticity diagram coordinates Cx, Cy and brightness Y control command values are based on the above-described equations (1) to (3). Conversion into R (red), G (green), and B (blue) luminance command values.

  On the other hand, based on information from the light emission time designating unit 4, the light emission intensity control unit 9 turns on or off the designated light emitter. The timing of lighting or extinguishing the light emitter at this time, the length of time, and the like are as described above with reference to FIG.

The light emission intensity of the illuminator thus lit is detected by the light emission intensity detection means 2. The detection is performed every R (red), G (green), and B (blue).
Next, the detected detection value is sent to the A / D conversion means 3 and converted into a digital signal.

  The detection value converted into the digital signal is stored in the light emission intensity storage means 5 together with the lighting or extinguishing timing and the length of time as information on the detection target light emitter. Information other than the detected value is sent from the light emission time designating means 4.

When one detection is completed, the information stored in the emission intensity storage unit 5 is sent to the emission intensity complementing unit 12. The light emission intensity complementing means 12 complements the values between the detection values described above.
Note that information such as the timing of lighting or extinguishing, the length of time, and the position of the section to be selected is sent from the light emission time designating unit 4. The detection value and the value obtained by complementation are sent to the emission intensity calculation means 6.

  The light emission intensity calculation means 6 calculates the light emission intensity for each light emitter or each desired region by calculating based on the input value. The obtained emission intensity is sent to the emission intensity control means 9.

  In the light emission intensity control means 9, the luminance command value converted by the RGB (red / green / blue) conversion means 8 is compared with the value sent from the light emission intensity calculation means 6, and this value is used as the luminance command value. The output to the light emitter is controlled so as to approach. At this time, each luminance of the light emitter can be detected again by the light emission intensity detecting means 2, and the above-described procedure can be repeated. By doing so, the accuracy of adjustment can be increased.

FIG. 10 is a schematic diagram for explaining the brightness adjusting means of the display device according to the third embodiment of the present invention. 10, the same elements as those described above with reference to FIGS. 1 to 9 are denoted by the same reference numerals, and detailed description thereof is omitted.
As shown in FIG. 10, the luminance adjusting means 13 includes a light emission intensity detecting means 14, an A / D (Analog / Digital) converting means 3, a light emission time designating means 4, a light emission intensity storage means 5, a light emission intensity calculating means 6, and an input. Means 7, light emission intensity control means 9, light emission output means 10, and light emission intensity complementing means 12 are provided.

  The chromaticity / brightness adjusting means 11 described above with reference to FIG. 8 can individually control the light emission intensities of R (red), G (green), and B (blue) light emitters. The luminance adjusting means 13 of the embodiment can control the emission intensity of one color (for example, white).

The light emission intensity detecting means 14 outputs a signal (luminance) corresponding to a change in the light emission intensity of the light irradiated to the light receiving unit.
The input means 15 is for inputting a luminance control command value in order to display a desired luminance. The input luminance control command value is sent to the light emission intensity control means 9. The input may be performed manually by the user or automatically transmitted from command means (not shown).

Further, the light emission intensity complementing means 12 is not necessarily required, and the configuration of this portion can be the same as that shown in FIG.
The operation of the brightness adjusting unit 13 is substantially the same as that of the chromaticity / brightness adjusting unit 11 except that the brightness control command value input to the input unit 15 is sent to the light emission intensity control unit 9 as it is, and a description thereof will be omitted.

FIG. 11 is a schematic view for illustrating a display device according to the fourth embodiment of the invention.
As shown in FIG. 11, the direct type backlight 26 is provided with an R (red) light emitting diode 27R, a G (green) light emitting diode 27G, and a B (blue) light emitting diode 27B. Moreover, the light emission intensity detection means 2 is provided in the place which can detect the light from each light-emitting body.

  In this configuration, the case where the light emission intensity of a specific light emitting diode 27a is detected will be described. The above light emission intensity may be detected in comparison between the light emitting diode 27a and other light emitting diode groups. That is, the above-described emission intensity may be detected by turning on and off the light emitting diode 27a and the other light emitting diode groups alternately.

  At this time, the light emitting diode to be detected is not limited to a single one, but may be a desired region such as a central portion or a left end portion. Further, only R (red) light emitting diodes 27R can be combined in any combination such as every other one.

  The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples.

  As for the above-described specific examples, those skilled in the art appropriately modified the design are included in the scope of the present invention as long as they have the characteristics of the present invention.

  For example, elements such as the backlight unit 18, the light guide plate 20, the light source 21, the light guide 23, the light incident prism 24, the reflection plate 25, the light emitter, the liquid crystal panel 17, the color filter, and the direct type backlight 26 used in the present invention include However, the present invention is not limited to the illustrated shape and size, and the same effect can be obtained even if the cross-sectional shape, dimensions, material, arrangement, and the like are changed as appropriate. It is included in the range.

  Further, as the light emission intensity detecting means 2, those having different spectral sensitivities (color sensors) for each wavelength region of R (red), G (green), and B (blue) have been exemplified. Those having no sensitivity (for example, a photodiode having no color filter) can also be used. However, in consideration of the sensor sensitivity at the boundary of each color, it is preferable to use one having spectral sensitivity (such as a color sensor).

  Although a liquid crystal display device has been described as an example of a display device, the present invention is not limited to this, and can be widely applied to display devices including a plurality of light emitters.

  Further, although the light emitting diode has been described as an example of the light emitting body, the light emitting diode is not limited thereto, and may be a cold cathode tube, an organic EL (Electro Luminescence), an inorganic EL (Electro Luminescence), or the like. However, in order to increase the number of times for dividing the lighting time, it is preferable to use a light emitter that can respond to high frequencies, and among these, a light emitting diode is more preferable.

It is a block diagram for demonstrating the chromaticity / brightness | luminance adjustment means of the display apparatus which concerns on 1st Embodiment. It is a schematic diagram showing the display apparatus which can provide the chromaticity / brightness | luminance adjustment means 1 illustrated in FIG. It is a schematic diagram explaining the detected value of the emitted light intensity in the case of making the light-emitting body provided in both right and left ends light simultaneously. It is a schematic graph for demonstrating the 1st specific example of this embodiment. It is a schematic graph which illustrates the case where there is no attenuation of the emitted light intensity of a light-emitting body. It is a schematic graph for demonstrating the 2nd example of this invention. It is a schematic graph for demonstrating the 2nd example of this invention. It is a block diagram for demonstrating the chromaticity / brightness | luminance adjustment means of the display apparatus which concerns on the 2nd Embodiment of this invention. It is a schematic diagram for explaining the complementation performed in the emission intensity complementation means 12. It is a schematic diagram for demonstrating the brightness | luminance adjustment means of the display apparatus which concerns on the 3rd Embodiment of this invention. It is a schematic diagram for illustrating the display apparatus concerning the 4th Embodiment of this invention.

Explanation of symbols

  1 chromaticity / brightness adjustment means, 2 emission intensity detection means, 3 A / D conversion means, 4 emission time designation means, 5 emission intensity storage means, 6 emission intensity calculation means, 7 input means, 8 RGB (red / green / red) Blue) Conversion means 8, 9 Light emission intensity control means, 10 Light emission output means, 11 Chromaticity / brightness adjustment means, 12 Light emission intensity complementing means, 13 Brightness adjustment means, 14 Light emission intensity detection means, 15 Input means, 16 Liquid crystal display device , 17 liquid crystal panel, 18 backlight unit, 20 light guide plate, 21 light source, 22 light emitting diode (light emitter), 23 light guide, 24 light incident prism, 25 reflector, 26 direct type backlight, 27B light emitting diode, 27G light emitting Diode, 27R light emitting diode, 27a light emitting diode

Claims (6)

A display device capable of independently changing the emission intensity of the first and second light emitters,
Emission intensity detecting means capable of detecting the emission intensity of the first and second light emitters;
A light emission time designating unit for designating a detection period in which one of the first and second light emitters is turned on and the other one of the first and second light emitters is turned off;
A light emission intensity calculating means for calculating the light emission intensity of either one of the first and second light emitters based on a detection result by the light emission intensity detecting means in the detection period;
A display device comprising:   The light emission time designating unit repeatedly sets a lighting section in which the first and second light emitters are to be turned on simultaneously and a light-out section in which the first and second light emitters are to be turned off simultaneously. The display device according to claim 1, wherein the detection period is sequentially shifted for each lighting section.   The display device according to claim 2, further comprising emission intensity complementing means for complementing between detection values in the different detection periods. A detection method for detecting the light emission intensity of the light emitter in a display device capable of independently changing the light emission intensity of the first and second light emitters,
Light emission capable of detecting the light emission intensity of the first and second light emitters by turning on one of the first and second light emitters and turning off the other of the first and second light emitters. A detection method characterized by detecting an emission intensity of one of the first and second light emitters by an intensity detection means.   The lighting period in which the first and second light emitters are to be turned on simultaneously and the light-off period in which the first and second light emitters are to be turned off simultaneously are set repeatedly, and the detection period is set for each lighting period. The detection method according to claim 3, wherein the detection is performed by sequentially shifting. The detection method according to claim 5, wherein a gap between detection values in different detection periods is complemented.

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