JP4506159B2 - LIGHTING DEVICE AND METHOD, DISPLAY DEVICE AND METHOD, AND PROGRAM - Google Patents

Description

  The present invention relates to an illuminating device and method, a display device and method, and a program, and in particular, the chromaticity of luminance and chromaticity of light incident from a plurality of lamps and emitted from a light guide plate even when the situation changes. The present invention relates to an illumination device and method, a display device and method, and a program that can hold almost all of the coordinates as a target value.

  In recent years, liquid crystal display devices have become widespread. This liquid crystal display device displays an image by controlling the transmittance of light incident on the liquid crystal panel for each pixel. Therefore, a backlight device that makes light incident on the liquid crystal panel is often incorporated on the back side of the liquid crystal panel.

  The light source of the backlight device is often a single cold cathode tube (hereinafter referred to as a lamp) in a notebook personal computer or the like, whereas in a stationary personal computer or a television receiver, etc. In many cases, it is a plurality of lamps (see Patent Documents 1 to 4).

  By the way, in the liquid crystal display device, the chromaticity (chromaticity coordinates) of the light emitted from the lamp of the backlight device corresponding to the target chromaticity (target value of the chromaticity coordinates) of the light emitted from the liquid crystal panel. Was decided. In other words, for example, when the target is to emit light with a chromaticity of 6500 degrees or 9300 degrees from the liquid crystal panel (corresponding to 6500 degrees or 9300 degrees on the black body curve in the chromaticity diagram) When the chromaticity coordinate of the chromaticity (point) is a target value), the lamp is manufactured as follows. In other words, in order to obtain a target chromaticity on the liquid crystal surface of the liquid crystal panel, a change in chromaticity due to color attenuation between the lamp and the liquid crystal panel is taken into account, and a phosphor corresponding to the chromaticity change is prepared to prepare the lamp. It has been produced. That is, according to the target chromaticity, the phosphor blending type is set.

Thus, the chromaticity of the light from the lamp is generally fixed (made as such).
Japanese Patent Laid-Open No. 11-174976 Japanese Patent Laid-Open No. 9-292614 JP-A-8-286184 JP 2001-351425 A

  However, in practice, if the lamp current is changed for the purpose of adjusting the brightness of the liquid crystal panel (adjusting the brightness of the light from the lamp), the chromaticity of the light from the lamp changes according to the change in the current. As the current increases, the chromaticity coordinates change in the green direction. As a result, the chromaticity of light from the liquid crystal panel deviates from the target chromaticity (the chromaticity changes). There was a first problem.

  Furthermore, when the accumulated time during which the lamp is lit (that is, the accumulated time during which the current flows through the lamp, hereinafter referred to as the accumulated operation time) becomes longer, for example, from about 3000 hours to about 10,000 hours, The phosphor of the blue color of the phosphor deteriorates, the chromaticity coordinate of the chromaticity of the light from the lamp changes in the yellow direction, and as a result, the chromaticity of the light from the liquid crystal panel deviates from the target chromaticity. There was a second problem that the chromaticity coordinates are shifted in the yellow direction.

  Furthermore, if the temperature of the lamp changes due to heat generation due to the lamp current itself or the ambient temperature change, the chromaticity coordinates of the chromaticity of the light from the lamp change in the green direction, and as a result, the liquid crystal panel There is a third problem that the chromaticity of the light from the light shifts from the target chromaticity (in the chromaticity coordinates, the light shifts in the green direction).

  Note that the occurrence of the first problem is not disclosed or suggested in any of Patent Documents 1 to 4. That is, none of the inventions of Patent Documents 1 to 4 considers the chromaticity change caused by the lamp current change. Therefore, as a matter of course, in the inventions of Patent Documents 1 to 4, even if they are combined, it is difficult to solve the first problem.

  On the other hand, the second and third problems are not disclosed in Patent Document 1 and Patent Document 2, but are disclosed in Patent Document 3 and Patent Document 4 as a solution. There has been suggested a method of adjusting the chromaticity of light emitted from the backlight device by individually controlling the currents of the lamps.

  However, both Patent Document 3 and Patent Document 4 merely suggest such a vague solution technique, and a specific technique for solving the second problem and the third problem, That is, a specific method of how to control the lamp current in order to keep the actual chromaticity at the target value of the chromaticity coordinates when aging or temperature change occurs is disclosed. Not.

  For this reason, in the inventions of Patent Document 3 and Patent Document 4, it is difficult to say that both the second problem and the third problem are solved. Therefore, in the inventions of Patent Documents 1 to 4, even if they are combined, it is difficult to solve both the second problem and the third problem.

  Furthermore, in the inventions of Patent Document 3 and Patent Document 4, the following new fourth problem occurs. That is, the fourth problem is that the actual luminance of the light emitted from the backlight device varies only by individually controlling the currents of the plurality of lamps (the luminance cannot be maintained at the target value). It is a problem.

  Summarizing the above first to fourth issues into one, the following issues arise. That is, in the conventional inventions such as Patent Documents 1 to 4, when the situation changes (when the lamp current changes due to brightness adjustment or the like, when the phosphor in the lamp deteriorates over time, or around the lamp The chromaticity coordinates of the brightness and chromaticity coordinates of the light incident from a plurality of lamps and emitted from the light guide plate may remain at the target values (fixed values). In some cases, it may be a variable value for the purpose of adjustment or the like), and it is difficult to hold it.

  The present invention has been made in view of such a situation. Even if the situation changes, the luminance and chromaticity coordinates of the chromaticity of light incident from a plurality of lamps and emitted from the light guide plate are obtained. In either case, the target value can be maintained.

The illumination device according to the present invention includes a plurality of lamps each manufactured to emit light at a chromaticity corresponding to each of preset chromaticity coordinates, and light incident from each of the plurality of lamps in a predetermined direction. The light guide plate that emits light and each of the plurality of lamps are driven to perform control to maintain the actual level of the total current of the plurality of lamps at the target level, and the chromaticity coordinates of the chromaticity of the light emitted from the light guide plate A lamp driving device that executes control for varying a distribution ratio of the total current to each of the plurality of lamps according to the target value and the target level of the total current.
It further includes a timing device that counts the operating time of the plurality of lamps and outputs the accumulated operating time counted so far as the accumulated operating time, and the lamp driving device further includes the accumulated operating time output from the timing device. Accordingly, it is possible to execute control for varying the distribution ratio of the total current to each of the plurality of lamps.
The timing device further acquires the actual level or target level of the total current of the plurality of lamps when timing the operation time of the plurality of lamps, and counts the time according to the acquired actual level or target level of the total current. The weighted operation time is weighted, and the addition time of the weighted operation time and the accumulated operation time so far can be output as the current accumulated operation time.
A thermometer that is arranged in the vicinity of at least a part of the plurality of lamps and that measures a temperature around the arrangement place is further provided, and the lamp driving device further includes a plurality of thermometers according to the temperature measured by the thermometer. Control can be performed to vary the distribution ratio of the total current to each of the lamps.

In the lighting device of the present invention, each of the plurality of lamps manufactured to emit light with chromaticity corresponding to each of the preset chromaticity coordinates is driven, and as a result, the light emitted from each of the plurality of lamps. The incident light enters the light guide plate and is emitted in a predetermined direction. At this time, control for maintaining the actual level of the total current of the plurality of lamps at the target level is executed, and the target value of the chromaticity coordinates of the chromaticity of the light emitted from the light guide plate and the target level of the total current are set. In response, control is performed to vary the distribution ratio of the total current to each of the plurality of lamps.

In the illumination method of the present invention, a plurality of lamps each manufactured to emit light with chromaticity corresponding to each of preset chromaticity coordinates, and light incident from each of the plurality of lamps in a predetermined direction. An illuminating device including at least a light guide plate that emits drives each of the plurality of lamps, a target value of chromaticity coordinates of chromaticity of light emitted from the light guide plate, and a target level of a total current of the plurality of lamps In accordance with the control step, the control step of executing control for maintaining the actual level of the total current at the target level and executing control for varying the distribution ratio of the total current to each of the plurality of lamps is included.

A first program according to the present invention is configured to transmit a plurality of lamps each made to emit light at a chromaticity corresponding to each of chromaticity coordinates set in advance, and light incident from each of the plurality of lamps. A lighting device including at least a light guide plate that emits in the direction is driven to control each of the plurality of lamps to maintain the actual level of the total current of the plurality of lamps at a target level, and is emitted from the light guide plate. The computer includes a process including a control step for performing control to vary the distribution ratio of the total current to each of the plurality of lamps according to the target value of the chromaticity coordinates of the chromaticity of the light and the target level of the total current. Let it run.

In the illumination method and the first program of the present invention, a plurality of lamps each produced so as to emit light at a chromaticity corresponding to each of preset chromaticity coordinates, and light incident from each of the plurality of lamps In a lighting device including at least a light guide plate that emits light in a predetermined direction, each of the plurality of lamps is driven, control for maintaining the actual level of the total current of the plurality of lamps at a target level is executed , and the light guide plate Control for varying the distribution ratio of the total current to each of the plurality of lamps is executed according to the target value of the chromaticity coordinates of the chromaticity of the light emitted from the lamp and the target level of the total current.

The display device of the present invention includes a plurality of lamps each manufactured to emit light at a chromaticity corresponding to each of preset chromaticity coordinates, and light incident from each of the plurality of lamps in a predetermined direction. Executes control to drive the light guide plate that emits light, the display panel that displays the image using light incident from the light guide plate, and each of the plurality of lamps to maintain the total current level of the plurality of lamps at the target level. In addition, control is performed to vary the distribution ratio of the total current to each of the plurality of lamps according to the target value of the chromaticity coordinates of the chromaticity of the light emitted from the light guide plate and the target level of the total current. A lamp driving device.
It further includes a timing device that counts the operating time of the plurality of lamps and outputs the accumulated operating time counted so far as the accumulated operating time, and the lamp driving device further includes the accumulated operating time output from the timing device. Accordingly, it is possible to execute control for varying the distribution ratio of the total current to each of the plurality of lamps.
The timing device further acquires the actual level or target level of the total current of the plurality of lamps when timing the operation time of the plurality of lamps, and counts the time according to the acquired actual level or target level of the total current. The weighted operation time is weighted, and the addition time of the weighted operation time and the accumulated operation time so far can be output as the current accumulated operation time.
A thermometer that is arranged in the vicinity of at least a part of the plurality of lamps and that measures a temperature around the arrangement place is further provided, and the lamp driving device further includes a plurality of thermometers according to the temperature measured by the thermometer. Control can be performed to vary the distribution ratio of the total current to each of the lamps.

In the display device of the present invention, each of the plurality of lamps manufactured to emit light with chromaticity corresponding to each of the preset chromaticity coordinates is driven, and as a result, the light emitted from each of the plurality of lamps. The emitted light is incident on the light guide plate and emitted in a predetermined direction, and an image is displayed using the light. At this time, control for maintaining the actual level of the total current of the plurality of lamps at the target level is executed, and the target value of the chromaticity coordinates of the chromaticity of the light emitted from the light guide plate and the target level of the total current are set. In response, control is performed to vary the distribution ratio of the total current to each of the plurality of lamps.

According to the display method of the present invention, a plurality of lamps each manufactured to emit light with chromaticity corresponding to each of preset chromaticity coordinates, and light incident from each of the plurality of lamps in a predetermined direction. A display device having at least a light guide plate that emits light and a display panel that displays an image using light incident from the light guide plate drives each of the plurality of lamps, and targets the actual level of the total current of the plurality of lamps In addition to executing the control to maintain the level, the distribution ratio of the total current to each of the plurality of lamps is determined according to the target value of the chromaticity coordinates of the chromaticity of the light emitted from the light guide plate and the target level of the total current. A control step for executing variable control is included.

A second program according to the present invention is configured to transmit a plurality of lamps each made to emit light at a chromaticity corresponding to each of chromaticity coordinates set in advance, and light incident from each of the plurality of lamps. A plurality of lamps that drive each of the plurality of lamps with respect to a display device that includes at least a light guide plate that emits light in the direction and a display panel that displays light incident on the light guide plate using the light. Control to maintain the actual level of the total current at the target level, and according to the target value of the chromaticity coordinates of the chromaticity of the light emitted from the light guide plate and the target level of the total current, The computer is caused to execute a process including a control step of executing control for changing the distribution ratio of the total current to each.

In the display method and the second program of the present invention, a plurality of lamps each produced so as to emit light with chromaticities corresponding to preset chromaticity coordinates, and light incident from each of the plurality of lamps. In a display device including at least a light guide plate that emits light in a predetermined direction and a display panel that displays an image using light incident from the light guide plate, each of the plurality of lamps is driven, Each of the plurality of lamps is controlled according to the target value of the chromaticity coordinate of the chromaticity of the light emitted from the light guide plate and the target level of the total current, while maintaining the actual level of the current at the target level. The control for varying the distribution ratio of the total current to is executed.

  As described above, according to the present invention, a plurality of lamps each produced so as to emit light with chromaticity corresponding to each of preset chromaticity coordinates, and light incident from each of the plurality of lamps are predetermined. It is possible to provide a lighting device that includes at least a light guide plate that emits light in the direction and a display device that displays an image using light from the lighting device. In particular, even if the situation changes, both the luminance and chromaticity coordinates of light incident from a plurality of lamps and emitted from the light guide plate are almost the target values (there may be fixed values). In addition, it is possible to provide a lighting device or a display device that can be held at a variable value for the purpose of adjustment or the like.

  Embodiments of the present invention will be described below. Correspondences between constituent elements described in the claims and specific examples in the embodiments of the present invention are exemplified as follows. This description is to confirm that specific examples supporting the invention described in the claims are described in the embodiments of the invention. Therefore, even if there are specific examples that are described in the embodiment of the invention but are not described here as corresponding to the configuration requirements, the specific examples are not included in the configuration. It does not mean that it does not correspond to a requirement. On the contrary, even if a specific example is described here as corresponding to a configuration requirement, this means that the specific example does not correspond to a configuration requirement other than the configuration requirement. not.

  Further, this description does not mean that all the inventions corresponding to the specific examples described in the embodiments of the invention are described in the claims. In other words, this description is an invention corresponding to the specific example described in the embodiment of the invention, and the existence of an invention not described in the claims of this application, that is, in the future, a divisional application will be made. Nor does it deny the existence of an invention added by amendment.

According to the present invention, a lighting device is provided. This illumination device (for example, the backlight device 1 in FIG. 1 and the like) has a chromaticity (for example, the chromaticity (point) 35 and the chromaticity in the chromaticity diagram of FIG. 3) corresponding to each of the preset chromaticity coordinates. (Dot) 36, or a plurality of lamps (for example, FIG. 1 etc.) manufactured to emit light at chromaticity (point) 151-A to chromaticity (point) 151-D in the chromaticity diagram of FIG. Lamp 12-A and lamp 12-B), a light guide plate (for example, light guide plate 11 in FIG. 1) that emits light incident from each of the plurality of lamps in a predetermined direction, and a plurality of lamps Each is driven, and control for maintaining the actual level of the total current of the plurality of lamps at the target level is performed , and the target value of the chromaticity coordinates of the chromaticity of light emitted from the light guide plate, and the total current Depending on the target level, each of the plurality of lamps Wherein and a distribution ratio of the total current lamp driver to perform the control for varying (e.g., an inverter unit 13 of FIG. 2) that.
This lighting device further includes a time measuring device (for example, the time measuring device 15 in FIG. 1 or the like) that measures the operation time of the plurality of lamps and outputs the accumulated operation time measured so far as the accumulated operation time. The lamp driving device can further execute control for varying a distribution ratio of the total current to each of the plurality of lamps in accordance with the cumulative operation time output from the timing device.
The timing device of the lighting device further acquires the actual level or the target level of the total current of the plurality of lamps when timing the operation time of the plurality of lamps (see, for example, FIG. 4). In accordance with the actual level or the target level of the acquired total current, the operation time that has been timed is weighted, and the addition time of the weighted operation time and the accumulated operation time so far is calculated. The accumulated operation time at the present time can be output.
The lighting device further includes a thermometer (for example, a thermometer 14 in FIG. 1 or the like) that is disposed in the vicinity of at least a part of the plurality of lamps and measures a temperature around the arrangement place. The drive device can further perform control to vary the distribution ratio of the total current to each of the plurality of lamps according to the temperature measured by the thermometer.

According to the present invention, an illumination method is provided. In this illumination method, a plurality of lamps (for example, lamp 12-A and lamp 12-B in FIG. 1 and the like) each manufactured to emit light with chromaticity corresponding to each of preset chromaticity coordinates, An illumination device (for example, the backlight device 1 of FIG. 1 or the like) including at least a light guide plate (for example, the light guide plate 11 of FIG. 1 or the like) that emits light incident from each of the plurality of lamps in a predetermined direction. , Driving each of the plurality of lamps, and executing control to maintain the actual level of the total current of the plurality of lamps at a target level, and target of chromaticity coordinates of chromaticity of the light emitted from the light guide plate A control step for executing control for varying the distribution ratio of the total current to each of the plurality of lamps according to the value and the target level of the total current (for example, current command control processing in FIG. 6). Including.

According to the present invention, it is also possible to provide the first program corresponding to the illumination method described above . This first program is executed by a computer (for example, the microcomputer 71 in FIG. 5 or the CPU 201 in FIG. 17).

According to the present invention, a display device is provided. This display device includes the above-described illumination device and a display panel (for example, LCD 2 in FIG. 1) that displays an image using light incident from a light guide plate.

According to the present invention, a display method is provided. This display method may be basically the same as the illumination method described above except that the target is a display device (for example, a display device including at least the backlight device 1 and the LCD 2 in FIG. 1). it can.

According to the present invention, it is also possible to provide the second program corresponding to the display method described above . The second program is executed by a computer (for example, the microcomputer 71 in FIG. 5 or the CPU 201 in FIG. 17).

  Hereinafter, a backlight device for a liquid crystal display device will be described as an embodiment of the illumination device of the present invention with reference to the drawings, and a liquid crystal display device will be described as an embodiment of the display device of the present invention.

  FIG. 1 is a cross-sectional view illustrating a configuration example of a backlight device of the present embodiment and a liquid crystal display device of the present embodiment on which the backlight device is mounted.

  As shown in FIG. 1, the liquid crystal display device of the present embodiment includes a backlight device 1 and an LCD (Liquid Crystal Display) 2 (note that LCD generally refers to the entire liquid crystal display device or the like. Here, a liquid crystal panel in particular is provided).

  The backlight device 1 is provided with a light guide plate 11, two lamps 12 -A and 12 -B, an inverter unit 13, a thermometer 14, and a timing device 15.

  The light guide plate 11 is disposed on the back surface of the LCD 2 (the display surface of the LCD 2 is the front surface), and directs light incident from the two lamps 12-A and 12-B toward the LCD 2 (in a predetermined direction). ) Exit.

  In addition, a diffusion sheet, a prism sheet, or the like may be disposed between the front surface of the light guide plate 11 (the surface facing the back surface of the LCD 2) and the back surface of the LCD 2. In addition, a reflective sheet or the like may be disposed on the back side of the light guide plate 11.

  Each of the two lamps 12-A and 12-B is composed of, for example, a fluorescent lamp. In the example of FIG. 1, a predetermined surface 11 out of four surfaces perpendicular to the surface of the light guide plate 11 is used. -1 (the right side surface 11-1 in FIG. 1) is disposed substantially parallel to the surface 11-1 (along the surface 11-1).

  The inverter unit 13 has two outputs. Of these two outputs, the first output is connected to the lamp 12-A, and the second output is connected to the lamp 12-B. Yes. That is, the inverter unit 13 can individually drive the lamp 12-A and the lamp 12-B. Specifically, the inverter unit 13 individually applies a high-frequency voltage to each of the lamp 12-A and the lamp 12-B, so that each of the lamp 12-A and the lamp 12-B is individually applied. Make it emit light.

  At this time, the inverter unit 13 can individually control the currents of the lamp 12-A and the lamp 12-B. The current control method itself is not particularly limited. For example, a PWM (Pulse Width Modulation) control method, an analog current control method, or the like can be applied. Note that the PWM control method is a method of controlling the average current by switching the current on-state and off-state by switching and changing the ratio (duty) between the on-state and off-state. This PWM control method is sometimes called a duty control method or a pulse width control method. On the other hand, the analog current control method is a method for controlling the magnitude of the current value in an analog manner.

  What should be noted here is that the inverter unit 13 is intended to keep the actual luminance of the light emitted from the light guide plate 11 at the target value, that is, for the purpose of solving the fourth problem described above. Control for maintaining the actual level of the sum of currents (hereinafter referred to as total current) of a plurality of lamps (in the example of FIG. 1, lamp 12-A and lamp 12-B) at a target level (a level corresponding to the target luminance). For the purpose of maintaining the chromaticity coordinates of the actual chromaticity of the light emitted from the light guide plate 11 at the target value, that is, for the purpose of solving the first to third problems described above. The control is performed to vary the distribution ratio (hereinafter referred to as current ratio) of the total current for each of the plurality of lamps.

  Specifically, for example, for the purpose of solving the above first problem, that is, the target level of the total current of the plurality of lamps is updated by brightness adjustment or the like, and as a result, the actual level of the total current is changed. Even in such a case, in order to keep the chromaticity coordinates of the actual chromaticity of the light emitted from the light guide plate 11 substantially at the target value, a plurality of the currents corresponding to the current target level or the actual level of the total current of the plurality of lamps are set. The current ratio of each of the lamps is variably controlled. That is, the current ratio of each of the plurality of lamps is changed in accordance with the change in the target level or actual level of the total current.

  Further, for example, for the purpose of solving the above-described second problem, that is, even when a plurality of lamps have deteriorated over time, the chromaticity coordinates of the actual chromaticity of the light emitted from the light guide plate 11 are almost equal to the target value. For the purpose of maintaining, the current ratio of each of the plurality of lamps is variably controlled in accordance with the cumulative operation time of the plurality of lamps (supplied from the time measuring device 15 described later). That is, the current ratio of each of the plurality of lamps is changed according to the accumulated operation time.

  Further, for example, for the purpose of solving the above-described third problem, that is, even when the temperature around the plurality of lamps changes, the chromaticity coordinates of the actual chromaticity of the light emitted from the light guide plate 11 are obtained. For the purpose of maintaining substantially the target value, the current ratio of each of the plurality of lamps is variably controlled according to the ambient temperature of the plurality of lamps (supplied from a thermometer 14 described later). That is, the current ratio of each of the plurality of lamps is changed in accordance with the ambient temperature change.

  As shown in FIG. 2, the inverter unit 13 that performs such control has a signal A for instructing the current level of the lamp 12-A (hereinafter, such a signal is referred to as an individual luminance control signal A). Is input to the lamp driving unit 22-A, and a signal B (hereinafter referred to as an individual luminance control signal B) for instructing the current level of the lamp 12-B is input to the lamp driving unit 22-B. A current command unit 21 is provided. The current command unit 21 receives the measurement result of the thermometer 14 when the above-described third problem needs to be solved, and the time measuring device 15 when the above-described second problem needs to be solved. Each measurement result is input. Note that the measurement results of the thermometer 14 and the time measuring device 15 and the details of the usage method will be described later.

  The inverter unit 13 also drives the lamp 12-A, and controls the current of the lamp 12-A based on the individual luminance control signal A from the current command unit 21, and the lamp 12- A lamp driving unit 22 -B that drives B and controls the current of the lamp 12 -B based on the individual luminance control signal B from the current command unit 21 is provided.

  Returning to FIG. 1, the thermometer 14 is arranged in the vicinity of at least a part of the plurality of lamps (here, the lamp 12 -A and the lamp 12 -B), measures the temperature around the arrangement place, The measurement result (current temperature) is supplied to the inverter unit 13 (more precisely, as shown in FIG. 2 described above). An instruction (trigger) for starting and ending the measurement of the thermometer 14 may be supplied from the inverter unit 13 (current command unit 21), or a luminance command (see FIG. It may be supplied from a control unit (not shown) to be input to the unit 21 or may be supplied from other than those.

  The time measuring device 15 measures the operation time of the plurality of lamps (here, the time during which current flows through the lamp 12-A and the lamp 12-B), and accumulates the operation time counted so far (hereinafter, referred to as “time”). The accumulated operation time is output as a measurement result to the inverter unit 13 (more precisely, as shown in FIG. 2 described above). An instruction (trigger) for starting and ending the timing operation of the timing device 15 may be supplied from the inverter unit 13 (current command unit 21), or a luminance command (see FIG. It may be supplied from a control unit (not shown) to be input to the command unit 21 or may be supplied from other than those.

  The timing device 15 further acquires the target level or actual level of the total current of the plurality of lamps when measuring the operation time of the plurality of lamps, and according to the acquired target level or actual level of the total current. The measured operation time is weighted, and the addition time of the weighted operation time and the accumulated operation time so far can be output to the inverter unit 13 as the current accumulated operation time (measurement result).

  When the inverter unit 13 performs current ratio adjustment (correction of current ratio for the purpose of solving the above-described second problem) to correct a chromaticity shift caused by aging deterioration of a plurality of lamps, By using the total operation time weighted according to the measurement result output from the device 15 in this way, that is, according to the level of the total current, a plurality of lamps can be obtained as compared with a case where a simple total operation time is used. It is possible to adjust the current ratio that more accurately reflects the degree of aging degradation.

  As described above, the backlight device 1 of the present embodiment is provided with the inverter unit 13 in addition to the light guide plate 11, the lamp 12 -A and the lamp 12 -B, the thermometer 14, and the time measuring device 15. The following method is applied to the inverter unit 13. That is, the method applied to the inverter unit 13 is to drive each of the lamp 12-A and the lamp 12-B, and to set the actual level of the total current of the lamp 12-A and the lamp 12-B to the target level. Control to maintain, the target value of the chromaticity coordinate of the chromaticity of the light emitted from the light guide plate 11, and the current situation (current of the total current for the lamp 12-A and the lamp 12-B) The current ratio between the lamp 12-A and the lamp 12-B (for each of the lamp 12-A and the lamp 12-B) according to the target level or the actual level, the accumulated operation time, the ambient temperature, or the like). This is a method of executing control for varying the total current distribution ratio).

  Hereinafter, this technique applied to the inverter unit 13 will be described in more detail with reference to the chromaticity diagram of FIG.

  In the chromaticity diagram of FIG. 3, a curve 31 indicates a spectral color locus. That is, on the spectrum color locus 31, each monochromatic light of a spectrum having a pure color is arranged. Each numerical value shown in the vicinity of the spectral color locus 31 indicates the wavelength of each monochromatic light. A straight line 32 indicates a pure purple locus. That is, pure purple light that is not in the light spectrum and is obtained by mixing purple and red monochromatic light is arranged on the pure purple locus 32. Accordingly, all the colors can be expressed as points within the range surrounded by the spectral color locus 31 and the pure purple locus 32, that is, points of coordinates (x, y) in the chromaticity diagram. This point is called chromaticity, and coordinates (x, y) for specifying the position of chromaticity are called chromaticity coordinates (x, y).

  A curve 33 indicates a black body curve. The black body curve refers to a locus of chromaticity of light emitted from a black body (an ideal object that completely absorbs light of all wavelengths) when burned. Each numerical value shown in the vicinity of the black body curve 33 indicates the temperature of the black body emitting light of the chromaticity (point) indicated by the numerical value. This temperature is called a color temperature, and the chromaticity (point) on the black body curve 33 is indicated by the color temperature. That is, the chromaticity (point) on the black body curve 33 can be indicated by chromaticity coordinates or by color temperature.

  By the way, in this chromaticity diagram, the first light of the first chromaticity (point) of the first chromaticity coordinate and the second light of the second chromaticity (point) of the second chromaticity coordinate. Are spatially mixed, the third chromaticity (point) of the third light in which the first light and the second light are mixed is the first chromaticity (point) and the second chromaticity (point). It is located on a straight line connected with the chromaticity (point). However, the position on the straight line depends on the first light amount (luminance) of the first light and the second light amount (luminance) of the second light. Therefore, by changing the ratio of the first light quantity (luminance) of the first light and the second light quantity (luminance) of the second light, the position of the third chromaticity (point) (that is, the color) (Degree coordinates) can be varied (adjusted).

  That is, the amount of light (brightness) of the lamp 12-A manufactured to emit the first light at the first chromaticity at the first chromaticity coordinate and the second chromaticity at the second chromaticity coordinate. The third light emitted from the light guide plate 11 (that is, the third light emitted from the LCD 2) is changed by changing the ratio with the light amount (luminance) of the lamp 12-B manufactured to emit the second light. The chromaticity coordinates of the third chromaticity of the light can be varied (adjusted).

  Note that each setting method of the first chromaticity coordinates of the first chromaticity of the lamp 12-A and the second chromaticity coordinates of the second chromaticity of the lamp 12-B is not particularly limited. As shown in FIG. 3, it is preferable to apply a setting method for setting the black body curve 33 within a predetermined range 34. That is, it is preferable to apply a setting method in which one of chromaticity 35 or chromaticity 36 is set as the first chromaticity and the other is set as the second chromaticity. This is because the target chromaticity of the liquid crystal display device is often set by the color temperature (that is, the chromaticity on the black body curve 33) as described above. That is, when the chromaticity of light emitted from the surface of the light guide plate 11 is adjusted by the color temperature, the color temperature 35 (chromaticity 35 on the black body curve 33) and the color temperature 36 (color on the black body curve 33). This is because it is more efficient to use the degree 36).

  Furthermore, the range 34 to which the color temperature 35 and the color temperature 36 belong may be set within ± 0.015 [UV]. This is because the straight line connecting the color temperature 35 and the color temperature 36 substantially coincides with the black body line 33.

  Incidentally, the light amount (luminance) of the lamp 12-A can be adjusted (changed) by controlling (changing) the current of the lamp 12-A. Similarly, the light quantity (luminance) of the lamp 12-B can be adjusted by controlling the current of the lamp 12-B.

  Furthermore, if the total of the light quantity (luminance) of the lamp 12-A and the light quantity (luminance) of the lamp 12-B is not changed (otherwise, no change in ambient temperature, aging, etc. occurs), the light from the light guide plate 11 The brightness of light (light from the LCD 2), that is, the final brightness is kept constant.

  Therefore, the target chromaticity (from the light guide plate 11) is maintained while maintaining the total current of the lamp 12-A and the lamp 12-B at a target level (a level corresponding to the target value of the luminance of the light from the light guide plate 11). The luminance of light from the light guide plate 11 is applied to the inverter unit 13 by applying a method of changing the current ratio between the lamp 12-A and the lamp 12-B in accordance with the target chromaticity coordinates of light chromaticity). The chromaticity of the light can be adjusted while keeping the value approximately at the target value. That is, the above-described fourth problem (the problem that the inventions of Patent Document 3 and Patent Document 4 have) can be solved.

  However, even if the inverter unit 13 adjusts the chromaticity by applying such a method, for example, the actual level (target level) of the total current of the lamp 12-A and the lamp 12-B is changed from the adjustment time. If it changes, the 1st chromaticity of the 1st light from lamp | ramp 12-A will change to the 4th chromaticity coordinate different from the set 1st chromaticity coordinate. Similarly, the second chromaticity of the second light from the lamp 12-B also changes to a fifth chromaticity coordinate different from the set second chromaticity coordinate. As a result, the third light in which the first light and the second light are mixed, that is, the chromaticity coordinates of the third chromaticity of the third light emitted from the light guide plate 11 are also the first chromaticity coordinates. From the first straight line connected by the first chromaticity of the chromaticity coordinate and the second chromaticity of the second chromaticity coordinate, the first chromaticity of the fourth chromaticity coordinate and the fifth chromaticity coordinate It will change on the 2nd straight line connected with the 2nd chromaticity of chromaticity coordinates.

  Further, even if the first straight line and the second straight line are the same straight line, the second color of the second chromaticity coordinate from the first chromaticity of the first chromaticity coordinate. And the distance from the first chromaticity of the fourth chromaticity coordinate to the second chromaticity of the fifth chromaticity coordinate are different from each other. If the ratio of the amount of light (brightness), that is, the current ratio between the lamp 12-A and the lamp 12-B does not change, the third light of the third light in which the first light and the second light are mixed is eventually obtained. The chromaticity coordinate of the chromaticity of 3 also changes.

  As described above, when the actual level (target level) of the total current of the lamp 12-A and the lamp 12-B changes from the adjustment time, the actual chromaticity of the light (third light) from the light guide plate 11 is shifted. The first problem described above occurs.

  Therefore, for the purpose of solving the first problem, in the present embodiment, the total current of the lamps 12-A and 12-B corresponds to the target level (the target value of the luminance of light from the light guide plate 11). In addition to the target chromaticity (target value of the chromaticity coordinates of the chromaticity of light from the light guide plate 11), the total current of the lamp 12-A and the lamp 12-B is further increased. A method of executing control that varies the current ratio in consideration of the target level or the actual level is applied to the inverter unit 13. However, in the following, for simplicity of explanation, the method of variably controlling the current ratio based on the target chromaticity and the target level of the total current among the methods for solving the first problem is the inverter unit 13. It has been applied to.

  Further, for example, when a long time elapses from the adjustment time (when the lamp 12-A and the lamp 12-B are used for a long time), the aging of the lamp 12-A and the lamp 12-B occurs, As a result, the second problem described above occurs that the actual chromaticity of the light from the light guide plate 11 is shifted for the same reason (the reason described above) when the total current level is changed. .

  Therefore, for the purpose of solving the second problem, in the present embodiment, in addition to the target chromaticity, the control for maintaining the total current of the lamp 12-A and the lamp 12-B at the target level is performed. A method of executing control to vary the current ratio in consideration of the cumulative operation time of the lamp 12-A and the lamp 12-B is applied to the inverter unit 13.

  Further, for example, when the ambient temperature between the lamp 12-A and the lamp 12-B changes from the adjustment time point, the light from the light guide plate 11 has the same reason as that when the total current level changes (the reason described above). The above-mentioned third problem occurs that the actual chromaticity of the image is shifted.

  Therefore, for the purpose of solving the third problem, in the present embodiment, in addition to the target chromaticity, the control for maintaining the total current of the lamp 12-A and the lamp 12-B at the target level is performed. A method of executing control to vary the current ratio in consideration of the ambient temperature between the lamp 12-A and the lamp 12-B is applied to the inverter unit 13.

  As described above, the solving methods for the first problem (and the fourth problem), the second problem (and the fourth problem), and the third problem (and the fourth problem) are individually provided in the order. As described above, when solving these problems at the same time, the above-described solutions may be simply combined. That is, for example, when it is desired to solve the first problem and the second problem (and the fourth problem) at the same time, the inverter unit 13 sets the target chromaticity and the target of the total current of the lamp 12-A and the lamp 12-B. The current ratio may be set in consideration of both the level and the cumulative operation time of the lamp 12-A and the lamp 12-B. The same applies to other combinations of tasks.

  FIG. 4 shows a detailed configuration example of the inverter unit 13 to which a technique capable of solving such problems is applied. The details of the configuration of the inverter unit 13 will be described below with reference to FIG.

  In the inverter unit 13 of FIG. 4, the lamp driver 22 -A is provided with a control circuit 41 -A, a transformer 42 -A, a detection resistor 43 -A, and a feedback circuit 44 -A.

  The control circuit 41-A converts the DC voltage applied from the input power supply 45 into a high-frequency AC voltage and applies it to the primary side (not shown) of the transformer 42-A. At this time, since the individual luminance control signal A described above is input from the current command unit 21 and a signal corresponding to the actual current of the lamp 12-A is input from the feedback circuit 44-A, the control circuit 41- A is the difference between the individual brightness control signal A (corresponding to the command value of the current of the lamp 12-A) and the signal input from the feedback circuit 44-A (corresponding to the actual value of the current of the lamp 12-A) ( On the basis of the error), the level of the high-frequency AC voltage supplied to the transformer 42-A is controlled so that the current of the level corresponding to the individual luminance control signal A flows through the lamp 12-A almost stably. That is, the control circuit 41-A controls the current of the lamp 12-A using feedback control.

  The transformer 42-A boosts the high-frequency AC voltage applied to the primary side of the control circuit 41-A and applies it to the lamp 12-A from the secondary side (not shown).

  The feedback circuit 44-A detects the actual current of the lamp 12-A as a voltage across the detection resistor 43-A, further converts the level as necessary, and supplies it to the control circuit 41-A. .

  The lamp driving unit 22-B also has the same functions and configurations as the control circuit 41-A to the feedback circuit 44-A in the lamp driving unit 22-A, and has a control circuit 41-B to a feedback circuit 44-B. Each is provided. Note that the description of each of the control circuit 41-B to the feedback circuit 44-B overlaps with the description of each of the control circuit 41-A to the feedback circuit 44-A, and is omitted here.

  As described above, with reference to FIG. 4, the configuration of the lamp driving unit 22 -A and the lamp driving unit 22 -B in the inverter unit 13 has been described in detail.

  Next, with reference to FIG. 5, the details of the configuration of the remaining current command unit 21 in the inverter unit 13 will be described. That is, FIG. 5 is a block diagram showing an embodiment of the current command unit 21.

  By the way, also in the conventional inverter unit, the current control of the two lamps is performed for the purpose of adjusting the luminance of the light from the light guide plate (not for the purpose of adjusting the individual luminance for each of the two lamps). However, conventionally, a voltage signal called a luminance control signal, for example, a luminance control signal (necessary to vary) in a range of 0 [V] (minimum luminance level) to 3 [V] (maximum luminance level). The level may be adjusted accordingly), but is distributed as a current command to each of the lamp driving units of the two lamps. That is, the current commands for the two lamps (conventional signals corresponding to the individual luminance control signal A and the individual luminance control signal B) are always the same command, and the currents of the two lamps are always at the same level. It was controlled to be.

  For this reason, the conventional current command unit includes, for example, an input terminal for inputting the brightness control signal (hereinafter referred to as a brightness control signal input terminal) and two identical commands (two voltage signals at the same level). , A generation unit that generates the individual luminance control signal A and the individual luminance control signal B here, and an output terminal that outputs the two commands generated by the generation unit (hereinafter referred to as luminance) The control signal output terminal).

  As described above, the luminance control signal can be said to be a command indicating the target value of the luminance of light from the light guide plate 11. Therefore, hereinafter, the luminance control signal is referred to as a luminance command. Further, as described above, the adjustment of the luminance of the light from the light guide plate 11 is performed by adjusting (controlling) the total current of the lamp 12-A and the lamp 12-B, so that the luminance control signal (luminance command) is After all, it can be said that the signal determines (instructs) the target level of the total current of the lamp 12-A and the lamp 12-B. Therefore, hereinafter, the luminance control signal (luminance command) is also referred to as a total current command as appropriate.

  The current command unit 21 of the present embodiment also has the purpose of keeping the luminance of light from the light guide plate 11 at a target value, and therefore can be varied within the range of the conventional luminance command (0 [V] to 3 [V]. Assume that a voltage signal is input from an external control unit (not shown). Therefore, as shown in FIG. 5, in the current command unit 21 of the present embodiment, as in the conventional current command unit, the brightness control signal input terminal 51, the brightness control signal output terminal 54, and the brightness A control signal output terminal 55 is provided.

  However, in the present embodiment, as described above, the levels of the two individual luminance control signals A and B output from the current command unit 21 are not the same, and the lamp 12-A It is varied according to the current ratio with the lamp 12-B (however, the current ratio may be the same level when the current ratio is set to 1: 1). In view of this, the current command unit 21 of the present embodiment includes a lamp 12-A and a lamp 12-B based on a luminance command (total current command) and a chromaticity command (base current ratio command) described later. A generation unit having a function of setting the current ratio and generating the individual luminance control signal A and the individual luminance control signal B based on the current ratio is required.

  Furthermore, this generation unit, when it is necessary to solve the first problem described above, the magnitude of the luminance command (total current command) (target level of the total current of the lamp 12-A and the lamp 12-B) If it is necessary to solve the second problem described above, the measured value of the time measuring device 15 (the accumulated operation time of the lamp 12-A and the lamp 12-B) is used to solve the third problem described above. If necessary, the current ratio between the lamp 12-A and the lamp 12-B is set in consideration of the measured value of the thermometer 14 (the ambient temperature between the lamp 12-A and the lamp 12-B). It is necessary to have a (correct) function.

  In other words, the form of the generation unit is not particularly limited as long as it has such a function, and can take various forms. Specifically, for example, it is shown in FIG. 5 as a generation unit (a portion excluding the luminance control signal input terminal 51, the luminance control signal output terminal 54, and the luminance control signal output terminal 55) of the current command unit 21 in FIG. As shown, a microcomputer 71 is applied.

  The microcomputer 71 receives the above-described luminance command (total current command) that is variable in the range of 0 [V] to 3 [V] from an external control unit (not shown) via the luminance control signal input terminal 51. In addition to the input, a chromaticity command is input.

  Here, the chromaticity command indicates the next signal. That is, as described above, the chromaticity of the light from the light guide plate 11 (the chromaticity of the light from the LCD 2) can be adjusted by changing the current ratio between the lamp 12-A and the lamp 12-B. Therefore, the chromaticity command refers to a signal necessary for setting a current ratio between the lamp 12-A and the lamp 12-B in the reference state (hereinafter referred to as a base current ratio). Since the chromaticity command can be said to be a base current ratio setting command in this way, hereinafter, the chromaticity command is also referred to as a base current ratio command as appropriate.

  However, the reference state is, for example, a state in which the ambient temperature (measured value of the thermometer 14) between the lamps 12-A and 12-B is a preset temperature (for example, 20 ° C.), the lamp 12 A state where the target level of the total current of -A and the lamp 12-B is a preset level (for example, a state where the luminance command is 3 [V]), and the lamp 12-A and the lamp 12-B Here, a state where three states such as a state in which the accumulated operation time (measured value of the timing device 15) is a predetermined time (for example, 0 hour) is shown here.

  Specifically, for example, the chromaticity command (base current ratio command) is also a voltage signal in the range of 0 [V] to 3 [V], and the voltage signal at the center of the range (that is, 1.5 [V]). Shows a command (command to set the base current ratio to approximately 1: 1) to make the currents of the lamp 12-A and the lamp 12-B substantially equal in the reference state. A voltage signal in the range of 0 [V] to less than 1.5 [V] causes a large current (high level current) to flow through the lamp 12-A and a small current (low level) to the lamp 12-B in the reference state. Level command). On the other hand, a voltage signal in the range of 1.5 [V] to 3 [V] (excluding 1.5 [V]) causes a small current (low-level current) to flow through the lamp 12-A in the reference state. A command for flowing a large current (high level current) to 12-B is shown.

  Specifically, for example, it is assumed that the current state is the reference state. That is, a luminance command (total current command) of 3 [V] is input to the microcomputer 71 via the luminance control signal input terminal 51, and the measurement result (lamp 12-A and lamp 12-B) at that time is displayed. ) Is 20 ° C., and the measurement result of the time measuring device 15 at that time (the cumulative operation time of the lamp 12-A and the lamp 12-B) is 0 hour.

  In this case, for example, when a chromaticity command (base current ratio command) of 1.5 [V] is input, the microcomputer 71 receives approximately 1 as the individual luminance control signal A and the individual luminance control signal B, respectively. Generate a voltage signal of 5 × G (G indicates a predetermined gain coefficient) [V]. For example, when a chromaticity command (base current ratio command) of 0 [V] is input, the microcomputer 71 converts a voltage signal of approximately 3 × G [V] as the individual luminance control signal A into individual luminance control. A voltage signal of approximately 0 × G [V] is generated as the signal B, respectively. On the other hand, for example, when a chromaticity command (base current ratio command) of 3 [V] is input, the current balance circuit 53 outputs a voltage signal of approximately 0 × G [V] as the individual luminance control signal A to the individual luminance. A voltage signal of approximately 3 × G [V] is generated as the control signal B, respectively.

  The microcomputer 71 has a relationship table (table) between the voltage level of the chromaticity command (base current ratio command) and the base current ratio between the lamp 12-A and the lamp 12-B, and the reference state. If so, the individual luminance control signal A and the individual luminance control signal B can be directly generated from the chromaticity command (base current ratio command).

  In the reference state, the individual luminance control signal A and the individual luminance control signal B generated in this way by the microcomputer 71 are supplied to the current command section via the luminance control signal output terminal 54 or the luminance control signal output terminal 55, respectively. 21 is output to the outside. That is, as described above, the individual luminance control signal A is input to the control circuit 41-A (FIG. 4) of the lamp driving unit 22-A, and the individual luminance control signal B is input to the lamp driving unit 22-B. It is input to the control circuit 41-B (FIG. 4).

  However, when a luminance command (total current command) having a voltage level different from 3 [V] (reference state) is input to the microcomputer 71 via the luminance control signal input terminal 51, the lamp 12- If the luminance control signal A and the luminance control signal B are generated while the current ratio between A and the lamp 12-B remains the base current ratio (not updated), the actual chromaticity of the light from the light guide plate 11 is generated. The problem that the change occurs, that is, the first problem described above occurs.

  In order to solve this first problem, the microcomputer 71 responds to the current voltage level of the luminance command (total current command), that is, the current target level of the total current, based on the base current ratio. The current ratio is set.

  That is, in order to solve the first problem, the microcomputer 71 may be regarded as correcting the base current ratio according to the level of the luminance command (total current command), that is, the target level of the total current.

  The correction method in this case is not particularly limited. For example, the voltage level that the luminance command can take is divided into two or more ranges (voltage ranges), and correction values corresponding to the respective voltage ranges are determined in advance. It is registered in the microcomputer 71 in the form of a table, and the current voltage level of the luminance command belongs to the microcomputer 71 from two or more correction values (including the correction value “0”) registered in the table. A technique for searching for a correction value corresponding to the voltage range can also be applied.

  Alternatively, for example, a function for inputting a target value of luminance (level of luminance command) as a parameter and outputting a correction value is generated in advance and registered in the microcomputer 71, and the microcomputer 71 is caused to calculate the function. A method of using the calculation result as a correction value can also be applied.

  In addition, after that (after the base current ratio is set in the reference state), for example, the lamp 12-A and the lamp 12-B continue to be used for a long time (accumulated operation time increases), and aged deterioration occurs. If the luminance control signal A and the luminance control signal B are generated while the current ratio between the lamp 12-A and the lamp 12-B remains the base current ratio (not updated), the light from the light guide plate 11 The problem that the actual chromaticity of light changes, that is, the above-described second problem occurs.

  Therefore, in order to solve the second problem, the microcomputer 71 uses the base current ratio as a reference to measure the current measured value of the time measuring device 15 (the current cumulative operation of the lamp 12-A and the lamp 12-B). Current ratio according to time) is set.

  In other words, in order to solve the second problem, the microcomputer 71 sets the base current ratio according to the current cumulative operation time of the lamp 12-A and the lamp 12-B (current measurement value of the time measuring device 15). You may think that it corrects.

  The correction method in this case is not particularly limited. For example, the time that the accumulated operation time (measured value of the measuring device 15) can take is divided into two or more time zones, and the correction corresponding to each time zone is performed. A value is determined in advance and registered in the microcomputer 71 in the form of a table, and the timing device 15 is selected from two or more correction values (including the correction value “0”) registered in the microcomputer 71 in the table. It is also possible to apply a method of searching for a correction value corresponding to a time zone to which the current measured value (current accumulated operation time) belongs.

  Specifically, for example, a predetermined time is set as a threshold (hereinafter, the time set as such a threshold is referred to as a set time), and further, 0 hours or more is set as a time zone in which the accumulated operation time can be taken. A first time zone that is less than or equal to the time and a second time zone after the set time are set, and the correction value in the first time zone is “0”, and the correction in the second time zone A table describing that the value is “α (α is an arbitrary positive value)” is registered in the microcomputer 71 in advance. The microcomputer 71 refers to the table, and if the accumulated operation time does not exceed the set time, searches and uses “0” as the correction value (without correcting the base current ratio). When the cumulative operation time is after the set time, “α” is searched for and used as a correction value. That is, for example, when the base current ratio is “n: m (n and m are arbitrary positive values)”, the microcomputer 71 determines the final corrected current ratio as “n−α: n + α” or the like. Set as current ratio.

  In the example described above, the set time (threshold value) is set to one, but may be set to two or more. In this case, the base current ratio can be corrected more finely.

  Further, the microcomputer regards the number of thresholds as infinite (without using the thresholds), inputs a cumulative operation time (measured value of the measuring device 15) as a parameter, generates a function that outputs a correction value in advance, and creates a microcomputer. It is also possible to apply a method in which the microcomputer 71 calculates the function and uses the calculation result as a correction value.

  After that (after the base current ratio is set in the reference state), for example, when the ambient temperature changes from 20 ° C. (reference state), the current ratio between the lamp 12-A and the lamp 12-B is If the luminance control signal A and the luminance control signal B are generated without changing the current ratio (not updated), the problem that the actual chromaticity of the light from the light guide plate 11 changes, that is, the above-described problem. The third problem will occur.

  Therefore, in order to solve the third problem, the microcomputer 71 sets a current ratio according to the current measurement value (current ambient temperature) of the thermometer 14 based on the base current ratio. is there.

  That is, in order to solve the third problem, the microcomputer 71 can also be regarded as correcting the base current ratio in accordance with the current ambient temperature (current measured value of the thermometer 14).

  The correction method in this case is not particularly limited. For example, values that can be taken by the measurement value of the thermometer 14 are divided into two or more ranges (temperature ranges), and correction values corresponding to the respective temperature ranges are set. Predetermined and registered in the microcomputer 71 in the form of a table, the current value of the thermometer 14 from the two or more correction values (including the correction value “0”) registered in the table in the microcomputer 71 is stored. It is also possible to apply a technique for searching for a correction value corresponding to the temperature range to which the measured value (current ambient temperature) belongs.

  Alternatively, for example, a function for inputting an ambient temperature (measured value of the thermometer 14) as a parameter and outputting a correction value is generated in advance, registered in the microcomputer 71, and the microcomputer 71 calculates the function. It is also possible to apply a method of using the calculation result as a correction value.

  As described above, even when the state is different from the reference state, the current ratio is appropriately corrected by the microcomputer 71, so that the individual luminance control signal A and the individual luminance control generated based on the corrected current ratio are obtained. Each of the signals B is also a current command suitable for the current state. Each of the individual luminance control signal A and the individual luminance control signal B is also output to the outside of the current command unit 21 via the luminance control signal output terminal 54 or the luminance control signal output terminal 55. That is, as described above, the individual luminance control signal A is input to the control circuit 41-A (FIG. 4) of the lamp driving unit 22-A, and the individual luminance control signal B is input to the lamp driving unit 22-B. It is input to the control circuit 41-B (FIG. 4). As a result, the actual current ratio between the lamp 12-A and the lamp 12-B can also be maintained at a current ratio suitable for the current state (that is, the chromaticity of light from the light guide plate 11 can be kept substantially at the target chromaticity. The current ratio is appropriately controlled.

  The configuration of the backlight device 1 shown in FIGS. 1 and 2 has been described above. Then, next, operation | movement of the backlight apparatus 1 shown by FIG. 1 and FIG. 2 is demonstrated.

  First, a control unit (not shown) generates a luminance command (total current command) based on a target value of the luminance of light from the light guide plate 11. That is, the control unit or the like generates a voltage level signal corresponding to the target luminance value as a luminance command (total current command). The control unit or the like also generates a chromaticity command (base current ratio command) based on the target chromaticity of light from the light guide plate 11 (target value of chromaticity coordinates). That is, the control unit or the like also generates a voltage level signal corresponding to the target chromaticity as a chromaticity command (base current ratio command). Then, the control unit or the like supplies each of the luminance command (total current command) and the chromaticity command (base current ratio command) to the current command unit 21.

  Then, the current command unit 21 sets a target level of the total current of the lamp 12-A and the lamp 12-B based on the supplied luminance command (total current command), and supplies the supplied chromaticity command (base The base current ratio is set based on the current ratio command), and the individual luminance control signal A and the individual luminance control signal B are generated based on the target level of the total current and the base current ratio.

  However, at this time, for example, when it is necessary to solve the first problem described above, the current command unit 21 further determines the voltage level of the luminance command (total current command), that is, the target level of the total current set in advance. Accordingly, the base current ratio is corrected, and the individual luminance control signal A and the individual luminance control signal B are generated based on the resulting current ratio and the target level of the total current.

  In addition, for example, when the above-described second problem needs to be solved, the current command unit 21 further bases on the measurement result of the timing device 15 (accumulated operation time of the lamp 12-A and the lamp 12-B). The current ratio is corrected, and the individual luminance control signal A and the individual luminance control signal B are generated based on the current ratio obtained as a result and the target level of the total current.

  Further, for example, when the above-described third problem needs to be solved, the current command unit 21 further bases on the measurement result of the thermometer 14 (temperature around the lamp 12-A and the lamp 12-B). The current ratio is corrected, and the individual luminance control signal A and the individual luminance control signal B are generated based on the current ratio obtained as a result and the target level of the total current.

  Specifically, for example, the current command unit 21 finally determines the current ratio between the lamp 12-A and the lamp 12-B (a result of performing the above-described correction or the like on the base current ratio) p: q ( When p and q are set to an arbitrary integer value), the individual luminance control signal A and the individual luminance control signal B each having a voltage level ratio of approximately p: q are generated.

  The individual luminance control signal A generated in this way is supplied to the lamp driver 22-A. On the other hand, the individual luminance control signal B generated in this way is supplied to the lamp driving unit 22-B.

  Such processing of the current command unit 21 is hereinafter referred to as current command control processing. Details of this current command control processing will be described later with reference to the flowcharts of FIGS.

  Next, paying attention to the lamp driving unit 22-A and the lamp driving unit 22-B, the lamp driving unit 22-A drives the lamp 12-A and based on the supplied individual luminance control signal A, the lamp 12- A current (level) is controlled. Similarly, the lamp driving unit 22-B drives the lamp 12-B and controls the current (level) of the lamp 12-B based on the supplied individual luminance control signal B.

  As a result of such independent current control between the lamp driving unit 22-A and the lamp driving unit 22-B, the total current of the lamp 12-A and the lamp 12-B is a target level (current corresponding to the luminance command). Level), the actual current ratio between the lamp 12-A and the lamp 12-B becomes substantially equal to the current ratio (set value) set by the current command unit 21. That is, each of the lamp 12-A and the lamp 12-B has a predetermined chromaticity (a chromaticity of a preset chromaticity coordinate in the reference state, and a chromaticity coordinate shifted from it in the other states). (Chromaticity) is emitted at a luminance (light quantity) corresponding to each controlled current level.

  Then, light in which the light of the lamp 12-A and the light of the lamp 12-B are spatially mixed is emitted from the surface of the light guide plate 11 (that is, the surface of the LCD 2). At this time, the current ratio between the lamp 12-A and the lamp 12-B is variably controlled according to the situation so that the actual chromaticity of the light is maintained at the target value of the chromaticity coordinates as described above. ing. As a result, the chromaticity coordinates of the actual chromaticity of the light emitted from the surface of the light guide plate 11 are kept substantially constant at the target value. Further, the total current of the lamp 12-A and the lamp 12-B is also controlled to be maintained at the target level (that is, as long as the target level of the total current does not change, the lamp 12-A and the lamp 12-B are controlled). Therefore, the brightness of the light emitted from the surface of the light guide plate 11 is kept substantially constant at the target value.

  Next, the details of the current command control process of the current command unit 21 will be described with reference to the flowcharts of FIGS.

  The flow chart of FIG. 6 considers the current command control process for solving the first problem described above, that is, the magnitude of the total current (the magnitude of the target level) of the lamp 12-A and the lamp 12-B. An example of a current command control process (hereinafter, referred to as a first current command control process in order to be distinguished from other current command control processes) is characterized by setting a current ratio.

  The flowchart of FIG. 7 takes into account the current command control process for solving the second problem described above, that is, the total operation time of lamp 12-A and lamp 12-B (measured value of timing device 15). An example of a current command control process (hereinafter, referred to as a second current command control process for distinguishing from other current command control processes) characterized by setting a current ratio is shown.

  The flowchart of FIG. 8 takes into account the current command control process for solving the third problem described above, that is, the ambient temperature (measured value of the thermometer 14) between the lamp 12-A and the lamp 12-B. An example of a current command control process (hereinafter, referred to as a third current command control process in order to be distinguished from other current command control processes) characterized by setting a current ratio is shown.

  9 is a current command control process for simultaneously solving the first to third problems, that is, the magnitude of the total current (target) for the lamp 12-A and the lamp 12-B. The current ratio is set in consideration of all of the level size), the total operation time (measured value of the time measuring device 15), and the surrounding temperature (measured value of the thermometer 14). An example of command control processing (hereinafter, referred to as fourth current command control processing in order to distinguish from other current command control processing) is shown.

  Hereinafter, the details of each of the first current command control process to the fourth current command control process will be described individually in that order.

  Here, for simplification of description, in any of the first current command control process to the fourth current command control process, the voltage level of the brightness command is assumed to be larger than 0 [V], and the input of the brightness command is performed. Is started (at the time when the voltage level of the luminance command changes from 0 [V] to a predetermined level), the current command unit 21 includes the first current command control process to the fourth current command control process. Start the corresponding process. That is, here, the luminance command is also used as a drive command (lamp drive command) for the lamp 12-A and the lamp 12-B. In other words, the brightness command of 0 [V] indicates a command to stop driving the lamp 12-A and the lamp 12-B.

  First, the first current command control process will be described with reference to the flowchart of FIG.

  In step S1, the current command unit 21 sets a target level for the total current of the lamp 12-A and the lamp 12-B based on the luminance command (total current command).

  In step S2, the current command unit 21 determines the currents of the lamp 12-A and the lamp 12-B based on the chromaticity command (base current ratio command) and the target level of the total current set in the process of step S1. Set the ratio. That is, the current command unit 21 sets the base current ratio based on the chromaticity command (base current ratio command), corrects the base current ratio according to the current target level of the total current, and finally outputs the correction result. Set as the correct current ratio.

  In step S3, the current command unit 21 determines whether the individual luminance control signal A and the individual luminance control signal B are based on the target level of the total current set in the process of step S1 and the current ratio set in the process of step S2. Generate and output each.

  In step S4, the current command unit 21 determines whether or not the luminance command (total current command) has changed.

  If it is determined in step S4 that the luminance command has not changed, the process returns to step S3, and the subsequent processes are repeated. That is, when the purpose is only to solve the first problem among the first to third problems, the same voltage level is maintained unless the luminance command changes (unless the target level of the total current changes). The individual luminance control signal A and the individual luminance control signal B are continuously output. That is, the setting of the current ratio between the lamp 12-A and the lamp 12-B is maintained as it is. As a result, the actual current ratio between the lamp 12-A and the lamp 12-B is also kept substantially constant.

  On the other hand, if it is determined in step S4 that the luminance command has changed, the current command unit 21 determines in step S5 whether or not the luminance command (lamp drive command) has stopped.

  That is, the voltage level of the luminance command is changed from the first level (here, for example, a level within a predetermined range larger than 0 [V] as described above) to the second level (0 [V] and the first level). In step S4, it is determined that the luminance command has changed, and in step S5, it is determined that the luminance command (lamp driving command) has not stopped, The processing is returned to step S1, and the subsequent processing is repeated. That is, until now, the first current ratio corresponding to the first level has been set, but this time, the second current ratio corresponding to the second level is set (the setting is updated). The individual luminance control signal A and the individual luminance control signal B are generated (updated) and output based on the second current ratio (set value) and the second level. As a result, the actual current ratio between the lamp 12-A and the lamp 12-B also changes from the approximately first current ratio (set value) to the approximately second current ratio (set value).

  Thereafter, when the voltage level of the luminance command changes from the second level to 0 [V], it is determined in step S4 that the luminance command has changed, and in step S5, the luminance command (lamp drive command) is stopped. Determination is made, and the first current command control process ends.

  Next, the second current command control process will be described with reference to the flowchart of FIG.

  FIG. 7 is a flowchart when the luminance command is constant (the luminance target value is constant).

  In step S <b> 21, the current command unit 21 (or a control unit (not shown) that supplies a brightness command or the like to the current command unit 21) starts the timing operation of the timing device 15.

  That is, in step S21, the time measuring device 15 starts measuring the operation time of the lamp 12-A and the lamp 12-B, and thereafter, until the end of the time measuring operation is instructed (until the process of step S28 described later). ), The time keeping operation is continued, and the current operation time is added to the current command unit 21 as the current accumulated operation time, which is the sum of the operation time thus measured and the accumulated operation time so far (until just before the operation time is measured). Output. At this time, as described above, the timing device 15 further acquires the target level or actual level of the total current of the plurality of lamps, and the operation time measured according to the acquired target level or actual level of the total current It is also possible to output the weighted operation time to the current command unit 21 as the current accumulated operation time.

  Next, in step S22, the current command unit 21 sets a target level of the total current of the lamp 12-A and the lamp 12-B based on the luminance command (total current command).

  In step S23, the current command unit 21 sets the current ratio between the lamp 12-A and the lamp 12-B based on the chromaticity command (base current ratio command). That is, the current command unit 21 sets the base current ratio based on the chromaticity command (base current ratio command).

  In step S24, the current command unit 21 determines whether or not the cumulative operation time has exceeded the set time.

  When the measured value (cumulative operation time) of the time measuring device 15 exceeds the set time (when it is determined in step S24 that the total operation time has exceeded the set time), the current command unit 21 determines the current ratio in step S25. To reset. That is, the current command unit 21 corrects the base current ratio according to the accumulated operation time, and sets the correction result as the final current ratio.

  In step S26, the current command unit 21 determines the individual luminance control signal A and the individual luminance control signal based on the target level of the total current set in the process of step S22 and the current ratio reset in the process of step S25. Each of B is generated and output.

  On the other hand, when the measured value (cumulative operation time) of the timing device 15 does not exceed the set time (when it is determined in step S24 that the accumulated operation time does not exceed the set time), the current command unit 21 Without executing the process of step S25 (that is, setting the base current ratio as the final current ratio), in step S26, the target level of the total current set in the process of step S22 and the process of step S23. Each of the individual luminance control signal A and the individual luminance control signal B is generated and output based on the set current ratio (base current ratio).

  As described above, when only the solution of the second problem among the first problem to the third problem is intended, it corresponds to the base current ratio (set value) as long as the cumulative operation time does not exceed the set time. The individual luminance control signal A and the individual luminance control signal B having the same voltage level are continuously output. As a result, the actual current ratio between the lamp 12-A and the lamp 12-B is also kept substantially constant at the base current ratio (set value).

  When the cumulative operation time exceeds the set time, the current ratio is updated from the base current ratio to another ratio, and the individual luminance control signal A having the same voltage level corresponding to the updated current ratio (set value). And the individual luminance control signal B are continuously output. As a result, the actual current ratio between the lamp 12-A and the lamp 12-B is also kept substantially constant at the updated current ratio (set value).

  The set time (threshold value) is set to one in the example of the flowchart of FIG. 7, but may be set to two or more as described above. That is, for example, the degree of lamp deterioration can be set in a plurality of stages, and the time for each of the stages can be set as the set time.

  Specifically, for example, the cumulative operation time set from the first stage to the third stage, the cumulative operation time for shifting from the first stage to the second stage is 3000 hours, and the cumulative operation time for shifting from the second stage to the third stage Is set to 10000 hours, 3000 hours can be set as the first set time, and 10000 hours can be set as the second set time. In this case, for example, the first correction value to the third correction value are associated with each of the first stage to the third stage in advance (such a table is created), and the current If the cumulative operation time is less than the first set time, the second correction value is used for the second setting. If the accumulated operation time is less than the first set time and less than the second set time, the second setting is used. When the time is longer than the time, the current command unit 21 may execute the current ratio resetting process (base current ratio correcting process) with the third correction value.

  Alternatively, as described above, the current ratio resetting process (base) using a function that sets the number of thresholds to infinity (without setting a threshold), inputs the accumulated operation time as a parameter, and outputs a correction value. The current command unit 21 may execute a current ratio correction process.

  When the process of step 26 is completed (when the individual luminance signal A and the individual luminance signal B are output), the current command unit 21 determines whether the lamp drive command (in this case, the luminance command) has stopped in step S27. Determine whether or not.

  If it is determined in step S27 that the lamp drive command has not stopped, the process returns to step S24, and the subsequent processes are repeated.

  On the other hand, if it is determined in step S27 that the lamp driving command has stopped, the current command unit 21 (or a control unit (not shown) that supplies a luminance command or the like to the current command unit 21) is determined in step S28. Then, the timing operation of the timing device 15 is terminated. Thereby, the second current command control process ends.

  Next, the third current command control process will be described with reference to the flowchart of FIG.

  FIG. 8 is a flowchart when the luminance command is constant (the luminance target value is constant).

  In step S <b> 41, the current command unit 21 (or a control unit (not shown) that supplies a brightness command or the like to the current command unit 21) starts temperature measurement of the thermometer 14.

  In step S42, the current command unit 21 sets a target level of the total current of the lamp 12-A and the lamp 12-B based on the luminance command (total current command).

  In step S43, the current command unit 21 determines the lamp 12 based on the chromaticity command (base current ratio command) and the ambient temperature (measured value of the thermometer 14) between the lamp 12-A and the lamp 12-B. A current ratio between -A and lamp 12-B is set. That is, the current command unit 21 sets the base current ratio based on the chromaticity command (base current ratio command), and sets the ambient temperature between the lamp 12-A and the lamp 12-B (measured value of the thermometer 14). Accordingly, the base current ratio is corrected, and the correction result is set as the final current ratio.

  In step S44, the current command unit 21 determines whether the individual luminance control signal A and the individual luminance control signal B are based on the target level of the total current set in the process of step S42 and the current ratio set in the process of step S43. Generate and output each.

  In step S45, the current command unit 21 determines whether the lamp drive command (in this case, the brightness command) has stopped.

  If it is determined in step S45 that the lamp drive command has not stopped, the process returns to step S43, and the subsequent processes are repeated.

  That is, when the purpose is to solve only the third problem among the first to third problems, the ambient temperature (measurement result of the thermometer 14) between the lamp 12-A and the lamp 12-B is obtained. Unless changed, the individual luminance control signal A and the individual luminance control signal B having the same voltage level are continuously output. That is, the setting of the current ratio between the lamp 12-A and the lamp 12-B is maintained as it is. As a result, the actual current ratio between the lamp 12-A and the lamp 12-B is also kept substantially constant.

  In contrast, when the ambient temperature between the lamp 12-A and the lamp 12-B changes, the current ratio (set value) between the lamp 12-A and the lamp 12-B is updated, and the updated current ratio is updated. Each of the individual luminance control signal A and the individual luminance control signal B having the same voltage level corresponding to (set value) continues to be output (however, until the ambient temperature changes again). As a result, the actual current ratio between the lamp 12-A and the lamp 12-B is also kept substantially constant at the updated current ratio (set value).

  Thereafter, when the lamp drive stop command is stopped (when it is determined in step S45 that the lamp drive command is stopped), the current command unit 21 (or a control unit (not shown) for supplying a luminance command or the like to the current command unit 21). Etc.) terminates the temperature measurement of the thermometer 14. As a result, the third current command control process ends.

  Next, the fourth current command control process will be described with reference to the flowchart of FIG.

  In step S <b> 61, the current command unit 21 (or a control unit (not shown) that supplies a brightness command or the like to the current command unit 21) starts the time measurement operation of the time measuring device 15 and the temperature measurement of the thermometer 14.

  In step S62, the current command unit 21 sets a target level of the total current of the lamp 12-A and the lamp 12-B based on the luminance command (total current command).

  In step S63, the current command unit 21 determines the chromaticity command (base current ratio command), the target level of the total current set in the process of step S62, and the ambient temperatures of the lamps 12-A and 12-B ( Based on the measured value of the thermometer 14, the current ratio between the lamp 12-A and the lamp 12-B is set. That is, the current command unit 21 sets a base current ratio based on the chromaticity command (base current ratio command), and performs a first correction according to the target level of the total current for the base current ratio, Each of the second corrections according to the temperature is performed, and the correction result (the base current ratio subjected to the first correction and the second correction) is temporarily set as a current ratio.

  In step S64, the current command unit 21 determines whether or not the cumulative operation time has exceeded the set time.

  When the measured value (cumulative operation time) of the timing device 15 exceeds the set time (when it is determined in step S64 that the accumulated operation time has exceeded the set time), the current command unit 21 determines the current ratio in step S65. To reset. That is, the current command unit 21 further performs a third correction corresponding to the accumulated operation time on the base current ratio subjected to the first correction and the second correction, and the correction result (first correction). To the base current ratio subjected to the third correction) is set as the final current ratio.

  In step S66, the current command unit 21 sets the target level of the total current set in the process in step S62 and the current ratio reset in the process in step S65 (the first to third corrections are performed). The individual luminance control signal A and the individual luminance control signal B are generated on the basis of the base current ratio) and output.

  On the other hand, when the measured value (cumulative operation time) of the timing device 15 does not exceed the set time (when it is determined in step S64 that the accumulated operation time does not exceed the set time), the current command unit 21 , Without performing the process of step S65 (that is, the base current ratio subjected to the first correction and the second correction is set as the final current ratio), in step S66, set in the process of step S62 The individual luminance control signal A and the individual luminance control signal B based on the target level of the total current and the current ratio (base current ratio subjected to the first correction and the second correction) set in step S63. Are generated and output.

  In step S67, the current command unit 21 determines whether or not the luminance command (total current command) has changed.

  If it is determined in step S67 that the luminance command has not changed, the process returns to step S63, and the subsequent processes are repeated. That is, as long as the luminance command does not change (unless the target level of the total current changes), the current ratio subjected to the same correction is set as the first correction corresponding to the target level of the total current. However, when the temperature changes (when the measured value of the thermometer 14 changes), a current ratio subjected to a correction different from the current correction is set as the second correction corresponding to the ambient temperature. Similarly, when the accumulated time (measured value of the time measuring device 15) exceeds the set time, a current ratio subjected to a correction different from the previous one is set as the third correction corresponding to the accumulated time.

  On the other hand, if it is determined in step S67 that the luminance command has changed, the current command unit 21 determines in step S68 whether the luminance command (lamp drive command) has stopped.

  When it is determined in step S68 that the luminance command has not stopped, that is, when the voltage level of the luminance command has changed from the first level to the second level (a level other than the 0 level and the first level). The processing is returned to step S62, and the subsequent processing is repeated. That is, when the luminance command is changed, a current ratio subjected to a correction different from the previous one is set as the first correction corresponding to the target level of the total current. In this case as well, when the temperature changes (when the measured value of the thermometer 14 changes), the current ratio is further subjected to a different correction as the second correction corresponding to the ambient temperature. Is set. Similarly, when the accumulated time (measured value of the time measuring device 15) exceeds the set time, a current ratio to which a different correction from before is further applied is set as the third correction corresponding to the accumulated time. .

  Thereafter, when the luminance command is stopped (when it becomes 0 [V]), it is determined in step S68 that the luminance command (lamp drive command) has been stopped, and the current command unit 21 (or the luminance command or the like is changed to the current command unit). A control unit (not shown) or the like that is supplied to 21) finishes the timing operation of the timing device 15 and the temperature measurement of the thermometer 14. As a result, the fourth current command control process ends.

  As described above, the current command unit 21 performs the fourth current command control process (current command control process according to the flowchart of FIG. 9), for example, thereby simultaneously solving the first problem to the third problem. can do.

  If only the first problem and the second problem are to be solved, that is, if it is not necessary to solve the third problem corresponding to the temperature change, the processing of step S63 is performed as “the chromaticity command and the total current. It is only necessary to correct the process of “setting the current ratio based on the target level”.

  Further, when it is desired to solve only the first problem and the third problem, that is, when it is not necessary to solve the second problem corresponding to the accumulated operation time (aging deterioration), the processes of step S64 and step 65 are simply omitted. do it.

  Further, when it is desired to solve only the second problem and the third problem, that is, when it is not necessary to solve the first problem corresponding to the target level of the total current, the processing in step S63 is simply performed as “chromaticity command, In addition, the processing is corrected to “the current ratio is set based on the ambient temperature” and the processing in step S67 may be omitted.

  By the way, the arrangement positions of the lamp 12-A and the lamp 12-B of the backlight device 1 are not limited to the locations shown in FIGS. 1 and 2, and the light from the lamp 12-A and the lamp 12-B are arranged. As long as the light spatially mixed with the light can be emitted from the light guide plate 11 in a predetermined direction of the LCD 2, any place may be used. For example, as shown in FIG. 10 (cross-sectional view) and FIG. 11 (top view of the LCD 2), the surface 11-2 on the surface 11-2 side of the four surfaces perpendicular to the surface of the light guide plate 11 The lamp 12-A is arranged substantially in parallel (along the surface 11-2), on the surface 11-1 side facing the surface 11-2, substantially in parallel with the surface 11-1 (on the surface 11-1). Along the lamp 12-B.

  Further, in the above-described example, the two-output inverter unit 13 (FIG. 4) is applied as the lamp driving device of the backlight device 1. However, if the device has the same function as the inverter unit 13, its configuration Is not particularly limited. That is, a drive device other than the inverter unit may be applied as the lamp drive device of the backlight device 1.

  Alternatively, for example, an inverter unit as shown in FIG. 12 may be applied as the lamp driving device of the backlight device 1.

  In the inverter unit of FIG. 12, each of the current command unit 21, the transformer 42-A, the detection resistor 43-A, the transformer 42-B, the detection resistor 43-B, and the input power source 45 corresponds to the corresponding circuit of FIG. It has basically the same function and configuration.

  However, in the inverter unit 13 of FIG. 4, two control circuits 41-A and 41-B are provided, but in the inverter unit of FIG. 12, one control circuit 81 is provided. Further, in the inverter unit 13 of FIG. 4, the feedback circuit 44-A that feeds back the actual current of the lamp 12-A (voltage signal corresponding thereto) to the control circuit 41-A and the actual current of the lamp 12-B (to it) The feedback circuit 44-B that feeds back the corresponding voltage signal) to the control circuit 41-B is provided. In the inverter unit of FIG. 12, the actual current of the lamp 12-A and the actual current of the lamp 12-B are provided. , That is, a total feedback circuit 82 that feeds back the actual level of the total current (a voltage signal corresponding thereto) to the control circuit 81 is provided.

  That is, the control circuit 81 has a luminance control signal (a command value of the total current of the lamp 12-A and the lamp 12-B) supplied from a control unit (not shown) and the signal fed back from the sum feedback circuit 82 ( The individual brightness supplied from the current command unit 21 while feedback controlling the total current of the lamp 12-A and the lamp 12-B using the actual value of the total current of the lamp 12-A and the lamp 12-B). Based on each of the control signal A and the individual luminance control signal B, open-loop control is individually performed for each of the current of the lamp 12-A and the current of the lamp 12-B.

  As a result, the brightness of light emitted from the light guide plate 11 (light emitted from the LCD 2) is appropriately controlled by closed control (feedback control) of the total current of the lamps 12-A and 12-B. The chromaticity of light emitted from the light guide plate 11 (light emitted from the LCD 2) is appropriately controlled by controlling the current ratio between the lamp 12-A and the lamp 12-B. That is, the inverter unit shown in FIG. 12 can achieve an effect that the brightness and chromaticity of light emitted from the light guide plate 11 (light emitted from the LCD 2) can be controlled simultaneously and appropriately.

  Further, since the output value of the total feedback circuit 82 (the actual level of the total current of the lamp 12-A and the lamp 12-B) is also supplied to the timing device 15, when viewed from the timing device 15 side, the lamp 12-A. When the weighted calculation of the total operation time according to the actual level of the total current of the lamp 12-B is performed, there is an effect that the calculation of the actual level of the total current of the lamp 12-A and the lamp 12-B becomes unnecessary. It becomes possible.

  Alternatively, for example, as shown in FIG. 13, as a lamp driving device of the backlight device 1, a current command device 91, a one-output lamp driving device (inverter unit) 92 -A, and a one-output lamp driving device ( An inverter unit) 92-B may be applied.

  13 is assumed to have basically the same function and configuration as the current command unit 21 in FIG. That is, the current command device 91 in FIG. 13 can be configured as shown in FIG. 5 described above. Therefore, the detailed description of the current command device 91 of FIG. 13 is omitted here.

  Further, the lamp driving device (inverter unit) 92-A and the lamp driving device (inverter unit) 92-B in FIG. 13 are respectively the lamp driving unit 22-A and the lamp driving unit 22-B in FIG. And basically have the same functions and configuration. Therefore, the detailed description of each of the lamp driving device (inverter unit) 92-A and the lamp driving device (inverter unit) 92-B in FIG. 13 is omitted here.

  Naturally, the arrangement position of the lamp 12-A is not limited to the example of FIG. 13 and may be arranged on the same side as the lamp 12-B as shown in FIG. 1 and FIG.

  Incidentally, in the backlight device 1 described above, the two lamps 12-A and 12-B are mounted, but the number of lamps is not particularly limited as long as the number is two or more.

  For example, each of four lamps 12-A to 12-D can be mounted as in the backlight device 101 shown in the cross-sectional view of FIG.

  In this case, the arrangement positions of the four lamps 12-A to 12-D are not particularly limited. For example, although not illustrated, the arrangement positions corresponding to FIG. That is, all the four lamps 12-A to 12-D are arranged on the surface 11-1 side of the light guide plate 11 so as to be substantially parallel to the surface 11-1 (along the surface 11-1). Also good. Alternatively, as shown in FIG. 14, the four lamps 12 -A to 12 -D are replaced with a first set of two lamps 12 -A and 12 -B and two lamps 12. -C and the lamp 12-D are divided into a second set, and all the lamps belonging to the first set are arranged on the surface 11-2 side of the light guide plate 11 substantially in parallel with the surface 11-2 ( All the lamps belonging to the second set are arranged on the surface 11-1 side facing the surface 11-2 substantially parallel to the surface 11-1 (surface 11-). 1). Alternatively, in FIG. 14, the lamp 12-A and the lamp 12-C may be regarded as a first set, and the lamp 12-B and the lamp 12-D may be regarded as a second set.

  However, when four lamps 12-A to 12-D are used in this way, as shown in FIG. 15, the four-output inverter unit 111 (or, although not shown, corresponds to FIG. 13). (Ie, a system comprising four lamp driving devices and a command device) is required.

  The inverter unit 111 includes a current command unit 121 and four lamp driving units 122-A to 122-D.

  In addition to the target value of the chromaticity coordinates of the chromaticity of the light emitted from the light guide plate 11 (FIG. 14), the current command unit 121 is configured for the four lamps 12-A to 12-D as necessary. In consideration of the current situation such as the target level of the total current, its accumulated operation time (measured value of the timer 15), or the ambient temperature (measured value of the thermometer 14), the four lamp driving units 122- A current ratio of each of A through lamp driver 122-D is set, and four individual luminance control signals A through D are generated based on the current ratio. Then, the current command unit 121 supplies the individual luminance control signal A to the individual luminance control signal D to the lamp driving unit 122-A to the lamp driving unit 122-D, respectively.

  Note that the method for setting the current ratio of each of the lamp driving units 122-A to 122-D is not particularly limited. For example, after adjusting the current ratio between the lamp 12-A and the lamp 12-B in the first group and the current ratio between the lamp 12-C and the lamp 12-D in the second group, The current ratio between the first group and the second group can also be adjusted. Alternatively, as described above, the way of thinking of the group can be changed. That is, in FIG. 14, the lamp 12-A and the lamp 12-C are regarded as the first group, and the lamp 12-B and the lamp 12-D. Can be regarded as the second group, the current ratio between the lamp 12-A and the lamp 12-C in the first group, the lamp 12-B and the lamp 12- in the second group, first. After adjusting the current ratio with D, the current ratio between the first group and the second group can also be adjusted.

  In these cases, if the current ratio in each group to be adjusted first is set to 1: 1, that is, the currents in the lamps 12-A and 12-B in the first group are the same. If the currents of the lamp 12-C and the lamp 12-D in the second group are set to be the same level, the current command unit 121 is set to the subsequent group. It is possible to easily set the current ratio between each other. As a result, the current command unit 121 can be realized with a simple configuration.

  In this case, each of the lamp driving units 122-A to 122-D stabilizes all currents of the lamps belonging to the same group at almost the same level for each of the first group and the second group. Control will be executed.

  By the way, the chromaticity of the light emitted from the four lamps 12-A to 12-D is not particularly limited.

  That is, a lamp having the first chromaticity coordinate may be applied as the lamp belonging to the first group, and a lamp having the second chromaticity coordinate may be applied as the lamp belonging to the second group. In this case, as shown in the chromaticity diagram of FIG. 3 described above, as the lamps belonging to the first group, the first chromaticity on the black body curve 33 (in the example of FIG. 3, chromaticity (color temperature)). 35 or a chromaticity (color temperature) 36), and a second color different from the first chromaticity on the black body curve 33 is applied as a lamp belonging to the second group. A lamp manufactured to emit light at a degree (in the example of FIG. 3, chromaticity (color temperature) 36 or chromaticity (color temperature) 35) can be applied.

  Alternatively, lamps having different chromaticity coordinates may be applied as the four lamps 12-A to 12-D. In this case, as shown in the chromaticity diagram of FIG. 16 (the chromaticity diagram similar to FIG. 3), each of the four lamps 12-A to 12-D includes a predetermined black body curve 33. Each of the four chromaticities (that is, chromaticity (point) 151-A to chromaticity (point) 151-D) corresponding to the vertex of the rectangular area 161 is manufactured so as to emit light. Each of the four lamps can be applied.

  Although not shown in the drawing, K lamps (K is an arbitrary integer value) manufactured so as to emit light with chromaticity 151-A are set as the first set so that light is emitted with chromaticity 151-B. The manufactured K lamps are set as the second set, and the K lamps manufactured so as to emit light with the chromaticity 151-C are set as the third set and emit with the chromaticity 151-D. The 4 × K lamps in which the K lamps manufactured as described above are used as the fourth group may be mounted on the backlight device.

  Further, although not shown, any one of N chromaticities corresponding to N vertices of a predetermined N (N is an arbitrary integer value of 3 or more) square region including the black body curve 33 is included. It is also possible to apply each of N lamps (or N sets of lamp groups) each manufactured to emit light.

  In this way, by applying N lamps (or N sets of lamp groups) in which each of the N chromaticities is set (in the above example, each of the four chromaticities is set). 4 lamps 12-A to 12-D (or four sets of lamp groups) are applied to adjust the chromaticity of light emitted from the light guide plate 11 (light emitted from the LCD 2). The degree of freedom can be significantly increased as compared to the case where two lamps (or two sets of lamp groups) each having two chromaticities are set. In other words, when two lamps (or two sets of lamp groups) are applied, light emitted from the light guide plate 11 only on a straight line connected by two chromaticities set for the lamps ( The chromaticity of the light emitted from the LCD 2 could not be adjusted. On the other hand, when N lamps (or N sets of lamp groups) are applied, a light guide plate is formed in an N-shaped area having N chromaticities set as apexes for the lamps. The chromaticity of the light emitted from 11 (light emitted from the LCD 2) can be adjusted.

  Incidentally, the series of processes described above can be executed by hardware, but can also be executed by software.

  When a series of processing is executed by software, a program constituting the software is a computer (for example, the microcomputer 71 in FIG. 5 described above) incorporated in dedicated hardware, or various programs. Is installed from a network or a recording medium, for example, in a general-purpose personal computer shown in FIG. 17 that can execute various functions.

  In FIG. 17, the CPU 201 executes various processes according to a program recorded in the ROM 202 or a program loaded from the storage unit 208 to the RAM 203. The RAM 203 also appropriately stores data necessary for the CPU 201 to execute various processes.

  The CPU 201, the ROM 202, and the RAM 203 are connected to each other via the bus 204. An input / output interface 205 is also connected to the bus 204.

  Connected to the input / output interface 205 are an input unit 206 such as a keyboard and a mouse, an output unit 207 composed of a display, a storage unit 208, and a communication unit 209 composed of a modem, a terminal adapter, and the like.

  In this case, the output unit 207 can be configured, for example, as a display device (including at least the backlight device 1 and the LCD 2) as shown in FIG. That is, in this case, the above-described series of processing for the output unit 207 is executed by the CPU 201 instead of the microcomputer 71 of FIG.

  A drive 210 is also connected to the input / output interface 205 as necessary, and a removable recording medium 211 made of a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, or the like is appropriately installed, and a computer program read therefrom Are installed in the storage unit 208 as necessary.

  By the way, as shown in FIG. 5 and FIG. 17, the recording medium including such a program is distributed to provide a program to the user separately from the apparatus main body, and is a magnetic disk on which the program is recorded ( It consists of floppy disk), optical disk (including compact disk-read only memory (CD-ROM), DVD (digital versatile disk)), magneto-optical disk (including MD (mini-disk)), or semiconductor memory. A ROM or diagram (not shown) of the microcomputer 71 of FIG. 5 on which a program is recorded, which is provided not only to the removable recording medium (package medium) 211 but also provided in advance to the apparatus main body to the user. 17 ROM 202 and a hard disk included in the storage unit 208.

  In the present specification, the system represents the entire apparatus including a plurality of apparatuses and processing units.

  In addition, in this specification, the step of describing the program recorded in the recording medium is not limited to the processing performed in time series along the order, but is not necessarily performed in time series, either in parallel or individually. The process to be executed is also included.

Illumination device (backlight device) according to the present embodiment, which is a configuration example of a backlight device in which two lamps are mounted and a display device (liquid crystal display device) according to the present embodiment to which the backlight device is applied. It is sectional drawing shown. It is a block diagram which shows the structural example of the backlight apparatus of FIG. 1, and the liquid crystal display device to which it is applied. It is a chromaticity diagram explaining the example of the chromaticity set to two lamps of the backlight apparatus of FIG. It is a block diagram which shows the detailed structural example of the inverter unit of the backlight apparatuses of FIG. It is a block diagram which shows the structural example of the electric current instruction | command part among the inverter units of FIG. It is a flowchart explaining the 1st example of the current command control process of the current command part of FIG. It is a flowchart explaining the 2nd example of the current command control process of the current command part of FIG. It is a flowchart explaining the 3rd example of the current command control process of the current command part of FIG. It is a flowchart explaining the 4th example of the current command control process of the current command part of FIG. FIG. 2 is a cross-sectional view of the backlight device of FIG. 1 when the lamp arrangement position is different from the state of FIG. 1. FIG. 9 is a block diagram illustrating a configuration example of the backlight device of FIG. 1 when the lamp arrangement position is in the state illustrated in FIG. 8. FIG. 5 is a block diagram showing another configuration example (configuration example different from FIG. 4) of the inverter unit in the backlight device of FIG. 1. It is a block diagram which shows the lamp drive system provided instead of the inverter unit among the backlight apparatuses of FIG. FIG. 3 is a cross-sectional view illustrating a configuration example of a backlight device in which four lamps are mounted, which is a lighting device (backlight device) according to the present embodiment. It is a block diagram which shows the structural example of the backlight apparatus of FIG. It is a chromaticity diagram explaining the example of the chromaticity set to four lamps of the backlight apparatus of FIG. It is a block diagram which shows the structural example of the illuminating device or display apparatus of the other form of this Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Backlight device, 2 LCD, 11 Light guide plate, 11-1, 11-2 The surface of a light guide plate, 12-A thru | or 12-D lamp, 13 Inverter unit, 14 Thermometer, 15 Time measuring device, 21 Current command part, 22-A, 22-B lamp drive unit, 33 black body curve, 34, 35 chromaticity, 71 microcomputer, 91 current command device, 92-A, 92-B lamp drive device (inverter unit), 111 inverter unit, 121 current command unit, 122-A to 122-D lamp drive unit, 151-A to 151-D chromaticity, 201 CPU, 202 ROM, 207 output unit, 211 removable recording medium, A, B individual luminance control signal

Claims (12)

A plurality of lamps each produced to emit light at a chromaticity corresponding to each of preset chromaticity coordinates;
A light guide plate that emits light incident from each of the plurality of lamps in a predetermined direction;
Each of the plurality of lamps is driven to perform control to maintain the actual level of the total current of the plurality of lamps at a target level, and the target value of the chromaticity coordinates of the chromaticity of the light emitted from the light guide plate And a lamp driving device that executes control for varying a distribution ratio of the total current to each of the plurality of lamps according to the target level of the total current. It further comprises a timing device that counts the operating time of the plurality of lamps and outputs the cumulative total of the operating times measured so far as a cumulative operating time,
2. The lighting device according to claim 1, wherein the lamp driving device further executes control to vary a distribution ratio of the total current to each of the plurality of lamps according to the cumulative operation time output from the timing device. . The timing device further acquires the actual level or the target level of the total current of the plurality of lamps when measuring the operating time of the plurality of lamps, and the actual level of the acquired total current Alternatively, the measured operation time is weighted according to the target level, and an addition time between the weighted operation time and the accumulated operation time so far is output as the current accumulated operation time. 2. The illumination device according to 2. A thermometer arranged near at least a part of the plurality of lamps and measuring a temperature around the arrangement location;
The lighting device according to claim 1, wherein the lamp driving device further executes control for varying a distribution ratio of the total current to each of the plurality of lamps according to the temperature measured by the thermometer. A plurality of lamps each manufactured to emit light with chromaticity corresponding to each of preset chromaticity coordinates, and a light guide plate that emits light incident from each of the plurality of lamps in a predetermined direction. A lighting device comprising at least
Each of the plurality of lamps is driven to perform control to maintain the actual level of the total current of the plurality of lamps at a target level, and the target value of the chromaticity coordinates of the chromaticity of the light emitted from the light guide plate And a control step of executing control for varying a distribution ratio of the total current to each of the plurality of lamps according to the target level of the total current. A plurality of lamps each produced so as to emit light with chromaticity corresponding to each of preset chromaticity coordinates, and a light guide plate that emits light incident from each of the plurality of lamps in a predetermined direction. For at least the lighting device
Each of the plurality of lamps is driven to perform control to maintain the actual level of the total current of the plurality of lamps at a target level, and the target value of the chromaticity coordinates of the chromaticity of the light emitted from the light guide plate And a program for causing a computer to execute a process including a control step of executing control for varying a distribution ratio of the total current to each of the plurality of lamps in accordance with the target level of the total current. A plurality of lamps each produced to emit light at a chromaticity corresponding to each of preset chromaticity coordinates;
A light guide plate that emits light incident from each of the plurality of lamps in a predetermined direction;
A display panel for displaying an image using light incident from the light guide plate;
Each of the plurality of lamps is driven to perform control to maintain the actual level of the total current of the plurality of lamps at a target level, and the target value of the chromaticity coordinates of the chromaticity of the light emitted from the light guide plate And a lamp driving device that executes control for varying a distribution ratio of the total current to each of the plurality of lamps according to the target level of the total current. It further comprises a timing device that counts the operating time of the plurality of lamps, and outputs a cumulative total of the operating times measured so far as a cumulative operating time,
The display device according to claim 7, wherein the lamp driving device further executes control for varying a distribution ratio of the total current to each of the plurality of lamps according to the cumulative operation time output from the time measuring device. . The timing device further acquires the actual level or the target level of the total current of the plurality of lamps when measuring the operating time of the plurality of lamps, and the actual level of the acquired total current Alternatively, the measured operation time is weighted according to the target level, and an addition time between the weighted operation time and the accumulated operation time so far is output as the current accumulated operation time. 9. The display device according to 8. A thermometer arranged near at least a part of the plurality of lamps and measuring a temperature around the arrangement location;
The display device according to claim 7, wherein the lamp driving device further executes control for varying a distribution ratio of the total current to each of the plurality of lamps according to the temperature measured by the thermometer. A plurality of lamps each manufactured to emit light with chromaticity corresponding to each of the preset chromaticity coordinates, a light guide plate that emits light incident from each of the plurality of lamps in a predetermined direction, and A display device comprising at least a display panel that displays an image using light incident from the light guide plate,
Each of the plurality of lamps is driven to perform control to maintain the actual level of the total current of the plurality of lamps at a target level, and the target value of the chromaticity coordinates of the chromaticity of the light emitted from the light guide plate And a control step of executing control for varying a distribution ratio of the total current to each of the plurality of lamps according to the target level of the total current. A plurality of lamps each manufactured to emit light with chromaticity corresponding to each of the preset chromaticity coordinates, a light guide plate that emits light incident from each of the plurality of lamps in a predetermined direction, and For a display device comprising at least a display panel that displays an image using the light incident from the light guide plate,
Each of the plurality of lamps is driven to perform control to maintain the actual level of the total current of the plurality of lamps at a target level, and the target value of the chromaticity coordinates of the chromaticity of the light emitted from the light guide plate And a program for causing a computer to execute a process including a control step of executing control for varying a distribution ratio of the total current to each of the plurality of lamps according to the target level of the total current.

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