JP5028301B2 - LIGHTING DEVICE AND DISPLAY DEVICE USING THE SAME - Google Patents

Description

  The present invention relates to an illumination device used for a backlight or the like, and a display device using the same.

  In recent years, for example, liquid crystal display devices have been widely used in liquid crystal televisions, monitors, mobile phones, and the like as flat panel displays having features such as thinness and light weight compared to conventional cathode ray tubes. Such a liquid crystal display device includes an illumination device (backlight) that emits light and a liquid crystal panel that displays a desired image by serving as a shutter for light from a light source provided in the illumination device. It is.

  Further, as the above illuminating device, an edge light type or a direct type is provided in which a linear light source composed of a cold cathode fluorescent tube or a hot cathode fluorescent tube is disposed on the side or below the liquid crystal panel. However, the cold cathode fluorescent tube as described above contains mercury and it is difficult to recycle the discarded cold cathode fluorescent tube. Therefore, an illumination device using a light emitting diode (LED) that does not use mercury as a light source has been proposed (see, for example, Patent Document 1 below).

  Further, in the LED as described above, when a change with time occurs, the luminance changes even if the same drive current is supplied. Furthermore, since each LED of RGB that emits light of each color of red (R), green (G), and blue (B) has different temporal changes, an illumination device using these RGB LEDs performs color correction. It is also required to do. Therefore, in the conventional illumination device described in Patent Document 1, it is proposed that a photosensor is installed for each predetermined number of LEDs, and the emission intensity of each RGB LED is controlled based on the detection result of the photosensor. Yes.

  Further, in the conventional lighting device, as described in, for example, Patent Document 2 below, based on the result of emitting only a selected LED among a plurality of LEDs in a time-sharing manner and receiving the light by an optical sensor. Thus, it has been shown that the light emission intensity of the LED is controlled, and the number of installed optical sensors can be reduced.

Moreover, in the conventional illumination device, for example, as described in Patent Document 3 below, an optical sensor is installed for each predetermined number of LEDs, and the output of the optical sensor is determined according to the distance from the LED to the optical sensor. It has been proposed that the accuracy of the detection result of the optical sensor can be improved.
JP 2007-53122 A JP 2005-157316 A JP 2005-310997 A

  However, in the conventional illumination device as described above, when the number of installed photosensors is reduced, it is not possible to prevent the accuracy of the detection results of the photosensors from being lowered, and LED (light source) drive control is performed. Caused the problem that it was not possible to perform accurately.

  More specifically, in the conventional illumination device, the detection signal of the optical sensor is corrected according to the distance from the LED to the optical sensor using a memory table. However, the output (detection signal) of the optical sensor usually decreases in inverse proportion to the square of the distance. For this reason, if the optical sensor and the LED are separated from each other, the output of the optical sensor may be a very weak value, that is, a value of almost zero. As a result, even when correction is performed using the memory table, the corrected value (detection result) is almost zero, and the output of the optical sensor cannot be appropriately corrected, and the detection result cannot be obtained with high accuracy. was there. Further, in this way, when the output of the optical sensor is a weak value, the S / N ratio of the output is generally lowered. Even if correction is performed using a memory table, the correction is performed. The latter value contains a lot of noise components, and the accuracy of the detection result of the optical sensor may be significantly reduced.

  As described above, in the conventional lighting device, when the number of installed photosensors is reduced, the accuracy of the detection result of the photosensor is reduced, and the accuracy cannot be improved. Could not be performed with high accuracy.

  In view of the above-described problems, the present invention can improve the detection accuracy of the photosensor even when the number of photosensors is reduced, and thus can perform drive control of the light source with high accuracy, And it aims at providing the display apparatus using the same.

In order to achieve the above object, an illumination device according to the present invention is an illumination device including a plurality of light sources,
An optical sensor provided for each predetermined number of light sources, detecting light from each of the predetermined number of light sources, and outputting a detection signal;
A light source control unit that performs drive control of the light source;
A detection signal from which the detection signal from the optical sensor is input, and a detection unit for detecting each detection result of the predetermined number of light sources;
A light detection control unit that performs drive control of the light detection unit;
The light detection control unit sets a detection period in which light from the predetermined number of light sources is detected by the light sensor,
At least one of the light source control unit and the light detection control unit includes the corresponding light source and the corresponding light source so that the detection signals from the photosensors for the predetermined number of light sources substantially coincide in the detection period. The present invention is characterized in that the light detection unit is driven and controlled.

  In the illumination device configured as described above, at least one of the light source control unit and the light detection control unit is configured so that the detection signals from the photosensors for a predetermined number of light sources substantially coincide with each other in the detection period. , Drive control of the corresponding light source and light detection unit. Thus, unlike the conventional example, the light detection unit can prevent the detection signal from the light sensor from having a very weak value, and the light detection unit can detect the detection result of the predetermined number of light sources. It can prevent that many noise components are included. As a result, even when the number of installed photosensors is reduced, it is possible to improve the detection accuracy of the photosensors, and thus it is possible to configure an illumination device that can perform drive control of the light source with high accuracy.

  In the illumination device, it is preferable that the light source control unit changes power supplied to a corresponding light source in accordance with each distance between the optical sensor and the predetermined number of light sources in the detection period.

  In this case, by increasing the power supplied to the light source far from the photosensor, the detection signal from the photosensor for the light source far from the photosensor becomes a very weak value in the photodetection unit. This can be surely prevented, and the detection accuracy of the optical sensor can be improved with certainty.

Further, in the illumination device, the light detection unit is provided with a detection gain amplification unit that amplifies a gain of a detection signal from the optical sensor,
In the detection period, the light detection control unit changes a gain of a detection signal from the light sensor according to each distance between the light sensor and the predetermined number of light sources with respect to the detection gain amplification unit. There may be provided a detection gain instruction section for instructing this.

  In this case, in the light detection unit, by increasing the gain of the detection signal for the light source far from the light sensor, the detection signal from the light sensor for the light source far from the light sensor becomes a very weak value. Can be reliably prevented, and the detection accuracy of the optical sensor can be reliably improved.

  In the illumination device, it is preferable that the light source controller changes the number of the light sources that are simultaneously turned on in accordance with each distance between the photosensor and the predetermined number of light sources in the detection period.

  In this case, by simultaneously turning on a plurality of light sources that are separated from the optical sensor, it is possible to reliably prevent the detection signals from the optical sensors for the plurality of light sources from having very weak values in the light detection unit. And the detection accuracy of the optical sensor can be improved with certainty. In addition, the detection period can be shortened.

Further, in the illumination device, the light source control unit changes the number of the light sources that are turned on simultaneously in accordance with each distance between the light sensor and the predetermined number of light sources in the detection period,
Predetermined lighting information about light sources that are simultaneously turned on is input to the light detection unit from the light source control unit, and using the input lighting information, a detection signal from the light sensor is It is preferable that a calculation unit that calculates each detection result of the predetermined number of light sources by performing a predetermined differential calculation is provided.

  In this case, when the calculation unit performs a predetermined differential calculation, light (noise) other than the light source such as outside light can be canceled out in each detection result of the light source in the light detection unit, and detection of the light sensor The accuracy can be improved more reliably.

In the above illumination device, the lighting device further includes a storage unit that stores detection results of the predetermined number of light sources from the light detection unit,
The light source control unit preferably performs drive control of a corresponding light source using a detection result stored in the storage unit.

  In this case, the light source control unit can more appropriately perform drive control of each light source in a state where the state of each light source such as a change with time is grasped.

  In the lighting device, the light source control unit and the light detection control unit may be integrally configured.

  In this case, an illumination device with a small number of parts and a simple structure can be easily configured.

  In addition, the display device of the present invention is characterized by using any one of the above illumination devices.

  In the display device configured as described above, the illumination device can improve the detection accuracy of the photosensor even when the number of photosensors is reduced, and thus can perform drive control of the light source with high accuracy. Therefore, a high-performance display device having excellent display quality can be easily configured.

Moreover, in the said display apparatus, while providing the display part which displays information,
The detection period is preferably set to a non-display period in which information is not displayed on the display unit.

  In this case, the detection operation by the photosensor and the photodetection unit can be performed without hindering the information display operation on the display unit.

In the display device, a liquid crystal panel is used for the display unit,
The detection period may be set to a black display period in the liquid crystal panel.

  In this case, since the detection period is set to the black display period of the liquid crystal panel, the detection operation by the light sensor and the light detection unit can be performed without causing the user to recognize that the light source is turned on. it can.

  ADVANTAGE OF THE INVENTION According to this invention, even when it reduces the number of installation of a photosensor, the detection accuracy of a photosensor can be improved, Therefore, the illuminating device which can perform drive control of a light source with high accuracy, and this are used. It is possible to provide a display device.

  Hereinafter, preferred embodiments of a lighting device of the present invention and a display device using the same will be described with reference to the drawings. In the following description, the case where the present invention is applied to a transmissive liquid crystal display device will be described as an example. Moreover, the dimension of the structural member in each figure does not faithfully represent the actual dimension of the structural member, the dimensional ratio of each structural member, or the like.

[First Embodiment]
FIG. 1 is a diagram for explaining a main configuration of a liquid crystal display device using the illumination device according to the first embodiment of the present invention. In the figure, the liquid crystal display device 1 of the present embodiment is provided with a liquid crystal panel 2 as a display unit for displaying information such as characters and moving images, and the liquid crystal panel 2 on the non-display surface side. Is provided with a lighting device 3 of the present invention that irradiates planar light (illumination light). In this embodiment, the liquid crystal panel 2 and the lighting device 3 are integrated as a transmissive liquid crystal display device 1. ing. The illuminating device 3 includes a diffusion plate 4 provided on the back surface of the liquid crystal panel 2, and appropriately diffuses light from a light emitting diode (LED), which will be described later, by the diffusion plate 4 to the liquid crystal panel 2. Thus, illumination light with uniform brightness is made incident.

  Further, the liquid crystal display device 1 includes a video signal processing circuit 5 to which an external video signal is input, a liquid crystal control circuit 6 that is connected to the video signal processing circuit 5 and that controls driving of the liquid crystal panel 2, and a liquid crystal A source driver 7 and a gate driver 8 connected to the control circuit 6 are provided. In addition, the liquid crystal display device 1 is connected to the video signal processing circuit 5, an LED control circuit 9 for controlling the driving of the LED and the photosensor described later, and an LED driving circuit connected to the LED control circuit 9. 10, a detection circuit 11, and a memory 12 are provided.

  The liquid crystal mode and the pixel structure of the liquid crystal panel 2 are arbitrary. Moreover, the drive mode of the liquid crystal panel 2 is also arbitrary. That is, as the liquid crystal panel 2, any liquid crystal panel that can display information can be used. Therefore, the detailed structure of the liquid crystal panel 2 is not shown in FIG.

  The video signal processing circuit 5 performs predetermined signal processing on the input video signal, and generates and outputs operation commands for the liquid crystal control circuit 6 and the LED control circuit 9. The operation command to the liquid crystal control circuit 6 includes, for example, video data in units of frames (including gradation values in units of pixels of the liquid crystal panel 2) included in the video signal. In addition, the operation command to the LED control circuit 9 includes, for example, data of light emission instruction values for a plurality of LEDs provided in the illumination device 3.

  The liquid crystal control circuit 6 is configured to generate a source signal and a gate signal based on an operation command from the video signal processing circuit 5 and output them to the source driver 7 and the gate driver 8, respectively. Thereby, in the liquid crystal panel 2, information display according to the video signal input to the video signal processing circuit 5 is performed. That is, the source driver 7 and the gate driver 8 are connected to a plurality of source lines and a plurality of gate lines arranged in a matrix within the liquid crystal panel 2 (not shown). When the source signal and the gate signal are respectively input to the line, the liquid crystal panel 2 is driven and information display according to the video signal is performed on the liquid crystal panel 2.

  Next, the illumination device 3 of the present embodiment will be specifically described with reference to FIGS.

  FIG. 2 is a diagram for explaining a main configuration of the lighting device, and FIG. 3 is a diagram for explaining the photosensor and the light emitting diode shown in FIG.

  As illustrated in FIG. 2, in the lighting device 3, a plurality of, for example, 16 light emitting diodes (LEDs) 13-1, 13-2,..., 13-15, 13-16 (hereinafter collectively “13”). Are provided on the chassis 15 at a predetermined interval. Each of these LEDs 13 includes, for example, red, green, and blue light emitting diodes 13r, 13g, and 13b that respectively emit red (R), green (G), and blue (B) light (not hatched and hatched in the figure, respectively). , A so-called three-in-one type (3 in 1) type is used. Each LED 13 constitutes a light source and can be mixed with white light.

  Further, the LED 13 is configured to be driven to be lit by being supplied with a drive current from the LED drive circuit 10 (FIG. 1). Further, as will be described later in detail, the LED drive circuit 10 supplies current to each LED 13 in accordance with an instruction signal from the LED control circuit 9. The light emission operation is performed with the amount of light corresponding to the value.

  In the lighting device 3, as shown in FIG. 2, one optical sensor 14 is installed on the chassis 15 for every predetermined number (for example, 16) of LEDs 13. The optical sensor 14 is disposed at the center position of the 16 LEDs 13-1 to 13-16, detects the emission intensity of each color light of RGB of each LED 13, and a detection signal corresponding to the detected emission intensity. (Output) is output to the detection circuit 11 (FIG. 1).

  Further, the optical sensor 14 performs a detection operation for each of the LEDs 13r, 13g, and 13b of RGB of each LED 13. This detection operation is performed by detecting the reflected light L2 from the diffusion plate 4. That is, as illustrated in FIG. 3, for example, when only the red LED 13r included in one LED 13 is turned on, the optical sensor 14 causes the red light L1 emitted from the LED 13r to be applied to the diffusion plate 4. The reflected light L2 after being reflected is incident and its emission intensity is detected.

  In the detection circuit 11, as will be described in detail later, a detection period for performing the detection operation of the optical sensor 14 is set in accordance with an instruction signal from the LED control circuit 9. And the detection circuit 11 acquires the detection result of the said light emission intensity of each LED13 from the detection signal of the optical sensor 14 within a detection period. Thereafter, the detection circuit 11 outputs the acquired detection result to the LED control circuit 9, and the detection result is held in a memory 12 as a storage unit.

  Next, the LED control circuit 9 and the detection circuit 11 will be described in detail with reference to FIGS. 4 and 5 respectively.

  4 is a block diagram showing a specific configuration of the LED control circuit shown in FIG. 1, and FIG. 5 is a block diagram showing a specific configuration of the detection circuit shown in FIG.

  In FIG. 4, the LED control circuit 9 performs drive control of the light sensor 14 (FIG. 2) and the light source control unit that performs drive control of the LED (light source) 13 (FIG. 2) using, for example, an IC or an ASIC. The light detection control unit is integrally configured. That is, the LED control circuit 9 includes a lighting operation instruction unit 16 included in the light source control unit that performs drive control of the LED 13 and a detection period setting included in the light detection control unit that performs drive control of the optical sensor 14. A unit 17 and a detection operation instruction unit 18 are provided.

  The lighting operation instruction unit 16 includes a current setting unit 16a that sets a driving current for each of the plurality of LEDs 13 based on an operation command from the video signal processing circuit 5 (FIG. 1), and lighting of each LED 13 based on the operation command. A lighting timing signal generation unit 16b that generates a lighting timing signal that indicates timing (driving timing) is provided.

  Note that the LED 13 can be driven to light using either current dimming or PWM dimming. When the LED 13 is driven to light using current dimming, the current setting unit 16a determines the magnitude of the drive current supplied to the LED 13 and uses the determined magnitude of the drive current as an instruction signal. Including, it outputs to the LED drive circuit 10 (FIG. 1). On the other hand, when the LED 13 is driven to light using PWM dimming, the current setting unit 16a determines the on-time of the duty ratio in PWM dimming, and indicates the determined on-time and a predetermined current value. It is included in the signal and output to the LED drive circuit 10. In the following description, the case where the LED 13 is driven to light using current dimming will be described as an example.

  The lighting timing signal generation unit 16b generates the lighting timing signal indicating the start of lighting of the LED 13, and includes the magnitude of the driving current of the LED 13 determined by the current setting unit 16a in the instruction signal to the LED driving circuit 10. Output. Further, the lighting timing signal generation unit 16 b outputs the generated lighting timing signal of the LED 13 to the detection operation instruction unit 18.

  In addition, the lighting operation instruction unit 16 performs the detection operation by the optical sensor 14, and the 16 LEDs 13-1 to 13-13 that are the detection target of the optical sensor 14 and the optical sensor 14 during a detection period described later. The power supplied to the corresponding LEDs 13-1 to 13-16 is changed according to each distance from -16, and the optical sensor 14 for the LEDs 13-1 to 13-16 (a predetermined number of light sources). The LEDs 13-1 to 13-16 are driven and controlled so that the detection signals from the LEDs substantially coincide with each other. (Details will be described later.)

  Further, in the lighting operation instruction unit 16, when the detection result of the LED 13 by the optical sensor 14 is stored in the memory 12 (FIG. 1), the current setting unit 16 a is stored in the memory 12 in addition to the operation command. A drive current to the corresponding LED 13 is determined using the detection result, and drive control of the LED 13 is performed. Thereby, in the illuminating device 3 of this embodiment, the lighting operation instruction | indication part 16 can perform drive control of each LED13 more appropriately in the state which grasped | ascertained states, such as a time-dependent change of each LED13. That is, even when the light emission intensity of the LED 13 decreases due to a change over time, the current setting unit 16a increases the drive current to the LED 13 according to the decrease in the light emission intensity based on the detection result in the memory 12. The light emission intensity of the LED 13 can always be set to a predetermined value.

  The detection period setting unit 17 sets a detection period (measurement mode) in which the optical sensor 14 performs a detection operation using an operation command from the video signal processing circuit 5 and the lighting operation instruction unit indicates that the detection period has been set. 16 and the detection operation instruction unit 18. Specifically, the detection period setting unit 17 sets the detection period in a non-display period in which no information is displayed in the liquid crystal panel (display unit) 2 (FIG. 1), and performs the lighting operation instruction unit 16 and the detection. It is configured to notify the operation instruction unit 18. Thus, by setting the detection period to the non-display period, the detection operation by the optical sensor 14 and the detection circuit (light detection unit) 11 can be performed without hindering the information display operation on the liquid crystal panel 2. Can do.

  More specifically, the detection period setting unit 17 immediately after the power of the liquid crystal display device 1 is turned on, that is, the period until the image after the power is turned on is displayed on the liquid crystal panel 2, Immediately after the power is turned off, that is, the period from when video display is stopped on the liquid crystal panel 2 to when the power is turned off is set as the detection period. Moreover, the detection period setting part 17 is comprised so that a several detection period can be set so that the detection operation with respect to all LED13 provided in the illuminating device 3 may be divided into plurality.

  That is, since a large number of RGB LEDs 13 are installed in the illumination device 3, the detection period setting unit 17, for example, takes a short period of time until an image after power-on is displayed on the liquid crystal panel 2 as described above. The detection period for some LEDs 13 is set. And the detection period setting part 17 performs the detection operation | movement with respect to all the LEDs 13 of the illuminating device 3 by setting the detection period with respect to the remaining LED13 to the said slight period after the next power-on suitably repeatedly. Also good. In other words, in the illuminating device 3, the detection period setting part 17 can also be made to implement the measurement mode with respect to all the LED13 in multiple times.

  In addition to the above description, the detection period setting unit 17 can also set the detection period in a period in which the user is not viewing information from the liquid crystal display device 1, for example. The period when the user is not viewing can be obtained, for example, by the detection period setting unit 17 statistically analyzing the viewing time zone of the user. Furthermore, in the case where the detection period is set in a period when the viewer is not viewing, it is preferable to set the detection period for the liquid crystal panel 2 in the black display period. Thereby, the detection operation by the optical sensor 14 and the detection circuit 11 can be performed without making the user recognize that the LED 13 is lit.

  The detection operation instruction unit 18 is provided with a detection timing signal generation unit 18 a that generates a detection timing signal that instructs the detection circuit 11 to sample the detection signal of the optical sensor 14. In addition, the detection operation instruction unit 18 is notified of the detection period from the detection period setting unit 17, and the lighting timing signal is input from the lighting timing signal generation unit 16 b. Then, the detection timing signal generator 18 a generates the detection timing signal and outputs it to the detection circuit 11 so that the lighting operation of the LED 13 and the detection operation of the optical sensor 14 are performed in synchronization.

  In addition to the above description, the light source control unit and the light detection control unit may be configured separately using separate ICs or the like. However, when the light source control unit and the light detection control unit are configured integrally as in the LED control circuit 9, it is possible to easily configure the lighting device 3 having a small number of parts and a simple structure. It is preferable in that it can be performed (the same applies to the second to fourth embodiments described later).

  As shown in FIG. 5, the detection circuit 11 includes an A / D converter 11a and a detection data output unit 11b. The detection circuit 11 receives a detection signal from the optical sensor 14 (FIG. 2). Based on the instruction signal from the light detection control unit, a light detection unit for detecting each detection result of a predetermined number of LEDs (light sources) 13-1 to 13-16 is configured.

  That is, the detection signal from the optical sensor 14 and the detection timing signal from the detection operation instruction unit 18 are input to the A / D converter 11a. The A / D converter 11a samples the detection signal from the optical sensor 14 based on the detection timing signal, and performs A / D conversion on the sampled detection signal. Thereafter, the A / D converter 11a outputs a detection signal after A / D conversion, that is, data of each detection result of the LEDs 13-1 to 13-16 to the detection data output unit 11b.

  The detection data output unit 11b outputs the data of the detection results of the LEDs 13-1 to 13-16 from the A / D converter 11a to the memory 12 (FIG. 1) via the LED control circuit 9 (FIG. 1). To do. The data of each detection result is held in the memory 12 as described above.

  Here, with reference to FIG.6 and FIG.7, operation | movement of the liquid crystal display device 1 of this embodiment comprised as mentioned above is demonstrated concretely. In the following description, the detection operation in the detection period will be mainly described.

  FIG. 6 is a flowchart showing an operation example of the lighting device, and FIG. 7 is a timing chart showing the lighting operation of the light emitting diode and the detection operation of the optical sensor shown in FIG. In FIG. 7, for simplification of the drawing, (a) to (h) show instruction signals to the LEDs 13-1 to 13-8, respectively, and (i) to (l) show the LEDs 13-13 to 13, respectively. The instruction signals to 13-16 are shown, and the instruction signals to the LEDs 13-9 to 13-12 are not shown (the same applies to FIGS. 12 and 15 described later).

  In FIG. 6, in the lighting device 3 of the present embodiment, when the detection period setting unit 17 notifies the lighting operation instruction unit 16 and the detection operation instruction unit 18 that the detection period has been set, the lighting device 3 emits light intensity of the LED 13. Detection operation is performed. That is, in the illuminating device 3 of this embodiment, the said measurement mode is started and as shown to FIG.6 S1, the lighting operation instruction | indication part 16 carries out lighting operation of LED13-1 to 13-16 sequentially. The detection operation instruction unit 18 outputs the detection timing signal to the detection circuit 11. Thereby, in the detection circuit 11, the detection signal from the optical sensor 14 is sampled, and the detection operation of each light emission intensity of the LEDs 13-1 to 13-16 is performed (step S2).

  Specifically, as illustrated in FIG. 7A to FIG. 7L, the lighting operation instruction unit 16 outputs an instruction signal to the LED drive circuit 10, and the LEDs 13-1 to 13-16. Are lit in sequence. Further, as shown in FIG. 7 (m), the detection operation instruction unit 18 detects the detection timing so that each lighting operation of the LEDs 13-1 to 13-16 and the detection operation of the optical sensor 14 are performed in synchronization. A signal is generated and output to the detection circuit 11.

  Further, as described above, the lighting operation instruction unit 16 changes the power supplied to the corresponding LEDs 13-1 to 13-16 according to the distances between the optical sensor 14 and the LEDs 13-1 to 13-16. The LEDs 13-1 to 13-16 are driven and controlled so that the detection signals from the optical sensors 14 for these LEDs 13-1 to 13-16 substantially coincide. That is, in the lighting operation instruction unit 16, the current setting unit 16a determines each drive current to the LEDs 13-1 to 13-16 so that the light emission intensity of the LED 13 increases in proportion to the distance from the optical sensor 14. ing.

  More specifically, the current setting unit 16a divides the magnitude of the drive current into three levels according to the distance from the optical sensor 14. That is, as illustrated in FIGS. 7A, 7 </ b> D, 7 </ b> I, and 7 </ b> L, the current setting unit 16 a is the LED 13 that is located farthest from the optical sensor 14. The drive current for -1, 13-4, 13-13, and 13-16 is maximized. Moreover, the current setting part 16a is the LED 13-6, 13-7, 13-10, and 13- which are in the position nearest to the optical sensor 14, as illustrated in FIGS. 7 (f) and 7 (g). As shown in FIGS. 7 (b), 7 (c), 7 (e), 7 (h), 7 (j), and 7 (k). , The drive current for the LEDs 13-2, 13-3, 13-5, 13-8, 13-9, 13-12, 13-14, and 13-15 in the middle position from the optical sensor 14 is the maximum and The intermediate value of the minimum drive current is used.

  As described above, the current setting unit 16a changes each drive current (supply power) to the LEDs 13-1 to 13-16, and detects each detection signal for the LEDs 13-1 to 13-16 from the optical sensor 14. Are substantially matched. Thereby, the detection circuit 11 can obtain a sufficient detection signal (photosensor output) even when the distance from the photosensor 14 is long, and the photosensor output from the LED 13 close to the photosensor 14 is saturated. It can be surely prevented.

  Subsequently, the detection circuit 11 sequentially outputs the detection results of the light emission intensities of the LEDs 13-1 to 13-16 to the LED control circuit 9. Then, the LED control circuit 9 stores the detection result from the detection circuit 11 in the memory 12 (step S3). Thereafter, the LED control circuit 9 determines whether or not the detection operation has been completed for all the LEDs 13 (step S4). If it is determined that the detection operation for all the LEDs 13 has not been completed, the process proceeds to step S1. Return. On the other hand, when it is determined that the detection operation for all the LEDs 13 has been completed, the LED control circuit 9 completes the measurement mode and shifts to a standby state in a state where information can be displayed.

  In the illumination device 3 of the present embodiment configured as described above, the lighting operation instruction unit (light source control unit) 16 is connected to the optical sensor 14 in the detection period set by the detection period setting unit (light detection control unit) 17. The power supplied to the corresponding LEDs 13-1 to 13-16 is changed according to the distances from the predetermined number of LEDs 13-1 to 13-16. Thereby, in the illuminating device 3 of this embodiment, unlike the said prior art example, each detection signal from the said optical sensor 14 about LED13-1, 13-4, 13-13, 13-16 away from the optical sensor 14 is shown. Can be prevented from becoming a very weak value, and the detection circuit (light detection unit) 11 prevents a large amount of noise components from being included in the detection results of the predetermined number of LEDs 13-1 to 13-16. be able to. As a result, in the present embodiment, even when the number of photosensors 14 is reduced, the detection accuracy of the photosensors 14 can be improved, and thus the lighting device 3 that can perform drive control of the LEDs 13 with high accuracy. Can be configured.

  Further, in the liquid crystal display device 1 of the present embodiment, even when the number of installed photosensors 14 is reduced, the detection accuracy of the photosensors 14 can be improved, and thus the drive control of the LED (light source) 13 can be performed with high accuracy. Therefore, the high performance liquid crystal display device 1 having excellent display quality can be easily configured.

[Second Embodiment]
FIG. 8 is a block diagram showing a specific configuration of the LED control circuit of the illumination device according to the second embodiment of the present invention, and FIG. 9 is a specific example of the detection circuit of the illumination device according to the second embodiment. It is a block diagram which shows a structure. In the figure, the main difference between this embodiment and the first embodiment is that a detection gain amplifying unit for amplifying the gain of the detection signal from the optical sensor is provided in the detection circuit, and the detection gain amplification is performed in the detection period. The LED control circuit is provided with a detection gain instructing unit that instructs the unit to change the gain of the detection signal from the optical sensor in accordance with each distance between the optical sensor and a predetermined number of light sources. In addition, about the element which is common in the said 1st Embodiment, the same code | symbol is attached | subjected and the duplicate description is abbreviate | omitted.

  That is, as shown in FIG. 8, the LED control circuit 19 of the illumination device 3 of the present embodiment includes a lighting operation instruction unit 20 that is included in the light source control unit and performs drive control of the LED 13, and the light detection control unit. Are included in a detection period setting unit 21 and a detection operation instruction unit 22 that control the driving of the optical sensor 14. The lighting operation instructing unit 20 is instructed to set the driving current for each of the plurality of LEDs 13 based on the operation command from the video signal processing circuit 5 and the lighting timing of each LED 13 based on the operation command. A lighting timing signal generation unit 20b that generates a lighting timing signal is provided. The current setting unit 20a is different from that of the first embodiment. For example, the same drive current (supplied power) is supplied to a predetermined number of LEDs 13-1 to 13-16 regardless of the distance from the optical sensor 14. It is set to be

  As in the first embodiment, the detection period setting unit 21 sets the detection period in which the optical sensor 14 performs the detection operation as the non-display period and sets the detection period, and the lighting operation instruction unit 20 And notifies the detection operation instruction unit 22.

  The detection operation instruction unit 22 includes a detection timing signal generation unit 22a that generates the detection timing signal for the detection circuit 11, and each detection signal from the optical sensor 14 for a predetermined number of LEDs 13-1 to 13-16. And a detection gain instruction unit 22b for instructing to change the gain. As will be described in detail later, the detection gain instruction unit 22b is configured so that the detection signals from the optical sensors 14 for the LEDs 13-1 to 13-16 (a predetermined number of light sources) substantially coincide with each other. The gain for the detection signal is changed, and a gain instruction signal indicating a gain instruction value for each of the LEDs 13-1 to 13-16 is output.

  As shown in FIG. 9, the detection circuit 23 is provided with a detection gain amplifying unit 23a, an A / D converter 23b, and a detection data output unit 23c. Based on this, the detection results of the predetermined number of LEDs 13-1 to 13-16 are detected, and the detection results are output to the LED control circuit 9 and stored in the memory 12.

  Specifically, a detection signal from the optical sensor 14 is input to the detection gain amplification unit 23a, and a detection timing signal from the detection timing signal generation unit 22a and a gain instruction signal from the detection gain instruction unit 22b are input. Have been entered. The detection gain amplifying unit 23a changes the gain of the detection signal from the optical sensor 14 based on the gain instruction signal, and samples the detection signal from the optical sensor 14 whose gain has been changed based on the detection timing signal. , Output to the A / D converter 23b. Thereafter, the A / D converter 23b performs A / D conversion on the detection signal from the detection gain amplifying unit 23a, and outputs the detection result data of the LEDs 13-1 to 13-16 to the detection data output unit 23c. . Then, the detection data output unit 23 c outputs the detection result data of the LEDs 13-1 to 13-16 to the memory 12 via the LED control circuit 9.

  Here, with reference to FIG. 10, the operation of the liquid crystal display device 1 of the present embodiment configured as described above will be specifically described. In the following description, the detection operation in the detection period will be mainly described.

  FIG. 10 is a timing chart showing the operation of the detection circuit and the detection operation of the optical sensor shown in FIG.

  As illustrated in FIG. 10A, the detection gain instruction unit 22b instructs the LEDs 13-1 to 13-16 to increase the gain for the detection signal in proportion to the distance from the optical sensor 14. A signal is generated and output to the detection gain amplifying unit 23a. That is, the detection gain instruction unit 22b divides the gain instruction value into three stages according to the distance from the optical sensor 14. Specifically, the detection gain instruction unit 22 b sets the gain instruction value for the LEDs 13-1, 13-4, 13-13, and 13-16 at the position farthest from the optical sensor 14 to max. Further, the detection gain instruction unit 22b sets the gain instruction value for the LEDs 13-6, 13-7, 13-10, and 13-11 at the closest position from the optical sensor 14 to min, and is an intermediate position from the optical sensor 14. The gain instruction values for the LEDs 13-2, 13-3, 13-5, 13-8, 13-9, 13-12, 13-14, and 13-15 are intermediate values of the above max and min.

  Further, the detection gain amplifying unit 23a performs a sampling operation on the detection signal from the optical sensor 14 based on the detection timing signal shown in FIG. 10B, and converts the detection signal for each LED 13-1 to 13-16 into a detection signal. On the other hand, gain detection processing (amplification processing) is performed with the gain instruction value shown in FIG. 10A, and each detection signal is detected.

  As described above, the detection gain instruction unit 22b changes the gain for each detection signal for the LEDs 13-1 to 13-16 in the detection gain amplification unit 23a, and substantially matches these detection signals. Yes. Thereby, the detection circuit 23 can obtain a sufficient detection signal (optical sensor output) even if the distance from the optical sensor 14 is long, and the optical sensor output from the LED 13 close to the optical sensor 14 is saturated. It can be surely prevented.

  In addition, since the detection gain amplifying unit 23a performs sampling after performing the above-described amplification processing on the detection signal, the detection gain instruction unit 22b can select an appropriate gain instruction value even when the detection signal becomes a very weak signal. , The detection gain amplifying unit 23a can reliably amplify the weak signal to a signal level that can be sampled, and reliably obtain a detection result.

  In the detection gain amplifying unit 23a, for example, the amplification process is executed by amplifying the amplitude of the detection signal from the optical sensor 14 or extending the detection time while keeping the detection time constant. It has become.

  With the above configuration, the present embodiment can achieve the same operations and effects as the first embodiment. Moreover, in the illuminating device 3 of this embodiment, LED13-1, 13-4, 13-13, 13-16 which the detection gain amplification part 23a left | separated from the optical sensor 14 according to the instruction | indication signal from the detection gain instruction | indication part 22b. By increasing the gain of the detection signal for the LED 13, the detection signals from the optical sensor 14 for the LEDs 13-1, 13-4, 13-13, and 13-16 are reliably prevented from becoming very weak values. It is possible to improve the detection accuracy of the optical sensor 14 with certainty.

[Third Embodiment]
FIG. 11 is a block diagram showing a specific configuration of the LED control circuit of the lighting apparatus according to the third embodiment of the present invention. In the figure, the main difference between the present embodiment and the first embodiment described above is that the LED control circuit performs the lighting operation at the same time according to each distance between the photosensor and the predetermined number of LEDs in the detection period. The number of points has changed. In addition, about the element which is common in the said 1st Embodiment, the same code | symbol is attached | subjected and the duplicate description is abbreviate | omitted.

  That is, as shown in FIG. 11, the LED control circuit 24 of the illumination device 3 of the present embodiment includes a lighting operation instruction unit 25 that is included in the light source control unit and controls driving of the LED 13, and the light detection control unit. Are included in a detection period setting unit 26 and a detection operation instruction unit 27 that control the driving of the optical sensor 14. The lighting operation instruction unit 25 is instructed to set the driving current of each of the plurality of LEDs 13 based on the operation command from the video signal processing circuit 5 and the lighting timing of each LED 13 based on the operation command. A lighting timing signal generation unit 25b that generates a lighting timing signal is provided. The current setting unit 25a is different from that of the first embodiment. For example, the same drive current (supplied power) is supplied to a predetermined number of LEDs 13-1 to 13-16 regardless of the distance from the optical sensor 14. It is set to be

  Also, the lighting timing signal generation unit 25b is different from that of the first embodiment so that the detection signals from the optical sensors 14 for the LEDs 13-1 to 13-16 (a predetermined number of light sources) substantially match. In addition, during the detection period, the number of LEDs 13 that are turned on simultaneously is changed according to the distance between the optical sensor 14 and a predetermined number of LEDs 13-1 to 13-16 (details will be described later). ).

  As in the first embodiment, the detection period setting unit 26 sets the detection period in which the optical sensor 14 performs the detection operation to the non-display period and sets the detection period, and the lighting operation instruction unit 25 And the detection operation instruction unit 27 is notified.

  The detection operation instruction unit 27 is provided with a detection timing signal generation unit 22a that generates the detection timing signal for the detection circuit 11, and the lighting operation of the LED 13 and the detection operation of the optical sensor 14 are synchronized. As is done, a detection timing signal is generated and output to the detection circuit 11.

  Here, the operation of the liquid crystal display device 1 of the present embodiment configured as described above will be specifically described with reference to FIG. In the following description, the detection operation in the detection period will be mainly described.

  FIG. 12 is a timing chart showing the lighting operation of the light emitting diode and the detection operation of the optical sensor in the illumination device according to the third embodiment.

  As illustrated in FIG. 12A to FIG. 12L, the lighting operation instruction unit 25 outputs an instruction signal to the LED drive circuit 10 and simultaneously performs the lighting operation according to the distance from the light sensor 14. The number of LEDs 13 to be changed is changed, and the LEDs 13-1 to 13-16 are turned on. Specifically, the lighting timing signal generation unit 25b operates to simultaneously turn on the LEDs 13-1 and 13-2 that are located away from the optical sensor 14, as shown in FIGS. 12 (a) and 12 (b). At the same time, as shown in FIGS. 12C and 12D, the LEDs 13-3 and 13-4 located at a position away from the optical sensor 14 are simultaneously turned on.

  Further, as illustrated in FIGS. 12E to 12H, the lighting timing signal generation unit 25b lights each of the LEDs 13-5 to 13-12 located near the optical sensor 14 independently. It is operating. Furthermore, as shown in FIGS. 12 (i) and 12 (j), the lighting timing signal generation unit 25b simultaneously turns on the LEDs 13-13 and 13-14 located at a position away from the optical sensor 14, As shown in FIG. 12 (k) and FIG. 12 (l), the LEDs 13-15 and 13-16 located at a position away from the optical sensor 14 are turned on simultaneously.

  Also, as shown in FIG. 12 (m), the detection operation instruction unit 27 generates the detection timing signal so that the lighting operation of the LED 13 and the detection operation of the optical sensor 14 are performed in synchronization. To the detection circuit 11.

  As described above, the lighting timing signal generation unit 25b changes the number of LEDs 13 that are simultaneously turned on according to the distance from the optical sensor 14, and substantially matches these detection signals. Thereby, the detection circuit 23 can obtain a sufficient detection signal (optical sensor output) even if the distance from the optical sensor 14 is long, and the optical sensor output from the LED 13 close to the optical sensor 14 is saturated. It can be surely prevented.

  When two LEDs 13 are turned on at the same time, the light emission intensity of each LED 13 cannot be detected. However, since the accumulated light emission times are relatively coincident between adjacent LEDs 13, there is no significant difference in the change with time. Therefore, in the LED control circuit 9 of the present embodiment, it is determined that, for example, the degrees of change with time of the LEDs 13-1 and 13-2 that are simultaneously turned on are the same, and the LEDs 13-1 and 13-2 Using the detection result, the light emission instruction value at the time of information display is corrected, and the lighting of the LEDs 13-1 and 13-2 can be performed in a state in which the influence of the change with time is eliminated as much as possible.

  With the above configuration, the present embodiment can achieve the same operations and effects as the first embodiment. Further, in the lighting device 3 of the present embodiment, the lighting operation instruction unit (light source control unit) 25 causes the plurality of LEDs (light sources) 13 separated from the optical sensor 14 to perform the lighting operation simultaneously, whereby a detection circuit (light detection unit). 11, it is possible to reliably prevent the detection signals from the optical sensors 14 for the plurality of LEDs 13 from having very weak values, and to reliably improve the detection accuracy of the optical sensors 14. Furthermore, in the illuminating device 3 of this embodiment, the detection period can be shortened.

[Fourth Embodiment]
FIG. 13 is a block diagram showing a specific configuration of the LED control circuit of the illumination device according to the fourth embodiment of the present invention, and FIG. 14 is a specific example of the detection circuit of the illumination device according to the fourth embodiment. It is a block diagram which shows a structure. In the figure, the main difference between this embodiment and the third embodiment is that each detection result of a predetermined number of LEDs is calculated by performing a predetermined differential operation on the detection signal from the optical sensor. This is the point that the detection circuit is provided with a calculation unit. In addition, about the element which is common in the said 3rd Embodiment, the same code | symbol is attached | subjected and the duplicate description is abbreviate | omitted.

  That is, as shown in FIG. 13, the LED control circuit 28 of the illumination device 3 of the present embodiment includes a lighting operation instruction unit 29 that is included in the light source control unit and performs drive control of the LED 13, and the light detection control unit. The detection period setting unit 30 and the detection operation instruction unit 31 that perform drive control of the optical sensor 14 are provided. The lighting operation instruction unit 29 instructs the lighting timing of each LED 13 based on the operation command and the current setting unit 29a that sets the drive current in each of the LEDs 13 based on the operation command from the video signal processing circuit 5. A lighting timing signal generation unit 29b that generates a lighting timing signal is provided. As in the third embodiment, the current setting unit 29a supplies the same drive current (supplied power) to a predetermined number of LEDs 13-1 to 13-16 regardless of the distance from the optical sensor 14, for example. It is set to be done.

  Further, in the lighting timing signal generation unit 29b, the detection signals from the optical sensors 14 for the LEDs 13-1 to 13-16 (a predetermined number of light sources) substantially coincide with each other as in the third embodiment. As described above, in the detection period, the number of LEDs 13 to be turned on at the same time is changed according to the distance between the optical sensor 14 and the predetermined number of LEDs 13-1 to 13-16 (details will be described later). .)

  Furthermore, unlike the third embodiment, the lighting timing signal generation unit 29b outputs predetermined lighting information for the LEDs 13 that are simultaneously turned on to a detection circuit (light detection unit) 32 described later. Yes. This lighting information includes information indicating the LEDs 13 that are simultaneously turned on and information such as a period during which the lighting operations are performed simultaneously. In the detection circuit 32, the lighting information is the detection results of the LEDs 13-1 to 13-16. Is used to calculate

  As in the first embodiment, the detection period setting unit 30 sets the detection period in which the optical sensor 14 performs the detection operation as the non-display period and sets the detection period, and the lighting operation instruction unit 29 The detection operation instruction unit 31 is notified.

  The detection operation instruction unit 31 is provided with a detection timing signal generation unit 31a that generates the detection timing signal for the detection circuit 32, and the lighting operation of the LED 13 and the detection operation of the optical sensor 14 are synchronized. As is done, a detection timing signal is generated and output to the detection circuit 32.

  As shown in FIG. 14, the detection circuit 32 is provided with an A / D converter 32 a, a calculation unit 32 b, and a detection data output unit 32 c, and based on an instruction signal from the LED control circuit 9. The detection results of a predetermined number of LEDs 13-1 to 13-16 are detected, and the detection results are output to the LED control circuit 9 and stored in the memory 12.

  Specifically, the detection signal from the optical sensor 14 and the detection timing signal from the detection operation instruction unit 31 are input to the A / D converter 32a. The A / D converter 32a samples the detection signal from the optical sensor 14 based on the detection timing signal, and performs A / D conversion on the sampled detection signal. Thereafter, the A / D converter 32a outputs the detection signal after A / D conversion, that is, the data of each detection result of the LEDs 13-1 to 13-16 to the arithmetic unit 32b.

  The calculation unit 32b uses the lighting information from the lighting timing signal generation unit 29b and the detection result data from the A / D converter 32a to obtain the detection result data of the predetermined number of LEDs 13-1 to 13-16. The calculation is performed by performing a predetermined differential operation. Then, the calculation unit 32b outputs the obtained detection result data of the LEDs 13-1 to 13-16 to the detection data output unit 32c.

  In addition, the detection data output unit 32 c outputs data of detection results of the LEDs 13-1 to 13-16 from the calculation unit 32 b to the memory 12 via the LED control circuit 9. The data of each detection result is held in the memory 12 as described above.

  Here, the operation of the liquid crystal display device 1 of the present embodiment configured as described above will be described in detail with reference to FIG. In the following description, the detection operation in the detection period will be mainly described.

  FIG. 15 is a timing chart showing the lighting operation of the light emitting diode and the detection operation of the optical sensor in the illumination device according to the fourth embodiment.

  As illustrated in FIG. 15A to FIG. 15L, the lighting operation instruction unit 29 outputs an instruction signal to the LED drive circuit 10 and simultaneously performs the lighting operation according to the distance from the light sensor 14. The number of LEDs 13 to be changed is changed, and the LEDs 13-1 to 13-16 are turned on. Specifically, as shown in FIGS. 15A to 15C, the lighting timing signal generation unit 29 b simultaneously turns on the LEDs 13-1 to 13-3 located at a position away from the optical sensor 14. At the same time, as shown in FIGS. 15B to 15D, the LEDs 13-2 to 13-4 located at a position away from the optical sensor 14 are simultaneously turned on. In addition, as shown in FIGS. 15A to 15D, in these LEDs 13-1 to 13-4, as will be described in detail later, the respective light emission intensities are obtained by the calculation unit 32b. The lighting operation is performed with the lighting timing shifted.

  Further, as illustrated in FIGS. 15E to 15H, the lighting timing signal generation unit 29b lights each of the LEDs 13-5 to 13-12 that are close to the optical sensor 14 individually. It is operating. Further, the lighting timing signal generation unit 29b simultaneously turns on the LEDs 13-13 to 13-15 located at a position away from the optical sensor 14, as shown in FIGS. 15 (i) to 15 (k). As shown in FIG. 15 (j) to FIG. 15 (l), the LEDs 13-14 to 13-16 located at a position away from the optical sensor 14 are turned on simultaneously. In addition, as shown in FIGS. 15 (i) to 15 (l), these LEDs 13-13 to 13-16, as will be described in detail later, have their light emission intensities obtained by the calculation unit 32b. The lighting operation is performed with the lighting timing shifted.

  As described above, the lighting timing signal generation unit 29b changes the number of LEDs 13 that are simultaneously turned on according to the distance from the optical sensor 14, and substantially matches these detection signals. As a result, the detection circuit 32 can obtain a sufficient detection signal (optical sensor output) even when the distance from the optical sensor 14 is long, and the optical sensor output from the LED 13 close to the optical sensor 14 is saturated. It can be surely prevented.

  Further, as shown in FIG. 15 (m), the detection operation instruction unit 31 generates the detection timing signal so that the lighting operation of the LED 13 and the detection operation of the optical sensor 14 are performed in synchronization. To the detection circuit 32.

  In the detection circuit 32, the A / D converter 32 a samples the detection signal from the optical sensor 14, performs A / D conversion, and outputs the data of the detection signal to the calculation unit 32 b. In the calculating part 32b, each detection result (light emission intensity) of LED13-1 to 13-16 is calculated using the data of the detection signal from the A / D converter 32a. In other words, the calculation unit 32b obtains each detection result for the LEDs 13-5 to 13-12 that are individually turned on based on the detection results at the corresponding detection timing.

  In addition, the calculation unit 32b performs predetermined calculation using the lighting information from the lighting timing signal generation unit 29b for the LEDs 13-1 to 13-4 and 13-13 to 13-16 that are simultaneously turned on. Thus, the detection results of the LEDs 13-1 to 13-4 and 13-13 to 13-16 are obtained.

  Specifically, for example, when obtaining the detection results of the LEDs 13-1 to 13-4, assuming that the detection results of the LEDs 13-1 to 13-4 are V1 to V4, respectively, at the first detection timing in FIG. Since the LEDs 13-1 to 13-3 are turned on at the same time, the detection signal at this detection timing includes the sum (= V1 + V2 + V3) of the detection results of these LEDs 13-1 to 13-3.

  Further, since the LEDs 13-2 and 13-3 are turned on simultaneously at the second detection timing in FIG. 15, the detection result of these LEDs 13-2 and 13-3 is included in the detection signal at this detection timing. The sum (= V2 + V3) is included. Therefore, the calculation unit 32b obtains the detection result of the LED 13-1 by subtracting the detection result at the second detection timing from the detection result at the first detection timing.

  Further, since only the LED 13-3 is turned on at the fourth detection timing in FIG. 15, the computing unit 32b obtains the detection result of the LED 13-3 based on the detection signal at the detection timing. Furthermore, the calculating part 32b calculates | requires the detection result of LED13-2 by subtracting the detection result of LED13-3 calculated | required from the detection result in the 2nd detection timing.

  Further, since the LEDs 13-2 to 13-4 are turned on simultaneously at the fifth detection timing in FIG. 15, the detection results at these detection timings include the detection results of these LEDs 13-2 to 13-4. The sum (= V2 + V3 + V4) is included. Therefore, the calculation unit 32b obtains the detection result of the LED 13-4 by subtracting the detection result at the second detection timing from the detection result at the fifth detection timing. Similarly, the calculating part 32b calculates | requires each detection result of LED13-13-13-13.

  With the above configuration, the present embodiment can achieve the same operations and effects as the third embodiment. Moreover, in the illuminating device 3 of this embodiment, the calculating part 32b performs a predetermined | prescribed differential calculation with respect to the detection signal from the optical sensor 14 using the said lighting information from an LED control circuit (light source control part). Thus, the detection results of a predetermined number of LEDs (light sources) 13-1 to 13-16 are calculated. Thereby, while shortening the detection period, in each detection result of the LEDs 13-1 to 13-16 in the detection circuit (light detection unit) 11, in-phase noise that does not change with time, for example, the LED 13 such as external light It is possible to cancel light other than the above, and the detection accuracy of the optical sensor 14 can be improved more reliably.

  The above embodiments are all illustrative and not restrictive. The technical scope of the present invention is defined by the claims, and all modifications within the scope equivalent to the configurations described therein are also included in the technical scope of the present invention.

  For example, in the above description, the case where the present invention is applied to a transmissive liquid crystal display device has been described. However, the lighting device of the present invention is not limited to this, and the image, The present invention can be applied to various display devices including a non-light emitting display unit that displays information such as characters. Specifically, the illumination device of the present invention can be suitably used for a transflective liquid crystal display device or a projection display device such as a rear projection using the liquid crystal panel as a light valve.

  In the above description, the case where a plurality of 3-in-1 type light emitting diodes each integrating RGB light emitting diodes is used as the light source has been described. However, the light source of the present invention is not limited to this, and R, G , B each using a single color light emitting diode, using a white (W) light emitting diode that emits white light, or integrating four light emitting diodes such as RGBW and GRGB, so-called four-in-one type light emission. A diode can also be applied. Moreover, other light emitting elements, such as discharge tubes, such as a cold cathode fluorescent tube, and EL (Electro-Luminescence) light emitting elements, can also be used for a light source.

  In the above description, one photosensor is installed for every 16 light emitting diodes and the light emission intensity of each of the 16 light emitting diodes is detected. The control unit sets a detection period in which light from each of the predetermined number of light sources is detected by the optical sensor, and at least one of the light source control unit and the light detection control unit receives from the optical sensor for the predetermined number of light sources in the detection period. It is only necessary to drive and control the corresponding light source and the light detection unit so that the respective detection signals substantially coincide with each other. Not.

  In the above description, the case where the direct type illumination device is configured has been described. However, the present invention is not limited to this. For example, a single light guide plate is provided below the light emitting surface of the illumination device. Other types of illumination devices such as an edge light type illumination device in which a plurality of light source substrates are arranged in parallel to at least one of the four sides surrounding the light guide plate, and a tandem type in which a light guide plate is provided for each light emitting element It can also be applied to.

  In addition to the above description, the first to fourth embodiments may be appropriately combined.

  The present invention can improve the detection accuracy of an optical sensor even when the number of installed optical sensors is reduced, and thus an illumination device capable of performing drive control of a light source with high accuracy, and a high Useful for high performance display devices.

It is a figure explaining the principal part structure of the liquid crystal display device using the illuminating device concerning the 1st Embodiment of this invention. It is a figure explaining the principal part structure of the said illuminating device. It is a figure explaining the photosensor and light emitting diode which were shown in FIG. It is a block diagram which shows the specific structure of the LED control circuit shown in FIG. FIG. 2 is a block diagram illustrating a specific configuration of a detection circuit illustrated in FIG. 1. It is a flowchart which shows the operation example of the said illuminating device. 3 is a timing chart showing a lighting operation of a light emitting diode and a detection operation of an optical sensor shown in FIG. 2. It is a block diagram which shows the specific structure of the LED control circuit of the illuminating device concerning the 2nd Embodiment of this invention. It is a block diagram which shows the specific structure of the detection circuit of the illuminating device concerning the said 2nd Embodiment. 10 is a timing chart showing the operation of the detection circuit shown in FIG. 9 and the detection operation of the optical sensor. It is a block diagram which shows the specific structure of the LED control circuit of the illuminating device concerning the 3rd Embodiment of this invention. It is a timing chart which shows the lighting operation of the light emitting diode, and the detection operation of a photosensor in the illuminating device concerning the said 3rd Embodiment. It is a block diagram which shows the specific structure of the LED control circuit of the illuminating device concerning the 4th Embodiment of this invention. It is a block diagram which shows the specific structure of the detection circuit of the illuminating device concerning the said 4th Embodiment. It is a timing chart which shows the lighting operation of a light emitting diode, and the detection operation of a photosensor in the illuminating device concerning the said 4th Embodiment.

Explanation of symbols

1 Liquid crystal display device 2 Liquid crystal panel (display unit)
3 Lighting device 9, 19, 24, 28 LED control circuit (light source control unit, light detection control unit)
16, 20, 25, 29 Lighting operation instruction unit (light source control unit)
17, 21, 26, 30 Detection period setting unit (light detection control unit)
18, 22, 27, 31 Detection operation instruction unit (light detection control unit)
11, 23, 32 Detection circuit (light detection unit)
22b Detection gain instruction section (light detection control section)
23a Detection gain amplification unit (light detection unit)
32b arithmetic unit 12 memory (storage unit)
13 Light-emitting diode (LED, light source)
14 Light sensor

Claims (9)

A lighting device comprising a plurality of light sources,
An optical sensor provided for each predetermined number of light sources, detecting light from each of the predetermined number of light sources, and outputting a detection signal;
A light source control unit that performs drive control of the light source;
A detection signal from which the detection signal from the optical sensor is input, and a detection unit for detecting each detection result of the predetermined number of light sources;
A light detection control unit that performs drive control of the light detection unit;
The light detection control unit sets a detection period in which light from the predetermined number of light sources is detected by the light sensor,
At least one of the light source control unit and the light detection control unit includes the corresponding light source and the corresponding light source so that the detection signals from the photosensors for the predetermined number of light sources substantially coincide in the detection period. Driving and controlling the light detector ; and
The light source control unit changes the number of the light sources that are turned on simultaneously in accordance with each distance between the optical sensor and the predetermined number of light sources in the detection period .
A lighting device characterized by that. The lighting device according to claim 1, wherein the light source control unit changes power supplied to a corresponding light source in accordance with each distance between the optical sensor and the predetermined number of light sources in the detection period. The light detection unit is provided with a detection gain amplification unit that amplifies the gain of the detection signal from the light sensor,
In the detection period, the light detection control unit changes a gain of a detection signal from the light sensor according to each distance between the light sensor and the predetermined number of light sources with respect to the detection gain amplification unit. The illumination device according to claim 1, wherein a detection gain instruction unit is provided for instructing this. The light source control unit changes the number of the light sources that are turned on simultaneously in accordance with each distance between the optical sensor and the predetermined number of light sources in the detection period,
Predetermined lighting information about light sources that are simultaneously turned on is input to the light detection unit from the light source control unit, and using the input lighting information, a detection signal from the light sensor is by performing a predetermined differential operation, the lighting device according to any one of claims 1 to 3, operation section is provided for calculating the respective detection results of said predetermined number of light sources. A storage unit for storing each detection result of the predetermined number of light sources from the light detection unit;
The light source control unit uses the detection result stored in the storage unit, the lighting device according to any one of claims 1-4 for controlling the driving of the corresponding light source. And the light source control unit and the light detection control unit, the lighting device according to any one of claims 1 to 5 which is integrally formed. Display device characterized by using the illumination device according to any one of claims 1-6. A display unit for displaying information is provided.
The display device according to claim 7 , wherein the detection period is set to a non-display period in which information is not displayed on the display unit. A liquid crystal panel is used for the display unit,
The display device according to claim 8 , wherein the detection period is set to a black display period in the liquid crystal panel.

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