Display system

Abstract

To provide a display system which performs luminance control as much as possible.SOLUTION: An LED 1, an LED 2, an LED 3 and an LED 4 which are arrayed from left to right in a lower part of a display 2 are successively driven in an AC manner, light is detected by a PD 1 disposed between the LED 1 and the LED 2 during a drive period of the LED 1 and the LED 2, and light is detected by a PD 2 disposed between the LED 3 and the LED 4 during a drive period of the LED 3 and the LED 4. If a fluctuation width of an AC component of the light detected by the PD 1 during the drive period of the LED 1 is small, luminance control of the display 2 is performed in accordance with illuminance that is detected by an illuminance sensor IS disposed closer to a left side of the LED 1. In a case where the fluctuation width of the AC component of the light detected by the PD 1 during the drive period of the LED 1 is not small but a fluctuation width of an AC component of the light detected by the PD 2 during the drive period of the LED 3 and the LED 4 is small, luminance control of the display 2 is performed in accordance with offset representing an intensity of the light detected by the PD 2 while the LEDs are turned off.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a technique for adjusting the brightness of a display in accordance with the illuminance of ambient light. [Background technology]

[0002] A known technique for adjusting the brightness of a display according to the illuminance of ambient light is to place an illuminance sensor near the display surface of a display equipped with a capacitive touch panel, and use the touch panel to detect the approach of an object to the display. When the approach of an object is not detected, brightness control is performed to adjust the brightness of the display according to the illuminance detected by the illuminance sensor, and when the approach of an object is detected, brightness control for adjusting the brightness of the display is stopped. This adjusts the brightness of the display according to the illuminance of the ambient light detected by the illuminance sensor, while preventing the illuminance from being inappropriately adjusted based on an erroneous illuminance when the illuminance sensor is unable to correctly detect the illuminance of the ambient light due to an object such as the user's hand being in the shadow (for example, Patent Document 1).

[0003] Also, as a technology related to the present application, a detection system is known in which a number of LEDs arranged along the bottom edge of a display are sequentially turned on to emit infrared light diagonally upwards and forward from the display, and a number of photodiodes arranged along the bottom edge of the display detect the reflected infrared light by an object to be detected, and the approach to the display surface of the display and the horizontal (left-right) position of the approaching object are detected from the distribution of the intensity of the reflected light detected when each LED is turned on (for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-83494 A [Patent Document 2] JP 2021-117189 A Summary of the Invention [Problem to be solved by the invention]

[0005] According to the above-mentioned technology of stopping brightness control that adjusts the brightness of the display when the approach of an object to the display is detected, the visibility of the display may be degraded because the brightness of the display cannot be adjusted to follow the ambient light during the period when the object is approaching the display.

[0006] For example, when brightness control is performed on a display placed between the driver's seat and the passenger seat of a car, where the brightness of the display is adjusted to be higher when the ambient light is bright and lower when the ambient light is dark, the visibility of the display may deteriorate.

[0007] That is, for example, when a car enters a dark tunnel with hands or fingers operating a touch panel placed over the display surface, hands gripping the steering wheel, or the user's personal belongings such as a drink or smartphone close to the display, the display brightness cannot be reduced in response to the decrease in ambient light, and the display brightness may become excessive compared to the ambient light, resulting in a dazzling display.

[0008] Therefore, an object of the present invention is to adjust the brightness of the display to a brightness appropriate for the ambient light as much as possible, even when an object is close to the display. [Means for solving the problem]

[0009] In order to achieve the above object, the present invention provides a display system for controlling the brightness of a display, comprising the display, an illuminance sensor disposed outside the display surface of the display, an approach detection device, and a brightness control means. Here, the approach detection device includes a plurality of light sources that are disposed outside the display surface of the display in a line in the left-right direction of the display surface and emit invisible light toward the front of the display surface, a plurality of photodetectors that are disposed outside the display surface of the display in a line in the left-right direction of the display surface and detect light in a wavelength range including the wavelength of the invisible light, a driving means that sequentially drives each of the light sources with an AC current and causes each of the light sources to repeat light emission and non-emission during a period in which the light source is AC driven, an AC component detection means that detects a fluctuation width of the AC component of light detected by the photodetector that is previously associated with the AC-driven light source during a period in which the light source is AC driven, and an offset detection means that detects an offset representing the magnitude of light detected by a target photodetector that is at least a part of the photodetectors among the plurality of photodetectors when the plurality of light sources are non-emitting. The brightness control means determines whether or not an object is present near the illuminance sensor based at least on the fluctuation range of the AC component of the light detected by the AC component detection means during a period when a light source near the illuminance sensor is driven by AC, and if it is determined that no object is present near the illuminance sensor, controls the brightness of the display based on the illuminance detected by the illuminance sensor, and if it is determined that an object is present near the illuminance sensor and there is a target photodetector whose detected light does not include light whose fluctuation range of the AC component detected by the AC component detection means is greater than a predetermined level, controls the brightness of the display based on the magnitude of the offset detected for the target photodetector present by the offset detection means.

[0010] Moreover, the display system may include a plurality of illuminance sensors spaced apart in the left-right direction, and the brightness control means may determine, for each illuminance sensor, whether or not an object is present near the illuminance sensor based at least on the fluctuation range of the AC component of light detected by the AC component detection means during a period when the light source nearest the illuminance sensor is AC driven, and if there is an illuminance sensor that can determine that no object is present nearby, control the brightness of the display based on the illuminance detected by the present illuminance sensor, and if there is no illuminance sensor that can determine that no object is present nearby and there is a target photodetector that does not include light in the detected light whose fluctuation range of the AC component detected by the AC component detection means is greater than a predetermined level, control the brightness of the display based on the offset detected by the offset detection means for the present target photodetector.

[0011] Here, these display systems may be configured such that the offset detection means detects an offset for the target photodetector during a period in which each of the light sources associated with the target photodetector is AC driven.

[0012] Furthermore, these display systems may be configured so that the brightness control means determines that an object is present near the illuminance sensor when the fluctuation range of the AC component of the light detected by the AC component detection means during a period in which a light source closest to the illuminance sensor is driven by AC exceeds a predetermined threshold value.

[0013] In these display systems, it is preferable that the target light detector includes a light detector that is furthest from the illuminance sensor in the left-right direction of the display surface. In addition, in these display systems, the photodetector pre-associated with the light source may be the photodetector located closest to the light source or located adjacent to the light source.

[0014] In these display systems, the illuminance sensor may be disposed either at a position near the left edge of the display surface or at a position near the right edge of the display surface. Alternatively, the illuminance sensor may be disposed near the center in the left-right direction of the display surface. In addition, a display system having multiple illuminance sensors as described above may be configured as a multi-display system by providing two of the illuminance sensors, and the two illuminance sensors may be positioned near the left end of the display surface and near the right end of the display surface. It is also preferable that these display systems include a position calculation means for calculating the left-right coordinates of the display surface of an object approaching the display surface as left-right coordinates from a distribution of the fluctuation range of the AC component, which is determined by positioning the fluctuation range of the AC component detected by the AC component detection means during a period when the light source is driven by AC, in the left-right coordinates of the display surface that are determined for each of the pairs of light sources and the photodetectors pre-associated with the light sources.

[0015] Furthermore, a gesture response processing means may be provided which identifies a gesture made by a user in front of a display surface of the display from the left-right coordinates calculated by the position calculation means, and performs processing according to the identified gesture. According to the above display system, even if the illuminance sensor is blocked by an object and cannot correctly detect the illuminance of the ambient light, if there is a photodetector of the approach detection device that is not blocked by an object, the illuminance of the ambient light can be second-optimally calculated using the amount of light detected by the photodetector when the multiple light sources are not emitting light, and the brightness of the display can be controlled.

[0016] Therefore, even if an object is close to the display, the brightness of the display can be adjusted to a brightness appropriate for the ambient light as much as possible. Furthermore, such adjustment of the display brightness can be performed by sharing the configuration of an approach detection device that detects the approach of an object such as a user's hand or finger and the left-right coordinates of the approaching position. Effect of the Invention

[0017] As described above, according to the present invention, it is possible to broadly identify which of the users on the left and right sides of the touch panel has touched the touch panel, regardless of the manner of touch. [Brief description of the drawings]

[0018] [Figure 1] 1 is a block diagram showing a configuration of an information processing system according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing the arrangement of displays according to the first embodiment of the present invention. [Diagram 3] 2 is a diagram showing the arrangement of a proximity detection sensor and an illuminance sensor according to the first embodiment of the present invention. FIG. [Figure 4] 5 is a diagram showing an operation sequence of the approach detection sensor according to the first embodiment of the present invention. FIG. [Diagram 5] 3 is a diagram showing a detection signal detected by the approach detection sensor according to the first embodiment of the present invention. FIG. [Figure 6] 3 is a diagram showing an offset and an AC component of a detection signal detected in the approach detection sensor according to the first embodiment of the present invention. FIG. [Figure 7] 5 is a flowchart showing a brightness control process according to the first embodiment of the present invention. [Figure 8] FIG. 11 is a diagram showing the arrangement of a proximity detection sensor and an illuminance sensor according to a second embodiment of the present invention. [Figure 9] 10 is a flowchart showing a luminance control process according to a second embodiment of the present invention. [Figure 10] 13 is a diagram showing an arrangement of an approach detection sensor and an illuminance sensor according to a third embodiment of the present invention, and an operation sequence of the approach detection sensor. FIG. [Figure 11] 13 is a flowchart showing a brightness control process according to a third embodiment of the present invention. [Figure 12] FIG. 13 is a diagram showing the arrangement of a proximity detection sensor and an illuminance sensor according to a fourth embodiment of the present invention. [Figure 13] 13 is a flowchart showing a brightness control process according to a fourth embodiment of the present invention. [Figure 14] FIG. 13 is a diagram showing another configuration example of the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the present invention will be described. First, the first embodiment will be described taking as an example an application to a right-hand drive automobile with a driver's seat on the right side and a passenger seat on the left side. However, the first embodiment can also be applied to a left-hand drive automobile with a driver's seat on the left side and a passenger seat on the right side by switching the left and right in the following description.

[0020] FIG. 1 shows the configuration of an information processing system according to the first embodiment. The information processing system is a system installed in an automobile, and includes a data processing device 1 that executes a car navigation application, a media player application, etc., a display 2 with a touch panel that the data processing device 1 uses for displaying images and inputting coordinates, an approach detection device 3, other peripheral devices 4 used by the data processing device 1, and an illuminance sensor IS that detects the illuminance of visible light.

[0021] Here, the display 2 is equipped with a backlight capable of changing the intensity of light emission, and the data processing device 1 can control the backlight to change the luminance of the display 2. Alternatively, the display 2 may be a self-luminous display such as an OLED or mLED capable of changing the luminance of light emission. As shown in FIG. 2, the display 2 is in the form of a display unit 10 integrated with the approach detection device 3 and the illuminance sensor IS, and is disposed on the dashboard of the automobile between the driver's seat and the passenger seat with the display surface facing rearward. Returning to FIG. 1, the approach detection device 3 includes an approach detection sensor 31 and an approach detection controller 32 . The approach detection sensor 31 has four infrared LEDs, LED1, LED2, LED3, and LED4, which emit infrared light, and two photodiodes (PD), PD1 and PD2, which detect light in the infrared wavelength range that includes the wavelength of the infrared light emitted by the infrared LEDs. The approach detection controller 32 also includes a drive unit 321 that drives LED1, LED2, LED3, and LED4 to emit light, a detection unit 322 that detects the outputs of PD1 and PD2, and a detection control unit 323 that controls the operation of the drive unit 321 and the detection unit 322 and notifies the data processing device 1 of the detection value of the detection unit 322.

[0022] Detection unit 322 includes intensity detection unit 3221, AC detection unit 3222, and OS detection unit 3223. Intensity detection unit 3221 converts the current signals output by PD1 and PD2 into detection signals representing the intensity of infrared light incident on PD1 and PD2. AC detection unit 3222 detects the magnitude of the AC component (alternating current component) of the converted detection signal (fluctuation range of the AC component). OS detection unit 3223 detects the magnitude of the offset of the converted detection signal.

[0023] Now, as shown in FIGS. 3a, 3b and 3c, LED1, LED2, LED3 and LED4 are arranged in that order from left to right at a position slightly below the bottom edge of the display 2. In addition, PD1 is positioned halfway between LED1 and LED2, and converts the incident light in the infrared wavelength range into a current signal and outputs it, while PD2 is positioned halfway between LED3 and LED4, and converts the incident light in the infrared wavelength range into a current signal and outputs it. The arrows in Figures 3a, 3b, and 3c indicate the central axes of the directivity angles of LED1, LED2, LED3, and LED4, and LED1, LED2, LED3, and LED4 irradiate infrared light obliquely toward the upper front of display 2. 3b, the illuminance sensor IS is disposed in a position slightly below the bottom edge of the display 2 and near the left side of LED1, that is, in a position closer to the passenger seat than LED1, LED2, LED3, LED4, PD1, and PD2. The reason why the illuminance sensor IS is disposed in a position closer to the passenger seat is that it is considered that the illuminance sensor IS is less likely to be blocked by the user's hand than if the illuminance sensor IS was disposed in a position closer to the driver's seat.

[0024] Next, the detection control section 323 of the approach detection controller 32 controls the operations of the drive section 321 and the detection section 322 so that the cycle shown in FIG. 4a is repeated. Here, each cycle is a period in which the driving unit 321 turns on only the LED1, and the detection unit 322 detects the detection signal L1 representing the intensity of infrared light incident on the PD1, the AC detection signal L1_AC representing the magnitude of the AC component of the detection signal L1, and the OS detection signal L1_OS representing the magnitude of the offset of the detection signal L1, and a period in which the driving unit 321 turns on only the LED2, and the detection unit 322 detects the detection signal L2 representing the intensity of infrared light incident on the PD1, the AC detection signal L2_AC representing the magnitude of the AC component of the detection signal L2, and the OS detection signal L2_OS representing the magnitude of the offset of the detection signal L2. the period during which the driving unit 321 lights up only LED3 and the detection unit 322 detects a detection signal L3 representing the intensity of infrared light incident on PD2, an AC detection signal L3_AC representing the magnitude of the AC component of the detection signal L3, and an OS detection signal L3_OS representing the magnitude of the offset of the detection signal L3; and the period during which the driving unit 321 lights up only LED4 and the detection unit 322 detects a detection signal L4 representing the intensity of infrared light incident on PD2, an AC detection signal L4_AC representing the magnitude of the AC component of the detection signal L4, and an OS detection signal L4_OS representing the magnitude of the offset of the detection signal L4.

[0025] Here, the lighting of LED1, LED2, LED3, and LED4 of the driving unit 321 is performed by AC driving. That is, as shown in Figure 4b, the drive current In flowing through LEDn, the nth LED, during the lighting period of LEDn, a drive signal of a predetermined frequency is applied to LEDn only during the lighting period of LEDn, and LEDn is repeatedly turned on (emitting light) and off (not emitting light) at that frequency (flashing). Here, let Ln be the detection signal representing the intensity of the light emitted by LEDn that is reflected by an object and enters PDm, the mth PD. As shown in Figures 5a and 5b, when the drive current In of LEDn is the same, the closer an object such as a user's hand or finger is to display 2, the greater the reflected light intensity and the larger the AC component of the detection signal Ln.

[0026] In addition, when there is ambient light originating from sunlight, since sunlight contains a sufficient amount of infrared light, an offset occurs in which the detection signal Ln increases uniformly as a whole due to the ambient light, as shown in Figures 5c and 5d, and this offset increases as the ambient light becomes stronger. Therefore, the magnitude of this offset follows the magnitude of the visible light component of the ambient light.

[0027] Then, as shown in Figures 6a and 6b, the AC detection unit 3222 of the detection unit 322 detects the magnitude of the AC component (fluctuation range of the AC component) of the nth detection signal Ln converted by the intensity detection unit 3221 as an AC detection signal Ln_AC, and the OS detection unit 3223 of the detection unit 322 detects the magnitude of the offset generated in the nth detection signal Ln converted by the intensity detection unit 3221 as an OS detection signal Ln_OS.

[0028] Here, the sunlight incident on PD1 and PD2 may contain AC components such as sunlight filtering through the trees or fluctuations caused by the movement of the car. However, the frequency of the AC components that are generated is low. Therefore, the frequency of the LED drive signal is set to a frequency that is sufficiently higher than the frequency of the AC components that may be generated in sunlight (for example, several kHz or more, several tens of kHz or more, or several hundred kHz or more) so that AC components in the frequency band of the AC components of sunlight are not detected by AC detection unit 3222, thereby eliminating the influence of the AC components of sunlight.

[0029] That is, for example, the frequency of the LED drive signal is set to a frequency sufficiently higher than the frequency of AC components that may be generated in sunlight, and the magnitude of the signal obtained by applying a bandpass filter to the detection signal in the AC detection unit 3222, which passes only the frequency band around the frequency of the drive signal, is detected as the AC detection signal Ln_AC.

[0030] The OS detector 3223 can detect the offset Ln_OS by, for example, detecting the magnitude of the detection signal LEDn during the period when the LEDn is turned off by the drive signal during the lighting period of the LEDn (light-off period) as the OS detection signal Ln_OS. Alternatively, the offset Ln_OS can be detected by, for example, determining the magnitude of the DC component of the detection signal LEDn using a low-pass filter, and subtracting a value obtained by multiplying the AC detection signal Ln_AC by a predetermined coefficient (for example, 1 / 2) from the magnitude of the determined DC component. The L1_AC, L1_OS, L2_AC, L2_OS, L3_AC, L3_OS, L4_AC, and L4_OS detected by the detection unit 322 in this manner are notified to the data processing device 1 via the detection control unit 323. The data processing device 1 detects the approach of an object and calculates the approach position Gx of the object when, for example, the maximum value of the notified detection signals L1_AC, L2_AC, L3_AC, and L4_AC exceeds a predetermined threshold value. The approach position Gx is calculated, for example, by calculating the horizontal coordinate obtained as the center of gravity of the intensity distribution of the detection signals L1_AC, L2_AC, L3_AC, and L4_AC detected by the detection unit 322 as the approach position Gx using the following formula, where x1 is the horizontal coordinate of a predetermined position between LED1 and PD1, x2 is the horizontal coordinate of a predetermined position between LED2 and PD1, x3 is the horizontal coordinate of a predetermined position between LED3 and PD2, and x4 is the horizontal coordinate of a predetermined position between LED4 and PD4.

[0031] Formula: Gx = ΣXi × Li_AC / ΣLi_AC Here, ΣXi×Li_AC represents the sum of Xi×Li_AC for each i from i=1 to i=n, ​​ΣLi_AC represents the sum of Li_AC for each i from i=1 to i=n, ​​and n represents the number of LEDs (n=4 in this first embodiment).

[0032] Then, the data processing device 1 performs a predetermined process according to the calculated approach position Gx, such as enlarging the icon displayed at the position corresponding to the approach position Gx on the display 2, recognizing an air gesture of the hand from the change over time in the approach position Gx, and changing the display screen or application according to the recognized gesture.

[0033] Furthermore, the data processing device 1 performs a brightness control process for controlling the backlight to control the brightness of the display 2. FIG. 7 shows the procedure for this brightness control process. As shown in the figure, in the brightness control process, first, it is determined whether L1_AC≧Th1 is satisfied (step 702). Th1 is a preset threshold value, and when Li_AC is equal to or greater than Th1, a value at which it can be considered that an object is approaching LEDi is set as Th1. If L1_AC≧Th1 is not satisfied, then an object is not approaching the illuminance sensor IS arranged near LED1, and therefore the illuminance sensor IS is not blocked by an object, so the luminance of the display 2 is controlled according to the illuminance represented by the detection value of the illuminance sensor IS (step 704). Then, the process returns to step 702.

[0034] Here, the brightness is controlled so that when the illuminance is high (bright), the brightness of the display 2 becomes high (bright), and when the illuminance represented by the detection value of the illuminance sensor IS is low (dark), the brightness of the display 2 becomes low (dark). On the other hand, when L1_AC≥Th1 is satisfied (step 702), it is determined whether L3_AC<Th2 and L4_AC<Th2 are satisfied (step 706). Th2 is a preset threshold value, and when Li_AC is less than Th2, Th2 is set as a value that can be regarded as no object approaching near LEDi. Note that Th2≤Th1.

[0035] And if L3_AC<Th2 and L4_AC<Th2 are satisfied, it means that no object is approaching near PD2, which is arranged between LED3 and LED4, so the illuminance of ambient light is calculated based on the magnitude of the offset of detection signal L3 detected by PD2, which is L3_OS, or the magnitude of the offset of detection signal L4 detected by PD2, which is L4_OS, and the luminance of display 2 is controlled according to the calculated illuminance and ambient light (step 708). Then, the process returns to the process from step 702.

[0036] Here, since the magnitude of the offset of the detection signal detected by the PD illuminated by ambient light as described above increases following the intensity of the ambient light, the illuminance that would be detected if illuminance sensor IS were not shielded can be calculated according to a preset conversion formula from the magnitude of the offset of detection signal L3 detected by PD2 not shielded by an object, which is L3_OS, or the magnitude of the offset of detection signal L4 detected by PD2, which is L4_OS.

[0037] Next, when at least one of L3_AC<Th2 and L4_AC<Th2 is not satisfied (step 706), since there is a possibility that PD2 is shielded by an object, the process directly returns to the process from step 702, and the luminance of display 2 is maintained at the current luminance. The first embodiment has been described above. In the above first embodiment, since L1_OS and L2_OS are not used for luminance control processing or calculation of the approaching position Gx, their detection and notification to the detection and data processing device 1 may not be performed. Next, a second embodiment will be described. This second embodiment differs from the first embodiment only in the arrangement of the illuminance sensor IS and the content of the luminance control process. That is, in this second embodiment, as shown in FIG. 8, the illuminance sensor IS is arranged at a position between the LEDs 2 and 3 at the center in the left-right direction of the display 2. Further, the data processing device 1 performs the luminance control process shown in FIG. 9 as the luminance control process. As shown in the figure, in the luminance control process of this second embodiment, first, it is determined whether L2_AC≥Th1 or L3_AC≥Th1 (step 902). If not satisfied, that is, if L2_AC<Th1 and L3_AC<Th1, since an object is not approaching near the LED2 or LED3 and thus not near the illuminance sensor IS, and the illuminance sensor IS is not shielded by the object, the luminance of the display 2 is controlled according to the illuminance represented by the detection value of the illuminance sensor IS (step 904). Then, the process returns to the process from step 902.

[0038] On the other hand, when at least one of L2_AC≥Th1 and L3_AC≥Th1 is satisfied (step 902), it is determined whether L1_AC<Th2 and L2_AC<Th2 are satisfied (step 906). If L1_AC<Th2 and L2_AC<Th2 are satisfied, since an object is not approaching near the LED1 or LED2 and thus not near the PD1 arranged therebetween, and the PD1 is not shielded by the object, the ambient light illuminance is calculated from the magnitude of the offset of the detection signal L1 detected by the PD1, i.e., L1_OS, or the magnitude of the offset of the detection signal L2 detected by the PD1, i.e., L2_OS, and the luminance of the display 2 is controlled according to the calculated illuminance according to the ambient light (step 908). Then, the process returns to the process from step 902.

[0039] On the other hand, when L1_AC<Th2 and L2_AC<Th2 are not satisfied (step 906), further, Determine whether L3_AC < Th2 and L4_AC < Th2 are satisfied (step 910). And if L3_AC < Th2 and L4_AC < Th2 are satisfied, then since an object is not approaching near PD2 and PD2 is not shielded by the object as it is near LED3 and LED4 and thus arranged therebetween, calculate the illuminance of the ambient light based on the magnitude of the offset of the detection signal L3 detected by PD2, i.e., L3_OS, or the magnitude of the offset of the detection signal L4 detected by PD2, i.e., L4_OS, and control the luminance of the display 2 according to the calculated illuminance and the ambient light (step 912). Then, return to the process from step 902.

[0040] On the other hand, when L3_AC < Th2 and L4_AC < Th2 are not satisfied (step 910), directly return to the process from step 902 and maintain the luminance of the display 2 at the current luminance. The second embodiment has been described above. Note that in the luminance control process of this second embodiment, when L2_AC ≥ Th1 or L3_AC ≥ Th1, if both L1_AC < Th2 and L2_AC < Th2 and L3_AC < Th2 and L4_AC < Th2 are satisfied, the illuminance of the ambient light may be calculated by any of L1_OS, L2_OS, L3_OS, and L4_OS, and the luminance of the display 2 may be controlled according to the calculated illuminance and the ambient light.

[0041] Next, the third embodiment will be described. This third embodiment is different from the first embodiment only in the number and arrangement of LEDs and PDs, the arrangement of the illuminance sensor IS, the control of the drive unit 321 and the detection unit 322 performed by the detection control unit 323 of the proximity detection controller 32, and the content of the luminance control process. That is, in the third embodiment, as shown in Fig. 10a, six LEDs, LED1, LED2, LED3, LED4, LED5, and LED6, are arranged in that order from left to right at a position slightly below the bottom edge of the display 2. In addition, three PDs, PD1, PD2, and PD3, are provided, with PD1 arranged at a position midway between LED1 and LED2, PD2 arranged at a position midway between LED3 and LED4, and PD3 arranged at a position midway between LED5 and LED6. In addition, an illuminance sensor IS is arranged at a position close to PD2 between LED3 and LED4.

[0042] Then, the detection control unit 323 controls the operations of the driving unit 321 and the detection unit 322 so that the cycle shown in FIG. 10b is repeated. Here, each cycle includes a period in which the driving unit 321 turns on only the LED1 and the detection unit 322 detects the detection signal L1 representing the intensity of infrared light incident on the PD1, the AC detection signal L1_AC representing the magnitude of the AC component of the detection signal L1, and the OS detection signal L1_OS representing the magnitude of the offset of the detection signal L1; a period in which the driving unit 321 turns on only the LED2 and the detection unit 322 detects the detection signal L2 representing the intensity of infrared light incident on the PD1, the AC detection signal L2_AC representing the magnitude of the AC component of the detection signal L2, and the OS detection signal L2_OS representing the magnitude of the offset of the detection signal L2; and a period in which the driving unit 321 turns on only the LED3 and the detection unit 322 detects the detection signal L3 representing the intensity of infrared light incident on the PD2, the AC detection signal L3_AC representing the magnitude of the AC component of the detection signal L3, and the OS detection signal L3_OS representing the magnitude of the offset of the detection signal L3. a period in which the drive unit 321 turns on only LED4 and the detection unit 322 detects a detection signal L4 representing the intensity of infrared light incident on PD2, an AC detection signal L4_AC representing the magnitude of the AC component of the detection signal L4, and an OS detection signal L4_OS representing the magnitude of the offset of the detection signal L4; a period in which the drive unit 321 turns on only LED5 and the detection unit 322 detects a detection signal L5 representing the intensity of infrared light incident on PD3, an AC detection signal L5_AC representing the magnitude of the AC component of the detection signal L5, and an OS detection signal L5_OS representing the magnitude of the offset of the detection signal L5; and a period in which the drive unit 321 turns on only LED6 and the detection unit 322 detects a detection signal L6 representing the intensity of infrared light incident on PD3, an AC detection signal L6_AC representing the magnitude of the AC component of the detection signal L6, and an OS detection signal L6_OS representing the magnitude of the offset of the detection signal L6.

[0043] Here, in the third embodiment as well, the lighting of each LED of the driving unit 321 is performed by AC driving. Moreover, the data processing device 1 performs the brightness control process shown in FIG. As shown in the figure, in the brightness control process of the third embodiment, it is first determined whether L3_AC≧Th1 or L4_AC≧Th1 (step 1102). And when it is not satisfied, that is, when L3_AC < Th1 and L4_AC < Th1, since there is no object approaching near the illuminance sensor IS arranged near LED3 and LED4 and thus between LED3 and LED4, and the illuminance sensor IS is not blocked by the object, the luminance of the display 2 is controlled according to the illuminance represented by the detected value of the illuminance sensor IS (step 1104). Then, the process returns to the process from step 1102.

[0044] On the other hand, when at least one of L3_AC ≥ Th1 and L4_AC ≥ Th1 is satisfied (step 1102), it is determined whether L1_AC < Th2 and L2_AC < Th2 are satisfied (step 1106). And if L1_AC < Th2 and L2_AC < Th2 are satisfied, since there is no object approaching near LED1 and LED2 and thus between them and near PD1, and PD1 is not blocked by the object, the ambient light illuminance is calculated from L1_OS which is the magnitude of the offset of the detection signal L1 detected by PD1 or L2_OS which is the magnitude of the offset of the detection signal L2 detected by PD1, and the luminance of the display 2 is controlled according to the calculated illuminance according to the ambient light (step 1108). Then, the process returns to the process from step 1102.

[0045] On the other hand, when L1_AC < Th2 and L2_AC < Th2 are not satisfied (step 1106), it is further determined whether L5_AC < Th2 and L6_AC < Th2 are satisfied (step 1110). And if L5_AC < Th2 and L6_AC < Th2 are satisfied, since there is no object approaching near LED5 and LED6 and thus between them and near PD3, and PD3 is not blocked by the object, the ambient light illuminance is calculated from L5_OS which is the magnitude of the offset of the detection signal L5 detected by PD3 or L6_OS which is the magnitude of the offset of the detection signal L6 detected by PD3, and the luminance of the display 2 is controlled according to the calculated illuminance according to the ambient light (step 1112). Then, the process returns to the process from step 1102.

[0046] On the other hand, when L5_AC < Th2 and L6_AC < Th2 are not satisfied (step 1110), the process directly returns from step 1102, and the brightness of the display 2 is maintained at the current brightness. The above is the description of the third embodiment. In this third embodiment as well, the data processing device 1 detects the approach of an object and calculates the approach position Gx of the object when the maximum value of the notified detection signals L1_AC, L2_AC, L3_AC, L4_AC, L5_AC, and L6_AC exceeds a predetermined threshold, and performs a predetermined process according to the calculated approach position Gx.

[0047] The calculation of the approach position Gx can be performed, for example, as described above, Gx = ΣXi × Li_AC / ΣLi_AC as follows. However, ΣXi × Li_AC represents the sum of Xi × Li_AC for each i from i = 1 to i = n, ΣLi_AC represents the sum of Li_AC for each i from i = 1 to i = n, and n represents the number of LEDs (n = 6 in this third embodiment). In addition, in the brightness control process of this third embodiment, when L3_AC ≥ Th1 or L4_AC ≥ Th1, and both L1_AC < Th2 and L2_AC < Th2 and L5_AC < Th2 and L6_AC < Th2 are satisfied, the illuminance of the ambient light may be calculated by any of L1_OS, L2_OS, L5_OS, and L6_OS, and the brightness of the display 2 may be controlled according to the calculated illuminance according to the ambient light.

[0048] Also, in the third embodiment, since L3_OS and L4_OS are not used for the brightness control process or the calculation of the approach position Gx, their detection and notification to the data processing device 1 may not be performed. Next, the fourth embodiment will be described. The fourth embodiment is different from the third embodiment only in the number and arrangement of the illuminance sensors IS and the content of the brightness control process. That is, in this fourth embodiment, as shown in FIG. 12, two illuminance sensors, an illuminance sensor IS1 and an illuminance sensor IS2, are provided. The illuminance sensor IS1 is arranged near the left side of the LED1, and the illuminance sensor IS1 is arranged near the right side of the LED6. Further, as a luminance control process, the data processing device 1 performs the luminance control process whose procedure is shown in FIG. 13. As shown in the figure, in the luminance control process of this fourth embodiment, first, it is determined whether L1_AC ≥ Th1 (step 1302). If it is not satisfied, that is, if L1_AC < Th1, an object is not approaching near the LED1 and thus near the illuminance sensor IS1, and the illuminance sensor IS1 is not shielded by the object. Therefore, the luminance of the display 2 is controlled according to the illuminance represented by the detected value of the illuminance sensor IS1 (step 1304). Then, the process returns to the process from step 1302.

[0049] On the other hand, if L1_AC ≥ Th1 (step 1302), it is determined whether L6_AC ≥ Th1 (step 1306). If it is not satisfied, that is, if L6_AC < Th1, an object is not approaching near the LED6 and thus near the illuminance sensor IS2, and the illuminance sensor IS2 is not shielded by the object. Therefore, the luminance of the display 2 is controlled according to the illuminance represented by the detected value of the illuminance sensor IS2 (step 1308). Then, the process returns to the process from step 1302.

[0050] On the other hand, if L6_AC ≥ Th1 (step 1306), it is determined whether L3_AC < Th2 and L4_AC < Th2 (step 1310). If L3_AC < Th2 and L4_AC < Th2 are satisfied, since an object is not approaching near or between LED3 and LED4 and thus near PD2, and PD2 is not shielded by the object, the ambient light illuminance is calculated based on the magnitude of the offset of the detection signal L3 detected by PD2, i.e., L3_OS, or the magnitude of the offset of the detection signal L4 detected by PD2, i.e., L4_OS, and the luminance of display 2 is controlled according to the calculated illuminance in accordance with the ambient light (step 1312). Then, the process returns to the process from step 1302.

[0051] On the other hand, when L3_AC < Th2 and L4_AC < Th2 are not satisfied (step 1310), the process directly returns to the process from step 1302, and the luminance of display 2 is maintained at the current luminance. The above is the description of the fourth embodiment. Note that in the luminance control process of this fourth embodiment, when both L1_AC ≥ Th1 and L6_AC ≥ Th1 are not satisfied, the luminance of display 2 may be controlled according to the illuminance represented by the detection value of either illuminance sensor IS1 or illuminance sensor IS2, or the luminance of display 2 may be controlled according to the illuminance represented by the average value of the detection values of illuminance sensor IS1 and illuminance sensor IS2. Also, in the fourth embodiment, since L1_OS, L2_OS, L5_OS, and L6_OS are not used for luminance control processing or calculation of the approach position Gx, detection and notification to the detection and data processing device 1 may not be performed. The above is the description of the embodiments of the present invention. Incidentally, in the above embodiments, Li_OS was detected together with Li_AC during the period when the i-th LED was driven by alternating current. However, during the period when not all LEDs are driven by alternating current, the offset of the light detected by the PD that outputs the detection signal Li may be used as Li_OS for luminance control.

[0052] Now, the luminance control according to this embodiment can also be applied when the combination of the LED, PD, and illuminance sensor is a combination other than the combinations shown in the first to fourth embodiments. For example, the combinations of LED and PD shown in Figures 14a, 14b, and 14c can be used. The dashed arrows in the figure indicate the correspondence between each LED and the PD that detects a detection signal during the lighting period of that LED. As shown in FIG. 14a, a configuration can be used in which multiple PDs (PD1, PD2) detect a detection signal during the lighting period of one LED (LED2), or as shown in FIG. 14b, a PD (PD2) is provided that detects a detection signal only during the lighting period of one LED (LED3), or a configuration can be used in which PDs (PD1 / PD2) are provided that detect detection signals during the lighting periods of three or more LEDs (LED1, LED2, LED3 / LED4, LED5, LED6). As shown in the first to fourth embodiments and in Figures 14a, 14b and 14c, by setting the PD that detects a detection signal during the lighting period of an LED to be the PD that is located closest to the LED or adjacent to the LED, it is possible to relatively effectively detect the above-mentioned approach position Gx and whether an object is present near the illuminance sensor IS or each PD.

[0053] Moreover, it is also possible to use a combination of these LEDs and PDs and an arbitrary number of illuminance sensors IS at arbitrary positions. Even with these configurations, it is possible to detect whether an object is present near the illuminance sensor IS or each PD from the AC detection signal detected during the lighting period of the corresponding LED in each PD, and perform brightness control using the illuminance sensor IS when no object is present near the illuminance sensor IS, and perform brightness control using a PD with no object present near the illuminance sensor IS when an object is present near the illuminance sensor IS.

[0054] As described above, according to this embodiment, even if the illuminance sensor is blocked by an object and cannot correctly detect the illuminance of the ambient light, if there is a PD of the approach detection sensor 31 that is not blocked by an object, the illuminance of the ambient light can be calculated using that PD to control the brightness of the display 2. Calculation of illuminance using the PD of the approach detection sensor 31 has inferior detection accuracy for visible light illuminance compared to an illuminance sensor because the PD is an infrared light photodiode. However, by calculating the illuminance of ambient light using the PD in this manner, it is possible to detect the illuminance of visible light in a second-best manner when the illuminance sensor cannot detect the illuminance of visible light.

[0055] Therefore, according to this embodiment, even if an object is approaching the display 2, the luminance of the display 2 can be adjusted to a luminance appropriate for the ambient light as much as possible. Moreover, such adjustment of the luminance of the display 2 can be performed by sharing the configuration of the approach detection device 3 that detects the approach and approaching position of an object such as a user's hand or finger. Furthermore, according to the second to fourth embodiments, there is an advantage that the configuration of the display unit 10 for left-hand drive vehicles and the configuration of the display unit 10 for right-hand drive vehicles can be made common. [Explanation of symbols]

[0056] 1...data processing device, 2...display, 3...approach detection device, 4...peripheral device, 10...display unit, 31...approach detection sensor, 32...approach detection controller, 321...drive unit, 322...detection unit, 323...detection control unit, 3221...intensity detection unit, 3222...AC detection unit, 3223...OS detection unit.

Claims

1. 1. A display system for controlling brightness of a display, comprising: The display; an illuminance sensor disposed outside a display surface of the display; A proximity detection device; A brightness control means; The approach detection device includes: A plurality of light sources that are arranged on the outside of a display surface of the display in a left-right direction of the display surface and emit invisible light toward a front of the display surface; a plurality of photodetectors arranged in a left-right direction on the outer side of a display surface of the display, the photodetectors detecting light in a wavelength range including the wavelength of the invisible light; a driving means for driving each of the light sources in sequence with an alternating current and causing each light source to repeatedly emit light and not emit light during a period in which the light source is being driven with an alternating current; an AC component detection means for detecting a fluctuation width of an AC component of light detected by the photodetector that is pre-associated with the AC-driven light source during a period in which the light source is AC-driven; and an offset detection means for detecting an offset representing an intensity of light detected by a target photodetector that is at least a part of the plurality of photodetectors when the plurality of light sources are not emitting light, The brightness control means determining whether or not an object is present near the illuminance sensor based on at least a fluctuation width of the AC component of the light detected by the AC component detection means during a period in which a light source near the illuminance sensor is AC-driven; When it is determined that no object is present near the illuminance sensor, the luminance of the display is controlled based on the illuminance detected by the illuminance sensor; A display system characterized in that, when it is determined that an object is present near the illuminance sensor, and when there is a target photodetector whose detected light does not include light whose fluctuation range of the AC component detected by the AC component detection means is greater than a predetermined level, the brightness of the display is controlled based on the offset detected by the offset detection means for the target photodetector present.

2. 2. The display system of claim 1, A plurality of the illuminance sensors are provided, the illuminance sensors being spaced apart in the left-right direction; The brightness control means determining whether or not an object is present near each illuminance sensor based on at least a fluctuation width of the AC component of the light detected by the AC component detection means during a period in which a light source closest to the illuminance sensor is AC driven; When an illuminance sensor is present that can determine that no object is present nearby, the luminance of the display is controlled based on the illuminance detected by the illuminance sensor that is present; A display system characterized in that, when there is no illuminance sensor that can determine that no object is present nearby, and when there is a target photodetector whose detected light does not include light whose fluctuation range of the AC component detected by the AC component detection means is greater than a predetermined level, the brightness of the display is controlled based on the offset detected by the offset detection means for the target photodetector present.

3. 3. A display system according to claim 1, further comprising: A display system, wherein the offset detection means detects an offset for the target photodetector during a period in which each of the light sources associated with the target photodetector is AC driven.

4. 3. A display system according to claim 1, further comprising: A display system characterized in that the brightness control means determines that an object is present near the illuminance sensor when the fluctuation range of the AC component of the light detected by the AC component detection means during a period in which a light source closest to the illuminance sensor is driven by AC exceeds a predetermined threshold value.

5. 3. A display system according to claim 1, further comprising: A display system, wherein the target photodetector includes a photodetector farthest from the illuminance sensor in the left-right direction of the display surface.

6. 3. A display system according to claim 1, further comprising: A display system, characterized in that the photodetector pre-associated with the light source is the photodetector that is located closest to the light source or is located adjacent to the light source.

7. 2. The display system of claim 1, A display system, wherein the illuminance sensor is disposed either at a position near the left edge of the display surface or at a position near the right edge of the display surface.

8. 2. The display system of claim 1, A display system, characterized in that the illuminance sensor is disposed near the center of the display surface in the left-right direction.

9. 3. The display system of claim 2, The illumination sensor includes two of the illumination sensors, The two illuminance sensors are disposed at a position near the left end of the display surface and a position near the right end of the display surface.

10. 3. A display system according to claim 1, further comprising: a position calculation means for calculating the left-right coordinates of an object approaching the display surface from a distribution of the fluctuation range of an AC component, the fluctuation range of the AC component detected by an AC component detection means during a period when the light source is driven by AC, in the left-right coordinates of the display surface that are determined for each of the pairs of light sources and the photodetectors pre-associated with the light sources.

11. A display system according to claim 10, A display system comprising: a gesture response processing means for identifying a user gesture made in front of a display surface of the display from the left-right coordinates calculated by the position calculation means, and performing processing according to the identified gesture.

Images