Electronic device, brightness control method, and program

Abstract

The present invention provides an electronic device, a brightness control method, and a program that can appropriately adjust brightness while further reducing the impact on the displayed image. [Solution] The electronic device 100 includes a digital display screen 141, an illuminance sensor 171 for measuring ambient light intensity, and a control unit for adjusting the brightness of the digital display screen 141. The control unit can switch between a first display mode and a second display mode, which has a relatively lower brightness compared to the first display mode. In the first display mode, the control unit adjusts the brightness of the digital display screen 141 based on the illuminance last acquired during the second display mode, from among the illuminance measured by the illuminance sensor 171.

Description

Technical Field

[0001] This invention relates to an electronic device, a brightness control method, and a program.

Background Art

[0002] Patent Document 1 discloses a technique that includes an illuminance sensor for measuring the illuminance of external light in order to adjust the brightness of a backlight in a liquid crystal display screen, and detects external light by the illuminance sensor while the backlight is periodically turned off.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, such temporary turning off of the light is likely to lead to visually unnatural displays such as screen flickering. The object of this invention is to provide an electronic device, a brightness control method, and a program that can appropriately adjust the brightness while further reducing the influence on the displayed image.

Means for Solving the Problems

[0005] To achieve the above object, the present invention includes a digital display screen, an illuminance sensor for measuring the illuminance of external light, and a control unit for adjusting the brightness of the digital display screen, and is provided with The control unit can switch between a first display mode and a second display mode having a relatively lower brightness compared to the first display mode, and in the first display mode, it adjusts the brightness of the digital display screen based on the illuminance last acquired during the second display mode from the illuminance measured by the illuminance sensor. It is an electronic device. [Effects of the Invention]

[0006] According to the present invention, it is possible to adjust the brightness appropriately while further reducing the impact on the displayed image. [Brief explanation of the drawing]

[0007] [Figure 1] This figure shows the structure of an electronic device according to one embodiment. [Figure 2] This is a block diagram showing the functional configuration of an electronic device. [Figure 3] This is a diagram explaining brightness settings. [Figure 4] This diagram shows the timing of operations related to brightness settings. [Figure 5] This diagram shows the timing of operations related to brightness settings. [Figure 6] This flowchart shows the control procedure for the brightness setting control process related to display operation. [Figure 7] This diagram shows the timing of operations related to brightness setting in the first display mode. [Figure 8] This diagram shows the timing of operations related to brightness setting in the first display mode. [Figure 9] This flowchart shows the control procedure for the brightness setting control process related to the display operation in another embodiment. [Figure 10] This flowchart shows the control procedure for the brightness setting control process related to the display operation in another embodiment. [Figure 11] This is a cross-sectional view of another example of an electronic device. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will now be described based on the drawings. As shown in the front view from the display side in Figure 1(a), the electronic device 100 is an electronic clock, or it may be a smartwatch. The electronic device 100 has a digital display screen, for example, an OLED (Organic Light Emitting Diode) display 141a, located inside an annular bezel 2 surrounding its outer edge. Thus, the OLED display 141a is housed within the bezel 2.

[0009] The cross-sectional view in Figure 1(b) is a cross-section along the cross-sectional line ii in Figure 1(a). Inside the bezel 2, a digital display screen 141, for example, an organic EL display 141a and a touch sensor 151 are positioned overlapping. These are covered above by a light-transmitting cover glass 3. The cover glass 3 may be transparent and is omitted in Figure 1(a). The organic EL display 141a, the touch sensor 151, and the cover glass 3 may be bonded together with a transparent adhesive sheet (optical glue).

[0010] The organic EL display 141a is a self-emissive display that displays images by emitting light on a pixel-by-pixel basis using organic EL. The organic EL display 141a may also be capable of outputting full-color images by emitting light in each of the RGB colors.

[0011] The touch sensor 151 detects touch operations by a user or other party and outputs information about the touch position. The touch operation detection method of the touch sensor 151 may be, for example, a capacitive method, but is not limited to this. It is sufficient that it can detect touch operations from the cover glass 3. The touch sensor 151 is light-transmitting and does not obstruct the output of light emitted by the organic EL display 141a from the display surface.

[0012] Below the organic EL display 141a, that is, on the back side of the organic EL display 141a as viewed from the side where the user views the display, the illuminance sensor 171 is located. The illuminance sensor 171 detects the illuminance of the light incident from above the display surface through the cover glass 3, the touch sensor 151, and the organic EL display 141a. However, as will be described later, the illuminance sensor 171 can also detect the light emitted when the organic EL display 141a is emitting light. The illuminance sensor 171 detects external light as described above, but it is difficult to visually recognize it from the display surface side.

[0013] Below the bezel 2, the housing 5 is located. A functional module (not shown) is housed in the housing 5. The organic EL display 141a, the touch sensor 151, and the illuminance sensor 171 are connected to the functional module, and signals are input and output between them and the functional module.

[0014] As shown in the block diagram of FIG. 2, the electronic device 100 includes a CPU 11 (Central Processing Unit, control unit), a RAM 12 (Random Access Memory), a storage unit 13, a display unit 14, an operation reception unit 15, a communication unit 16, a measurement unit 17, and the like.

[0015] The CPU 11 (control unit) is a processor that performs arithmetic processing and comprehensively controls the overall operation of the electronic device 100. The processor may be single or may be a plurality that operate in parallel or separately. The CPU 11 may be able to count a clock signal and execute a stopwatch function. Also, the CPU 11 may use the measurement value of the measurement unit 17 to determine the activity of the user of the electronic device 100, such as a motion state such as running, or obtain the amount of motion. Further, the CPU 11 adjusts the luminance of the digital display screen 141 as will be described later. The CPU 11 is at least included in the configuration of the computer of the present embodiment.

[0016] RAM12 provides the CPU11 with a working memory space and stores temporary data. RAM12 may be, but is not limited to, DRAM.

[0017] The memory unit 13 is a non-volatile memory that stores the program 131 and setting data. The non-volatile memory may be flash memory. The program 131 includes processing related to setting the brightness value for the display unit 14. The setting data includes the brightness setting 132 for the display unit 14.

[0018] The display unit 14 performs display operations based on the control of the CPU 11. The display unit 14 has a digital display screen 141. The digital display screen 141 may have the organic EL display 141a described above.

[0019] The operation reception unit 15 receives input operations from external sources such as a user and outputs an operation signal to the CPU 11 according to the received content. The operation reception unit 15 has a touch sensor 151. The operation reception unit 15 may also have push button switches or the like.

[0020] The communication unit 16 controls the transmission and reception of data with external devices. The communication unit 16 may have a communication driver or the like. The communication unit 16 may also be capable of controlling communication with external devices via short-range wireless communication, such as Bluetooth®.

[0021] The measurement unit 17 measures physical quantities and outputs the measurement results to the CPU 11. The measurement unit 17 includes an illuminance sensor 171 and a motion sensor 172. The illuminance sensor 171 measures the illuminance of light incident on the electronic device 100 from the outside, i.e., ambient light. The motion sensor 172 measures the motion of the electronic device 100. The motion sensor 172 may include, for example, an acceleration sensor. The measurement unit 17 may also have an analog-to-digital conversion unit. The analog-to-digital conversion unit converts the measured values ​​measured by each sensor into digital discrete values ​​at appropriate time intervals and resolutions and outputs them to the CPU 11.

[0022] The motion sensor 172 may also be capable of measuring ambient temperature and user biometric information, such as pulse rate and SpO2. Furthermore, motion measurement may include measurement of the device's posture. That is, based on the measurements of the measurement unit 17, it may be possible to infer whether or not the display screen of the electronic device 100 is visible to the user.

[0023] Next, the brightness setting for the display in the electronic device 100 will be explained. The electronic device 100 changes the display brightness of the organic EL display 141a according to the illuminance measured by the illuminance sensor 171. That is, when the surroundings of the electronic device 100 are dark, the display brightness decreases, and when the surroundings are bright, the display brightness increases.

[0024] On the other hand, the electronic device 100 also changes its display state by switching modes according to the user's usage. The first display mode is an active state, i.e., an active state, where the user is likely to be using the electronic device 100 or looking at the display screen. The second display mode is a standby state, i.e., a state where the user is not using the device or looking at the display screen and is not active. In the second display mode, the brightness is set to be relatively lower than in the first display mode. In other words, the inactive second display mode may be a power-saving display state that reduces power consumption by lowering the brightness. Accordingly, in the second display mode, the processing speed of the CPU 11 and the communication frequency of the communication unit 16 may be lower than in the first display mode.

[0025] An active state, specifically when the user is using the device, may include the period during operation input or the period from operation input to the set time. Furthermore, if the measurement unit 17 determines that the electronic device 100 has changed to a position suitable for viewing the display content, the period from that change to the set time may be considered an active state. Similarly, when the communication unit 16 receives data from an external device and displays content corresponding to that data using the display unit 14, the period from the display update to the set time is also included in the active state. The set time for each of the above conditions may be defined separately. If none of these conditions apply, i.e., if an active state has not occurred for longer than the set time, the display is in the second display mode. Non-active states may include situations where no display content other than the date and time display has been updated, or when the electronic device 100 is stationary.

[0026] In the second display mode, if any operation or movement occurs to the electronic device 100, the system may quickly switch back to the first display mode. On the other hand, in the first display mode, the set time may be, for example, 3 to 15 seconds. In other words, even while the user is having the electronic device 100 perform various functions, the system may frequently switch from the first display mode to the second display mode depending on the status of input operations, the visibility of the display screen, etc.

[0027] Furthermore, the electronic device 100 does not necessarily have to stop displaying information via the display unit 14, except under specific conditions such as low battery level. In other words, even if the device has not been used for a long period of time, the display in the second display mode may, in principle, continue. However, within the second display mode, a power-saving mode may be implemented, which may include stopping some of the display or reducing the number of display colors.

[0028] As shown in Figure 3, the brightness of the display screen of the electronic device 100 is set based on a combination of a first display mode or a second display mode and illuminance. The brightness setting here may be the maximum brightness value used for display, or a ratio to the maximum brightness value that can be output due to the configuration. The relationship between illuminance and brightness is stored in the storage unit 13 as a brightness setting 132 in advance. The illuminance level may be set to a specific range of illuminance in the measured value. Here, with illuminance 4 as the maximum range and illuminance 1 as the minimum range, the brightness is A1>Brightness A2, B1>Brightness B2, C1>Brightness C2, D1>Brightness D2, A1>Brightness B1>Brightness C1>Brightness D1, and A2>Brightness B2>Brightness C2>Brightness D2. Alternatively, the relationship between illuminance and brightness may be expressed by a mathematical formula or the like and stored in the storage unit 13.

[0029] Due to its characteristics, the illuminance sensor 171 detects not only ambient light but also the light emitted by the display unit 14. If the brightness of the light emitted from the display unit 14 is small enough not to affect the determination of the illuminance level, no problem occurs. On the other hand, if the brightness of the light emitted from the display unit 14 is high, the measurement value of the illuminance sensor 171 will be overestimated, and the display operation of the display unit 14 may be set to a brightness higher than the brightness that would normally be expected from ambient light.

[0030] During display operation in the first display mode, which has relatively high brightness, the electronic device 100 stops acquiring illuminance measurements from the illuminance sensor 171. In this case, the most recent illuminance measurement obtained during the second display mode continues to be treated as the current illuminance measurement. Note that the cessation of acquisition here is for the purpose of brightness adjustment and does not exclude the acquisition of illuminance measurements during other functional operations. On the other hand, during display operation in the second display mode, the electronic device 100 acquires the illuminance values ​​measured by the illuminance sensor 171 continuously or intermittently at predetermined time intervals. This time interval is referred to as the first interval. That is, the current illuminance measurement is updated each time it is acquired. Note that the measurement operation of the illuminance sensor 171 may continue even during the first display mode.

[0031] As shown in Figure 4, image data is output to the display unit 14 when the image changes, synchronized with a TE (Tearing Effect) signal or a vertical synchronization (VSYNC) signal that defines the update interval of the displayed image. Meanwhile, illuminance measurement data is acquired from the illuminance sensor 171 at the first interval, which is set as the first interval synchronized with a specified number of times such as the TE signal. The first interval may be changed in the second display mode.

[0032] In the second display mode, when any signal indicating an active operation is acquired, image data at the brightness of the first display mode is output to the display unit 14 in conjunction with the next TE signal, etc. When this image data is displayed by the display unit 14, the electronic device 100 switches to the first display mode. At this time, the illuminance data may be acquired independently of the first interval before the image is actually updated in synchronization with the next TE signal and VSYNC signal. This illuminance data is continuously reflected in the brightness value of the image data after switching to the first display mode.

[0033] Furthermore, if the interval between TE signals is short compared to the illuminance data acquisition time, it may be difficult to acquire illuminance data within one cycle of the TE signal. In this case, as shown in Figure 5, the image data may be output in synchronization with the second TE signal after the active signal input, delaying the image update by one cycle. Alternatively, as shown by the dashed line in Figure 5, after acquiring illuminance data in one cycle of the TE signal, the brightness setting corresponding to that illuminance data may be reflected in the image data before outputting the image data at the timing of the next TE signal.

[0034] The brightness setting operation related to the brightness control method of this embodiment is performed as shown in the flowchart of Figure 6. The brightness setting control process is performed continuously while the CPU 11 is measuring the display operation.

[0035] The CPU 11 determines whether the current display is in the first display mode (S1; mode determination step, mode determination means). If it is determined to be in the first display mode (S1; Y), the CPU 11 obtains the most recent stored illuminance measurement value (S2). The CPU 11 refers to the brightness setting 132 and obtains and sets the brightness setting for the first display mode according to the obtained illuminance measurement value (S3). Then, the CPU 11 proceeds to S4. Note that if the setting in S13 described later is maintained, S2 and S3 may be omitted. That is, in the first display mode, the brightness of the digital display screen 141 may be adjusted only at the timing immediately after transitioning from the second display mode.

[0036] If it is determined that the display is not in the first display mode (S1;N), the CPU 11 determines whether or not it has received an active signal that will trigger a transition to the first display mode (S11). If it is determined that an active signal has been received (S11;Y), the CPU 11 obtains an illuminance measurement value from the illuminance sensor 171 (S12). The CPU 11 refers to the brightness setting 132, obtains the brightness setting for the first display mode according to the illuminance measurement value, and sets it in RAM 12 or the like (S13). Then, the processing of the CPU 11 proceeds to S14.

[0037] If it is determined that an active signal has not been received (S11;N), the CPU 11 determines whether or not it is time to measure illuminance (S21). If it is determined that it is not time to measure illuminance (S21;N), the CPU 11 proceeds to S4. If it is determined that it is time to measure illuminance (S21;Y), the CPU 11 obtains the illuminance measurement value from the illuminance sensor 171 (S22). The CPU 11 refers to the brightness setting 132, obtains the brightness setting for the second display mode according to the illuminance measurement value, and sets it in RAM 12 or the like (S23). Then, the CPU 11 proceeds to S14.

[0038] When the process moves from S13 and S23 to S14, the CPU 11 stores the acquired illuminance measurement value in the RAM 12 as the most recent measurement value (S14). Then, the CPU 11 proceeds to S4. The processing in steps S22 and S23 is included in the first adjustment step and first adjustment means of this embodiment. The processing content in steps S2, S3, S12, and S13 is included in the second adjustment step and second adjustment means of this embodiment.

[0039] When transitioning to S4, CPU11 waits until the timing of the next TE signal (S4). Then, CPU11's processing returns to S1.

[0040] In the above, illuminance measurements were acquired only during the second display mode. However, in the electronic device 100 of one embodiment, if the first display mode lasts for a long time, the actual illuminance incident from the outside may change significantly during that time. The electronic device 100 may also acquire illuminance measurements under specific conditions and in conjunction with specific operations, even in the first display mode.

[0041] As shown in Figure 7, at the timing of a certain TE signal, image data D1 may be output to the display unit 14 with the brightness value of a portion of the displayed image that overlaps with the illuminance sensor 171 in a plan view set to zero. This display state of an image with a partially set brightness value to zero, i.e., partially turned off, is called the third display mode. The portion of the image referred to here may be wider than the portion that overlaps with the illuminance sensor 171, as long as it includes at least the portion that overlaps with the illuminance sensor 171. When the image I1 with the portion of the image turned off is displayed at the timing of the TE signal after one cycle, illuminance measurement data is acquired from the illuminance sensor 171. At the timing of the TE signal after two cycles, the original image data D0 is retransmitted, and at the timing of the TE signal after three cycles, the original image I0 is restored, returning to the first display mode. Thus, the period of the third display mode, during which the image is temporarily switched, is two cycles of the TE signal and VSYNC signal, which are the image update intervals. Twice the update interval of the displayed image is approximately the threshold visible to the user or shorter.

[0042] The conditions for changing to such a third display mode may be, for example, simply that the first display mode has continued for a reference time or longer. Alternatively, even in the first display mode, conditions may be included such as the brightness value of the image in a portion of the area overlapping with the illuminance sensor 171 in a plan view being below a reference value. Note that the above part may be a reference value below a non-zero brightness value, for example, a predetermined fixed value, or a predetermined percentage of the brightness value that was intended to be displayed in the first display mode, for example, 10%.

[0043] The timing for turning off the image in the aforementioned partial area or reducing its brightness value may be one cycle before the timing for updating the image to another image. As shown in Figure 8, before switching from image I0 to image I2, image data D1 is output to display image I1 with the aforementioned partial area turned off, and illuminance measurement data is acquired from the illuminance sensor 171. At the same time, image data D2 is output, and at the timing of the TE signal two cycles later, the image switches to image I2 corresponding to image data D2. In this case, at the timing of the TE signal two cycles later, image data D2a relating to the same image I2a to which the brightness setting reflecting the illuminance measurement value has been applied may be output.

[0044] In this case, brightness is controlled according to the flowchart shown in Figure 9. This flowchart adds steps S31-S34 and S41-S42 to the process shown in the flowchart in Figure 6. Other processes are the same, and the same reference numerals are used for identical processes, omitting detailed explanations.

[0045] If the S1 discrimination process branches to "Y", the CPU 11 determines whether it is in the third display mode, that is, whether a portion of the image in the area overlapping with the illuminance sensor 171 in a plan view is turned off (partially turned off) (S31). If it is determined that it is in the third display mode (S31; Y), the CPU 11 acquires the illuminance measurement value from the illuminance sensor 171 (S32). The CPU 11 outputs the image data D0 with the partial turn-off released to the display unit 14 (S33). The CPU 11 stores the acquired illuminance measurement value in RAM 12 or the like as the most recent measurement value (S34). Then, the CPU 11's processing moves on to S3.

[0046] If it is determined that the display is not in the third display mode (S31; N), the CPU 11 determines whether the measurement conditions of the illuminance sensor 171 are met (S41). If it is determined that the measurement conditions are met (S41; Y), the CPU 11 outputs partially turned-off image data to the display unit 14 (S42). Then, the CPU 11 proceeds to S4. If it is determined that the measurement conditions are not met (S41; N), the CPU 11 proceeds to S2.

[0047] Furthermore, even when transitioning to the third display mode, if it is clear that there is no need to reduce the brightness value, it is not necessarily required to output image data that partially turns off the lights. For example, if it is determined that no display will be shown in the aforementioned area for a specific display, such as a time display, then illuminance can be measured without outputting image data that reduces the brightness value.

[0048] Furthermore, the set brightness value will be lower in areas such as outdoors at night or in shaded areas indoors. For example, if the brightness D1 set in the first display mode is less than the brightness A2 in the second display mode when the illuminance level is 1, then illuminance can be measured without further partial dimming from brightness D1.

[0049] In other words, in these cases, as in other examples of brightness setting control processing shown in Figure 10, the CPU 11 may further determine whether or not to output partially turned-off image data after step S41 (S51). If it is determined that partial turning off is unnecessary (S51;N), the CPU 11 omits step S42 and proceeds to processing S4, treating the image data as partially turned off without updating it. As a result, the display mode is switched from the first to the third display mode at the timing of the next TE signal and VSYNC signal. If it is determined that partial turning off is necessary (S51;Y), the CPU 11 proceeds to processing S42, as in Figure 9 above.

[0050] When returning from the third display mode to the first display mode, the CPU 11 may also determine whether or not partial illumination occurred during the transition to the third display mode (S52). If it is determined that partial illumination did not occur (S52; N), S33 is omitted and the CPU 11 proceeds to S34. If it is determined that partial illumination occurred (S52; Y), the CPU 11 proceeds to S33.

[0051] As shown in Figure 11, the electronic device 100 may have a liquid crystal display 141d in its display unit 14 instead of an organic EL display 141a, which includes a liquid crystal panel 141b and a backlight 141c. In this case, the illuminance sensor 171 may be located in a gap in the backlight 141c or the like. The backlight 141c may be an LED (Light Emitting Diode) or a plurality of miniLEDs.

[0052] In this case, the brightness value of the backlight 141c is changed between the first display mode and the second display mode. That is, in the second display mode, the brightness value should be lower than in the first display mode. On the other hand, the liquid crystal panel 141b is polarized to transmit light, at least in the area that overlaps with the illuminance sensor 171 in a planar view.

[0053] As shown in the flowchart of Figure 9, when illuminance measurement is performed in the first display mode, the backlight 141c only needs to be partially turned off around the illuminance sensor 171. For this purpose, the backlight 141c may be capable of separate illumination control for at least the area around the illuminance sensor 171 and the rest of the backlight. Alternatively, the backlight 141c may be capable of illumination control divided into multiple blocks from the outset.

[0054] As described above, the electronic device 100 of this embodiment includes a digital display screen 141 that displays digital information, an illuminance sensor 171 that measures the illuminance of ambient light, and a CPU 11 that adjusts the brightness of the digital display screen 141. The CPU 11 can switch between a first display mode and a second display mode in which the brightness is relatively lower than that of the first display mode. In the first display mode, the brightness of the digital display screen 141 is adjusted based on the illuminance last acquired during the second display mode, from among the illuminance measured by the illuminance sensor 171. In other words, the electronic device 100 does not acquire illuminance measurements, at least for the purpose of brightness adjustment, during the first display mode. In this case, the most recent, i.e., last illuminance value measured during the second display mode is continuously used. Since the first display mode is not usually maintained for a long time, it is unlikely that the digital display screen 141 will remain in a state where it is difficult to see, especially in a state where the brightness is insufficient, for a long time. Therefore, the electronic device 100 can adjust the brightness appropriately while further reducing the impact on the displayed image.

[0055] In the first display mode, the CPU 11 may stop acquiring illuminance measured by the illuminance sensor 171. The timing at which the CPU 11 adjusts the brightness of the digital display screen based on the last acquired illuminance in the second display mode may be immediately after transitioning from the second display mode to the first display mode. That is, when transitioning to the first display mode, the CPU 11 may adjust the brightness according to the first display mode immediately after the transition based on the illuminance measured immediately before the transition and maintain that setting. As described above, the display in the first display mode attracts the user's attention immediately after the transition, but often returns to the second display mode in a short time afterward. Therefore, if appropriate adjustments are made immediately after the transition, a stable and comfortable display state can be provided to the user without having to subsequently adjust the brightness value based on illuminance values ​​with low measurement accuracy.

[0056] The second display mode may be entered if a predetermined active condition related to the first display mode has not occurred for a set period of time or longer.

[0057] The illuminance sensor 171 may be located on the back side of the digital display screen 141 as viewed from the user's perspective. If the display unit 14 is light-transmitting, positioning the illuminance sensor 171 on its back side reduces the enlargement of the electronic device 100, especially in plan view.

[0058] In the second display mode, illuminance measurements may be acquired from the illuminance sensor 171 at predetermined first intervals. When switching from the second display mode to the first display mode, illuminance may also be measured before the switch. In other words, illuminance measurements only need to be acquired periodically at appropriate intervals during the second display mode, without unnecessarily increasing the processing load. On the other hand, when transitioning to the first display mode, acquiring illuminance measurements immediately before the transition makes it possible to refer to the most recent illuminance value after transitioning to the first display mode.

[0059] The digital display screen 141 may be an organic EL display 141a or a liquid crystal display 141d. In a self-emissive digital display screen 141, such as the organic EL display 141a, the brightness value of each pixel is directly controlled according to the display content, so the brightness can be easily reduced in the second display mode. On the other hand, even with a liquid crystal display 141d, the brightness of the backlight 141c can be reduced. Therefore, this electronic device 100 is less affected by the light emission of the digital display screen 141 when measuring illuminance in the second display mode.

[0060] If the digital display screen 141 is a liquid crystal display 141d, the CPU 11 may control the polarization of the liquid crystal display 141d so that it transmits light in at least the area that overlaps with the illuminance sensor 171 in a planar view. In other words, the electronic device 100 partially controls the polarization so that ambient light reaches the illuminance sensor 171 without obstruction, while reducing the brightness of the backlight 141c. This reduces discomfort related to user visibility, and makes it easier to obtain ambient light illuminance with greater accuracy, as the illuminance sensor 171 is less affected by either the liquid crystal panel 141b or the backlight 141c.

[0061] The CPU 11 may, while the first display mode is in progress, temporarily switch to a third display mode in which the brightness value of a portion of the digital display screen 141, including at least the area that overlaps with the illuminance sensor 171 in a plan view, is set to a reference value or lower, and acquire the measured value of the illuminance sensor 171. As described above, the first display mode does not usually last for long. However, depending on the situation, it may be better to acquire the illuminance even in the middle of the first display mode. In this case, instead of turning off the entire display image, the brightness can be reduced only in a portion of the area including the area that overlaps with the illuminance sensor 171, thereby acquiring the illuminance measurement while reducing the impact on the display. In particular, since the illuminance sensor 171 itself is often smaller than the digital display screen 141, the impact on the image tends to be small.

[0062] Before temporarily switching to the third display mode, the CPU 11 may switch to the third display mode without changing the displayed image on the digital display screen 141 if the brightness value of a portion of the digital display screen 141, including the area that overlaps with the illuminance sensor 171 in a plan view, is originally below the reference value. Since the displayed image is not changed, the electronic device 100 can effectively reduce the influence of the light emitted by the display unit 14 on the illuminance without affecting the displayed image, and can appropriately measure the illuminance due to ambient light.

[0063] The switching period to the third display mode may be less than or equal to twice the update interval of the displayed image on the digital display screen 141. Since the image update interval is shorter than the interval perceptible to human vision, a partial decrease in brightness value to this extent has little impact on the displayed image. Therefore, the electronic device 100 can adjust the brightness of the displayed image by appropriately acquiring illuminance information in near real-time while reducing the degradation of the image quality.

[0064] The brightness control method of this embodiment includes the following steps: (1) Determine whether the image displayed on the digital display screen 141 is in a first display mode or a second display mode with relatively lower brightness compared to the first display mode. (2) In the first display mode, adjust the brightness of the digital display screen 141 based on the last acquired illuminance in the second display mode from the illuminance of the ambient light measured by the illuminance sensor 171. This brightness control method reduces the influence of light emission from the display unit 14 of the device on brightness adjustment. On the other hand, this brightness control method allows for illuminance measurement with virtually no effect on the displayed image. Therefore, this brightness control method can appropriately adjust brightness while further reducing the impact on the displayed image.

[0065] By installing and executing the program 131 related to the above-described brightness control method on a computer, appropriate brightness adjustment becomes possible with a simple configuration controlled by the CPU 11.

[0066] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are possible. For example, the examples of setting an active state are not limited to those described above. For instance, the criteria for determining the attitude of the electronic device 100, which is presumed to be viewing the display, may be set loosely. Also, whether or not to transition to the first display mode when the display is updated may be set individually depending on the display content.

[0067] Furthermore, although the above explanation described an example where illuminance measurements are not acquired during the first display mode, this is not the only example. Illuminance measurements may be acquired, but the acquired measurements do not need to be reflected in the brightness setting. In this case, if the acquired measurements change significantly, the CPU 11 may switch to the third display mode.

[0068] Furthermore, although the illuminance was measured and the measured value acquired in synchronization with the TE signal or VSYNC signal in the above description, it is not limited to this. In the second display mode, the illuminance measured value may be acquired at appropriate intervals and timings. Immediately before switching to the first display mode, it is sufficient that the measured value acquired before actually switching to the first display mode is obtained. Also, if the illuminance measured value is originally acquired at short intervals, it is not necessary to acquire the illuminance measured value again immediately before switching to the first display mode. In addition, the image refresh in the electronic device 100 does not have to be based on the TE signal or VSYNC signal. Furthermore, although the brightness of the second display mode was set in the above description based on the acquired illuminance measured value in the second display mode, the brightness may be fixed at a minimum value in the second display mode.

[0069] Furthermore, although the above explanation used organic EL displays 141a and liquid crystal displays 141d as examples of digital display screens 141, other types of display screens may be used as long as the emitted light can affect illuminance measurement. For example, micro-LEDs may be used as self-emissive elements.

[0070] Furthermore, the contents of this disclosure can be applied as long as the illuminance sensor 171 is located in a place where the light emitted from the digital display screen 141 affects the measurement.

[0071] Furthermore, although the above explanation used an electronic watch, including a smartwatch, as an example of electronic device 100, it is not limited to this. It may be any other electronic device, and in particular, it may be an electronic device that is carried and moved by the user.

[0072] Furthermore, while the above description uses a storage unit 13 consisting of non-volatile memory such as flash memory as an example of a computer-readable medium for storing the program 131 related to brightness control of the present invention, the invention is not limited to these. Other computer-readable mediums that can be used include other non-volatile memories such as HDDs and MRAMs, and portable recording media such as CD-ROMs and DVD discs. In addition, a carrier wave can also be used as a medium for providing the program data according to the present invention via a communication line.

[0073] Furthermore, the specific configurations, structures, processing operations, and procedures shown in the above embodiments can be modified as appropriate without departing from the spirit of the present invention. The scope of the present invention includes the scope of the invention described in the claims and its equivalents. [Explanation of Symbols]

[0074] 11 CPU (control unit), 141 Digital display screen, 171 Illuminance sensor

Claims

1. Digital display screen, An illuminance sensor that measures the illuminance of ambient light, A control unit for adjusting the brightness of the digital display screen, Equipped with, The control unit can switch between a first display mode and a second display mode having a relatively lower brightness compared to the first display mode, and in the first display mode, it adjusts the brightness of the digital display screen based on the illuminance last acquired during the second display mode from the illuminance measured by the illuminance sensor. electronic equipment.

2. In the first display mode, the control unit stops acquiring the illuminance measured by the illuminance sensor, and the timing for adjusting the brightness of the digital display screen based on the last acquired illuminance in the second display mode is immediately after transitioning from the second display mode to the first display mode. The electronic device according to claim 1.

3. The electronic device according to claim 1, wherein the second display mode is entered when a predetermined active condition relating to the first display mode has not occurred for a set period of time or longer.

4. The electronic device according to claim 1, wherein the illuminance sensor is located on the back side of the digital display screen as viewed from the user's viewing side.

5. In the second display mode, illuminance measurements are acquired from the illuminance sensor at predetermined first intervals. When switching from the second display mode to the first display mode, the illuminance is measured before the switch. The electronic device according to claim 1.

6. The electronic device according to claim 1, wherein the digital display screen is an organic EL (Electro-Luminescent) display or a liquid crystal display.

7. The aforementioned digital display screen is a liquid crystal display. The control unit controls the polarization of the liquid crystal display so that it transmits light in at least the region that overlaps with the illuminance sensor in a plan view. The electronic device according to claim 6.

8. The electronic device according to claim 1, wherein the control unit temporarily switches to a third display mode during the continuation of the first display mode, in which the brightness value of a portion of the digital display screen, including at least an area that overlaps with the illuminance sensor in a plan view, is set to a reference value or less, and the measured value of the illuminance sensor is acquired.

9. The electronic device according to claim 8, wherein, before temporarily switching to the third display mode, if the brightness value of a part of the area is less than or equal to the reference value, the control unit switches to the third display mode without changing the display image on the digital display screen.

10. The electronic device according to claim 8, wherein the switching period to the third display mode is no more than twice the update interval of the display image on the digital display screen.

11. The system determines whether the image displayed on the digital display screen is in a first display mode or a second display mode with relatively lower brightness compared to the first display mode. In the first display mode, the brightness of the digital display screen is adjusted based on the last acquired illuminance of the ambient light measured by the illuminance sensor during the second display mode. Brightness control method.

12. Computers, Mode determination means for determining whether the image displayed on the digital display screen is in a first display mode or a second display mode with relatively lower brightness compared to the first display mode. In the first display mode, a first adjustment means adjusts the brightness of the digital display screen based on the last acquired illuminance during the second display mode, from among the illuminance of ambient light measured by the illuminance sensor. A program that makes something function as such.

Images