Electronic device and ambient light illuminance measurement method

Abstract

To calculate more accurate ambient light illuminance.SOLUTION: A semiconductor device (3) includes: a light measuring instrument (4); a storage device (5) that stores a first measurement value measured by the light measuring instrument (4) during a first measurement period (T1) in synchronization with a vertical synchronization signal (S1) of a display panel (2); and a communication interface (22) that transmits the first measurement value and a second measurement value to calculate light emission illuminance of a light emitting element (17R) based on the first measurement value and subtract a value based on the light emission illuminance from the second measurement value, measured by the light measuring instrument (4) during a second measurement period (T2).SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a semiconductor device, an electronic device, an ambient light illuminance measuring method, and a computer-readable recording medium, which are provided with a light measuring device arranged on the back side of a display panel to measure the ambient light illuminance of the display panel. [Background technology]

[0002] Illuminance sensors that measure ambient light illuminance are used to control the brightness of smartphone displays. Conventionally, illuminance sensors were placed above the display to measure ambient light illuminance, but as smartphone displays have become larger and full-screen displays, illuminance sensors have begun to be placed behind the smartphone display (back, under-display).

[0003] If an illuminance sensor is placed behind the display, the sensor will be illuminated by both ambient light and light emitted from the display. Therefore, the ambient light must be calculated by subtracting the light from the display from the output of the illuminance sensor.

[0004] There is known an electronic device that includes a display and an optical sensor disposed on the back side of the display for receiving ambient light that has passed through the display (Patent Document 1). This electronic device calculates the ambient light illuminance based on a count value of a first subframe and a count value of a second subframe obtained by integrating incident light of the optical sensor for a first subframe modulated with at least one modulation parameter and a second subframe modulated with at least one modulation parameter between vertical synchronization signals of the display. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] US Patent Application Publication No. 2021 / 0056896 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the above-mentioned conventional techniques have the problem that, because they do not take into account the timing of the display's light emission when it is turned on and off, it is not possible to accurately subtract the light from the display, making it difficult to calculate ambient light illuminance more accurately.

[0007] An object of one embodiment of the present invention is to provide a semiconductor device, an electronic device, an ambient light illuminance measuring method, and a computer-readable recording medium that are capable of calculating ambient light illuminance more accurately. [Means for solving the problem]

[0008] In order to solve the above problem, a semiconductor device according to one embodiment of the present invention includes a light measuring device arranged on the opposite side of a display surface of a display panel having self-luminous elements to measure the ambient light illuminance of the display panel, a memory device that stores first measurement values ​​measured by the light measuring device over multiple first measurement periods that are shorter than the on / off periods of the self-luminous elements in synchronization with a synchronization signal of the display panel, and a calculation unit that calculates the luminous illuminance of the self-luminous elements based on the first measurement values ​​stored in the memory device, and calculates the ambient light illuminance by subtracting a value based on the luminous illuminance from a second measurement period measured by the light measuring device over a second measurement period that is longer than the first measurement period.

[0009] In order to solve the above problem, another semiconductor device according to one embodiment of the present invention includes a light measuring device arranged on the opposite side of a display surface of a display panel having self-luminous elements to measure the ambient light illuminance of the display panel, a memory device that stores a plurality of first measurement values ​​measured by the light measuring device in a first measurement period that is shorter than the on / off period of the self-luminous elements in synchronization with a synchronization signal of the display panel, and a communication interface that transmits the first measurement values ​​and the second measurement values ​​to calculate the luminous illuminance of the self-luminous elements based on the first measurement values ​​and subtract a value based on the luminous illuminance from a second measurement value measured by the light measuring device in a second measurement period that is longer than the first measurement period.

[0010] In order to solve the above problem, an electronic device according to one embodiment of the present invention comprises a display panel having self-luminous elements and a semiconductor device arranged on the opposite side of the display surface of the display panel, wherein the semiconductor device comprises: a light measuring device for measuring the ambient light illuminance of the display panel; a memory device that stores a plurality of first measurement values ​​measured by the light measuring device in synchronization with a synchronization signal of the display panel during a first measurement period that is shorter than the on / off period of the self-luminous elements; and a calculation unit that calculates the luminous illuminance of the self-luminous elements based on the first measurement values ​​stored in the memory device, and calculates the ambient light illuminance by subtracting a value based on the luminous illuminance from a second measurement value measured by the light measuring device during a second measurement period that is longer than the first measurement period.

[0011] In order to solve the above problem, an ambient light illuminance measurement method according to one embodiment of the present invention is a method for measuring the ambient light illuminance of a display panel equipped with self-luminous elements, and includes a storage step of storing in a memory device a plurality of first measurement values ​​measured by a light measuring device arranged on the opposite side of the display surface of the display panel in synchronization with a synchronization signal of the display panel during a first measurement period that is shorter than the on / off period of the self-luminous elements, and a calculation step of calculating the luminous illuminance of the self-luminous elements based on the first measurement values ​​stored in the memory device, and calculating the ambient light illuminance by subtracting a value based on the luminous illuminance from a second measurement value measured by the light measuring device during a second measurement period that is longer than the first measurement period.

[0012] In order to solve the above-mentioned problems, a computer-readable recording medium according to one aspect of the present invention stores a program based on an ambient light illuminance measuring method according to one aspect of the present invention. [Effects of the Invention]

[0013] According to one embodiment of the present invention, it is possible to provide a semiconductor device, an electronic device, an ambient light illuminance measuring method, and a computer-readable recording medium that are capable of calculating ambient light illuminance more accurately. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a plan view of an electronic device according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line AA' shown in FIG. [Figure 3] FIG. 2 is a block diagram of a semiconductor device provided in the electronic device. [Figure 4] FIG. 10 is a block diagram of a modified example of the semiconductor device. [Figure 5] 4 is a cross-sectional view illustrating the relationship between ambient light around a display panel provided in the electronic device and light emission from self-luminous elements of the display panel. FIG. [Figure 6] 10 is a graph for explaining a measurement period of an optical measuring instrument provided in the semiconductor device. [Figure 7] 10 is a schematic diagram for explaining a mode of storing measurement data measured during the measurement period in a memory device provided in the semiconductor device. FIG. [Figure 8] 4 is a flowchart illustrating an operation of the electronic device. [Figure 9] FIG. 10 is a block diagram of another modified example of the semiconductor device. [Figure 10] FIG. 10 is a block diagram of yet another modified example of the semiconductor device. [Figure 11] 10 is a flowchart showing the operation of the electronic device according to the second embodiment. [Figure 12] 10 is a graph illustrating the operation of the electronic device according to the third embodiment. [Figure 13] 4 is a flowchart illustrating an operation of the electronic device. DETAILED DESCRIPTION OF THE INVENTION

[0015] [Embodiment 1] Hereinafter, one embodiment of the present invention will be described in detail.

[0016] Fig. 1 is a plan view of an electronic device 1 according to embodiment 1. Fig. 2 is a cross-sectional view taken along line AA' shown in Fig. 1.

[0017] The electronic device 1 includes a display panel 2 and a semiconductor device 3 arranged on the opposite side of the display surface 18 of the display panel 2. The electronic device 1 may be, for example, a portable electronic device such as a smartphone, game console, or watch, or an image display device such as a television, personal computer, or monitor. The display panel 2 includes a substrate 9, a TFT (Thin Film Transistor) layer 10 formed on the substrate 9, an organic EL (Electro-Luminescence) layer 11 formed on the TFT layer 10, and a cover glass 12 formed on the organic EL layer 11.

[0018] The organic EL layer 11 has a plurality of pixels 19 arranged in a matrix along the X direction and the Y direction. Each pixel 19 includes a red light emitting element 17R (self-light emitting element), a green light emitting element 17G (self-light emitting element), and a blue light emitting element 17B (self-light emitting element) arranged side by side along the X direction.

[0019] The display panel 2 further includes a gate driver 15 for controlling the operation timing of each of the light-emitting elements 17R, 17G, and 17B, a source driver 16 for supplying display data to each of the light-emitting elements 17R, 17G, and 17B, and a display circuit 13 for supplying a vertical synchronizing signal (VSYNC) S1 (synchronization signal) for controlling the operation timing and a signal indicating the light-emitting duty of each of the light-emitting elements 17R, 17G, and 17B to the gate driver 15 and the semiconductor device 3, and for supplying a display signal for each of the light-emitting elements 17R, 17G, and 17B to the source driver 16. Each of the light-emitting elements 17R, 17G, and 17B may be, for example, an OLED (organic light-emitting diode).

[0020] FIG. 3 is a block diagram of the semiconductor device 3 provided in the electronic device 1. As shown in FIG.

[0021] The semiconductor device 3 includes a light measuring device 4 for measuring the illuminance of ambient light around the display panel 2, a storage device 5 for storing the measurement values ​​measured by the light measuring device 4, an AD conversion circuit 20 for AD converting the measurement values ​​measured by the light measuring device 4, a control unit 21 for writing the measurement values ​​AD converted by the AD conversion circuit 20 into the storage device 5, and a control unit 21 for reading the measurement values ​​stored in the storage device 5 and The display circuit 13 controls the display panel 2 and has a communication interface 22 that transmits control signals to the source driver 16 to control the brightness of the light-emitting elements 17R, 17G, and 17B. The communication interface 22 is compliant with, for example, I2C (Inter-Integrated Circuit) or SPI (Serial Peripheral Interface).

[0022] Although the case where the communication interface 22 reads out the measurement values ​​stored in the storage device 5 has been described, the present invention is not limited to this. The control unit 21 may also read out the measurement values. Figure 4 is a block diagram of a semiconductor device 3A according to a modified example. Components similar to those described above are given the same reference numerals. Detailed descriptions of these components will not be repeated.

[0023] The semiconductor device 3A includes a control unit 21A. When the control unit 21A reads out the measurement values ​​stored in the storage device 5, the control unit 21A can write and read the measurement values ​​to and from the storage device 5, and the control unit 21A can also transmit the measurement values ​​read out from the storage device 5 to the communication interface 22, as shown in FIG.

[0024] The light measuring device 4 may or may not be provided for each of the plurality of pixels 19 .

[0025] The storage device 5 includes a first storage unit 6 that stores first measurement values ​​measured by the light measurement device 4 during a first measurement period T1 (FIG. 6) that is shorter than the on / off period of each of the light emitting elements 17R, 17G, and 17B in synchronization with a vertical synchronization signal S1 of the display panel 2, and a second storage unit 7 that stores second measurement values ​​measured by the light measurement device 4 during a second measurement period T2 (FIG. 6) that is longer than the first measurement period T1. The first storage unit 6 includes a memory array.

[0026] The display panel 2 has a calculation unit 8 that calculates the emission illuminance of each light-emitting element 17R, 17G, and 17B based on the first measurement value, and calculates the ambient light illuminance by subtracting a value based on the emission illuminance from a second measurement value measured by the light measuring instrument 4 during the second measurement period T2.

[0027] The calculation unit 8 may be built into the semiconductor device 3 as will be described later with reference to FIGS.

[0028] FIG. 5 is a cross-sectional view illustrating the relationship between ambient light 23 around the display panel 2 provided in the electronic device 1 and reflected light 24 from the display panel 2. As shown in FIG.

[0029] The optical measuring device 4 of the semiconductor device 3 receives ambient light 23 from the display panel 2 that passes through the display panel 2 and reflects light 24 emitted from each of the light-emitting elements 17R, 17G, and 17B of the display panel 2 and reflected by the cover glass 12. This poses a problem in that the emitted light illuminance of each of the light-emitting elements 17R, 17G, and 17B is superimposed on the ambient light illuminance that the optical measuring device 4 is intended to measure.

[0030] Fig. 6 is a graph illustrating the first measurement period T1 and the second measurement period T2 of the optical measuring instrument 4 provided in the semiconductor device 3. Fig. 7 is a schematic diagram illustrating the manner in which measurement data measured in the first measurement period T1 is stored in the memory device 5 provided in the semiconductor device 3. Fig. 8 is a flowchart illustrating the operation of the electronic device 1.

[0031] The optical measurement device 4 synchronizes with the vertical synchronization signal S1 (synchronization signal) of the display panel 2 and measures the first measurement value in a first measurement period T1 that is shorter than the on / off period T0 of each of the light emitting elements 17R, 17G, and 17B.

[0032] The on / off period T0 includes an off period 25 during which the light emission of each of the light-emitting elements 17R, 17G, and 17B is off, and an on period 26 during which the light emission is on. During the off period 25, only ambient light 23 from outside the display panel 2 is incident on the light measurement device 4. During the on period 26, reflected light 24 based on the light emitted from each of the light-emitting elements 17R, 17G, and 17B is added to the ambient light 23 and incident on the light measurement device 4. In the example shown in FIG. 6, the light emission of each of the light-emitting elements 17R, 17G, and 17B is completely off during the off period 25.

[0033] Therefore, when the first measurement period T1 is included in the off period 25, only the ambient light 23 is incident on the light measurement device 4. When the first measurement period T1 is included in the on period 26, the reflected light 24 is added to the ambient light 23 and incident on the light measurement device 4. Whether each of the multiple first measurement periods T1 is included in the off period 25 or the on period 26 can be determined based on the on / off period T0 and the light emission duty, which represents the ratio between the off period 25 and the on period 26.

[0034] The brightness of the display panel 2 is controlled by the light emitting duty of each of the light emitting elements 17R, 17G, and 17B. Based on a signal indicating the light emitting duty supplied from the display circuit 13, the control unit 21 of the semiconductor device 3 can identify at which address in the first memory unit 6 the first measurement value when each of the light emitting elements 17R, 17G, and 17B is on and the first measurement value when each of the light emitting elements 17R, 17G, and 17B is off is stored.

[0035] The dashed line extending in the horizontal direction relating to the ambient light 23 shown in FIG. 6 represents the level of a pitch-dark state in which the illuminance of the ambient light 23 is zero lux.

[0036] Then, the AD conversion circuit 20 AD converts the first measurement value measured by the optical measuring instrument 4 and supplies the converted value to the control unit 21. Next, the control unit 21 stores the first measurement value supplied from the AD conversion circuit 20 in the first memory unit 6 of the storage device 5 in order from the first address.

[0037] The addresses in the first memory unit 6 do not correspond to the pixels 19 of the light-emitting elements 17R, 17G, and 17B. It is common to provide a light measuring device 4 that is larger than the pixels 19 of the light-emitting elements 17R, 17G, and 17B. The first memory unit 6 stores a first measurement value that corresponds to the amount of light incident on the light measuring device 4, regardless of the number of pixels 19.

[0038] In this way, the first measurement values ​​are written into the first storage unit 6 in order from the leading address 0 during the first measurement period T1 in synchronization with the vertical synchronization signal S1. When the next vertical synchronization signal S1 is generated, the first measurement values ​​are again overwritten from the leading address.

[0039] For example, as shown in FIG. 7, if the first measurement period T1 synchronized with the vertical synchronization signal S1 is repeated 32 times from 0th to 31st, the 0th to 2nd first measurement periods T1 are OFF measurement periods T4 during which the light emission of each light-emitting element 17R, 17G, and 17B is OFF. The 5th to 7th first measurement periods T1 are ON measurement periods T3 during which the light emission is ON. The 9th to 11th first measurement periods T1 are OFF measurement periods T4 during which the light emission is OFF. The 13th to 15th first measurement periods T1 are ON measurement periods T3 during which the light emission is ON. The 17th to 19th first measurement periods T1 are OFF measurement periods T4 during which the light emission is OFF. The 21st to 23rd first measurement periods T1 are ON measurement periods T3 during which the light emission is ON. The 25th to 27th first measurement periods T1 are OFF measurement periods T4 during which the light emission is OFF. The 29th to 31st first measurement periods T1 are ON measurement periods T3 during which the light emission is ON.

[0040] The remaining third, fourth, eighth, twelfth, sixteenth, twentieth, twenty-fourth, and twenty-eighth first measurement periods T1 represent transient measurement periods T5 in which a transition from on to off or from off to on may occur during the first measurement periods T1. Therefore, the measured values ​​of these transient periods cannot be used in the calculation.

[0041] Furthermore, the optical measuring instrument 4 measures a second measurement value during a second measurement period T2 that is longer than the first measurement period T1. Then, the AD conversion circuit 20 AD converts the second measurement value measured by the optical measuring instrument 4 and supplies it to the control unit 21. Next, the control unit 21 stores the second measurement value supplied from the AD conversion circuit 20 in the second memory unit 7 of the storage device 5.

[0042] The second storage unit 7 stores the second measurement values ​​measured during the second measurement period T2. Every time a second measurement value is measured, the second measurement value is overwritten in the same second storage unit 7.

[0043] Then, the communication interface 22 transmits the first measurement value stored in the first storage unit 6 and the second measurement value stored in the second storage unit 7 to the calculation unit 8.

[0044] Next, the calculation unit 8 calculates the light emission illuminance of each light-emitting element 17R, 17G, and 17B based on the first measurement value transmitted from the communication interface 22, and calculates the ambient light illuminance by subtracting a value based on the light emission illuminance from the second measurement value transmitted from the communication interface 22.

[0045] The calculation unit 8 calculates the light emission illuminance of each of the light emitting elements 17R, 17G, and 17B by subtracting the first measurement value when each of the light emitting elements is off from the first measurement value when each of the light emitting elements is on, based on the light emitting duty of each of the light emitting elements 17R, 17G, and 17B.

[0046] The first memory unit 6 stores a measurement value obtained by adding together the reflected light 24 from each of the light-emitting elements 17R, 17G, and 17B and the ambient light 23 during the first measurement period T1. The second memory unit 7 stores a measurement value obtained by adding together the reflected light 24 from each of the light-emitting elements 17R, 17G, and 17B and the ambient light 23 during the second measurement period T2. However, during the first measurement periods T1 at the 0th to 2nd, 9th to 11th, 17th to 19th, and 25th to 27th timings when the light-emitting elements 17R, 17G, and 17B are not emitting light, the measurement value of the ambient light 23 is stored.

[0047] The control unit 21 determines address information for reading out the first measurement information from the first storage unit 6, taking into consideration the on / off information based on the light emitting duty of each of the light emitting elements 17R, 17G, and 17B. For example, the control unit 21 determines address information that specifies the address at which the first measurement value when each light emitting element is off is stored and the address at which the first measurement value when each light emitting element is on is stored.

[0048] The control unit 21 reads out the first measurement value from the first storage unit 6 using the determined address information.

[0049] The control unit 21 designates the first measurement value when each of the light-emitting elements 17R, 17G, and 17B is on (for example, the first measurement value at address 6 in the first storage unit 6) as OLED_ON to identify the address when the light-emitting element is on. The control unit 21 then designates the first measurement value when each of the light-emitting elements 17R, 17G, and 17B is off (for example, the first measurement value at address 1 in the first storage unit 6) as OLED_OFF to identify the address when the light-emitting element is off.

[0050] The calculation unit 8 preferably calculates an average value of the first measurement values ​​read from each OLED_ON address in the first storage unit 6. The calculation unit 8 also preferably calculates an average value of the first measurement values ​​read from each OLED_OFF address in the first storage unit 6. This makes it possible to obtain more stable OLED_ON and OLED_OFF values.

[0051] The calculation unit 8 calculates the light emission intensity OLED_mag of each light-emitting element 17R, 17G, and 17B using the first measurement value when each light-emitting element 17R, 17G, and 17B is on and the first measurement value when each light-emitting element 17R, 17G, and 17B is off, using the following equation (1). OLED_mag=OLED_on-OLED_off…(Equation 1), Then, the calculation unit 8 calculates the ambient light illuminance using the following (Equation 2).

[0052] Ambient light illuminance = Measurement value in second memory unit - OLDE_mag × (second measurement period T2 / (first measurement period T1 × 2)) ... (Equation 2) In this way, the calculation unit 8 calculates the light emission illuminance of each of the light-emitting elements 17R, 17G, and 17B by subtracting the first measurement value when each of the light-emitting elements 17R, 17G, and 17B is off from the first measurement value when each of the light-emitting elements 17R, 17G, and 17B is on, based on the light-emitting duty of each of the light-emitting elements 17R, 17G, and 17B.

[0053] The on / off period T0 includes an on period 26 in which each of the light emitting elements 17R, 17G, and 17B is in an on state, and an off period 25 in which each of the light emitting elements 17R, 17G, and 17B is in an off state.

[0054] A portion of the multiple first measurement periods T1 is an on-measurement period T3 measured during the on-period 26. Another portion of the multiple first measurement periods is an off-measurement period T4 measured during the off-period 25. The remainder of the multiple first measurement periods T1 is a transient measurement period T5 during which a transition from the on-period 26 to the off-period 25 or from the off-period 25 to the on-period 26 may occur.

[0055] The first storage unit 6 stores the plurality of first measurement values ​​in order from the first address.

[0056] The calculation unit 8 then calculates the emission illuminance of each of the light-emitting elements 17R, 17G, and 17B by subtracting the first measurement value in the OFF measurement period T4 from the first measurement value in the ON measurement period T3.

[0057] The calculation unit 8 calculates the ambient light illuminance by subtracting a value based on the light emission illuminance, the first measurement period T1, and the second measurement period T2 from the second measurement value.

[0058] FIG. 8 is a flowchart showing the operation of the electronic device 1.

[0059] First, the optical measuring device 4 measures first measurement values ​​during a first measurement period T1 synchronized with the vertical synchronization signal S1 of the display panel 2. Then, the control unit 21 stores the first measurement values ​​in the first storage unit 6 in order from the first address.

[0060] Next, the light measuring device 4 measures a second measurement value during a second measurement period T2 synchronized with the vertical synchronization signal S1. The control unit 21 stores the second measurement value in the second memory unit 7. The second measurement period T2 may be equal to or shorter than the interval between vertical synchronization signals S1, or may be longer than the interval between vertical synchronization signals S1. Generally, indoor light is superimposed with fluctuations at frequencies of 100 Hz and 120 Hz, which are double the commercial power frequency of 50 Hz and 60 Hz. Therefore, setting the second measurement period T2 to 100 ms can eliminate the effects of these frequency fluctuations.

[0061] Then, the control unit 21 determines the address from which the first storage unit 6 is to be read, using the light emitting duty of each of the light emitting elements 17R, 17G, and 17B (step S11).

[0062] Thereafter, the control unit 21 reads the first measurement values ​​OLED_ON and OLED_OFF from the first storage unit 6, and reads the second measurement value from the second storage unit 7 (step S12).

[0063] Then, the communication interface 22 transmits the first measurement value OLED_ON, the first measurement value OLED_OFF, and the second measurement value read by the control unit 21 to the calculation unit 8.

[0064] Next, the calculation unit 8 calculates the light emission intensity OLED_mag of each of the light emitting elements 17R, 17G, and 17B based on the first measurement value OLED_ON and the first measurement value OLED_OFF transmitted from the communication interface 22 (step S13).

[0065] Thereafter, the calculation unit 8 calculates the ambient light illuminance based on the above (Equation 2) using the second measurement value transmitted from the communication interface 22 and the light emission intensity OLED_mag of each of the light emitting elements 17R, 17G, and 17B (step S14).

[0066] 9 is a block diagram of a semiconductor device 3B according to another modification. Components similar to those described above are designated by the same reference numerals. Detailed description of these components will not be repeated.

[0067] The semiconductor device 3B includes a calculation unit 8. The calculation unit 8 calculates the emission illuminance of each of the light-emitting elements 17R, 17G, and 17B based on the first measurement value stored in the first storage unit 6, and calculates the ambient light illuminance by subtracting a value based on the emission illuminance from the second measurement value stored in the second storage unit 7. The communication interface 22 transmits the ambient light illuminance calculated by the calculation unit 8 to the display circuit 13 that controls the display panel 2.

[0068] In this way, the calculation unit 8 may be provided in the semiconductor device 3A instead of the display panel 2.

[0069] 10 is a block diagram of a semiconductor device 3C according to yet another modification. Components similar to those described above are given the same reference numerals. Detailed description of these components will not be repeated.

[0070] The semiconductor device 3C includes a control unit 21C. The control unit 21C writes and reads measurement values ​​to and from the storage device 5, and supplies the measurement values ​​read from the storage device 5 to the calculation unit 8. The control unit 21C then supplies the ambient light illuminance calculated by the calculation unit 8 to the communication interface 22. The communication interface 22 then transmits the ambient light illuminance calculated by the calculation unit 8 to the display circuit 13 that controls the display panel 2.

[0071] [Embodiment 2] Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals will be used to designate components having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0072] FIG. 11 is a flowchart showing the operation of the electronic device according to the second embodiment.

[0073] In the second embodiment, the ambient light illuminance is calculated by reading measurement values ​​for all first measurement periods T1 during the vertical synchronization signal S1 without having address information synchronized with the vertical synchronization signal S1.

[0074] First, the operation of the electronic device according to the second embodiment will be described when it includes the semiconductor device 3C shown in Fig. 10. The control unit 21C reads all of the first measurement values ​​from addresses 0 to 31 within the period between vertical synchronization signals S1 that are stored in the first storage unit 6 (step S21). Then, the calculation unit 8 selects the maximum and minimum values ​​of all of the first measurement values ​​within the period between vertical synchronization signals S1 (step S22).

[0075] Next, the calculation unit 8 sets the maximum value as the first measurement value OLED_ON, sets the minimum value as the first measurement value OLED_OFF, and calculates the emission intensity OLED_mag of each of the light-emitting elements 17R, 17G, and 17B based on the first measurement values ​​OLED_ON and OLED_OFF (step S23).

[0076] Thereafter, the calculation unit 8 calculates the ambient light illuminance using the second measurement value and the light emission intensity OLED_mag of each of the light emitting elements 17R, 17G, and 17B based on the following (Equation 2) (step S24).

[0077] Ambient light illuminance = Measurement value in second memory unit - OLDE_mag × (second measurement period T2 / (first measurement period T1 × 2)) ... (Equation 2) Then, the communication interface 22 transmits the ambient light illuminance calculated by the calculation unit 8 to the display circuit 13 that controls the display panel 2.

[0078] 9, the calculation unit 8 reads all of the first measurement values ​​stored in the first storage unit 6. When the electronic device includes the semiconductor device 3 of FIG. 3, the communication interface 22 reads all of the first measurement values ​​in the first storage unit 6. When the electronic device includes the semiconductor device 3A of FIG. 4, the control unit 21A reads all of the first measurement values ​​in the first storage unit 6.

[0079] In this way, the calculation unit 8 selects the maximum and minimum values ​​from the first measurement values ​​read out from the first memory unit 6, and calculates the emission illuminance of each light-emitting element 17R, 17G, and 17B by subtracting the minimum value from the maximum value.

[0080] [Embodiment 3] Fig. 12 is a graph for explaining the operation of the electronic device according to embodiment 3. Fig. 13 is a flowchart showing the operation of the electronic device. Components similar to those described above are given the same reference numerals. Detailed description of these components will not be repeated.

[0081] In the third embodiment, a method for calculating the ambient light illuminance when the light emission of each of the light emitting elements 17R, 17G, and 17B is not completely turned off will be described.

[0082] 12 shows an example in which the light emission of each of the light-emitting elements 17R, 17G, and 17B is not completely turned off during the off period 25. In this case, even during the off period 25, reflected light 24 based on the light emission from each of the light-emitting elements 17R, 17G, and 17B is added to the ambient light 23 and enters the light measuring instrument 4, so that the ambient light illuminance is always compensated for using a predetermined compensation coefficient based on the light that enters the light measuring instrument 4.

[0083] The electronic device according to the third embodiment will be described by taking as an example a case where the electronic device includes the semiconductor device 3C shown in FIG.

[0084] First, the optical measurement device 4 measures a first measurement value during a first measurement period T1 synchronized with the vertical synchronization signal S1 of the display panel 2, and measures a second measurement value during a second measurement period T2 synchronized with the vertical synchronization signal S1. Then, the control unit 21C stores the first measurement values ​​in order from the leading address in the first memory unit 6, and the control unit 21C stores the second measurement values ​​in the second memory unit 7. Then, the control unit 21C determines the address from which to read data in the first memory unit 6 using the light emitting duties of each of the light emitting elements 17R, 17G, and 17B (step S31).

[0085] Thereafter, the control unit 21C reads the first measurement value OLED_ON and the first measurement value OLED_OFF from the first storage unit 6, and reads the second measurement value from the second storage unit 7 (step S32).

[0086] Next, the calculation unit 8 calculates the light emission intensity OLED_mag of each of the light emitting elements 17R, 17G, and 17B based on the first measurement value OLED_ON and the first measurement value OLED_OFF (step S33).

[0087] Thereafter, the calculation unit 8 calculates the ambient light illuminance using the second measurement value and the light emission intensity OLED_mag of each of the light emitting elements 17R, 17G, and 17B based on the following (Equation 3) (step S34).

[0088] Ambient light illuminance = Measurement value in second memory unit - OLDE_mag × (second measurement period T2 / (first measurement period T1 × 2)) - compensation coefficient ... (Equation 3) The compensation coefficient is a coefficient corresponding to the light that is always incident on the light measuring device 4 during both the off period 25 and the on period 26. The compensation coefficient is a value that depends on the size of the light measuring device 4 and the luminance of the display panel 2, and is a value that is determined in advance by actual measurements.

[0089] In this way, the calculation unit 8 calculates the ambient light illuminance based on the compensation coefficient for compensating for the influence of light constantly input to the light measuring instrument 4 when the light emission of each of the light-emitting elements 17R, 17G, and 17B is not completely turned off.

[0090] [Software implementation example] The functions of the calculation unit 8 and the control unit 21 (hereinafter referred to as the "device") of the electronic device 1 are realized by a program for causing a computer to function as the device, and by a program for causing a computer to function as each control block of the device.

[0091] In this case, the device includes a computer having at least one control device (e.g., a processor) and at least one storage device (e.g., a memory) as hardware for executing the program. The control device and storage device execute the program, thereby realizing the functions described in each of the above embodiments.

[0092] The program may be non-transitory and may be recorded on one or more computer-readable recording media. The recording media may or may not be included in the device. In the latter case, the program may be supplied to the device via any wired or wireless transmission medium.

[0093] Furthermore, some or all of the functions of the control blocks can be realized by logic circuits. For example, an integrated circuit in which a logic circuit that functions as each of the control blocks is formed is also included in the scope of the present invention. In addition, the functions of the control blocks can also be realized by, for example, a quantum computer.

[0094] 〔summary〕 The semiconductor device 3A according to aspect 1 of the present invention includes a light measuring device 4 arranged on the side opposite to the display surface 18 of a display panel 2 having self-luminous elements (each of the light-emitting elements 17R, 17G, and 17B) for measuring the ambient light illuminance of the display panel 2, a memory device 5 that stores a first measurement value measured by the light measuring device 4 in synchronization with a synchronization signal (vertical synchronization signal S1) of the display panel 2 during a first measurement period T1 that is shorter than the on / off period T0 of the self-luminous elements (each of the light-emitting elements 17R, 17G, and 17B), and a calculation unit 8 that calculates the luminance of the self-luminous elements (each of the light-emitting elements 17R, 17G, and 17B) based on the first measurement value stored in the memory device 5, and calculates the ambient light illuminance by subtracting a value based on the luminance illuminance from a second measurement period T2 measured by the light measuring device 4 during a second measurement period T2 that is longer than the first measurement period T1.

[0095] According to the above configuration, a light measuring device disposed on the opposite side of a display surface of a display panel including self-luminous elements measures a first measurement value in a first measurement period that is shorter than the on / off period of the self-luminous elements in synchronization with a synchronization signal of the display panel. The first measurement value measured by the light measuring device is then stored in a storage device. Next, the emission illuminance of the self-luminous elements is calculated based on the first measurement value stored in the storage device. Thereafter, the ambient light illuminance is calculated by subtracting a value based on the emission illuminance from a second measurement value measured by the light measuring device in a second measurement period that is longer than the first measurement period.

[0096] Therefore, the light emission illuminance of the self-luminous element can be accurately subtracted from the second measurement value measured by the light measuring instrument during the second measurement period based on the synchronization signal of the display panel, thereby realizing a semiconductor device that can calculate ambient light illuminance more accurately.

[0097] In the semiconductor device 3A according to aspect 2 of the present invention, in the above aspect 1, it is preferable that the calculation unit 8 calculates the light emitting illuminance of the light emitting elements (each of the light emitting elements 17R, 17G, and 17B) based on the light emitting duty of the light emitting elements (each of the light emitting elements 17R, 17G, and 17B) by subtracting a first measurement value when the light emitting elements (each of the light emitting elements 17R, 17G, and 17B) are off from a first measurement value when the light emitting elements (each of the light emitting elements 17R, 17G, and 17B) are on.

[0098] According to the above configuration, it is possible to accurately subtract the light emission illuminance of the self-luminous element based on the light emission duty of the self-luminous element.

[0099] In the semiconductor device 3A according to aspect 3 of the present invention, in the above aspect 1, it is preferable that the calculation unit reads out the first measurement values ​​stored in the memory device, selects the maximum and minimum values ​​from the read out first measurement values, and calculates the luminous illuminance of the self-luminous element by subtracting the minimum value from the maximum value.

[0100] According to the above configuration, address information of the first measurement value based on the synchronization signal of the display panel and the light emitting duty of the self-luminous elements is not required, so that the light emitting illuminance of the self-luminous elements can be subtracted with a simple configuration.

[0101] In the semiconductor device 3A according to aspect 4 of the present invention, in any one of aspects 1 to 5 above, it is preferable that the calculation unit 8 calculates the ambient light illuminance based on a compensation coefficient for compensating for the influence of light that is constantly input to the light measuring instrument 4 when the light emission of the self-luminous elements (each of the light-emitting elements 17R, 17G, and 17B) is not completely turned off.

[0102] According to the above configuration, it is possible to calculate the ambient light illuminance of a display panel that includes self-luminous elements whose illuminance does not become zero during the off period.

[0103] A semiconductor device 3A according to a fifth aspect of the present invention is the semiconductor device 3A of the second aspect, wherein the on / off period T0 includes an on period 26 in which the self-luminous elements (each of the light-emitting elements 17R, 17G, and 17B) are on and an off period 25 in which the self-luminous elements (each of the light-emitting elements 17R, 17G, and 17B) are off, and a part of the plurality of first measurement periods T1 is an on measurement period T3 measured in the on period 26, and another part of the plurality of first measurement periods T1 is an off measurement period T4 measured in the off period 25. It is preferable that the remaining of the plurality of first measurement periods T1 is a transient measurement period T5 in which a transition from the on period 26 to the off period 25 or from the off period 25 to the on period 26 may occur, the memory device 5 stores the plurality of first measurement values ​​in order from the starting address, and the calculation unit 8 calculates the light emission illuminance of the self-luminous elements (each of the light-emitting elements 17R, 17G, and 17B) by subtracting the first measurement value of the off measurement period T4 from the first measurement value of the on measurement period T3.

[0104] According to the above configuration, it is possible to subtract the first measurement value when the self-luminous element is off from the first measurement value when the self-luminous element is on.

[0105] In the semiconductor device 3A according to aspect 6 of the present invention, in the above aspect 2, it is preferable that the calculation unit 8 calculates the ambient light illuminance by subtracting a value based on the light emission illuminance, the first measurement period T1, and the second measurement period T2 from the second measurement value.

[0106] According to the above configuration, it is possible to calculate the ambient light illuminance more accurately.

[0107] In the semiconductor device 3A according to aspect 7 of the present invention, in any one of aspects 1 to 6 above, it is preferable that the memory device 5 includes a first memory unit 6 that stores the first measurement value and a second memory unit 7 that stores the second measurement value.

[0108] According to the above configuration, the ambient light illuminance can be calculated based on the first measurement value stored in the first storage unit and the second measurement value stored in the second storage unit.

[0109] Another semiconductor device 3 relating to aspect 8 of the present invention includes a light measuring device 4 arranged on the opposite side of the display surface 18 of a display panel 2 having self-luminous elements (each light-emitting element 17R, 17G, 17B) for measuring the ambient light illuminance of the display panel 2, a memory device 5 that stores a plurality of first measurement values ​​measured by the light measuring device 4 in synchronization with a synchronization signal (vertical synchronization signal S1) of the display panel 2 during a first measurement period T1 that is shorter than the on / off period T0 of the self-luminous elements (each light-emitting element 17R, 17G, 17B), and a communication interface 22 that transmits the first measurement values ​​and the second measurement values ​​to calculate the luminous illuminance of the self-luminous elements (each light-emitting element 17R, 17G, 17B) based on the first measurement values ​​and to subtract a value based on the luminous illuminance from a second measurement value measured by the light measuring device 4 during a second measurement period T2 that is longer than the first measurement period T1.

[0110] An electronic device 1 according to a ninth aspect of the present invention comprises a display panel 2 having self-emitting elements (each of the light-emitting elements 17R, 17G, and 17B) and a semiconductor device 3 arranged on the opposite side of the display surface 18 of the display panel 2, wherein the semiconductor device 3 comprises a light measuring device 4 for measuring the ambient light illuminance of the display panel 2, a memory device 5 for storing a plurality of first measurement values ​​measured by the light measuring device 4 in synchronization with a synchronization signal (vertical synchronization signal S1) of the display panel 2 during a first measurement period T1 that is shorter than the on / off period T0 of the self-emitting elements (each of the light-emitting elements 17R, 17G, and 17B), and a calculation unit 8 for calculating the luminance illuminance of the self-emitting elements (each of the light-emitting elements 17R, 17G, and 17B) based on the first measurement values ​​stored in the memory device 5, and for calculating the ambient light illuminance by subtracting a value based on the luminance illuminance from a second measurement period T2 measured by the light measuring device 4 during a second measurement period T2 that is longer than the first measurement period T1.

[0111] The ambient light illuminance measurement method of aspect 10 of the present invention is a method for measuring the ambient light illuminance of a display panel 2 equipped with self-luminous elements (each of the light-emitting elements 17R, 17G, and 17B), and includes a storage step of storing in a memory device 5 a plurality of first measurement values ​​measured by a light measuring device 4 arranged on the opposite side of the display surface 18 of the display panel 2 in synchronization with a synchronization signal (vertical synchronization signal S1) of the display panel 2 during a first measurement period T1 that is shorter than the on / off period T0 of the self-luminous elements (each of the light-emitting elements 17R, 17G, and 17B), and a calculation step of calculating the emission illuminance of the self-luminous elements (each of the light-emitting elements 17R, 17G, and 17B) based on the first measurement values ​​stored in the memory device 5, and calculating the ambient light illuminance by subtracting a value based on the emission illuminance from a second measurement period T2 measured by the light measuring device 4 during a second measurement period T2 that is longer than the first measurement period T1.

[0112] A computer-readable recording medium according to an eleventh aspect of the present invention stores a program based on the ambient light illuminance measuring method according to the eighth aspect of the present invention.

[0113] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment. [Explanation of symbols]

[0114] 1 Electronic equipment 2 Display panel 3. Semiconductor Devices 4 Light measuring instrument 5 Storage device 6 1st memory section 7 2nd memory section 8 Calculation section 17R Red light-emitting element (self-emitting element) 17G Green light-emitting element (self-emitting element) 17B Blue light-emitting element (self-emitting element) 18 Display surface 22 Communication Interface 23 Ambient light 25 Off Period 26 On period S1 Vertical sync signal (sync signal) T0 On / Off Period T1 First measurement period T2 Second measurement period T3 On measurement period T4 Off measurement period T5 transient measurement period

Claims

1. a display panel having self-luminous elements; a semiconductor device disposed on the opposite side of the display surface of the display panel; The semiconductor device is a light measuring device arranged to measure the ambient light illuminance of the display panel; a storage device that stores a plurality of first measurement values ​​measured by the light measurement device in a plurality of first measurement periods that are shorter than the on / off periods of the self-luminous elements in synchronization with a synchronization signal of the display panel; a calculation unit that calculates the light emission illuminance of the self-luminous element based on a first measurement value stored in the storage device, and calculates the ambient light illuminance by subtracting a value based on the light emission illuminance from a second measurement value measured by the light measuring device over a second measurement period that is longer than the first measurement period.

2. The electronic device described in claim 1, wherein the calculation unit calculates the light emitting illuminance of the light emitting element by subtracting a first measurement value when the light emitting element is off from a first measurement value when the light emitting element is on, based on the light emitting duty of the light emitting element.

3. The electronic device according to claim 1, wherein the calculation unit reads out the first measurement values ​​stored in the storage device, selects the maximum and minimum values ​​from the read out first measurement values, and calculates the luminous illuminance of the self-luminous element by subtracting the minimum value from the maximum value.

4. The electronic device according to claim 1 , wherein the calculation unit calculates the ambient light illuminance based on a compensation coefficient for compensating for the influence of light constantly input to the light measuring device when the light emission of the light-emitting element is not completely turned off.

5. the on-off period includes an on-period in which the self-luminous element is in an on-state and an off-period in which the self-luminous element is in an off-state, some of the plurality of first measurement periods are on-measurement periods in which measurement is made during the on-periods, another portion of the plurality of first measurement periods are off-measurement periods in which measurement is made during the off-periods, and the remainder of the plurality of first measurement periods are transient measurement periods in which a transition from the on-period to the off-period or from the off-period to the on-period may occur; the storage device stores the plurality of first measurement values ​​in order from a leading address; The electronic device according to claim 2 , wherein the calculation unit calculates the light emission illuminance of the self-luminous element by subtracting the first measurement value in the off-measurement period from the first measurement value in the on-measurement period.

6. The electronic device according to claim 2 or 4, wherein the calculation unit calculates the ambient light illuminance by subtracting a value based on the light emission illuminance, the first measurement period, and the second measurement period from the second measurement value.

7. The electronic device according to claim 1 , wherein the storage device includes a first storage unit that stores the first measurement value and a second storage unit that stores the second measurement value.

8. a display panel having self-luminous elements; a semiconductor device disposed on the opposite side of the display surface of the display panel; The semiconductor device is a light measuring device arranged to measure the ambient light illuminance of the display panel; a storage device that stores a plurality of first measurement values ​​measured by the light measurement device in a first measurement period that is shorter than an on / off period of the self-luminous elements in synchronization with a synchronization signal of the display panel, and a second measurement value measured by the light measurement device in a second measurement period that is longer than the first measurement period; the display panel includes a calculation unit that calculates light emission illuminance of the self-luminous element based on the first measurement value and subtracts a value based on the light emission illuminance from the second measurement value; The electronic device wherein the semiconductor device further includes a communication interface that transmits the first measurement value and the second measurement value to the calculation unit.

9. An ambient light illuminance measurement method for measuring the ambient light illuminance of a display panel having self-luminous elements, comprising: a storage step of storing a plurality of first measurement values ​​measured by a light measuring device disposed on an opposite side of a display surface of the display panel in a first measurement period that is shorter than an on / off period of the self-luminous elements in synchronization with a synchronization signal of the display panel; and calculating the light emission illuminance of the self-luminous element based on a first measurement value stored in the storage device, and calculating the ambient light illuminance by subtracting a value based on the light emission illuminance from a second measurement value measured by the light measuring instrument over a second measurement period longer than the first measurement period.

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