Lighting apparatus, control method for lighting apparatus, storage medium, and program product

Abstract

The invention discloses a lighting apparatus, a control method for the lighting apparatus, a storage medium, and a program product. The lighting apparatus includes: a light source; a capacitor for storing energy that causes the light source to emit light; at least one processor; and a memory coupled to the processor, the memory storing instructions that, when executed by the processor, cause the processor to function as: a charging unit for charging the capacitor with the battery; a detection unit for detecting the voltage of the capacitor; and a control unit for controlling a light emission operation of the light source based on a change amount of the voltage of the capacitor.

Description

Technical Field

[0001] Aspects of the present embodiment relate to a lighting device, a control method used for the lighting device, and a storage medium. Background Art

[0002] In a lighting device (so-called flash device) which is one of the accessories such as a digital camera, a discharge tube used as a light source generates heat due to a light emission operation, and components of a circuit and a battery also generate heat due to a discharge during light emission and a charge for light emission preparation. Regarding heat generation from the discharge tube, a control component is provided for appropriately controlling a temperature rise of an optical panel arranged in front of the discharge tube so that the optical panel is within a temperature range in which the optical panel can be safely used (for example, see Japanese Unexamined Patent Application Publication No. 2021-60558). In addition, a control component is provided for controlling an operation of a circuit so that various electronic components and electrical components constituting the circuit are within a temperature range in which the various electronic components and electrical components constituting the circuit can be safely used (for example, see Japanese Unexamined Patent Application Publication No. 2017-62275).

[0003] Generally, in a lighting device that emits a flash such as a flash device, a specific amount of energy (charge) is stored in a capacitor, and then the stored energy is supplied to a discharge tube at once to generate a flash. Therefore, the capacitor is charged using a battery. A nickel-metal hydride battery or an alkaline battery is generally used in a flash device. However, since the battery has an internal resistance, when the capacitor is charged by the battery, the battery generates heat, resulting in a temperature rise of the battery. As a means for suppressing an internal temperature rise of the flash device, it is desired to suppress a temperature rise of the battery, but Japanese Unexamined Patent Application Publication No. 2021-60558 and Japanese Unexamined Patent Application Publication No. 2017-62275 do not discuss a temperature rise of the battery. On the other hand, if the execution of a charging operation is excessively suppressed in order to suppress a temperature rise of the battery, there will be a problem that light cannot be emitted at a desired shooting timing. Summary of the Invention

[0004] A first aspect of the present embodiment provides a lighting device including: a light source; a capacitor for storing energy for causing the light source to emit light; at least one processor; and a memory coupled to the processor, the memory storing instructions which, when executed by the processor, cause the processor to function as: a charging unit for charging the capacitor using a battery; a detection unit for detecting a voltage of the capacitor; and a control unit for controlling a light emission operation of the light source based on a change amount of the voltage of the capacitor.

[0005] Other features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. Brief Description of the Drawings

[0006] Figure 1 is a block diagram showing a schematic configuration of a flash device according to an embodiment.

[0007] Figure 2 shows Figure 1 a cross-sectional view showing a schematic configuration of the flash device shown.

[0008] Figure 3 is a flowchart of a light emission process executed in Figure 1 the flash device shown.

[0009] Figure 4 is a flowchart of a state confirmation process executed in S302.

[0010] Figure 5 is a flowchart of a charging time control process executed in S305.

[0011] Figure 6A is a flowchart of a first gradient determination process executed in S505, and Figure 6B is a flowchart of a second gradient determination process executed in S507.

[0012] Figure 7 is a graph showing the charging characteristics of the main capacitor for each type of battery.

[0013] Figure 8 is Figure 7 a partial enlarged view of.

[0014] Figure 9 is a diagram illustrating the relationship between the type of battery, the voltage of the main capacitor, and the first to fourth thresholds. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] Embodiments will be described in detail below with reference to the accompanying drawings. Note that the following embodiments are not intended to limit the scope of the claimed disclosure. In the embodiments, multiple features are described, but the disclosure is not limited to requiring all such features, and multiple such features can be appropriately combined. Further, in the drawings, the same reference numerals are given to the same or similar configurations, and redundant descriptions thereof are omitted.

[0016] Embodiments of the present disclosure will be described in detail below with reference to the drawings. Here, as a lighting device according to the present embodiment, a flash device that can be attached to a imaging device such as a digital camera as an accessory or detached from the imaging device will be adopted.

[0017] Figure 1 is a block diagram showing a schematic configuration of a flash device 100 according to the present embodiment. Figure 2It is a cross-sectional view showing a schematic configuration of the flash device 100. It should be noted that Figure 1 and Figure 2 the same reference numerals in

[0018] denote the same components. The flash device 100 includes a main body portion 100a and a light emitting unit 100b. The main body portion 100a is configured to be attached to / detached from an attachment / detachment portion of a camera device (not shown). The light emitting unit 100b is rotatable relative to the main body portion 100a in the vertical direction (up and down direction) and the horizontal direction (lateral direction). It should be noted that the vertical direction and the horizontal direction refer to the vertical direction and the horizontal direction when the camera device to which the flash device 100 is attached is held in a normal position and viewed from the front.

[0019] The flash device 100 includes an FPU 101, a battery 200, a boost circuit block 102, a trigger circuit 103, a light emission control circuit 105, a discharge tube 104, a photodiode 106, an integration circuit 107, a comparator 108, and an AND gate 109. In addition, the flash device 100 includes a reflector 110, an optical panel 111, an input unit 113, a display unit 114, a zoom drive circuit 115, a camera connection terminal 116, and a cooling unit 117. The discharge tube 104 and the reflector 110 constitute a reflector unit 112.

[0020] The FPU 101 is a microcomputer that comprehensively controls each unit (each component) of the flash device 100. The FPU 101 is configured as a single-chip integrated circuit (single-chip IC) having a built-in microcomputer including a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), an input / output control circuit (I / O control circuit), a multiplexer, a timer circuit, an electrically erasable programmable read-only memory (EEPROM), an A / D converter, a D / A converter, etc. The battery 200 serves as a power source (VBAT) for the flash device 100. The boost circuit block 102 includes a booster 102a, resistors 102b and 102c for voltage detection, and a main capacitor 102d. The boost circuit block 102 raises the voltage of the battery 200 to several hundred volts by the booster 102a and stores the energy (charge) for light emission in the main capacitor 102d. It should be noted that the voltage (charging voltage) of the main capacitor 102d is divided by the resistors 102b and 102c, and the divided voltage is input to the A / D conversion terminal MCV_AD of the FPU 101.

[0021] The trigger circuit 103 applies a pulsed voltage to the discharge tube 104 to excite the discharge tube 104. The light emission control circuit 105 controls the start and stop of the light emission of the discharge tube 104. The discharge tube 104 (light source) is excited by receiving a pulsed voltage of several kilovolts applied from the trigger circuit 103, and emits a flash by using the energy stored in the main capacitor 102d.

[0022] The photodiode 106 is a sensor that receives the light emitted from the discharge tube 104, and receives the light emitted from the discharge tube 104 directly or via a glass fiber or the like. The integration circuit 107 integrates the light reception current of the photodiode 106, and inputs the output to the inverting input terminal of the comparator 108 and the A / D converter terminal INT_AD of the FPU 101. The non-inverting input terminal of the comparator 108 is connected to the D / A converter terminal INT_DAC in the FPU 101, and the output of the comparator 108 is connected to one input terminal of the AND gate 109. The other input terminal of the AND gate 109 is connected to the light emission control terminal FL_START of the FPU 101, and the output of the AND gate 109 is input to the light emission control circuit 105.

[0023] The light emitting unit 100b mainly includes a discharge tube 104, a reflector 110, and an optical panel 111, and the irradiation direction of the light emitted from the discharge tube 104 is changed by rotation with respect to the main body portion 100a. The reflector 110 reflects the light emitted from the discharge tube 104 and guides the light in a predetermined direction. The optical panel 111 is included in a zoom optical system (not shown), and is incorporated such that the relative position (zoom position) with respect to the reflector unit 112 can be changed. By changing the relative position between the reflector unit 112 and the optical panel 111, the irradiation angle of the flash device 100 can be changed, and the guide number can be changed.

[0024] The input unit 113 includes a power switch, a mode setting switch for setting the operation mode of the flash device 100 including the drive setting of the cooling unit 117 in response to a user operation, setting buttons for setting various other parameters in response to a user operation, and the like. The FPU 101 receives signals from the input unit 113 and performs various processes. The display unit 114 includes a liquid crystal panel and a light emitting element, and displays various states of the flash device 100.

[0025] The zoom drive circuit 115 includes a zoom detection unit 115a and a zoom drive unit 115b. The zoom detection unit 115a detects information related to the relative position between the reflector unit 112 and the optical panel 111 by using an encoder or the like. The zoom drive unit 115b includes a motor that moves the reflector unit 112. The FPU 101 calculates the movement amount of the reflector unit 112 of the zoom drive unit 115b by using the focal length information of the shooting lens that can be obtained via the imaging device.

[0026] The camera connection terminal 116 includes a plurality of terminals connected to the imaging device. Specifically, the camera connection terminal 116 includes an SCLK_S terminal for synchronizing communication between the imaging device and the flash device 100, and a GND terminal for electrically connecting the imaging device and the flash device 100. In addition, the camera connection terminal 116 includes a MOSI_S terminal for receiving data transmitted from the imaging device (control unit) and a MISO_S terminal for transmitting data from the flash device 100 to the imaging device (control unit).

[0027] The cooling unit 117 is a module including a fan for cooling the optical panel 111, and is connected to the FAN_PWM terminal and the FAN_FG terminal of the FPU 101. The cooling unit 117 can change the rotation speed of the fan by PWM control from the FPU 101 to change the output air volume. In addition, the cooling unit 117 can maintain the indicated rotation speed by feeding back the rotation speed information to the FPU 101.

[0028] Next, the light emission process performed by the flash device 100 will be described. Figure 3 is a flowchart illustrating the light emission process performed by the flash device 100. The CPU of the FPU 101 loads a predetermined program stored in its own ROM into its own RAM and comprehensively controls the operations of the respective units of the flash device 100 to implement Figure 3 each process (each step) indicated by the S number in. When the power switch included in the input unit 113 is operated to be turned on and the FPU 101 of the flash device 100 becomes operable (enabled), the FPU 101 starts the process of S301. It should be noted that although Figure 3 is not shown in, when the power switch has been operated to be turned off, the light emission process ends.

[0029] In S301, the FPU 101 initializes its own memory and its own ports, reads the states of the switches included in the input unit 113 and the preset input information, and sets the method for determining the light emission amount, the light emission timing, etc. in the set light emission mode.

[0030] In S302, the FPU 101 performs a status confirmation process. The status confirmation process is a process of storing the status result that has been confirmed in S301 in its own RAM, and will be described in detail below.

[0031] In S303, the FPU 101 reads the voltage value of the main capacitor 102d from the MCV_AD terminal, which is an A / D conversion terminal, and stores the voltage value of the main capacitor 102d in its own RAM.

[0032] In S304, the FPU 101 starts the operation of the boost circuit block 102, thereby starting to charge the main capacitor 102d. It should be noted that after the charging starts, the process of returning to S304 after S302 is skipped.

[0033] In S305, the FPU 101 performs a charging time control process. The charging time control process is generally a process of controlling the time for determining the completion of charging in S310 for the charging operation that starts in S304 after light emission (S312) has been performed. It should be noted that the charging time control process will be described in detail below.

[0034] In S306, the FPU 101 obtains the focal length information of the shooting lens from the control unit of the imaging device via the camera connection terminal 116, and stores the obtained focal length information in its own RAM. It should be noted that in the case where the focal length information has been stored in the RAM, the stored focal length information is updated with the newly obtained focal length information in S306.

[0035] In S307, the FPU 101 drives the zoom drive circuit 115 to move the reflector unit 112 so that the light distribution corner of the light emitted by the discharge tube 104 falls within the range according to the focal length information obtained in S306. It should be noted that in the case where it is not necessary to move the reflector unit 112, the process of S307 is skipped.

[0036] In S308, the FPU 101 displays the information related to the light emission mode that has been confirmed in S301 and the information related to the focal length information that has been obtained in S306 on the display unit 114. In addition, in the case where the FPU 101 has detected an error in any hardware related to the light emission process in S302, the FPU 101 issues a warning according to the content of the detected error (for example, performs a warning display on the display unit 114). [[ID=!]]

[0037] In S309, the FPU 101 determines whether a predetermined charging completion waiting time has elapsed. It should be noted that in the charging time control process performed in S305, the charging completion waiting time is set under predetermined conditions, and the details will be described below. When the FPU 101 determines that the charging completion waiting time has elapsed (Yes in S309), the FPU 101 executes the process of S310. On the other hand, when the FPU 101 determines that the charging completion waiting time has not elapsed (No in S309), the FPU 101 executes the process of S302.

[0038] In S310, the FPU 101 determines whether the charging of the main capacitor 102d is completed based on the voltage of the MCV_AD terminal. In the present embodiment, the minimum voltage value at which the FPU 101 determines that the charging of the main capacitor 102d is completed is set to 270V. That is, in the flash device 100, when the voltage of the main capacitor 102d is 270V or higher, the discharge tube 104 becomes capable of emitting light.

[0039] When the FPU 101 determines that the charging of the main capacitor 102d is completed (Yes in S310), the FPU 101 sends a charging completion signal to the imaging device (control unit) via the camera connection terminal 116, and then executes the process of S311. On the other hand, when the FPU 101 determines that the charging of the main capacitor 102d is not completed (No in S310), the FPU 101 executes the process of S302.

[0040] In S311, the FPU 101 determines whether a light emission instruction has been received based on whether a light emission start signal has been received from the imaging device (control unit). When the FPU 101 determines that a light emission instruction has been received (Yes in S311), the FPU 101 executes the process of S312. On the other hand, when the FPU 101 determines that a light emission instruction has not been received (No in S311), the FPU 101 executes the process of S302.

[0041] In S312, the FPU 101 performs a light emission process (emits light). The light emission process is executed by the FPU 101 sending a light emission instruction to the light emission control circuit 105 according to the light emission start signal received from the imaging device, and the light emission control circuit 105 causing the discharge tube 104 to emit light according to the light emission instruction. After the light emission is completed, the FPU 101 stores information related to the light emission, such as the voltage information of the main capacitor 102d, in its own RAM. It should be noted that when pre-light emission for light control is performed before the main light emission, the process of S313 is executed after the main light emission is completed.

[0042] In S313, the FPU 101 determines whether the light emission performed in S312 is the first light emission (whether the light emission performed in S312 is the first light emission after the start of S301). When the FPU 101 determines that the light emission performed in S312 is the first light emission (yes in S313), the FPU 101 executes the process of S314. On the other hand, when the FPU 101 determines that the light emission performed in S312 is not the first light emission (the light emission performed in S312 is the second or subsequent light emission) (no in S313), the FPU 101 executes the process of S302. It should be noted that although this determination will be described below, the FPU 101 calculates the expected temperature or a value (substitute value) used as an alternative to the expected temperature of the part (portion) that needs to be protected from the heat generated by the flash device 100, and when the calculated value is equal to or less than a predetermined value, it is determined that this is the first light emission.

[0043] In S314, the FPU 101 executes a light emission control process and then executes the process of S302. The light emission control process is a process of controlling light emission and charging so that excessive heat is not abnormally generated even when heat caused by light emission is continuously applied to the panel due to continuous light emission or the like. In the light emission control process, the FPU 101 parameterizes the influence of the heat caused by the light emission of the discharge tube 104 on the flash device 100 by using the heating amount, the heat dissipation amount, the distance to the heat source, etc. In addition, the FPU 101 controls the next light emission timing based on the calculated value of the expected temperature or the substitute value of the part that needs to be protected from the heat generated by the flash device 100.

[0044] It should be noted that when starting the light emission control process in S314, the FPU 101 continues to calculate the expected temperature or the substitute value until the calculated value of the expected temperature or the substitute value of the part that needs to be protected from the heat generated by the flash device 100 becomes equal to or less than a predetermined value. In other words, after S314, in parallel with the process of S302 and subsequent processes, the FPU 101 continues to calculate the expected temperature or the substitute value.

[0045] In addition, after the light emission control process has been performed in S314, when the calculated value obtained by parallel calculation is equal to or greater than a predetermined value, in S310, the FPU 101 determines that this is the second or subsequent light emission, and since there is no need to execute the light emission control process again, the FPU 101 executes the process of S302 without going to S314.

[0046] Figure 4 is a flowchart illustrating the status confirmation process executed in S302.

[0047] In S401, the FPU 101 processes the hardware to be detected. The target hardware has been pre-registered in the ROM of the FPU 101, and the FPU 101 detects whether the registered target hardware has been set. The target hardware refers to components (parts) that have an impact as an optical system or a heat source, such as the cooling unit 117 that cools the optical panel 111, and optical accessories such as a color filter and a bounce adapter that have been attached in front of the optical panel 111 ( Figure 2 not shown in the figure) and the like. It should be noted that the target hardware may include an external power supply (not shown) for accelerating the charging of the main capacitor 102d, a modeling LED (not shown) for making it easier to understand the optical axis of the light emitted from the optical panel 111, and the like.

[0048] In S402, the FPU 101 obtains the status information of the target hardware detected in S401 and performs error detection processing on the target hardware based on the obtained status information. The status information includes, for example, the specifications of the target hardware and information related to whether the target hardware is operable. Additionally, for example, even if the cooling unit 117 is set to be operable in the setting of the light emission mode performed in S301, there may be a case where the cooling unit 117, which is the target hardware, is inoperable due to a failure or the like. In this case, the fact that the cooling unit 117 is inoperable is detected as error information. Whenever the status of the target hardware changes, the status information and the error information are updated.

[0049] In S403, the FPU 101 stores the status information and the error information of the target hardware obtained in S402 in its own RAM, then ends the status confirmation process and executes the process of S303.

[0050] Figure 5 is a flowchart illustrating the charge time control process executed in S305. For ease of description, it is assumed here that the maximum voltage value of the main capacitor 102d is 330V.

[0051] In S501, the FPU 101 obtains the current voltage of the main capacitor 102d as the current voltage value and stores the current voltage value in its own RAM.

[0052] In S502, the FPU 101 reads out the voltage value of the main capacitor 102d obtained and stored in the RAM in S303 as the previous voltage value.

[0053] In S503, the FPU 101 determines whether the previously read voltage value in S502 is equal to or lower than 280V. When the FPU 101 determines that the previously read voltage value is equal to or lower than 280V (Yes in S503), the FPU 101 ends the charging time control process and then executes the process of S306. On the other hand, when the FPU 101 determines that the previously read voltage value is higher than 280V (No in S503), the FPU 101 executes the process of S504.

[0054] In S504, the FPU 101 determines whether the previously read voltage value in S502 is equal to or lower than 300V. When the FPU 101 determines that the previously read voltage value is equal to or lower than 300V (Yes in S504), the FPU 101 executes the process of S505. On the other hand, when the FPU 101 determines that the previously read voltage value is higher than 300V (No in S504), the FPU 101 executes the process of S506.

[0055] In S505, the FPU 101 executes the first gradient determination process, then ends the charging time control process and executes the process of S306. The first gradient determination process will be described in detail below with reference to Figure 6A Detailed description of the first gradient determination process.

[0056] In S506, the FPU 101 determines whether the previously read voltage value in S502 is equal to or lower than 320V. When the FPU 101 determines that the previously read voltage value is equal to or lower than 320V (Yes in S506), the FPU 101 executes the process of S507. On the other hand, when the FPU 101 determines that the previously read voltage value is higher than 320V (No in S506), the FPU 101 ends the charging time control process and then executes the process of S306.

[0057] In S507, the FPU 101 executes the second gradient determination process, then ends the charging time control process and executes the process of S306. The second gradient determination process will be described in detail below with reference to Figure 6B Detailed description of the second gradient determination process.

[0058] Figure 6A Is a flowchart of the first gradient determination process executed in S505.

[0059] In S601, the FPU 101 reads out the current voltage value stored in the RAM in S501, and calculates the change amount of the charging voltage of the main capacitor 102d (hereinafter referred to as "voltage gradient ΔAD") based on the read current voltage value and the previously read voltage value in S502.

[0060] Here, a method for calculating the voltage gradient ΔAD will be described. The voltage gradient ΔAD is expressed by Expression 1 below. Here, "ADpre" represents the previous voltage value read in S502, "ADcur" represents the current voltage value obtained in S501, and "N" represents the time elapsed from obtaining the previous voltage value to obtaining the current voltage value.

[0061] [Expression 1]

[0062]

[0063] In S602, the FPU 101 determines whether the voltage gradient ΔAD is equal to or less than a predetermined first threshold. The first threshold will be described in detail below, but generally, the first threshold is used to determine whether the temperature rise of the battery 200 caused by charging the main capacitor 102d by the battery 200 is small. When the FPU 101 determines that the voltage gradient ΔAD is greater than the first threshold ( "No" in S602), the FPU 101 ends the first gradient determination process and then executes the process of S306. On the other hand, when the FPU 101 determines that the voltage gradient ΔAD is equal to or less than the first threshold ( "Yes" in S602), the FPU 101 executes the process of S603.

[0064] In S603, the FPU 101 determines whether the voltage gradient ΔAD is equal to or less than a predetermined second threshold. The second threshold is a value less than the first threshold. The second threshold will be described in detail below, but generally, the second threshold is used to determine whether the temperature rise of the battery 200 caused by charging the main capacitor 102d by the battery 200 is large. When the FPU 101 determines that the voltage gradient ΔAD is greater than the second threshold ( "No" in S603), the FPU 101 executes the process of S604. On the other hand, when the FPU 101 determines that the voltage gradient ΔAD is equal to or less than the second threshold ( "Yes" in S603), the FPU 101 executes the process of S605.

[0065] In S604, the FPU 101 stores the setting of the charge completion waiting time in its own RAM so that the charge completion waiting time is generated after the next light emission operation, ends the first gradient determination process, and executes the process of S306. The charge completion waiting time is the elapsed time required until it is determined again whether charging is completed (S310) after the next light emission operation (S312) has been performed. In other words, the charge completion waiting time is the time for delaying the execution of the determination in S310 by a specific period. When the charge completion waiting time has been set, the measurement of the charge completion waiting time starts simultaneously with the end of the next light emission operation (S312), and after the process returns to S302, the elapsed time of the charge completion waiting time is measured in S309. Regardless of the voltage value of the main capacitor 102d obtained in S303, the determination of charge completion in S310 is not performed unless the charge completion waiting time has elapsed.

[0066] In S605, the FPU 101 stores the setting of the charge completion waiting time in its own RAM so that the charge completion waiting time is generated after the next light emission operation, and simultaneously displays a warning on the display unit 114, then ends the first gradient determination process, and executes the process of S306. The charge completion waiting time generated in S605 may be the same as the charge completion waiting time generated in S604, or may be longer than the charge completion waiting time generated in S604.

[0067] It should be noted that, although details will be described below, the charge completion waiting time generated in S604 and the charge completion waiting time generated in S605 are set to suppress the temperature rise of the battery 200 caused by the discharge of the battery 200 when charging the main capacitor 102d with the battery 200. In the first gradient determination process, the voltage gradient ΔAD when the voltage of the main capacitor 102d is in the range of 280V to 300V is compared with the first threshold or the second threshold, and the temperature rise of the battery 200 is determined to be in one of the three stages of "large", "medium", and "small". When it is determined that the voltage gradient ΔAD is greater than the first threshold, the temperature rise of the battery 200 is determined to be small, and when it is determined that the voltage gradient ΔAD is equal to or less than the first threshold and greater than the second threshold, the temperature rise of the battery 200 is determined to be medium. When it is determined that the voltage gradient ΔAD is equal to or less than the second threshold, the temperature rise of the battery 200 is determined to be large.

[0068] In addition, examples of the warnings issued in S605 include warning displays on the liquid crystal panel of the display unit 114, blinking or lighting of light-emitting elements, etc. The content of the warning display includes, for example, notifying the user of the low battery level or temperature rise of the battery 200. In the case of still image shooting, a warning can be issued by emitting a sound (for example, a warning tone).

[0069] Figure 6B is a flowchart of the second gradient determination process executed in S507. In the Figure 6B flowchart, Figure 6A the "first threshold" in S602 of the flowchart of Figure 6A is replaced with the "third threshold" in S612, and Figure 6A the "second threshold" in S603 of the flowchart of

[0070] is replaced with the "fourth threshold" in S613. The third threshold serves the role corresponding to the first threshold, and the fourth threshold serves the role corresponding to the second threshold. The contents of the processes of S611 to S615 are respectively similar to

[0071] the contents of the processes of S601 to S605 in the flowchart of

[0072] Figure 7 is a graph showing the relationship between the charging time and voltage when the main capacitor 102d has been charged by using a nickel-metal hydride battery and an alkaline battery as the battery 200 based on actual measurement values.

[0073] The solid line graph 701 represents the charging characteristics when using a nickel-metal hydride battery in a state where the remaining battery power is sufficient, and it can be seen that the time required for the main capacitor 102d to reach its maximum voltage value of 330V is shorter than that of any other battery. The dashed line graph 702 represents the charging characteristics when using a nickel-metal hydride battery in a state where the remaining battery power has decreased, and it can be seen that the charging time is slightly longer than that of the solid line graph 701.

[0074] The single dotted line graph 703 represents the charging characteristics when using an alkaline battery in a state where the remaining battery power is sufficient, and it can be seen that the charging time is slightly longer than that of the solid line graph 701. The double dotted line graph 704 represents the charging characteristics when using an alkaline battery in a state where the remaining battery power has decreased, and it can be seen that the charging time required to reach the maximum voltage value of 330V is significantly longer than the charging times of the other graphs 701 to 703.

[0075] Generally, alkaline batteries have a higher internal resistance than nickel-metal hydride batteries. Therefore, when charging the main capacitor 102d, the temperature of the alkaline battery is more likely to rise than that of the nickel-metal hydride battery. In addition, when using an alkaline battery with a low remaining battery power (low remaining capacity), the charging time of the main capacitor 102d becomes longer, and heat is continuously generated during charging. For example, when using an alkaline battery with a low remaining battery power, the voltage of the main capacitor 102d reaches 320V approximately 7 seconds after the start of charging, but heat is continuously generated during this period. On the other hand, when using a nickel-metal hydride battery (regardless of the remaining battery power), the voltage of the main capacitor 102d reaches 320V approximately 4 seconds after the start of charging. Therefore, compared with an alkaline battery with a low remaining battery power, the next three seconds can be used to cool the battery. In other words, when using an alkaline battery with a low remaining battery power, it can be seen that the state in which the battery temperature may rise due to charging continues for a long time. The same is true for the time required for the voltage of the main capacitor 102d to reach 270V at which it can emit light. And if charging is continuously performed to 270V using an alkaline battery with a low remaining battery power, there is a risk that the battery temperature will rise.

[0076] Therefore, when using a new alkaline battery as the battery 200, the battery does not generate much heat at the beginning of use. However, as the number of light emissions increases and the remaining battery power decreases, the temperature of the battery may rise due to the charging of the main capacitor 102d. Therefore, it is necessary to suppress the temperature rise of the battery. The first gradient determination process and the second gradient determination process in S305 are performed to suppress the temperature rise of the battery 200 caused by the charging of the main capacitor 102d. In other words, the first gradient determination process and the second gradient determination process in S305 are performed to cool the battery by setting (setting) the time when charging is not performed.

[0077] Next, the differences in the charging characteristics in the curves showing the charging characteristics of each battery will be described. Figure 7 in the curves showing the charging characteristics of each battery. Figure 8 is Figure 7 a partial enlarged view of the curves 701 to 704 shown.

[0078] By comparing the gradients of the curves 701 to 704 when the voltage of the main capacitor 102d rises from 280V to 300V, it can be seen that except for the alkaline battery with a low remaining battery power, the gradients of the three types of batteries are the same, but the gradient of the alkaline battery with a low remaining battery power is smaller than that of the other three types of batteries. The same is true for the gradient when the voltage charged in the main capacitor 102d rises from 300V to 320V.

[0079] In addition, it can be seen that the voltage gradient when the voltage of the main capacitor 102d rises is different according to the voltage range (for example, the range from 280V to 300V and the range from 300V to 320V) in one curve (the same battery). In addition, it can be seen that in both the range from 280V to 300V and the range from 300V to 320V, the alkaline battery with a low remaining battery power has a smaller voltage gradient than the other batteries.

[0080] Thus, the voltage rise curve when charging the main capacitor 102d depicts different trajectories according to the type of battery used for charging and the remaining battery power of the battery used for charging. Therefore, in this embodiment, two ranges (the range from 280V to 300V and the range from 300V to 320V) are set, and thresholds for comparison with the voltage gradient ΔAD are set for each set range. Next, the relationship between the first threshold to the fourth threshold used for comparison with the voltage gradient ΔAD in the first gradient determination process and the second gradient determination process and the state of the battery 200 will be described.

[0081] Figure 9 is a diagram illustrating the relationship between the battery type for the battery 200, the voltage of the main capacitor 102d, and the first threshold to the fourth threshold. Figure 9The curves 701 to 704 in Figure 8 are the same as the curves 701 to 704 in Figure 9 and additionally shown in

[0082] threshold lines 905 to 908 representing the first threshold to the fourth threshold.

[0083] The gradients of the threshold lines 905 and 907 are set as follows. That is, approximate lines of the curves 701 to 704 in the voltage range of 280 V to 300 V of the main capacitor 102d are obtained. The threshold line 905 is set by determining a predetermined time 905a with respect to the voltage difference 905b such that the threshold line 905 becomes a line having a gradient slightly smaller than the gradient of the approximate lines of the curves 701 to 703. Further, the threshold line 907 is set by determining a predetermined time 907a with respect to the voltage difference 907b such that the threshold line 907 becomes a line having a gradient slightly larger than the gradient of the approximate line of the curve 704. The method for setting the gradients of the threshold lines 906 and 908 is similar to the method for setting the gradients of the threshold lines 905 and 907, and thus the description thereof will be omitted.

[0084] Next, the first gradient determination process shown in Figure 6A and the second gradient determination process shown in Figure 6B will be described by specific examples, where the first threshold is "A1", the second threshold is "A2", the third threshold is "B1", and the fourth threshold is "B2".

[0085] When the power supply of the flash device 100 is turned on (when the power switch is turned on), Figure 3 the light emission process of the flowchart shown in Figure 3The process in [ ] returns to the process of S302 according to a predetermined judgment result or after the process of S314, and when the process returns to S302, the voltage value of the main capacitor 102d is obtained as the latest previous voltage value in S303.

[0086] Next, taking the graph 701 (i.e., the graph 701 when the nickel-metal hydride battery has a high remaining battery charge) when the battery 200 of the flash device 100 is a nickel-metal hydride battery with a high remaining battery charge as an example, the Figure 6A first gradient judgment process shown in [ ] and Figure 6B the second gradient judgment process shown in [ ] will be described.

[0087] Assume that the voltage gradient ΔAD when using a nickel-metal hydride battery with a high remaining battery charge and the previous voltage value is greater than 280V and less than or equal to 300V can be represented by Figure 9 the straight line 901 in [ ]. In this case, the gradient of the straight line 901 is greater than the gradient of the threshold straight line 905. In other words, the value of the voltage gradient ΔAD is greater than the first threshold A1 corresponding to the threshold straight line 905. Therefore, when using a nickel-metal hydride battery with a high remaining battery charge, the judgment in S602 becomes "No", and the first gradient judgment process ends.

[0088] In addition, assume that the voltage gradient ΔAD when using a nickel-metal hydride battery with a high remaining battery charge and the previous voltage value is greater than 300V and less than or equal to 320V can be represented by Figure 9 the straight line 902 in [ ]. In this case, the gradient of the straight line 902 is greater than the gradient of the threshold straight line 906. In other words, the value of the voltage gradient ΔAD is greater than the third threshold B1 corresponding to the threshold straight line 906. Therefore, when using a nickel-metal hydride battery with a high remaining battery charge, the judgment in S612 becomes "No", and the second gradient judgment process ends.

[0089] It should be noted that in this embodiment, the same judgment result can be obtained when using a nickel-metal hydride battery with a low remaining battery charge and when using an alkaline battery with a high remaining battery charge (when the nickel-metal hydride battery has a low remaining battery charge and when the alkaline battery has a high remaining battery charge).

[0090] Next, taking the graph 704 (i.e., the graph 704 when the alkaline battery has a low remaining battery charge) when the battery 200 of the flash device 100 is an alkaline battery with a low remaining battery charge as an example, the Figure 6A first gradient judgment process shown in [ ] and Figure 6BThe second gradient determination process shown.

[0091] Assume that the voltage gradient ΔAD in the case of using an alkaline battery with a low remaining battery charge and a previous voltage value greater than 280V and equal to or less than 300V can be represented by Figure 9 the straight line 903 in. In this case, the gradient of the straight line 903 is less than the gradients of the threshold straight line 905 and the threshold straight line 907. In other words, the value of the voltage gradient ΔAD is less than the second threshold A2 corresponding to the threshold straight line 907. Therefore, in the case of using an alkaline battery with a low remaining battery charge, the determination in S602 becomes "Yes", the determination in S603 also becomes "Yes", and the process of S605 is executed, after which the first gradient determination process ends.

[0092] Assume that the voltage gradient ΔAD in the case of using an alkaline battery with a low remaining battery charge and a previous voltage value greater than 300V and equal to or less than 320V can be represented by Figure 9 the straight line 904 in. In this case, the gradient of the straight line 904 is less than the gradients of the threshold straight line 906 and the threshold straight line 908. In other words, the value of the voltage gradient ΔAD is less than the fourth threshold B2 corresponding to the threshold straight line 908. Therefore, in the case of using an alkaline battery with a low remaining battery charge, the determination in S612 becomes "Yes", the determination in S613 also becomes "Yes", and the process of S615 is executed, after which the second gradient determination process ends.

[0093] When the voltage of the main capacitor 102d is in the range of 280V to 320V, the charging characteristics (graph 703) of an alkaline battery with a high remaining battery charge are very similar to the charging characteristics (graph 701) of a nickel-metal hydride battery with a high remaining battery charge. However, although the nickel-metal hydride battery only experiences a small decrease in charging performance as the remaining battery charge decreases, the alkaline battery experiences a significant decrease in charging performance as the remaining battery charge decreases. Therefore, in the case of using a new alkaline battery (an alkaline battery with a high remaining battery charge), the determinations in S602 and S612 will respectively become "No" at the start of use, but as the number of illuminations increases and the remaining battery charge decreases, the determinations in S602 and S612 will respectively become "Yes". As referred to Figure 7As described above, this indicates that the time required for charging is becoming longer, and thus the time during which heat is generated due to charging is becoming longer. Therefore, measures are taken to suppress the temperature rise of the alkaline battery by generating a charging completion waiting time after the next light emission operation. Therefore, when the voltage gradient ΔAD is equal to or less than the first threshold A1 or equal to or less than the third threshold B1, but greater than the second threshold A2 or greater than the fourth threshold B2 (being "No" in S603 or "No" in S613), a charging completion waiting time is generated after the next light emission operation.

[0094] When the remaining battery power of the alkaline battery further decreases, the determination result of S603 or the determination result of S613 becomes "Yes", a charging completion waiting time is generated, and a warning is issued in parallel. In view of this situation, the warnings issued in S605 and the warnings issued in S615 inform the user that the battery is in a state where the battery temperature may rise and the remaining battery power has decreased.

[0095] When the voltage gradient ΔAD is between the first threshold A1 and the second threshold A2 and when the voltage gradient ΔAD is less than the second threshold A2, the corresponding charging completion waiting times of S604 and S605 can be configured to extend the waiting time in stages according to the voltage gradient ΔAD. This can also be applied to the corresponding charging completion waiting times of S614 and S615. This makes it easier to understand the state of the battery 200 when the lighting device (flashlight device 100) continuously performs light emission operations.

[0096] It should be noted that from the perspective of suppressing the battery temperature rise, the first gradient determination process and the second gradient determination process are not necessary for nickel-metal hydride batteries. However, since it is not easy to determine whether the battery in use is an alkaline battery or a nickel-metal hydride battery, in this embodiment, regardless of the type of the battery 200, the first gradient determination process and the second gradient determination process are both performed.

[0097] As described above, as Figure 7 shown, the graphs 701 to 704 showing the charging characteristics of the main capacitor 102d depict different curves (different trajectories) similar to quadratic curves according to the type of the battery and the remaining battery power of the battery. Therefore, in this embodiment, a plurality of ranges obtained by dividing the voltage of the main capacitor 102d by a predetermined potential width are set, and the first gradient determination process or the second gradient determination process is performed according to which range the previous voltage value belongs to. At this time, the thresholds used to determine the voltage gradient ΔAD based on the previous voltage value and the current voltage value are different between the first gradient determination process and the second gradient determination process. As a result, the accuracy of the gradient determination process can be improved. It should be noted that in this embodiment, the number of the plurality of ranges set for the voltage of the main capacitor 102d is two, but it can be three or more than three.

[0098] In order to further improve the accuracy of the gradient judgment process, the voltage of the main capacitor 102d can be divided into more ranges, thresholds can be set for each range, and the magnitude relationship between the threshold and the voltage gradient ΔAD can be determined. In addition, a polynomial representing the threshold can be created based on the voltage curve of the main capacitor 102d, which changes according to the capacity of the battery 200 expected to be used, and the threshold corresponding to the detected current voltage value can be determined according to this polynomial. In this case, it is not necessary to set a range for the voltage of the main capacitor 102d.

[0099] In the present embodiment, the first gradient judgment process and the second gradient judgment process are executed when the previous voltage value of the main capacitor 102d is in the range of 280V to 320V, but the gradient judgment process can be executed when the previous voltage value is any voltage greater than 0V. This is because, for example, when the minimum voltage value at which charging is determined to be completed is 300V, if the light emission operation is continuously performed at the moment when the voltage has reached 300V, there is a possibility that the gradient judgment process will not be correctly performed.

[0100] As described above, according to the present embodiment, in the light emission control of the flash device 100, when the battery 200 is not in a state where heat may be generated, light emission can be performed without setting an unnecessary charging completion waiting time. On the other hand, when the battery 200 is in a state where heat may be generated, the temperature rise of the battery 200 can be suppressed by setting a charging completion waiting time. As a result, the flash device 100 can be protected from the heat generated by the battery 200, and even when continuous light emission is being performed, the number of light emissions does not need to be unnecessarily limited (reduced).

[0101] In addition, according to the present embodiment, light emission can be restricted without stopping the charging circuit, so that the control flow can be prevented from becoming complicated. In addition, one method of suppressing the temperature rise of the battery 200 is to provide a thermistor that suppresses current in the charging circuit, but the resistance of each thermistor component varies greatly with temperature, which may cause individual differences between flash devices. On the other hand, in the above embodiment, gradient judgment (control) is used, so that there are no individual differences between flash devices.

[0102] It should be noted that in the case of continuous light emission with a small amount of light, the voltage of the main capacitor 102d increases or decreases within a certain range. However, even in this case, it is possible to determine whether the battery 200 is in a state where heat may be generated each time light is emitted with a small amount of light. In the case of issuing a warning in S605 or S615, this indicates that the remaining battery power of the alkaline battery being used is low, which makes it easier for the user to determine when to replace the battery 200, etc.

[0103] Finally, modifications of the above-described embodiments will be described. For example, the processing order in the flowcharts shown in the above-described embodiments is merely an example, and the processing order can be changed if there is no inconvenience.

[0104] For example, in the above-described embodiment, the voltage gradient ΔAD has been obtained based on the previous voltage value and the current voltage value. As an alternative, the elapsed time from when the voltage of the main capacitor 102d reaches 280 V to when the voltage of the main capacitor 102d reaches 300 V can be measured by using the timer circuit provided in the FPU 101, and the value obtained by dividing the voltage difference of 20 V by the elapsed time can be used as the voltage gradient AD in the first gradient determination process. Similarly, the elapsed time from when the voltage of the main capacitor 102d reaches 300 V to when the voltage of the main capacitor 102d reaches 320 V can be measured by using the timer circuit provided in the FPU 101, and the value obtained by dividing the voltage difference of 20 V by the elapsed time can be used as the voltage gradient AD in the second gradient determination process. The processing contents of S303 and S305 are changed according to this processing content.

[0105] Furthermore, in the above-described embodiment, when the voltage gradient ΔAD becomes equal to or less than the first threshold or equal to or less than the third threshold, the charging completion waiting time is immediately generated. As an alternative, when the determination that the voltage gradient ΔAD becomes equal to or less than the first threshold or equal to or less than the third threshold continues for a predetermined number of times, the charging completion waiting time can be generated for the first time, and thereafter, the charging completion waiting time can be generated according to the determination result that the voltage gradient ΔAD becomes equal to or less than the first threshold or equal to or less than the third threshold. In addition, in the case where a thermometer is provided at a predetermined position (for example, the light emitting unit 100b) inside the flash device 100, when the temperature indicated by the thermometer has exceeded a predetermined temperature, the first gradient determination process and the second gradient determination process can be performed. In addition, the number of light emissions or the elapsed time since the power supply of the flash device 100 has been turned on can be considered as the execution conditions for the first gradient determination process and the second gradient determination process.

[0106] In the above-described embodiment, the maximum voltage value of the main capacitor 102d has been set to 330V. However, in this case, after the voltage value of the main capacitor 102d has reached the maximum voltage value of 330V, there is a voltage range in which the voltage changes (increases or decreases) due to discharging and intermittent charging. Therefore, in this voltage range, since the battery 200 does not always perform a charging operation, it can be determined that the battery 200 is not in a state of generating heat, and the first gradient determination process and the second gradient determination process may not be performed. As a result, Figure 3 the load on the FPU 101 in the light emission control process of

[0107] Other embodiments

[0108] Embodiments of the present invention can also be implemented by the following method, that is, by providing software (including a computer program product including computer programs / instructions) that executes the functions of the above-described embodiments to a system or device through a network or various storage media, and a computer (central processing unit (CPU), microprocessing unit (MPU)) of the system or device reads and executes the computer programs / instructions.

[0109] Although the present disclosure has been described with reference to exemplary embodiments, it should be understood that the present disclosure is not limited to the disclosed exemplary embodiments. The scope of the appended claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

[0110] This application claims the benefit of Japanese Patent Application No. 2024-010795, filed on January 29, 2024, which is incorporated herein by reference in its entirety.

Claims

1. An illumination device, comprising: a light source; a capacitor for storing energy for causing the light source to emit light; at least one processor; and a memory coupled to the processor, the memory storing instructions which, when executed by the processor, cause the processor to function as: a charging unit for charging the capacitor using a battery; a detection unit for detecting the voltage of the capacitor; and a control unit for controlling the light-emitting operation of the light source based on a change amount of the voltage of the capacitor.

2. The illumination device according to claim 1, wherein the control unit compares the change amount with a predetermined first threshold, and in a case where the change amount is equal to or less than the first threshold, waits for a predetermined waiting time to elapse after causing the light source to emit light next time, and then determines whether charging of the capacitor is completed.

3. The illumination device according to claim 2, wherein the control unit compares the change amount with a second threshold which is determined in advance to be smaller than the first threshold, and in a case where the change amount is equal to or less than the second threshold, sets the waiting time and issues a warning in parallel.

4. The illumination device according to claim 3, wherein the processor is further caused to function as a setting unit which sets a plurality of ranges obtained by dividing the voltage of the capacitor with a predetermined potential width, and sets the first threshold and the second threshold for each of the plurality of ranges, and the control unit compares the change amount with the first threshold and the second threshold set for the range to which the voltage of the capacitor belongs among the plurality of ranges.

5. The illumination device according to claim 4, wherein the plurality of ranges are set between a minimum voltage value at which the light source becomes capable of emitting light and a maximum voltage value of the capacitor.

6. The illumination device according to any one of claims 2 to 5, wherein in a case where the change amount is greater than the first threshold, the control unit does not wait for the waiting time to elapse after causing the light source to emit light next time, and determines whether charging of the capacitor is completed.

7. The illumination device according to any one of claims 2 to 5, wherein in a case where the determination that the change amount becomes equal to or less than the first threshold continues for a predetermined number of times, the control unit causes the waiting time to be generated for the first time.

8. The illumination device according to any one of claims 1 to 5, wherein a thermometer is provided at a predetermined position inside the illumination device, and in a case where the temperature indicated by the thermometer has exceeded a predetermined temperature, the control unit controls charging of the capacitor based on a change amount of the voltage of the capacitor.

9. A control method for an illumination device, the control method comprising the following steps: when charging a capacitor for storing energy for causing a light source to emit light using a battery, obtaining a change amount of the voltage of the capacitor; comparing the change amount with a predetermined first threshold; and When the amount of change is equal to or less than the first threshold, after the next time the light source emits light, wait for a predetermined waiting time to elapse, and then determine whether the charging of the capacitor is completed.

10. A non-transitory computer-readable storage medium storing a program for causing a computer to execute a control method for a lighting device, The control method includes the following steps: When charging a capacitor for storing energy for causing a light source to emit light using a battery, obtain the amount of change in the voltage of the capacitor; Compare the amount of change with a predetermined first threshold; And When the amount of change is equal to or less than the first threshold, after the next time the light source emits light, wait for a predetermined waiting time to elapse, and then determine whether the charging of the capacitor is completed.

11. A computer program product including a program for causing a computer to execute a control method for a lighting device, The control method includes the following steps: When charging a capacitor for storing energy for causing a light source to emit light using a battery, obtain the amount of change in the voltage of the capacitor; Compare the amount of change with a predetermined first threshold; And When the amount of change is equal to or less than the first threshold, after the next time the light source emits light, wait for a predetermined waiting time to elapse, and then determine whether the charging of the capacitor is completed.

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