JP2015224913A - Illuminance meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely allow a numerical number indicative of illuminance displayed on a display unit to be visually recognized without requiring an operation for lighting up a lighting unit.SOLUTION: An illuminance meter comprises: a light reception unit 2; an operation unit 3 that has a hold key 11; a display unit 4 that has a display screen; a lighting unit 5 that lights a display screen; and a processing unit 6. The processing unit 6 is configured to: repeatedly execute measurement processing to measure a new illuminance value IL; and switch an update display operation causing the newly measured illuminance value IL to be updatedly displayed on the display screen and a non-update display operation causing information other than the newly measured illuminance value IL to be displayed to execute the update display operation or the non-update display operation on the display screen on the basis of an operation content detected in inspection processing and relative to the operation unit 3. Further, the processing unit 6 is configured to execute lighting control processing, which controls execution of lighting of the display screen by the lighting unit 5 and stoppage of the lighting thereby, for causing the lighting unit 5 to light in a state where the non-update display operation is under way and the newly measured illuminance value IL is equal to or less than a first threshold.

Description

  The present invention relates to an illuminometer that includes a light receiving unit and measures illuminance.

  As this type of illuminometer, the present applicant has already proposed the illuminometer disclosed in Patent Document 1 below. This illuminometer includes a light receiving unit that receives light from the outside, a measurement unit that measures illuminance from the received light, a display unit that displays the illuminance on a liquid crystal screen, and a light (illumination unit) that illuminates the liquid crystal screen of the display unit ) And an operation unit having a single hold light key that can freely hold a display value of the illuminance (indicating illuminance) and freely turn on and off the light. In this illuminometer, the measurement unit is configured to include a microcomputer, and executes a hold backlight processing routine together with a process of measuring the illuminance and displaying the illuminance in real time on the display unit.

  In this illuminometer, when the hold light key is pressed by the measurement unit executing this hold backlight processing routine, the display value (value indicating the measured illuminance) displayed on the display unit at that time is displayed. Hold. In the hold state of the display value, when the hold light key is continuously pressed for 1 second or more, the light is turned on. On the other hand, when the hold value key is pressed for less than 1 second in the display value hold state, the light is not turned on.

  According to this illuminance meter, a single hold light key is provided, and the illuminance is displayed by making the operation time for pressing the hold light key less than a certain time (for example, 1 second as described above) or more than a certain time. It is possible to perform single operations such as holding values, releasing the holding state of the illuminance display value, turning on the light, and performing operations related to turning off the light and releasing the holding state of the display value of the illuminance. It can be realized. In addition, when the light is turned on, the display operation of the illuminance display value is always performed first, so that erroneous measurement due to the light of the light can be reliably prevented.

Japanese Patent No. 342157 (page 4-5, FIG. 6-9)

  However, this illuminometer has the following problems to be improved. That is, in this illuminometer, the pressing time of the hold light key (pressing time of 1 second or more in the above example) is the lighting condition of the light (illumination unit). For this reason, since the illuminometer requires at least this pressing time for the lighting operation of the light, there is a problem to be improved that the operation time required until the lighting of the light is increased accordingly. In addition, since the light can be turned on only when a predetermined operation is performed on a single hold light key, the operator must turn on the light if he does not remember how to operate the hold light key. There is also a problem to be improved that it cannot be lit. In addition, if the hold light key is pressed to hold the display value of the illuminance displayed on the display unit and then the hold light key is stopped before it reaches the predetermined time by mistake, When you try to confirm the display value of the illuminance displayed on the display unit by turning on, the hold light key will be pressed again, so the display value that was initially held will be pressed again. Updated with the displayed value. For this reason, there is a problem to be improved that the display value that is initially held cannot be confirmed with the light turned on.

  The present invention has been made in order to improve such a problem, and the illuminance capable of reliably recognizing information such as a numerical value indicating the illuminance displayed on the display unit while making an operation for lighting the illumination unit unnecessary. The main purpose is to provide a total.

  In order to achieve the above object, the illuminance meter according to claim 1 receives a light from the outside and outputs an illuminance signal indicating the illuminance of the received light, an operation unit, and a display having a display screen. A measurement process for measuring the illuminance of the received light based on the illuminance signal, a display process for displaying information on the display screen on the display unit, and detecting that the operation unit is operated A processing unit that executes a detection process, and the processing unit repeatedly executes the measurement process to measure the new illuminance, and based on the operation content for the operation unit detected in the detection process, An update display operation for executing the display process for updating and displaying the numerical value indicating the measured new illuminance on the display screen as the information representing the current illuminance, and information other than the current illuminance as the information. An illuminometer that switches and executes a non-updated display operation for executing the display process to be displayed on a display screen, and includes an illumination unit that illuminates the display screen, and the processing unit includes the display screen by the illumination unit Illumination control processing for controlling the execution of illumination and the stop of illumination when the non-updated display operation is performed and the numerical value indicating the measured new illuminance is equal to or less than a predetermined threshold value An illumination control process is executed to cause the unit to execute the illumination.

  The illuminometer according to claim 2 is the illuminometer according to claim 1, wherein a first threshold value and a second threshold value higher than the first threshold value are defined as the threshold value, In the illumination control process, the processing unit causes the illumination unit to execute the illumination when the non-update display operation is being performed and the numerical value indicating the measured new illuminance is equal to or less than the first threshold value. When the numerical value indicating the measured new illuminance is not less than the second threshold value during the non-update display operation, the illumination unit stops the illumination.

  The illuminometer according to claim 3 is the illuminometer according to claim 1 or 2, wherein the processing unit stops the illumination with respect to the illumination unit when the update display operation is started in the illumination control process. Let

  In the illuminometer according to claim 1, the processing unit is an illumination control process for controlling execution of illumination of the display screen and stop of illumination by the illumination unit, and the newly measured illuminance during the non-update display operation. An illumination control process is executed to cause the illumination unit to perform illumination when the numerical value shown is equal to or less than the threshold value. Therefore, according to this illuminometer, when the brightness around the illuminometer is lowered to a level where the operator can visually recognize the numerical value displayed on the display screen of the display unit, the non-update display operation If it is inside, it is possible to automatically illuminate the display screen by the illumination unit without manually performing an operation for illumination. Thereby, according to this illuminometer, for example, when the brightness around the illuminometer is reduced during a non-update display operation in which a numerical value indicating illuminance is displayed on the display screen without being updated. Even if it exists, the numerical value which shows this illumination intensity can be visually recognized reliably.

  According to the illuminometer of claim 2, the processing unit is based on a comparison between the two threshold values of the first threshold value and the second threshold value and a numerical value indicating the current illuminance being measured. Even if the brightness around the illuminance meter slightly varies in the state where the numerical value indicating the illuminance is below the first threshold value and the lighting unit is turned on by controlling the lighting unit to turn on / off Until the numerical value indicating the illuminance being measured is equal to or higher than the second threshold value, the illumination unit can be stably maintained in the lighting state. For this reason, it is possible to avoid the occurrence of an unfavorable state in which the illumination unit repeatedly turns on and off in a short time due to variations in brightness around the illuminometer.

  According to the illuminance meter according to claim 3, in order to execute control to turn off the illumination unit when the processing unit starts the update display operation, light leaks from the illumination unit to the light receiving unit during the update display operation. It is possible to accurately measure the illuminance.

1 is a configuration diagram showing a configuration of an illuminometer 1. FIG. 3 is a flowchart for explaining the operation of the illuminometer 1.

  Hereinafter, embodiments of the illuminometer will be described with reference to the accompanying drawings.

  First, a configuration of an illuminometer 1 as an example of an illuminometer will be described with reference to FIG. The illuminometer 1 includes, as an example, a light receiving unit 2, an operation unit 3, a display unit 4, an illumination unit 5, a processing unit 6, and a housing (not shown). While measuring, the numerical value (henceforth illuminance value IL) which shows the measured illuminance is comprised on the display part 4 so that a display is possible. In addition, as an example, the housing is configured as a box-shaped handy type that can be held with one hand, and the light receiving unit 2, the operation unit 3, and the display unit 4 are arranged on the same wall surface (front wall). The illumination part 5 and the process part 6 are arrange | positioned inside the housing | casing.

  The light receiving unit 2 includes a photoelectric conversion element such as a photoelectric tube or a photodiode as a light receiving sensor, and receives light from the outside by the light receiving sensor and outputs an illuminance signal S1 representing the illuminance of the received light. In this case, the light receiving unit 2 may employ a configuration in which an amplifier is built in, an analog signal output from the light receiving sensor is amplified by the amplifier, and the analog signal is output as the illuminance signal S1. It is also possible to adopt a configuration in which a / D converter is built in, an analog signal output from the light receiving sensor is converted into a digital signal by the A / D converter, and this digital signal is output as the illuminance signal S1.

  For example, the operation unit 3 causes the display unit 4 to display various operations such as a memory operation, a timer operation, and a zero adjustment operation on the hold key 11 and the processing unit 6 (information other than a numerical value indicating current illuminance described later). An execution key (not shown) for executing the operation) and a stop key (not shown) (for example, an escape key) for stopping the execution of these various operations, and indicating which key has been operated. An operation signal S2 (indicating the operation content for the operation unit 3) is output. The display unit 4 is configured by a non-self-luminous display such as a liquid crystal display, for example, and configured to be able to display an illuminance value IL for the measured illuminance of light on a display screen (not shown).

  The illumination unit 5 includes a light emitting diode, an EL (ElectroLuminescence) panel, and the like, and is controlled by the processing unit 6 to be in a lighting state or a light-off state. In addition, the illumination unit 5 illuminates the display screen by irradiating the display screen of the display unit 4 with illumination light when in the lighting state. Moreover, the illumination part 5 is arrange | positioned as an example in the position which can illuminate the display screen of the display part 4, such as the side of the display part 4 in a housing | casing, and a back surface side.

  The processing unit 6 includes a computer, and executes measurement processing, display processing, detection processing, and illumination control processing. In this case, in the measurement process, the processing unit 6 measures the illuminance of the light received by the light receiving unit 2 based on the illuminance signal S1 from the light receiving unit 2 (specifically, the illuminance value IL indicating the illuminance is obtained). calculate). In the display process, the processing unit 6 causes the display unit 4 to display this information on the display screen by outputting the information to be displayed on the display screen to the display unit 4. In the illuminometer 1, the illuminance value IL and numerical values and characters displayed during various operations such as memory operation, timer operation, and zero adjustment operation are output from the processing unit 6 to the display unit 4 as this information. .

  Further, in the detection process, the processing unit 6 detects the operation content (such as the operation of the hold key 11) on the operation unit 3 based on the operation signal S2 from the operation unit 3, and the detected operation content. An operation associated in advance is executed. For example, when the hold key 11 is operated continuously, the processing unit 6 displays the measured new illuminance value IL on the display screen every time the hold key 11 is operated (that is, the update of the illuminance value IL). Display operation) and non-updated display operation (display of the measured new illuminance value IL on the display screen) in which the illuminance value IL displayed on the display screen is continuously displayed when the hold key 11 is operated. Execute the operation by switching between

  Further, when the detected operation content is a memory operation execution key, for example, the processing unit 6 displays characters indicating that the memory operation is in progress on the display screen and stores the illuminance value IL displayed on the display screen. Then, a non-update display operation of displaying the stored illuminance value IL on the display screen is executed. Further, when the detected operation content is an execution key for a timer operation (an operation for measuring the illuminance value IL when a set time has elapsed), the processing unit 6 displays a character indicating that the timer is operating on the display screen. And a non-update display operation of displaying the set time on the display screen. In addition, when the detected operation content is an execution key for a zero adjustment operation (an operation for adjusting the zero value of the illuminance value IL), the processing unit 6 displays a character indicating the zero adjustment operation on the display screen. Execute. In addition, when the detected operation content indicates that the stop key has been operated, the processing unit 6 includes the various non-update display operations described above (including the non-update display operation when the hold key 11 is operated). ) Is stopped, and the display operation of the new measured illuminance value IL on the display screen (that is, the update display operation of the illuminance value IL) is executed.

  Further, in the lighting control process, the processing unit 6 shifts the lighting unit 5 to a lighting state (executes illumination of the display screen) and shifts to a lighting state (display) based on various conditions described later. Execute one of the controls to stop lighting the screen).

  Next, the operation of the illuminometer 1 will be described. It is assumed that the illuminometer 1 is turned on and each component of the illuminometer 1 is in an operating state. In addition, it is assumed that the hold key 11 of the operation unit 3 has never been operated.

  In this state, the light receiving unit 2 receives light from the outside in real time by the light receiving sensor and outputs an illuminance signal S1 representing the illuminance of the received light. The processing unit 6 repeatedly executes the measurement process, and measures new illuminance (illuminance value IL indicating the current illuminance) in real time based on the illuminance signal S1 output from the light receiving unit 2. Further, the processing unit 6 outputs a newly measured illuminance value IL to the display unit 4, thereby executing display processing for causing the display unit 4 to update and display the illuminance value IL on the display screen. (Update display operation) is executed repeatedly.

  Further, the processing unit 6 repeatedly performs the measurement process and the display process as described above, and also repeatedly performs the detection process, and whether or not the operation signal S2 is output from the operation unit 3 (that is, The hold key 11, the execution key for the various operations described above, and whether or not an operation on the stop key has been performed) is detected in real time. In this detection process, the display unit 4 displays the illuminance value IL indicating the illuminance newly measured in the measurement process until the first detection of the output of the operation signal S2 in this detection process. Execute the operation to update and display on the screen.

  In addition, the processing unit 6 repeatedly executes the illumination control process 50 illustrated in FIG. 2 while repeatedly performing the measurement process, the display process, and the detection process as described above. In the illumination control process 50, the processing unit 6 controls the execution of illumination on the display screen of the display unit 4 and the stop of the illumination by executing a control for causing the illumination unit 5 to shift to a lighting state or a non-lighting state. To do.

  Specifically, in the illumination control process 50, as shown in FIG. 2, the processing unit 6 first determines whether an update display operation is being performed or a non-update display operation is being performed (step 51). In this example, the processing unit 6 operates the hold key 11 again during the non-update display operation in which the illuminance value IL displayed on the display screen is continuously displayed when the hold key 11 is operated. Shifts to the update display operation. The processing unit 6 also shifts to the update display operation when the stop key is operated. On the other hand, when the hold key 11 is operated again during the update display operation, the processing unit 6 continuously displays the illuminance value IL displayed on the display screen without updating it with the new illuminance value IL. It shifts to the non-update display operation of making Further, the processing unit 6 shifts to a non-update display operation of displaying numerical values and characters for various operations when an execution key for executing the various operations described above such as a memory operation is operated. .

  When the processing unit 6 determines in step 51 that the update display operation is being performed as described above, the processing unit 6 controls the illumination unit 5 to be turned off (step 55), and returns to step 51. As described above, in the illuminometer 1, the processing unit 6 performs an update display operation in which the illuminance value IL indicating the new illuminance measured in the repeatedly executed measurement process is updated and displayed on the display screen of the display unit 4. The illumination unit 5 can always be turned off. Thereby, in this illuminance meter 1, the illuminance value IL (incorrect illuminance value IL) measured in a state where the light from the illumination unit 5 is incident on the light receiving unit 2 is displayed on the display unit 4. Measurement can be reliably prevented.

  Further, when the processing unit 6 determines in step 51 that the non-update display operation is being performed, the illuminance value IL (current illuminance value IL) of the illuminance newly measured in the measurement process and the first stipulated in advance. The threshold value ILr1 is compared to determine whether or not the illuminance value IL is equal to or less than the first threshold value ILr1 (step 52). In this case, the first threshold value ILr1 is, for example, the brightness around the illuminometer 1 that is just enough to allow the operator to visually recognize the illuminance value IL displayed on the display screen of the display unit 4. Sometimes, the processing unit 6 is defined in advance to match the illuminance value IL measured in the measurement process. Note that a second threshold value ILr2, which will be described later, is defined in advance to a value slightly larger (that is, a bright value) than the first threshold value ILr1.

  If it is determined in step 52 that the illuminance value IL is greater than the first threshold value ILr1, the processing unit 6 then determines that the illuminance value IL is the second threshold value ILr2 (> first threshold value ILr2). It is determined whether or not the threshold value ILr1) is greater than or equal to (step 53). As a result of the determination in step 53, when the illuminance value IL is less than the second threshold value ILr2 (that is, when ILr2> IL> ILr1), the illuminance value IL is higher than the first threshold value ILr1. The brightness around the illuminometer 1 is brightness that allows the operator to visually recognize the illuminance value IL displayed on the display screen of the display unit 4. In this case, the processing unit 6 performs control for the lighting unit 5 to maintain the lighting / light-off state of the lighting unit 5 in the current state (in this case, the light-off state) (step 54). 51.

  Further, when the illuminance value IL is greater than or equal to the second threshold value ILr2 (that is, when IL ≧ ILr2) as a result of the determination in step 53, the illuminance value IL is greater than the first threshold value ILr1. Since it is equal to or higher than the high second threshold value ILr2, the brightness around the illuminometer 1 is such that the operator can sufficiently view the illuminance value IL displayed on the display screen of the display unit 4. . For this reason, the processing unit 6 executes control for shifting the illumination unit 5 to the extinguished state (step 55), and proceeds to step 51.

  On the other hand, when it is determined as a result of the determination in step 52 that the illuminance value IL is equal to or less than the first threshold value ILr1, the processing unit 6 performs control for causing the illumination unit 5 to shift to the lighting state. (Step 56), the process proceeds to step 51. Thus, when the illuminance value IL is equal to or less than the first threshold value ILr1, that is, the brightness around the illuminometer 1 allows the operator to visually recognize the illuminance value IL displayed on the display screen of the display unit 4. The illumination unit 5 is automatically turned on by the processing unit 6 when the brightness is less than or equal to the minimum brightness (the brightness at which the illuminance value IL is not easily visible). For this reason, even if the brightness of the surroundings of the illuminometer 1 is such that the illuminance value IL is not easily visible, the operator can display the display screen of the display unit 4 by the illumination from the illumination unit 5. The illuminance value IL displayed on can be easily visually confirmed.

  Further, as described above, the processing unit 6 performs the non-update display operation (the measurement of illuminance at a desired timing is completed, and the illuminance value IL at this timing is displayed on the display screen without being updated. That is, only when the illuminance value IL indicating the new illuminance measured in the measurement process is not updated and displayed on the display screen of the display unit 4), the illumination unit 5 is controlled to be in a lighting state. It is possible to reliably prevent the occurrence of a situation in which the light of the illuminating unit 5 adversely affects the illuminance measurement by the illuminometer 1 (which causes erroneous measurement as described above).

  In the state where the illumination unit 5 is controlled to be lit, the surroundings of the illuminometer 1 are brightened, and the illuminance value IL of the illuminance measured by the processing unit 6 in the measurement process exceeds the first threshold value ILr1. When the state is reached, the processing unit 6 determines in step 52 that the illuminance value IL is not less than or equal to the first threshold value ILr1, and proceeds to step 53. In this case, until the brightness around the illuminometer 1 reaches a brightness at which the illuminance value IL of the illuminance measured by the processing unit 6 in the measurement process is equal to or greater than the second threshold value ILr2, the processing unit 6 Then, the process proceeds to step 54, where the lighting unit 5 is controlled to maintain the lighting / extinguishing state of the lighting unit 5 in the current state (in this case, the lighting state). Only when the brightness reaches a brightness at which the illuminance value IL of the measured illuminance is equal to or greater than the second threshold value ILr2, the processing unit 6 proceeds to step 55 and is turned off with respect to the illumination unit 5. The control to shift to is executed.

  As a result, in the illuminometer 1, the brightness around the illuminometer 1 is reduced to a brightness at which the illuminance value IL of the measured illuminance is equal to or less than the first threshold value ILr1, whereby the processing unit 6 is illuminated. In the state where the unit 5 is controlled to be in the lighting state, the brightness around the illuminometer 1 varies slightly, and the illuminance value IL of the measured illuminance exceeds the first threshold value ILr1, or the first threshold value. Even if the state where the value is less than or equal to the value ILr1 is repeated, the illumination unit 5 is maintained in the lighting state until the illuminance value IL of the measured illuminance becomes equal to or greater than the second threshold value ILr2. For this reason, it is possible to avoid the occurrence of an unfavorable state in which the illumination unit 5 is repeatedly turned on and off in a short time due to variations in brightness around the illuminometer 1.

  As described above, in the illuminometer 1, the processing unit 6 is in a non-update display operation (for example, the illuminance value IL at the operation timing of the hold key 11 is displayed on the display screen without being updated. When the new illuminance value IL is not updated and displayed on the display screen), and the illuminance value IL of the illuminance newly measured in the measurement process is equal to or lower than the first threshold value ILr1. An illumination control process for shifting the lighting state to 5 is executed.

  Therefore, according to the illuminometer 1, when the brightness around the illuminometer 1 is lowered to a level that allows the operator to visually recognize the illuminance value IL displayed on the display screen of the display unit 4, If the non-update display operation is in progress, the display screen can be automatically illuminated by the illumination unit 5 without manually performing an operation for illumination. Thus, according to the illuminometer 1, during the non-update display operation in which the illuminance value IL at the operation timing of the hold key 11 is displayed on the display screen of the display unit 4 without being updated, the illuminometer 1 Even when the brightness of the surrounding area of the camera is lowered, the illuminance value IL can be reliably recognized. In addition, during the non-update display operation in which numerical values and characters displayed during various operations such as a memory operation, a timer operation, and a zero adjustment operation are displayed on the display screen of the display unit 4, Even when the brightness of the screen is lowered, the numerical values and characters for these various operations can be reliably recognized. Further, according to the illuminometer 1, the light receiving unit 2 that is the basic configuration of the illuminometer can be used to control the lighting unit 5 to be turned on / off, so that the ambient brightness is detected. As a result, the illuminometer 1 can be manufactured without increasing the manufacturing cost.

  Further, according to the illuminometer 1, the processing unit 6 compares the two threshold values of the first threshold value ILr1 and the second threshold value ILr2 with the illuminance value IL indicating the current illuminance being measured. On the basis of the above, the lighting unit 5 is controlled to be turned on / off, so that the brightness around the illuminometer 1 in the state where the illuminance value IL is equal to or lower than the first threshold value ILr1 and the illuminating unit 5 is turned on. Even if the light intensity varies slightly, the illumination unit 5 can be stably maintained in the lighting state until the illuminance value IL of the measured illuminance becomes equal to or greater than the second threshold value ILr2. For this reason, it is possible to avoid the occurrence of an unfavorable state in which the illumination unit 5 repeatedly turns on and off in a short time due to variations in brightness around the illuminometer 1.

  Moreover, according to this illuminometer 1, since the control part 6 performs control which turns off the illumination part 5 when the process part 6 starts an update display operation | movement, the leakage of the light from the illumination part 5 to the light-receiving part 2 is prevented. Thus, the illuminance value IL can be accurately measured.

  In the illuminance meter 1 described above, it is preferable that the processing unit 6 controls the lighting unit 5 to be turned on / off based on the two threshold values of the first threshold value ILr1 and the second threshold value ILr2. However, after the illuminance value IL is equal to or less than the first threshold value ILr1 and the illumination unit 5 is turned on, when the brightness around the illuminometer 1 slightly varies, Even if the lighting state becomes slightly unstable (a state in which the lighting state and the extinguishing state occur alternately in a short time), if such a state is acceptable, one threshold value (first threshold value). Based on the value ILr1), it is possible to adopt a configuration for controlling the lighting / extinguishing state of the illumination unit 5.

DESCRIPTION OF SYMBOLS 1 Illuminance meter 2 Light-receiving part 3 Operation part 4 Display part 5 Illumination part 6 Processing part 11 Hold key IL Illuminance value

Claims (3)

A light receiving unit that receives light from the outside and outputs an illuminance signal indicating the illuminance of the received light, an operation unit, a display unit having a display screen, and an illuminance of the received light based on the illuminance signal. A measurement process for measuring, a display process for displaying information on the display screen on the display unit, and a processing unit for executing a detection process for detecting that the operation unit is operated,
While the processing unit repeatedly executes the measurement process to measure the new illuminance, the numerical value indicating the measured new illuminance is calculated based on the operation content for the operation unit detected in the detection process. An update display operation for executing the display process for updating and displaying the information on the display screen as the information representing, and a non-update display operation for executing the display process for displaying information other than the current illuminance on the display screen as the information. Illuminance meter to switch between,
An illumination unit for illuminating the display screen;
The processing unit is an illumination control process for controlling execution of illumination of the display screen and stop of illumination by the illumination unit, and the numerical value indicating the measured new illuminance is in advance during the non-update display operation. An illuminometer that executes an illumination control process that causes the illumination unit to perform the illumination when the illumination value is equal to or less than a prescribed threshold value. As the threshold value, a first threshold value and a second threshold value higher than the first threshold value are defined,
In the illumination control process, the processing unit performs the illumination on the illumination unit during the non-update display operation and when the numerical value indicating the measured new illuminance is equal to or less than the first threshold value. The illuminometer according to claim 12, wherein the illumination unit is stopped when the numerical value indicating the measured new illuminance is equal to or greater than the second threshold value during the non-update display operation.   The illuminometer according to claim 1, wherein the processing unit causes the lighting unit to stop the lighting when the update display operation is started in the lighting control processing.

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