Optical measuring device

Abstract

Optical measuring device comprising: a measuring device body (1); a lighting unit (4; 5) which is removably attached to the measuring device and has a light-emitting diode (44; 49) as a light source; and a lighting control (6) which is configured to control the lighting unit according to a light intensity command value, wherein the lighting unit includes a storage unit (48) in which calibration values ​​are stored to cause the light-emitting diode (44; 49) to produce a light intensity corresponding to the light intensity command value, the lighting control (6), upon receiving the light intensity value, reads a calibration value corresponding to the light intensity command value from the calibration values ​​stored in the storage unit (48), controls the light-emitting diode (44; 49) on the basis of the calibration value, and the light-emitting diode (44;49) causes the light intensity to be produced according to the light intensity command value, the lighting unit (4; 5) includes a cable (41), a light-emitting unit (42) provided at one end of the cable (41) and comprising the light-emitting diode (44; 49), and a connection unit (47) provided at the other end of the cable and connected to the lighting control, and the storage unit (48) is provided in the connection unit (47).

Description

The present invention relates to an optical measuring device. More particularly, the invention relates to an optical measuring device provided with a lighting unit having a light-emitting diode as a light source.2. Description of the Related Art

[0002] There is known an optical measuring apparatus provided with various illumination units (for example, an incident-light illumination unit or a transmission illumination unit) mounted on a meter body and configured to measure the shape or the like of a measured object (a measured object) Work) while the measured object is irradiated with light from one of the illumination units.For example, an image processing measuring apparatus described in Unexamined Japanese Patent Laid-Open Publication No. 2004-220834 includes an LED (Light Emitting Diode), a CCD (Charge Coupled Device) camera (image pickup device), and a control device for controlling the LED and the CCD camera is configured. The control device illuminates the measured object while controlling a current applied to the LED in accordance with an input light intensity command value, and acquires image information by controlling the CCD camera and receiving reflected light from the measured object. Thereafter, the shape of the measured. Object measured by processing the acquired image information.In the optical measuring apparatus, a difference in brightness affects measurement results, and therefore, it is necessary to cause the lighting unit to produce a precise light intensity corresponding to the given light intensity command (target) value. However, in the optical measuring apparatus having the lighting unit with the LED as the light source, the light intensity varies depending on individual LEDs even if they have the same model number. Therefore, a countermeasure is applied to generate predetermined light intensities corresponding to the light intensity command values.For example, as shown in FIG. 7, a conversion table (calibration value) including current command values ​​and relative PWM (pulse width modulation) duty cycles required to cause an LED 44 of a lighting unit 4 to have a light intensity which corresponds to a light intensity command value (0 to 100%) given from the meter body or a PC (personal computer) 3 is stored in a storage unit 48 of a lighting controller 6.In addition to the memory unit 48, the lighting controller 6 is provided with a D / A converter 61, a PWM generator 62, a control unit 63 configured to supply the current command value and the relative PWM duty, the light intensity command value from the memory unit 48 Receiving the light intensity command value to read and setting the current command value and the relative PWM duty to the D / A converter 61 and the PWM generator 62, and provided to a constant current generator 64.Upon receiving the light intensity command value, the control unit 63 reads out calibration values ​​(current command value and relative PWM duty) corresponding to the light intensity command value from the memory unit 48, and sets the current command value and the relative PWM duty to the D / A converter 61 and the PWM generator 62 a. A control pulse of the set PWM duty ratio is generated from the PWM generator 62. Then, the constant current generator 64 applies a current converted by the D / A converter 61 corresponding to the current command value to the LED 44 of the lighting unit 4 when the control pulse generated by the PWM generator 62 is ON. Accordingly, the LED 44 emits light having the light intensity corresponding to the light intensity command value.In the related art optical measuring apparatus, since the calibration values ​​are stored in a lighting control separate from the lighting unit, there are the following problems. (a) In general, the operating time of the LED is longer than that of fluorescent lamps or the like, but the brightness is lower. Therefore, in applications requiring the precision of brightness, replacement at regular intervals is desired. Accordingly, when replacing the lighting unit, a process of writing the calibration values ​​to the lighting controller is required.It is an important setting that affects the measurement accuracy, and it must be done with a high degree of reliability; A service technician of the manufacturer must go to the location of the user in order tomake the adjustment. (b) The registration of the calibration value at the time of mounting can be performed only when a combination of the lighting control and the lighting unit is determined.Therefore, in the second half of the assembly, the measuring device, when almost complete, must wait for a time-consuming light calibration, so that disadvantages such as an increased number of components in the middle of the assembly and a reduction of the space efficiency result.A countermeasure such as the time-consuming light calibration is performed in advance and the calibration data is stored in an FD (flexible disk) is also conceivable, but the pairwise handling of the FDs and the lighting units is cumbersome. (c) When a wrong measuring unit is connected, that is, when a lighting unit other than the predetermined lighting unit is connected to the lighting controller, the apparatus may be used with a wrong brightness.SUMMARY OF THE INVENTIONTo solve the above-described problems, it is an object of the invention to provide an optical measuring apparatus which achieves the reduction of the cost of replacing a lighting unit and improving the production efficiency as well as eliminating the risk of using the device with a false light intensity.An optical measuring device comprising: a measuring device body; a lighting unit attached to the measuring device, which is particularly removably attached to the measuring device, and having a light-emitting diode as a light source; and a lighting controller configured to control the lighting unit according to a light intensity command value, wherein the lighting unit includes a storage unit in which calibration values ​​are stored to cause the light emitting diode to generate a light intensity corresponding to the light intensity command value, and the lighting control upon reception of the light intensity command value Light intensity value reads out a calibration value corresponding to the light intensity command value from the calibration values ​​stored in the memory unit, controls the light emitting diode based on the calibration value, and causes the light emitting diode to generate the light intensity corresponding to the light intensity command value.With this configuration, since the memory unit in which the calibration values ​​for causing the light-emitting diode to generate the light intensity corresponding to the light intensity command value is stored on the lighting unit, the operation for writing the calibration values ​​can be eliminated when replacing the lighting unit. removably attached to the meter body. Thus, since no service technician needs to go to a user's location to make an adjustment, the cost of replacing the lighting unit is reduced.Since the light calibration can be performed at any time after the lighting unit is assembled, an improvement in production efficiency is achieved. In other words, disadvantages are eliminated, such as an increase in the number of components in the middle of assembly and a reduction in space efficiency.At the same time eliminating the risk of the connection of a false lighting unit in the use of the device with a false light intensity is achieved.Preferably, a conversion table includes current command values ​​to be applied to the light-emitting diode and relative turn-on durations when controlling the pulse of a current to be applied to the light-emitting diode according to the light intensity command value stored as the calibration values ​​in the memory unit, and the lighting controller reads out a current command value and a duty ratio corresponding to the light intensity command value from the conversion table upon receipt of the light intensity value, and applies a current corresponding to the current command value to the light emitting diode in the lighting unit when a control duty of the read duty ratio is ON.In this configuration, since the current command values ​​to be applied to the light emitting diode and the duty ratios when the pulses of the current are to be applied to the light emitting diode corresponding to the light intensity command values ​​are stored as the calibration values, in this configuration, the light intensity becomes the light emitting Diode precisely controlled using the two calibration values; namely the current command value and the relative duty cycle.Preferably, different duty ratios for low light intensity command values ​​than the calibration values ​​are stored in the low light intensity command values, and verDifferent current command values ​​are stored as the calibration values ​​in high light intensity command values ​​from the light intensity command values.In general, in a region where a applied current is low, the light intensity can be easily controlled by changing the applied current disturbance, so that the precise light intensity can not be obtained. However, in a range of applied current of a certain reference value or higher, the light intensity can be smoothly controlled by changing the applied current, so that the precise light intensity can be obtained.Since the different duty ratios for the low light intensity command values ​​(a range lower than a predetermined reference light intensity command value) are stored as the calibration values ​​in the low light intensity command values ​​and different current command values ​​as the calibration values ​​in the high light intensity command values ​​(a range not lower than the predetermined one According to the invention, the light intensity of the light emitting diode can be precisely controlled by controlling the pulse width in the low light intensity command values, and the light intensity of the light emitting diode can be precisely controlled by controlling the current to be applied to the light emitting diode in the high light intensity command values being controlled. Therefore, in the entire range of the light intensity command value, the light intensity of the light emitting diode can be precisely controlled.Preferably, the lighting unit includes a cable, a light-emitting unit provided at one end of the cable and having the light-emitting diode, and a connection unit provided at the other end of the cable and connected to the lighting controller and the storage unit is provided in the connection unit.Since the lighting unit includes the cable, the light-emitting unit and the connection unit, and the connection unit is provided with the storage unit, that is, since the storage unit is provided in the connection unit other than the light-emitting unit as the light source, in this configuration as much as possible prevents the storage unit from being affected by the heat from the light-emitting unit.Preferably, the light-emitting unit includes a heat-emitting blower, and the operation of the heat-emitting blower is controlled by the lighting controller when the connection unit is connected to the lighting controller.In this configuration, since the heat-emitting blower is provided in the light-emitting unit and the operation of the heat-emitting blower is controlled by the lighting controller when the connection unit is connected to the lighting controller, it is particularly suitable for the lighting unit having a high light intensity.BRIEF DESCRIPTION OF THE DRAWINGSFig. 1 is a schematic drawing showing an embodiment of an optical measuring apparatus according to the invention;Fig. 2 is a drawing showing a lighting unit in the same embodiment;Fig. 3 is a block diagram showing a lighting controller in the same embodiment;Fig. 4 is a graph showing a control state regarding a high light intensity command value and a low light intensity command value in the same embodiment;Fig. 5 is a graph showing a relationship showing the light intensity command value and the brightness of image data taken by a CCD camera in the same embodiment;Fig. 6 is a drawing showing another example of the lighting unit; andFig. 7 is a drawing showing a relation between a lighting controller and a lighting unit in the related art.DESCRIPTION OF THE PREFERRED EMBODIMENTSAn embodiment of the invention will now be described with reference to the drawings.<Rough configuration of a microscope (see FIG. 1)>An optical measuring apparatus according to the embodiment is an example of the application to a microscope. The microscope includes a measuring device body 1, a CCD (batchCoupled Device) camera 2 as an image pickup device, which is removably attached to the measuring device body 1, a PC(Personal computer) 3 for measuring the shape or the like of a measured object W by processing image information acquired by the CCD camera 2, an incident illumination unit 4 and a transmission illumination unit 5 removably attached to the gauge body 1, and a lighting controller 6 thereto is configured to control the incident illumination unit 4 and the transmission illumination unit 5.The measuring device body 1 includes a table 11 made of a glass plate for placing the measured object W, an objective lens 12 arranged on the table 11 so as to be movable up and down, half mirrors 13 and 14 mounted on a table optical axis of the objective lens 12, a reflecting mirror 15 configured to let an incident light enter the half mirror 13, and an observation optical system 16 including an eyepiece for observing reflected light from the half mirror 14.The CCD camera 2 includes an image pickup lens 21 configured to image light transmitted through the half mirrors 13 and 14 at a predetermined position, and an image pickup element 22 configured to receive the light imaged by the image pickup lens 21.The PC 3, which includes a CPU (central processing unit), a memory and the like, is configured to control the entire microscope, and is capable of scanning the image information of the measured object W received from the CCD camera 2 and to store the same in the memory as image data (arrow A in Fig. 1) and to output control signals for adjusting gain, exposure time and the like of the CCD camera 2 (arrow B in Fig. 1).<Incident illumination unit (see FIG. 2)>The incident illumination unit 4 is configured to illuminate the measured object W in Fig. 1 from above, and includes a cable 41, a light emitting unit 42 provided at one end of the cable 41, and a connection unit 47 provided at the other end of the cable 41 and connected to the lighting controller 6 as shown in FIG.The light-emitting unit 42 includes a shell 43 configured to be removably mounted on the meter body 1, a light-incident LED 44 as a light-emitting diode inserted in the shell 43, and a collimator lens 45, configured to direct light emitted from the light-incident LED 44 and to guide it to enter the reflective mirror 15. On an outer peripheral portion of the shell 43 into which the light-incident LED 44 is inserted, there are a number of heat-emitting fins 46 as a heat-emitting device. Accordingly, the heat is emitted from the light-incident LED 44 via the heat-emitting fins 46.The connection unit 47 is provided with a storage unit 48. A conversion table including current command values ​​and duty ratios to be applied to the light-incident LED 44 when controlling the pulse of the current to be applied to the light-incident LED 44 in accordance with the light-intensity command value is stored as calibration values ​​in the memory unit 48. Specifically, in the memory unit 48, different duty ratios for low light intensity command values ​​are stored as the calibration values ​​in the low light intensity command values ​​(a range in which the light intensity command values ​​are smaller than a predetermined reference light intensity command value L1), and different current command values ​​are used as the calibration values ​​in high light intensity command values ​​(not lower than the predetermined one) Reference light intensity command value L) is stored from the light intensity command values.<Transmission lighting unit>The transmission illumination unit 5 is configured to illuminate the measured object W in Fig. 1 from below, and is substantially the same as the incident illumination unit as a basic configuration. Therefore, a detailed description will be replaced by the illustration in FIG. However, in a storage unit 48 of the transmission illumination unit 5, a conversion table including current command values ​​and duty ratios to be applied to a transmission light LED 49 are stored as the calibration values ​​when controlling the pulse of the current to be applied to the transmission light LED 49 in accordance with the light intensity command value.<Illumination control (see FIG. 3)>As shown in Fig. 3, the lighting controller 6 includes a D / A converter 61, a PWM generator 62, a control unit 63 configured to output current instruction values ​​and duty ratios corresponding to the light intensity instruction value from the storage units 48 of the incident illumination unit 4 and the transmission lighting unit 5 on receptionof the light intensity command value from the PC 3 and set the current command values ​​and duty ratios read out therefrom to the D / A converter 61 and the PWM generator 62, and a constant current generator 64 configured to apply currents corresponding to the current command values ​​supplied from the D / A converter 61 are converted when the control pulse from the PWM generator 62 to the LEDs 44 and 49 of the lighting unit is turned ON.<Measurement of the measured object>In the measurement of the measured object W, when the incident light illumination unit 4 is used, the light emitted from the light incident LED 44 is reflected by the reflecting mirror 15 via the collimator lens 45 and emitted from above the measured object W via the objective lens 12. The reflected light from the measured object W passes through the objective lens 12, the half mirrors 13 and 14, and enters the CCD camera 2, and a part of the reflected light reflected by the half mirror 14 enters the observation optical system 16 and is observed by the observation optical system 16.When the transmission illumination unit 5 is used, the measured object W is irradiated with the light emitted from the transmission light LED 49 from below. The light which has passed through the measured object W passes through the objective lens 12, the half mirrors 13 and 14, and enters the CCD camera 2, and a part of the light reflected by the half mirror 14 enters the optical one Observation system 16 and is observed by the observation optical system 16.Thereafter, the PC 3 scans the image information of the measured object W taken by the CCD camera 2 and put in the memory as the image data, and processes the image data supplied to measure the shape of the measured object W.<Light intensity control (see Figs. 4 and 5)>Fig. 4 is a graph showing a control state by the current command values ​​and duty ratios stored in the storage units 48 of the incident illumination unit 4 and the transmission illumination unit 5. In Fig. 4A, a side axis indicates the light intensity command value, and a vertical axis indicates the applied current. In Fig. 4B, the side axis indicates the light intensity command value, and the vertical axis indicates the duty ratio of the pulse.Fig. 5 is a graph showing a relationship illustrating the light intensity command value and the brightness of the image data taken by the CCD camera 2. In Fig. 5, the side axis indicates the light intensity command value and the vertical axis indicates the brightness of the image data.The control unit 63 controls the light intensities of the light-incident LED 44 and the transmission light LED 49 on the basis of the calibration values ​​read from the storage units 48.First of all, when the light intensity command values ​​read from the storage units 48 become the lowLight intensity command values ​​are pulses of currents to be applied to the light-incident LED 44 and the transmission light LED 49. In particular, in the case of the low light intensity command value (when the light intensity command value is smaller than thatReference light intensity command value L is), a no-break state is designated as low, and a current having a reference value I from which the reference light intensity command value L can be detected is designated as high, as shown in Fig. 4A, and the light intensity in the low light intensity command value area is determined by controlling the light intensity command value controlled duty cycle of the pulse, as shown in Fig. 4B.When the light intensity command values ​​read from the memory units 48 are the high light intensity command values, currents to be applied to the light incident LED 44 and the transmission light LED 49 are also controlled. Specifically, in the case of the high light intensity command value (when the light intensity command value is not smaller than the reference light intensity command value L), the pulse control is stopped (100% duty ratio) as shown in FIG. 4B, and the light intensity in the high light intensity command value amount is controlled by controlling the applied current, such as shown in Fig. 4A.Therefore, the brightness of the image data taken by the CCD camera 2 has a substantially linear relationship as shown in Fig. 5.The brightness of the image data taken by the CCD camera 2 is not limited to being linear, as shown in Fig. 5, but may be different curves by changing the calibration values. Since the human eye is generally sensitive to a change in a dark area, a curved line, such as a quadratic function, which assumes a smaller change, can also be used.when he is dark.<Advantages of the embodiment>(1) Since the storage units 48 storing the calibration values ​​for causing the light-incident LED 44 and the transmission light LED 49 to generate the light intensities corresponding to the light-intensity command value are mounted on the incident-light illumination unit 4 and the transmission illumination unit 5 removably mounted on the measurement device body 1 are provided, an operation for writing the calibration values ​​when the incident illumination unit and the transmission illumination unit 5 are exchanged can be eliminated. Thus, since no service technician needs to go to the user's location to perform a setting operation, the cost of replacing the incident illumination unit 4 and the transmission illumination unit 5 is lowered.Since the light calibration can be performed at any time after the incident illumination unit 4 and the transmission illumination unit 5 are assembled, an improvement in the production unit is achieved. In other words, disadvantages such as the increase in the number of components in the middle of the course of assembly and a reduction in space efficiency are eliminated.At the same time, the elimination of the risk of the connection of the false lighting unit and the use of the device with a false lighting unit caused by connecting a wrong measuring unit is achieved. (3) Since the current command values ​​to be applied to the LEDs 44 and 49 and the duty ratios when controlling the pulses of the currents to be applied to the LEDs 44 and 49 corresponding to the light intensity command value are stored as the calibration values, the light intensities of the LEDs 44 and 49 become low Using the two calibration values ​​precisely controlled; namely the current command value and the relative duty cycle.In particular, since the different duty ratios for the low light intensity command values ​​as the calibration values ​​in the low light intensity command values ​​and the different current command values ​​as the calibration values ​​in the high light intensity command values ​​are stored from the light intensity command values, the light intensities of the LEDs 44 and 49 can be reduced to low by controlling the pulse width Light intensity command values ​​can be precisely controlled, and the light intensities in the high light intensity range can be controlled precisely as in the related art by controlling the currents to be applied to the LEDs 44 and 49 in the high light intensity command values. Therefore, throughout the scope of the light intensity command value, the light intensities of the LEDs 44 and 49 can be precisely controlled. (4) Since the incident illumination unit 4 and the transmission illumination unit 5 respectively include the cable 41, the light emitting unit 42 and the connection unit 47, and the connection unit 47 is provided with the storage unit 48, that is, the storage unit in the connection unit 47 of the light emitting unit 42 is provided separately from the light source, the memory unit 48 is prevented as much as possible from heat from the light emitting unit 42.<Modifications (see Fig. 6)>The invention is not limited to the above-described embodiment, and modifications or developments within the scope permitting accomplishment of the invention are included in the invention.The incident illumination unit 4 and the transmission illumination unit 5 are not limited to the structure described in the embodiment. For example, a structure shown in Fig. 6 is applicable. A lighting unit 7 shown in FIG. 6 includes a heat-emitting blower 50 as the heat-emitting device inserted in the light-emitting unit 42. The heat-emitting blower 50 is configured to be operated by the lighting controller 6 when the connection unit 47 is connected to the lighting controller 6.Therefore, according to the configuration described above, since the heat-emitting blower 50 is provided in the light-emitting unit 42 and the heat-emitting blower 50 is operated by the lighting controller 6 when the connection unit 47 is connected to the lighting controller 6, the negative Effect of heat from the light-emitting unit 42 avoided as much as possible.In this structure, since the heat from the light-emitting unit 42 can be discharged efficiently to the outside, it is particularly suitable for a measuring device requiring a lighting unit with high light intensity.Although the light intensity in the low light intensity range is controlled by controlling the duty ratio of the pulse corresponding to the low light intensity command value in the aboveis controlled embodiment described, the invention is not limited thereto. For example, the light intensity in the low light intensity command value range can be controlled by controlling the high current value of the pulse.Also, the light intensity in the low light intensity range can be controlled by controlling the exposure time of the CCD camera 2 according to the low light intensity command value. Alternatively, the light intensity in the low light intensity range can be controlled by controlling the gain of the image pickup device, and the light intensity in the low light intensity range can be controlled by controlling the gain and the exposure time of the image pickup device.Although the lighting units 4 and 5 using a single color LED 44 and 49 have been described in the embodiment described above, the invention is also applicable to an optical measuring apparatus configured to combine light in a desired color by combining from LEDs of, for example, R (red), G (green) and B (blue), and to irradiate the measured object W with the generated light to measure the measured object W.For example, although the light intensity command value is given by the PC 3 in the above-described embodiment, a configuration in which the light intensity command value is set in the meter body 1 and this set light intensity command value is supplied from the meter body 1 to the lighting controller 6 is applicable.Although, in the embodiment described above, the control unit 63 reads out the calibration values ​​corresponding to the light intensity command value from the memory units 48 upon receiving the light intensity command value from the PC 3 and controls the LEDs 44 and 49 based on the calibration values, the invention is not limited thereto. For example, when an EEPROM (Electrically Erasable and Programmable Read Only Memory) is used as the memory units 48, the cost is lowered. However, since the access speed to the EEPROM is low, the light modulation response becomes slow. Therefore, by configuring the control unit 63 to have a CPU or RAM (Random Access Memory) 9, thereby reading the calibration values ​​from the memory units 48 and storing them in RAM upon activation of the CPU, and reading the LEDs 44 and 49 by reading the calibration values in accordance with the light intensity command value from the RAM, the light modulation response is improved.The present invention is applicable to a microscope, an image measuring apparatus, and so on, having oneLighting unit is provided, which has a light-emitting diode as the light source.QUOTES INCLUED IN THE DESCRIPTIONThis list of documents listed by the applicant has been generated automatically and is included solely for the purpose of better informing the reader. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.Cited patent literatureJP 2004-220834

[0003]

Claims

[1] Optical measuring device with: a measuring device body (1 ); a lighting unit (4; 5) which is removablely attached to the measuring device and has a light-emitting diode (44; 49) as a light source; and a lighting controller (6) configured to control the lighting unit according to a light intensity command value, the lighting unit including a memory unit (48) in which calibration values ​​are stored to cause the light-emitting diode (44; 49) to produce a light intensity according to the light intensity command value, and The lighting control (6) upon receiving the light intensity value reads a calibration value corresponding to the light intensity command value from the calibration values ​​stored in the storage unit (48), controls the light-emitting diode (44; 49) on the basis of the calibration value and causes the light-emitting diode (44; 49) to generate the light intensity according to the light intensity command value. [2] Optical measuring device according to claim 1, wherein a conversion table that includes current command values ​​to be applied to the light-emitting diode (44; 49) and relative duty cycles when controlling the pulse of the current to be applied to the light-emitting diode (44; 49) according to the light intensity command value, when the calibration values ​​are stored in the memory unit (48), and The lighting control (6) reads a current command value and a relative on-time corresponding to the light intensity command value from the conversion table upon receipt of the light intensity command value and applies a current corresponding to the current command value to the light-emitting diode (44; 49) in the lighting unit when a control pulse of the read relative on-time is ON. [3] Optical measuring device according to claim 1 or 2, wherein in the storage unit (48) different relative duty cycles for low light intensity command values ​​are stored as the calibration values ​​in the low light intensity command values ​​and different current command values ​​are stored as the calibration values ​​in a high light intensity command value from the light intensity command values. [4] Optical measuring device according to any one of claims 1 to 3, wherein the lighting unit (4; 5) includes a cable (41), a light-emitting unit (42) provided at one end of the cable (41) and comprising the light-emitting diode (44; 49), and a connecting unit (47) provided at the other end of the cable and connected to the lighting control, and the storage unit (48 ) is provided in the connection unit (47 ). [5] Optical measuring device according to claim 4, wherein the light-emitting unit (42) includes a heat-emitting fan (50); and the operation of the heat-emitting fan (50) is controlled by the lighting control (6) when the connecting unit (47) is connected to the lighting control (6).

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