JP4524224B2 - Lens centering device, lens centering method, and lens centering program - Google Patents

Description

  The present invention relates to a lens centering device, a lens centering method, and a lens centering program for centering a minute lens used in, for example, an endoscope.

  In the process of combining a plurality of minute lenses used in an endoscope or the like, a centering operation for measuring the amount of eccentricity of the lens and centering the lens is performed. In this centering operation, the reflected light of the light beam applied to the lens is imaged and observed by a camera, and the position of the lens is adjusted so that the eccentricity is less than or equal to the target size.

For example, Japanese Patent Application No. 2003-195917 discloses a lens centering device that allows easy adjustment of the optical system of the centering device even when there are many changes in the shape of a lens spot image or disturbance image.
Japanese Patent Application No. 2003-195917

  However, the target eccentricity differs depending on the shape of the lens, and it is left to the discretion of each worker to determine whether or not the target is satisfied. There was a problem that.

  The present invention has been made paying attention to such a problem, and the object is to perform centering with accuracy without variation by calculating the target eccentricity corresponding to different lens shapes. A lens centering apparatus, a lens centering method, and a lens centering program are provided.

To achieve the above object, a first aspect of the present invention is the lens centering device, irradiating means for irradiating a light beam from the light source to the lens, the reflected light from the lens while rotating the lens An imaging means for acquiring an imaging signal by capturing, a measurement eccentric circle creating means for creating a measurement eccentric circle based on a spot image obtained from the imaging signal, and a lens to be measured based on data obtained with respect to the lens Identifying means for identifying, target eccentric circle creating means for creating a target eccentric circle based on the identified lens parameters, the size of the measurement eccentric circle created by the measurement eccentric circle creating means, and the creation of the target eccentric circle An allowable range determination for comparing the size of the target eccentric circle created by the means and determining whether the measured eccentric circle is within the allowable range based on the comparison result Means.

      Moreover, the 2nd aspect of this invention is further equipped with the display means which compares and displays the said measurement eccentric circle and the said target eccentric circle in the 1st aspect.

According to a third aspect of the present invention, in the first aspect, there is provided an input unit that inputs in advance a device-specific parameter and a lens-specific parameter for each target lens, and the specifying unit acquires the lens. The lens to be measured is specified from the data input via the input means using the data obtained , and the target eccentric circle creating means determines the specified lens parameters and the input device-specific parameters. To create a target eccentric circle .

According to a fourth aspect of the present invention, in the first aspect, the measurement eccentric circle creating means is a plurality of sampling points obtained when sampling a spot image obtained from the reflected light from the lens at regular intervals. The locus of the spot image is obtained from the above to create the measurement eccentric circle .

Further, according to a fifth aspect of the present invention, in any one of the first to fourth aspects, the data acquired regarding the lens includes a curvature and a middle thickness of the lens, and the curvature and the middle thickness are: Calculated based on the sampling coordinate value when the lens is slid while contacting the measurement terminal and the current measurement value is sampled at a fixed period, or based on the reflected light when the lens is irradiated with laser light Or manually input in advance by an operator.

According to a sixth aspect of the present invention, in the lens centering method, an irradiation step of irradiating the lens with a light beam from a light source, and an imaging signal is acquired by capturing reflected light from the lens while rotating the lens. An imaging step, a measurement eccentric circle creating step for creating a measurement eccentric circle using a spot image obtained from the imaging signal, a specifying step for identifying a lens to be measured based on data acquired with respect to the lens, a target eccentric generating step of generating a target circular eccentric based on the parameters of the identified lens, the measurement and the magnitude of the measuring eccentric created in eccentric creation step, the target eccentricity created in the target eccentric creation step An allowance for comparing the size of the circle and determining whether the measured eccentric circle is within an acceptable range based on the comparison result Comprising a circumference determination step.

Further, a seventh aspect of the present invention is the lens centering program, a computer, and irradiating means for irradiating a light beam from a light source to the lens, captures reflected light from the lens while rotating the lens imaging An imaging unit for acquiring a signal, a measurement eccentric circle generating unit for generating a measurement eccentric circle using a spot image obtained from the imaging signal, and a lens to be measured based on data acquired with respect to the lens Specific means, target eccentric circle creation means for creating a target eccentric circle based on the specified lens parameters, the size of the measurement eccentric circle created by the measurement eccentric circle creation means, and the target eccentric circle creation means An allowable range determining means for comparing the size of the target eccentric circle and determining whether the measured eccentric circle is within the allowable range based on the comparison result The lens is centered by functioning as a lens centering means .

  According to the present invention, adjustment within the same allowable eccentricity is possible for each lens shape and characteristic.

  In addition, since the size of the target circle calculated from the radius of curvature input in advance and the allowable eccentricity value is displayed, it is possible to easily determine whether the measured eccentric circle is within the allowable eccentricity value. it can.

  Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram showing a basic system configuration of the lens centering device of the present embodiment. An eccentricity adjusting machine 100 for adjusting the eccentricity when performing lens processing generally rotates with a lens holder (not shown) for holding the lens 1 to be processed and a lens holder detachably held. A lens holding shaft (not shown) and a movement adjusting mechanism (not shown) supported by the lens holding shaft and moving and adjusting the lens holder in a direction perpendicular to the rotation axis of the lens holding shaft and an inclination direction. Prepare. The eccentricity measuring device 101 includes a light source 24 and a CCD camera 20. An arithmetic processing unit 103 and a monitor 104 are connected to the eccentricity measuring device 101 via an image processing circuit 102. An input unit 105 is connected to the arithmetic processing unit 103. The light source 24 emits predetermined spot light toward the lens 1. The CCD camera 20 captures the reflected light from the lens 1 and captures a spot image. The image processing circuit 102 performs a calculation for detecting a spot image from the imaging signal. The arithmetic processing unit 103 performs predetermined arithmetic processing on the spot image data to detect the shape and area of the spot image and calculate the position locus.

  When adjusting the eccentricity of the lens 1, the light source 21 is driven to irradiate the lens 1 with spot light. In this state, the lens holder, that is, the lens 1 is rotated by rotating the lens holding shaft. At this time, the reflected image from the lens 1 incident on the CCD camera 20 is observed by the CCD camera 20. When the reflected image is observed while rotating the lens 1 in this way, the reflected image draws a circle having a radius corresponding to the eccentricity, and the radius of the circle at this time is measured. Then, the eccentricity adjustment and the observation of the reflected image are alternately repeated until the radius of the reflected image becomes a reference value or less.

  FIG. 2 is a diagram showing a specific system configuration of the lens centering device. FIG. 3 is an enlarged view of a portion A in FIG. On the pedestal unit 208, as elements of an eccentricity adjusting machine, a lens shaft unit 205, a lens shaft rotating motor 203 that rotates the lens shaft unit 205, an eccentricity adjustment stage 202 that adjusts the eccentricity of the lens 1, and an eccentricity adjustment A left-right drive motor 206 that drives the stage 202 in the left-right direction (vertical direction in the figure) and a front-rear drive motor 207 that drives the eccentricity adjustment stage 202 in the front-rear direction (horizontal direction in the figure) are provided. As shown in FIG. 3, an end of an eccentricity adjustment stage 202 is provided with a fastening yatoe 301 and a lens yatoy 300 as lens holders for holding the lens 1.

  Further, an outer diameter machining spindle 200 for grinding the outer periphery of the lens and an inner diameter determining machining spindle 201 for machining the lens front part are provided. A grindstone 302 for grinding the lens is provided at the tip of the outer diameter machining spindle 200.

  Further, an eccentricity measuring device 101 for measuring the eccentricity before the lens processing and a curvature / medium thickness measuring device 110 for measuring the curvature and the inner thickness of the lens 1 are arranged. The curvature / medium measuring device 110 is connected to the arithmetic processing unit 103 described with reference to FIG.

  The details of the eccentricity adjustment flow when a contact-type measuring device is used as an example of the curvature / medium thickness measuring device 110 will be described below with reference to FIG. All parameters specific to the apparatus and parameters specific to the lens are input in advance for each target lens via the input unit 105 (step S1). The arithmetic processing unit 103 creates a table based on the input data. As parameters unique to the apparatus, a distance (mm) from the lens surface to the reticle, a pixel calibration value (pixel / mm), a surface reticle magnification of the reference lens, a maximum magnification of the CCD camera, and the like can be considered. Here, pixel is the number of pixels of the CCD. The reticle is a regular image forming position of the reflected image, and is a range indicated by a distance (mm) B from the lens surface to the reticle in FIG. The reticle magnification is a reflected image locus radius a (mm) when the lens is decentered by 1 mm. The pixel calibration value is a locus radius P (pixel) in an image when the lens 1 is decentered by 1 mm at the maximum magnification of the CCD camera 20. An image of the locus radius P is shown as an example on the monitor 104 in FIG.

  Parameters set for each lens include curvature (mm), fillet (mm), refractive index, CCD camera magnification (during centering adjustment), target lens eccentric circular radius (μm), lens outer diameter (mm) ), Lens inner diameter (mm), and the like.

  Next, the eccentricity adjustment stage 202 is moved to a position where the lens 1 comes into contact with the curvature measurement start position, that is, the measurement terminal 111 (step S2, FIG. 5A). Next, the current measurement value is sampled at a constant period while sliding the lens 1 along the lens surface toward the curvature measurement end position (step S3). Then, it is determined whether or not the lens 1 has reached the measurement end position (step S4). Steps S3 and S4 are repeatedly executed until the measurement end position is reached, but when the lens 1 reaches the measurement end position, the process proceeds to step S5 to calculate the curvature from the locus of the sampling coordinates. Here, since the lens 1 is convex, the sampling coordinates draw a circular trajectory passing through the apex position shown in FIG. 5B from the curvature measurement start position to the curvature measurement end position. It is assumed that the locus of sampling coordinates is sequentially stored in the internal memory of the arithmetic processing unit 103.

  In step S5, the curvature of the lens 1 is calculated from the locus of sampling coordinates. Next, the inside of the lens 1 is calculated from the difference between the vertexes of the sampling coordinates (FIG. 5B) and the coordinates (fixed value) of the lens attachment surface (step S6).

  Next, the eccentricity adjustment stage 202 is moved to face the eccentricity measuring device 101 (step S7). This is the centering position of the lens 1. Next, the target radius (R0) of the eccentric circle is calculated (step S8).

  FIG. 6 is a flowchart for explaining the procedure for calculating the eccentric circle target radius (R0). First, the target lens is specified by searching the table created in step S1 from the previously obtained curvature value and inner value of the lens (step S101). Next, a parameter specific to the specified target lens is read (step S102). Next, the eccentric target radius (R0) is calculated using the parameters of the target lens and the device-specific parameters already input (step S103).

  Returning to the flowchart of FIG. 4, next, the eccentric circle radius (R1) is measured (step S9).

  FIG. 7 is a flowchart for explaining the calculation procedure of the eccentric circle radius (R1). In step S111, for example, the spot image 150 is visually determined from the image displayed on the monitor 104, and the attachment position of the lens 1 is adjusted by the eccentricity adjustment stage 202 so that the spot image 150 is clearly displayed on the monitor 104. The spot image 150 displayed on the screen of the monitor 104 is touch-inputted with a finger to select the spot image 150 (step S111). Next, the lens shaft portion 205 is driven to rotate the lens 1 in the outer peripheral direction (step S112). Next, the center of gravity a and area S of the selected spot image 150 are calculated by the arithmetic processing unit 103, and the center of gravity position a of the spot image 150 is stored as a first sampling point (step S113). Next, it waits for a fixed time to elapse (step S114).

  Next, in order to detect the spot image 150 when the lens 1 is rotated in the outer circumferential direction, for example, a spot image after a certain time expected from the position of the first sampling point and the rotation speed of the lens shaft portion 205 is used. Is calculated and set by the arithmetic processing unit 103 (step S115). Next, a spot image within a movable range after a certain time has elapsed is extracted (step S116). Next, the spot having the area closest to the area S obtained in step S113 is stored (step S117).

  Next, it is determined whether or not the lens 1 has been rotated once (step S118). If NO, the process returns to step S113, and the subsequent steps are executed again. If YES, the rotation of the lens 1 is stopped (step S119). Next, the locus of the spot image is obtained from a plurality of sampling points detected and calculated every predetermined time by rotating the lens 1, and the locus centroid is calculated (step S120). The locus centroid calculated in this way is displayed on the monitor 104, and the position of the lens 1 is adjusted by the eccentricity adjustment stage 202 so that the spot image is positioned at the locus centroid displayed on the monitor 104. Thereby, the centering adjustment of the lens 1 by the reflected image of the lens 1 of the spot light can be performed.

  Returning to the flowchart of FIG. 4, next, the eccentric circle measurement radius (R1) and the eccentric circle target radius (R0) are compared (step S10). If R0 is determined to be larger than R1 in the comparison here, it means that the measured eccentric circle is smaller than the target eccentric circle, so OK is notified (displayed here) (step S12), and processing Exit. If it is determined in step S11 that R1 is larger than R0, it means that the measured eccentric circle is larger than the target eccentric circle. Step S14) is performed, and the processing after step S9 is repeated.

  FIG. 8 shows a display example of the monitor 104 at the time of eccentricity adjustment. The measurement eccentric circle (radius R1) 154 is a locus of a spot image composed of a plurality of sampling points 160a, 160b, 160c,... Detected and calculated at regular intervals by rotating the lens 1. From this locus, the locus center 151 is obtained. FIG. 8 shows a case where the measurement eccentric circle (radius R1) 154 is larger than the target eccentric circle (radius R0) 153, and further adjustment of the position of the lens 1 is necessary.

  By the way, in this embodiment, the target eccentric circle (radius R0) is calculated as the number of target pixels (CCD pixels) and then displayed on the monitor 104. Hereinafter, the calculation process of the target pixel number will be described in detail.

である。但し、ここでは第１面の偏心が０であることを前提にしている。 1. Reticle Magnification Calculation First, the reticle magnification calculation consists of the calculation of the first surface (front surface) and the second surface (back surface) of the lens. The reticle magnification calculation for the first surface is
r ₁ : curvature of the first lens surface [mm]
s ₁ : Distance from the first lens surface to the reticle (= 50 [mm])
a ₁ : First surface reticle magnification (When the first surface is shifted by 1 [mm], the reflected image draws a circle with radius a ₁ [mm])
If

It is. However, it is assumed here that the eccentricity of the first surface is zero.

である。 Next, the reticle magnification calculation for the second surface is
r ₁ : curvature of the first lens surface [mm]
r ₂ : curvature of the second lens surface [mm]
d: Medium meat [mm]
n: Refractive index [mm]
a ₂₁ : Shift second surface reticle magnification (when the second surface is shifted by 1 [mm]
(Reflected image draws a circle with radius a ₂₁ [mm])
a ₂₂ : Second surface reticle magnification for tilting (when the second surface is tilted by 1 [rad]
(Reflected image draws a circle with radius a ₂₂ [mm])
If

It is.

2. Reticle magnification → sensitivity conversion
P _cal : Pixel calibration value [pixel / mm] (The CCD camera magnification is the maximum.

である。 When the first surface of the reference lens is shifted by 1 [mm], the circle with the radius P _cal [pixel]
Shall be drawn. [Actually, 0.1mm or .001mm first side is shifted and measured.
Converted to equivalent to 1 mm shift])
a _lR : First lens reticle magnification of the reference lens C: Conversion coefficient [pixel / mm]
t ₁ : First surface sensitivity [pixel / μm]
t ₂₁ : Shift second surface sensitivity [pixel / μm]
t ₂₂ : Second surface sensitivity for tilt [pixel / min]
If

It is.

3. Sensitivity → target pixel conversion First, the target pixel number on the first side is
M _max : Maximum magnification of CCD camera
M _t : CCD camera magnification during adjustment (first side)
δ ₁ : First surface shift eccentric target value [μm] (2 μm in this case)
P ₁ : Target number of pixels on the first side [pixel]
If

Further, the target number of pixels on the second surface is obtained as follows.

δ _E : Target lens eccentricity [μm] (= outer diameter deflection / 2, 2μm in this case)
D: lens outer diameter [mm] (However, for a concave lens, D: lens inner diameter [mm])
P ₂ : Target pixel number on the second side [pixel]
M ₂ : Camera magnification during adjustment (2nd side)
x, ε, ex: Variables in the calculation process.

  Intermediate variables are calculated before calculating the target number of pixels.

a. When the first surface is convex

b. When the first surface is concave and the second surface is concave or flat

c. When the first surface is concave and the second surface is convex

Finally, the target number of pixels is calculated.

When the second surface is flat

When the second surface is the R surface

  The details of the eccentricity adjustment flow when using a non-contact type measuring device (here, a laser measuring device) as an example of the curvature / medium measuring device 110 will be described with reference to FIG. First, as in step S1 of FIG. 4, all the device-specific parameters and lens-specific parameters are input for each target lens via the input unit 105 (step S151). Next, the lens 1 is moved to the curvature and middle thickness measurement position (step S152). Next, the curvature of the lens 1 is calculated from the lens shape obtained by the laser measuring instrument (step S153). For example, as shown in FIG. 10, the lens shape can be obtained by emitting laser light from the reflective laser length measuring device 170 to irradiate the lens 1 and grasping the lens shape based on the reflected light.

  Next, the inside thickness is calculated from the difference between the coordinates of the top of the lens 1 obtained by the laser measuring instrument and the coordinates (fixed value) of the attachment surface (step S154). The coordinates of the top of the lens 1 and the coordinates of the pasting surface can also be obtained by the configuration of FIG. The next step S157 to step S164 correspond to step S7 to step S14 in FIG. 4, respectively, and the contents of the processing in each step are the same, so the description here is omitted.

  The details when the eccentricity adjustment is performed based on the data directly input by the operator will be described below with reference to FIG. First, all parameters specific to the device and parameters specific to the lens (including the curvature value and the median value measured in advance) are input for each target lens (step S171). The next step S177 to step S184 correspond to step S7 to step S14 in FIG. 4, respectively, and the contents of processing in each step are the same, so the description here is omitted.

  According to the above-described embodiment, adjustment within the same allowable eccentricity is possible even for lenses having different shapes. In addition, since the size of the target circle calculated from the radius of curvature input in advance and the allowable eccentricity value is displayed, it is possible to easily determine whether the measured eccentric circle is within the allowable eccentricity value. it can.

It is a figure which shows the basic system structure of the lens centering apparatus of this embodiment. It is a figure which shows the specific system configuration | structure of this lens centering apparatus. It is a figure which expands and shows the A section of FIG. It is a figure for demonstrating the detail of the eccentricity adjustment flow at the time of using a contact-type measuring device as an example of the curvature and the medium thickness measuring device 110. FIG. FIG. 3 is a diagram showing how a measurement terminal moves along the surface of a lens 1. It is a flowchart for demonstrating the procedure which calculates an eccentric circle target radius (R0). It is a flowchart for demonstrating the calculation procedure of an eccentric circle radius (R1). It is a figure which shows the example of a display of the monitor 104 which compared and displayed the target eccentric circle and the measurement eccentric circle. It is a figure for demonstrating the detail of the eccentricity adjustment flow at the time of using a non-contact-type measuring device (here laser measuring device). It is a block diagram for implement | achieving eccentricity adjustment with a laser measuring device. It is a figure for demonstrating the detail when eccentric adjustment is performed based on the data which the operator input directly.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens 20 CCD camera 24 Light source 50 Reflected image 100 Eccentricity adjustment machine 101 Eccentricity measuring device 102 Image processing circuit 103 Arithmetic processing unit 105 Input part 110 Curvature / medium thickness measuring device 111 Measuring terminal 202 Eccentricity adjustment stage

Claims (7)

In the lens centering device,
Irradiating means for irradiating the lens with light rays from a light source ;
Imaging means for acquiring an imaging signal by capturing reflected light from the lens while rotating the lens ;
A measurement eccentric circle creating means for creating a measurement eccentric circle based on the spot image obtained from the imaging signal ;
A specifying means for specifying a lens to be measured based on data acquired with respect to the lens;
A target eccentric circle creating means for creating a target eccentric circle based on the specified lens parameters ;
The size of the measurement eccentric circle created by the measurement eccentric circle creation means is compared with the size of the target eccentric circle created by the target eccentric circle creation means, and the measurement eccentric circle is within an allowable range based on the comparison result An acceptable range judging means for judging whether or not it is within,
A lens centering device comprising:   2. The lens centering device according to claim 1, further comprising display means for comparing and displaying the measurement eccentric circle and the target eccentric circle. It has an input means for inputting device-specific parameters and lens-specific parameters for each target lens in advance,
The specifying unit specifies a lens to be measured from data input through the input unit using data acquired with respect to the lens, and the target eccentric circle creating unit includes parameters of the specified lens and 2. The lens centering device according to claim 1, wherein a target eccentric circle is created using the input device-specific parameters. The measured eccentric creation means that creates the measurement circular eccentric seeking locus of the spot image from a plurality of sampling points obtained when a spot image obtained from the reflected light obtained by sampling at regular intervals from the lens The lens centering device according to claim 1, wherein: The data acquired with respect to the lens includes the curvature and the inner thickness of the lens, and the curvature and the inner thickness are obtained when the current measurement value is sampled at a constant period by sliding the lens in contact with the measurement terminal. 5. The calculation according to claim 1, wherein the calculation is performed based on coordinate values, calculation is performed based on reflected light when the lens is irradiated with laser light, or manual input is performed in advance by an operator. The lens centering device according to any one of the above. In the lens centering method,
An irradiation step of irradiating the lens with light rays from a light source ;
An imaging step of acquiring an imaging signal by capturing reflected light from the lens while rotating the lens ;
A measurement eccentric circle creating step of creating a measurement eccentric circle using the spot image obtained from the imaging signal ;
A specifying step of specifying a lens to be measured based on data acquired with respect to the lens;
A target eccentric circle creation step for creating a target eccentric circle based on the specified lens parameters ;
And magnitude of the measured eccentric created in the measuring eccentric creating step, said comparing the magnitude of the target eccentric created in the target eccentric creating step, the measuring eccentric circle allowable range based on the comparison result An allowable range determination step for determining whether or not it is within,
A lens centering method comprising the steps of : The computer,
Irradiating means for irradiating the lens with light rays from a light source ;
Imaging means for acquiring an imaging signal by capturing reflected light from the lens while rotating the lens ;
A measurement eccentric circle creating means for creating a measurement eccentric circle using a spot image obtained from the imaging signal ;
A specifying means for specifying a lens to be measured based on data acquired with respect to the lens;
A target eccentric circle creating means for creating a target eccentric circle based on the specified lens parameters ;
The size of the measurement eccentric circle created by the measurement eccentric circle creation means is compared with the size of the target eccentric circle created by the target eccentric circle creation means, and the measurement eccentric circle is within an allowable range based on the comparison result A lens centering program that functions as a lens centering unit that includes an allowable range determination unit that determines whether or not the lens is within the lens centering unit .

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