JP4717502B2 - Lens fixing device - Google Patents

Description

The present invention relates to a lens fixing device that fixes a lens to a lens frame .

  The conventional lens fixing device measures the amount of eccentricity of the lens to be fixed to the lens barrel, positions the lens based on the measured amount of eccentricity, and then applies the ultraviolet curable adhesive applied to the outer periphery of the lens. The lens is fixed to the lens barrel by irradiating with ultraviolet rays.

  In the above apparatus, the amount of eccentricity of the lens is measured by projecting a chart having a linear pattern in two directions onto a sensor via an optical system including the lens, and the illuminance in the X and Y directions of the chart image projected on the sensor. This is done by calculating the amount of coma flare from the distribution.

The apparatus determines the amount of lens movement by comparing the measured eccentricity with pre-measured reference data, and then moves the lens by the amount of movement on an XY fine movement stage (for example, patents) Reference 1).
JP 2000-121901 A

However, since the fixing device fixes the lens to the lens barrel by irradiating the adhesive with ultraviolet rays in a process different from the positioning of the lens, the lens may move before the adhesive is cured. Furthermore, as known in the art, UV curable adhesives cause curing shrinkage of about 5% in volume ratio when irradiated with ultraviolet rays. Therefore, when the lens is fixed to the lens frame , The lens moves.

  Further, when this adhesive is cured by ultraviolet rays, it takes about 20 to 30 seconds, so that the assembly process time becomes long and the assembly cost increases.

An object of the present invention is to provide a lens fixing device capable of adjusting and fixing a lens to be fixed to a lens frame with high accuracy and high speed.

In order to achieve the above object, a lens fixing device according to the present invention is a lens fixing device for fixing a lens to a lens frame, and a frame on which the lens frame supporting the lens is held, and one side of the frame A light source arranged on one side of the gantry, a chart arranged between the gantry and the light source, and a chart which is arranged on the other side of the gantry and is generated when the light source is turned on A reflecting member that reflects the projected image of the lens, a sensor that receives the projected image of the chart reflected by the reflecting member, and an adjusting unit that adjusts the position of the lens with respect to the lens frame based on an output from the sensor; The laser beam is disposed on the other side of the gantry and irradiates laser light from the outside of the reflecting member toward the lens frame after the adjustment of the position of the lens by the adjusting means is completed. Characterized in that it comprises a Heather irradiation unit.

  According to the present invention, the optical element is moved on a plane substantially orthogonal to the optical axis so as to correct the measured eccentricity, and the laser beam is irradiated onto the optical axis extension line of the optical element on which the optical element is supported. Therefore, the movement of the optical element and the irradiation of the laser beam can be performed in the same process, and the lens to be fixed to the lens barrel can be adjusted and fixed with high accuracy and high speed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram schematically showing a configuration of a lens fixing device according to a first embodiment of the present invention.

  The lens fixing device 100 in FIG. 1 measures the amount of eccentricity of the adjustment lens 1 held by the lens frame 2, moves the adjustment lens 1 so as to correct the measured amount of eccentricity, and then moves the laser. This is an apparatus for fixing the adjustment lens 1 to the lens frame 2 by irradiating light.

  The lens frame 2 includes an outer peripheral portion 2a fitted and held in the holding portion 5a of the gantry 5, a seating surface 2b that supports the adjustment lens 1 on the upper side and a lens 3 on the lower side, and an adjustment lens 1. The outer peripheral portion 1a is provided with an edge portion 2c that faces the outer peripheral portion 1a with a certain gap, and an edge portion 2d that holds the outer peripheral portion 3a of the lens 3.

  Further, since the edge 2c of the lens frame 2 faces the outer peripheral portion 1a of the adjustment lens 1 with a certain gap, the adjustment lens 1 is placed on the seat surface 2b by its own weight. It is possible to prevent the adjustment lens 1 from being tilted with respect to the seating surface 2b when the adjustment lens 1 is fixed.

  The lens fixing device 100 is disposed on the optical axis A between the master lens 4 for adjustment, the light source 8 (measurement means) disposed on the optical axis A on the master lens 4 side, and between the master lens 4 and the light source 8. 3, which will be described later, a master lens holding frame 6 that holds the master lens 4, and a gantry 5 that holds the master lens holding frame 6. Further, the lens fixing device 100 includes an XY stage 7 that holds the adjustment lens 1 on its outer peripheral portion so as to move the adjustment lens 1 held by the lens frame 2 attached to the gantry 5 within an XY plane including the lens surface. (Moving means) and a laser irradiation unit 10 disposed on the optical axis A on the adjustment lens 1 side.

  The laser irradiation unit 10 has a cylindrical lens holding frame 14 whose lower end is formed in a conical funnel shape, and a laser irradiation that is arranged on the upper end of the lens holding frame 14 and irradiates laser light 13 downward along the optical axis C. A lens 15 (diameter expanding means) having a negative power for diffusing the light beam of the laser beam 13 emitted from the laser irradiation port 12, and the lens holding frame 14. A lens 16 (diameter expansion means) having a positive power for converting the light beam of the laser beam 13 diffused by the lens 15 into a converged laser beam, and the center of the conical funnel portion of the lens holding frame 14 A reflecting member 11 having an upper end forming a conical surface and a lower end forming an inclined surface of 45 ° with respect to the horizontal, and an outer peripheral portion fixed to the lens holding frame 14. Donna to hold And a Jo focusing lens 17.

  In the lens fixing device 100, the light irradiated from the light source 8 is further reflected by the inclined surface at the lower end of the reflecting member 11 through the chart 9, the master lens 4, the lens 3, and the adjusting lens 1 in FIG. Are connected to a sensor 18 (measuring means) that receives light, an image processing apparatus 20 (measuring means) connected to the sensor 18, a laser irradiation port 12, an XY stage 7, a light source 8, and an image processing apparatus 20. And a control device 21 for controlling.

  FIG. 3 is a plan view of the chart 9 in FIG.

  In FIG. 3, a chart 9 has light-transmitting chart patterns Px and Py that are linear patterns in two orthogonal directions, and the other portions are portions that do not transmit light. The width of each chart pattern Px, Py depends on the optical performance required for the lens system to be adjusted. For example, when the optical performance is 100 / mm in spatial frequency, it is set to 5 microns.

  The operation of the lens fixing device of FIG. 1 will be described below with reference to FIGS.

  First, in FIG. 2, an automatic assembling apparatus (not shown) or an operator who performs assembly is such that the lens frame 2 with the lens 3 supported is fitted and held on the holding portion 5a of the gantry 5 at the outer peripheral portion 2a. The lens frame 2 is incorporated into the gantry 5. Subsequently, the lens incorporation gripping device 19 incorporates the adjustment lens 1 into the lens frame 2 so as to fit into the edge 2c. At this time, the XY stage 7 is in a state of being retracted upward along the optical axis A so as not to disturb the assembling work. After the adjustment lens 1 is incorporated into the lens frame 2 and the lens incorporation gripping device 19 is retracted, the XY stage 7 is lowered downward, and the lens gripping portion 7a of the XY stage 7 is connected to the outer peripheral portion 1a of the adjustment lens 1. Mates with a certain gap.

  Next, in FIG. 1, when the light source 8 is turned on, the projected image of the chart 9 is projected onto the sensor 18 through the master lens 4, the lens 3, and the adjustment lens 1 (FIG. 4). At this time, the projected image of the chart 9 is reflected by the reflecting surface 11a of the reflecting member 11 of the laser irradiation unit 10 in the direction of the optical axis B oriented at approximately 90 ° with respect to the optical axis A. In the projection, the flare width of the projection image of the chart 9 on the sensor 18 is minimized by the drive control device (not shown), that is, the projection image of the chart 9 is brought into focus on the sensor 18. Thus, drive control is performed along the optical axis A direction.

  Next, the light intensity distribution of the projected image of the chart 9 projected on the sensor 18 is taken into the image processing device 20, and the image processing device 20 calculates the illuminance distribution (FIGS. 5 and 6) and calculates the illuminance distribution of the adjustment lens 1. The amount of movement for performing eccentricity adjustment is determined. Then, the control device 21 controls the XY stage 7 so as to adjust the eccentricity of the adjustment lens 1 based on the movement amount determined by the XY stage 7. At this time, since the outer peripheral portion 1a of the adjustment lens 1 and the lens gripping portion 7a of the XY stage 7 are fitted to the adjustment lens 1 with a certain gap as described above, a horizontal driving force is provided. Adjustment is made only by acting.

  After adjusting the eccentricity of the adjustment lens 1, the laser irradiation unit 10 irradiates the laser beam 13 from the laser irradiation port 12. Then, the laser beam 13 whose diameter has been enlarged through the lenses 15 and 16 is reflected by the conical surface (conversion means) at the upper end of the reflecting member 11 and the conical portion (conversion means) at the bottom of the lens holding frame 14, respectively. The light is condensed on the boundary between the seating surface 1 b of the adjustment lens 1 and the seating surface 2 b of the lens frame 2 via the condenser lens 17. When the laser beam 13 is applied to the boundary between the seating surface 1b of the adjusting lens 1 and the seating surface 2b of the lens frame 2, the seating surface 1b of the adjusting lens 1 and the lens frame 2 made of thermoplastic resin are used. The seating surface 2b absorbs the laser beam, generates heat, and melts, and the resins are melted together to perform welding.

  The adjustment lens 1 may be made of, for example, a glass material. In this case, a known hot melt sheet (not shown) or the like is used as an intermediate member, and the seat surface 1b of the adjustment lens 1 and the seat surface of the lens frame 2 are used. 2b may be interposed between the hot melt sheet and the hot melt sheet to absorb and heat the laser beam to fix them.

  4 is a plan view showing projected images of the chart patterns Px and Py of FIG. 3 projected on the sensor 18 in FIG.

  In FIG. 4, chart images P1 and P2 of the chart patterns Px and Py in FIG. The image processing apparatus 20 in FIG. 1 takes in the light intensity distribution obtained by the sensor 18, and obtains the illuminance distribution in the Y direction at the measurement point S1 of the chart image P1 and the illuminance distribution in the X direction at the measurement point S2 of the chart image P2. Based on the calculation, a movement amount for adjusting the eccentricity of the adjustment lens 1 is determined (FIGS. 5 and 6).

  FIG. 5 is a diagram for explaining the Y-direction illuminance distribution at the measurement point S1 of the chart image P1 in FIG. 4 and shows the case of the adjustment start time.

  In FIG. 5, due to the eccentric component of the adjustment lens 1, the illuminance distribution does not have a symmetrical shape due to a relatively large flare occurring on the positive side in the Y-axis direction. In order to make this illuminance distribution symmetrical, the eccentricity of the adjustment lens 1 is adjusted.

  Here, the width of the right flare FR1 from the peak position of the illuminance at the start of eccentricity adjustment to the right slice level is WR1, the width of the left flare FL1 to the left slice level is WL1, and a command from the control device 21 The XY stage 7 decenters the adjustment lens 1 by an arbitrary amount δ1 in the direction in which the right flare FR1 decreases, and again measures the Y-direction illuminance distribution at the measurement point S1 of the chart image P1.

  FIG. 6 is a diagram for explaining the Y-direction illuminance distribution at the measurement point S1 of the chart image P1 in FIG. 4, and shows a case after the eccentricity adjustment of δ1 is completed.

  In FIG. 6, when the flare width from the illuminance peak position during the eccentricity adjustment to the slice level is set to WL2 and WR2, respectively, and the adjustment lens 1 is eccentric by the above-mentioned δ1, the above-mentioned left and right flare widths Assuming that the rate of decrease of the difference is linear, the eccentricity δ2 to be adjusted next is obtained by the following equation.

δ2 = δ1 * (WR2-WL2) / {(WR1-WL1)-(WR2-WL2)}
At this time, the amount of eccentricity and the moving direction in which the adjustment lens 1 is first moved are numerical data indicating the relationship between the amount of flare generated when the adjustment lens 1 is eccentric by a certain amount and the direction in which the adjustment lens 1 is generated. And the conditions of the eccentricity direction and the eccentricity amount of the adjustment lens 1 for correcting the flare amount first confirmed at the time of adjustment in accordance with the generation direction thereof are stored as described above. It is effective to converge the adjustment more quickly by calculating from numerical data.

  As a result, the XY stage is further driven and controlled by the required eccentricity amount δ2 obtained from the above equation in accordance with the control signal from the control device 21, and the eccentricity adjustment of the adjustment lens 1 is performed.

  Then, the illuminance distribution in the Y direction at the measurement point S1 of the chart image P1 is measured again to check whether the flare is within a specified flare difference. If the flare is within the specified value, the adjustment is completed there. If the flare difference does not fall within the specified value, the width of the flare from the illuminance peak position to the slice level is now set to WL3 and WR3, respectively, and the same formula as above is applied. The next eccentricity adjustment amount δ3 is obtained by the following equation.

δ3 = δ2 * (WR3-WL3) / {(WR2-WL2)-(WR3-WL3)}
In the same manner as described above, the XY stage is further driven and controlled by the necessary eccentric amount δ3 obtained from the above equation by the control signal from the control device 21, and the adjustment lens 1 is decentered to decenter the adjustment lens 1. The lead is adjusted. Then, this operation is continued until the flare difference converges within the specified value, and the adjustment operation ends when the difference falls within the specified value.

  In the above description, the eccentricity in the Y direction has been described. In the X direction, the measurement and adjustment of the eccentricity amount in the X direction can be performed in the Y direction based on the illuminance distribution in the X direction at the measurement point S2 of the chart image P2. What is performed simultaneously with the adjustment is as described above.

  When the eccentric adjustment of the adjustment lens 1 is completed, the control device 21 then issues a laser irradiation command signal to the laser irradiation unit 10, and the laser beam is irradiated on the outer peripheral portion of the adjustment lens 1 as described above. The adjustment lens 1 and the lens frame 2 are fixed by welding.

  According to the present embodiment, the steps of incorporating the adjusting lens 1 and the eccentricity adjusting step, and the step of welding and fixing the lens by laser irradiation are performed in the fixing device of the present invention. After the adjustment process, change the location to the next process, apply UV curable adhesive, do not need multiple steps to fix by irradiating with UV, and also fix the lens by laser beam welding The lens can be fixed in a short time.

  FIG. 7 is a diagram schematically showing a configuration of a lens fixing device according to the second embodiment of the present invention.

  The configuration of the second embodiment is basically the same as that of the first embodiment, and the same components are denoted by the same reference numerals and redundant description is omitted. Only things are explained.

  This embodiment differs from the XY stage 7 of the first embodiment in the configuration of the means for adjusting the eccentricity of the adjustment lens 1.

  In FIG. 7, the lens fixing device 100 includes a pair of motor holding members 23 in the X direction and the Y direction, which are mounted on the gantry 5 so as to be horizontally movable so as to be separated from or approach each other. A motor 22 is attached to each motor holding member 23, and a lens pressing member 24 is moved on the output shaft of the motor 22 in the axial direction as the output shaft of the motor 22 rotates (arrows D and E in FIG. 1). It is attached. Furthermore, the lens fixing device 100 includes a lens incorporation gripping device 25 that incorporates the adjustment lens 1 into the lens frame 2 (FIG. 8).

  The operation of the lens fixing device of FIG. 7 will be described below with reference to FIGS.

  In FIG. 8, the lens frame is arranged such that the lens frame 2 in a state where the lens 3 is supported by an automatic assembling apparatus or an assembly operator (not shown) is fitted and held by the holding portion 5a of the gantry 5 at the outer peripheral portion 2a. 2 is incorporated into the gantry 5. Subsequently, the lens incorporation gripping device 25 incorporates the adjustment lens 1 into the lens frame 2 so as to fit into the edge 2c. At this time, the motor holding member 23 holding the motor 22 is in a state of being separated (retracted) in the horizontal direction on the gantry 5 so as not to hinder the assembling work. After the adjustment lens 1 is incorporated into the lens frame 2 and the lens incorporation gripping device 25 is retracted, the motor holding member 23 moves to the adjustment standby position shown in FIG. In FIG. 7, the distal end portion 24 a of the lens pressing member 24 presses the outer peripheral upper portion 1 c of the adjustment lens 1 in an oblique direction to adjust the eccentricity of the adjustment lens 1. At this time, the seating surface 1b of the adjusting lens 1 is pressed against the seating surface 2b of the lens frame 2 by the component force of the oblique pressing force, and the eccentricity adjustment is performed without causing the lens to float or tilt. Can do. Then, the eccentricity adjustment and welding by laser light irradiation are performed in the same manner as in the first embodiment.

It is a figure which shows roughly the structure of the lens fixing device which concerns on the 1st Embodiment of this invention. It is a figure explaining operation | movement of the lens fixing device of FIG. It is a top view of the chart in FIG. It is a top view which shows the projection image of the chart pattern of FIG. 3 projected on the sensor in FIG. It is a figure explaining the Y direction illumination intensity distribution of the measurement point of the chart image in FIG. 4, and shows the case of the adjustment start time. It is a figure explaining the Y direction illuminance distribution of the measurement point of the chart image in FIG. 4, and shows the case after the eccentricity adjustment of δ1 is completed. It is a figure which shows schematically the structure of the lens fixing device which concerns on the 2nd Embodiment of this invention. It is a figure explaining operation | movement of the lens fixing device of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Adjustment lens 2 Lens frame 5 Base 7 XY stage 8 Light source 10 Laser irradiation unit 13 Laser light 18 Sensor 20 Image processing apparatus 21 Control apparatus 100 Lens fixing apparatus

Claims (4)

A lens fixing device for fixing a lens to a lens frame ,
A frame on which the lens frame supporting the lens is held;
A light source disposed on one side of the gantry;
A chart disposed between the gantry and the light source on one side of the gantry;
A reflecting member that is disposed on the other side of the gantry and reflects a projected image of the chart that is generated when the light source is turned on;
A sensor for receiving a projected image of the chart reflected by the reflecting member;
Adjusting means for adjusting the position of the lens with respect to the lens frame based on the output from the sensor;
A laser irradiation unit disposed on the other side of the gantry and configured to irradiate laser light from the outside of the reflecting member toward the lens frame after the adjustment of the position of the lens by the adjusting unit is completed. Lens fixing device. Wherein the reflecting member, the lens fixing device according to claim 1, characterized in Rukoto are formed conical surface which converts the laser beam emitted from the laser irradiation unit in cross section a ring-shaped light flux. At between the chart and the lens frame, lens fixing device according to claim 1 or 2 the master lens is characterized that you have been fixed to the frame. Lens fixing device according to any one of claims 1 to 3 and the laser irradiation unit and wherein the light source Rukoto disposed on the same axis.

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