JP3661546B2 - Lens array inspection apparatus and lens array inspection method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lens array inspection apparatus and inspection method for inspecting optical characteristics of a lens array configured by arranging a plurality of lenses in a matrix, and for example, inspection of a lens array employed in an illumination apparatus such as a projector It can be used as an apparatus and an inspection method.
[0002]
[Background]
2. Description of the Related Art Conventionally, a projector including a light source, an electro-optical device that modulates a light beam emitted from the light source according to image information, and a projection optical system that magnifies and projects the light beam modulated by the electro-optical device has been presented. Has been used.
[0003]
In such a projector, an integrator illumination optical system may be disposed between the light source and the electro-optical device in order to uniformly illuminate the image forming area of the electro-optical device with light flux emitted from the point light source. Many.
[0004]
As this integrator illumination optical system, there is known one using a lens array configured by arranging a plurality of small lenses in a matrix form in a plane orthogonal to the light emission direction. The integrator illumination optical system divides the light beam emitted from the light source into a plurality of partial light beams by a plurality of small lenses constituting the lens array, and superimposes each partial light beam in the image forming area of the electro-optical device. Can be uniformly illuminated, and by using such an integrator illumination optical system, it is possible to obtain a clear projected image without luminance unevenness.
[0005]
By the way, such a lens array is formed by casting molten glass or resin material into a mold corresponding to the shape of a plurality of small lenses constituting the lens array, or press-molding softened glass with a mold. Manufactured. Therefore, each small lens constituting the lens array may be deformed by heat treatment, or the small lens may be displaced due to differences in thermal expansion or contraction. Therefore, the optical characteristics of the optically set lens array are realized. It is necessary to inspect whether it is obtained in the product.
[0006]
Conventionally, the lens array is inspected by measuring the shape of the lens surface of the small lens using a surface shape measuring device or the like.
[0007]
[Problems to be solved by the invention]
However, in the conventional lens array inspection method described above, although the optical characteristics of the small lenses constituting the lens array can be grasped to some extent, the optical characteristics of the entire lens array cannot be grasped. Therefore, the final inspection of the lens array must be carried out while actually being incorporated in a projector or the like and confirming an actual projection image or the like, and there is a problem that the inspection cannot be effectively performed.
[0008]
An object of the present invention is to provide a lens array inspection apparatus and a lens array inspection method capable of measuring the optical characteristics of the entire lens array with high accuracy.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a lens array inspection apparatus according to the present invention is a lens array inspection apparatus that inspects optical characteristics of a lens array configured by arranging a plurality of lenses in a matrix. A work holder to which a lens array is attached and movable along the arrangement direction of the plurality of lenses, a light source that emits a light beam toward the lens array on the work holder, and between the work holder and the light source A plurality of lenses of a lens array attached to the work holder, and a first light source unit provided with a reference pattern forming unit that forms a reference pattern image for inspection based on a light beam from the light source. Among these, a measurement target selection unit in which an opening for selectively introducing a light beam through the reference pattern formation unit is formed in a lens to be measured, and the measurement target. An image detection unit that detects a reference pattern image for inspection that has passed through the lens selected by the target selection unit, and an arithmetic processing unit that performs arithmetic processing on a detection result detected by the image detection unit. .
[0010]
Here, the optical characteristics of the lens array to be inspected include the focal length of each lens constituting the lens array, the optical axis position of each lens, the size of each lens, the arrangement position of each lens on the lens array, and the like. It is done.
[0011]
Further, the image detection unit can be configured by an area sensor such as a CCD that converts the detected inspection reference pattern image into an electric signal, and the arithmetic processing unit is developed on an operating system that controls the computer. Those equipped with an image processing program can be employed.
[0012]
According to the present invention as described above, since the first light source unit, the reference pattern forming unit, and the measurement target selection unit are provided, the image detection unit uses the inspection reference pattern image that has actually passed through the lens to be measured. Can be detected. Therefore, the actual optical characteristics of the small lenses constituting the lens array can be grasped, and the optical characteristics of the lens array can be inspected with high accuracy.
[0013]
In addition, since an arithmetic processing unit that performs arithmetic processing on the detection result detected by the image detection unit is provided, even if a large number of small lens inspections are set, processing can be easily performed and each obtained By collectively processing the optical characteristics of the lens, it is possible to accurately grasp the optical characteristics of the entire lens array.
[0014]
The lens array inspection apparatus described above preferably includes the second light source unit that emits diffused light from a point light source.
[0015]
That is, when measuring the focal length and the optical axis position of each lens among the optical characteristics of the lens array described above, the detection accuracy of the image detector can be improved if the reference pattern image for inspection has a high contrast. . Therefore, it is preferable to employ a parallel light source that emits parallel light as the light source that constitutes the first light source unit in order to guide more emitted light to the small lenses of the lens array.
[0016]
On the other hand, when measuring the size of the lens and the arrangement position of the lens, it is necessary to detect the boundary portion with other adjacent lenses by the image detection unit, and such a boundary portion irradiates the lens with diffused light. It is recognized as a shadow at the time. Therefore, as a light source in such an inspection, it is preferable to separately provide a light source that emits diffused light as a second light source unit so that a shadow can be recognized.
[0017]
From the above, by providing the first light source unit and the second light source unit, it is possible to cope with the various measurement items described above, and therefore the inspection accuracy of the lens array can be further improved.
[0018]
Moreover, it is preferable that the size of the opening is configured to be variable as the measurement target selection unit described above, and such a measurement target selection unit includes a pair of substantially L-shaped plate members that are substantially L-shaped. The portions can be configured to overlap each other so as to face each other and be relatively movable.
[0019]
In other words, by configuring the size of the opening of the measurement object selection unit to be variable, the lens array inspection device can be used for inspection of a lens array in which lenses having different sizes are combined. The versatility of the inspection apparatus is further improved. In addition, by configuring the measurement target selection unit by superimposing substantially L-shaped plate materials, the size of the opening can be made variable with a simple structure, and the structure of the measurement target selection unit is simplified. Can be achieved.
[0020]
Furthermore, it is preferable to employ an image sensor including a charge coupled device (CCD) as the above-described image detection unit.
[0021]
That is, since the CCD is widely used as an image sensor, a highly versatile image processing program constituting the arithmetic processing unit can be adopted, and the cost of the lens array inspection apparatus can be reduced. it can.
[0022]
The lens array inspection method according to the present invention is a lens array inspection method for inspecting the optical characteristics of a lens array configured by arranging a plurality of lenses in a matrix, and the plurality of lenses constituting the lens array. Among these lenses, a pattern image detection step for projecting a predetermined inspection reference pattern image onto a lens to be measured and detecting an inspection reference pattern image that has passed through the lens, and an inspection detected in the image pattern detection step A focal length measuring step for measuring a focal length of the lens based on a reference pattern image for use; an optical axis position measuring step for measuring an optical axis position of the lens; and a lens area measuring step for measuring an area of the lens; And a lens position measuring step for measuring an array position of the lenses in the lens array. And it features.
[0023]
According to the present invention, the lens array inspection method includes a focal length measurement step, an optical axis position measurement step, a lens area measurement step, and a lens position measurement step. By precisely measuring the optical characteristics of the lens, the optical characteristics of the entire lens array can be measured with high accuracy.
[0024]
In the above, when the inspection reference pattern image is composed of the well-shaped image pattern arranged along the lens center line in the plane orthogonal to the emission direction of the light flux of the lens, the optical axis position measuring step described above Is a midpoint for calculating the midpoint of two intersections between a detection line setting process for setting a plurality of detection lines so as to straddle the well-shaped image pattern and the image pattern detected on each detection line A center line calculation process for calculating a center line orthogonal to each other by linear approximation based on a plurality of midpoints calculated from each detection line, and two center lines orthogonal to each other as an optical axis of the lens And an optical axis position setting process as a position.
[0025]
That is, by configuring the optical axis position measuring step by such a series of processes, the accurate optical axis position of the lens can be grasped, and the accuracy of the inspection of the lens array can be further improved.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
(1) Projector structure in which a lens array is used
FIG. 1 shows the structure of a projector 100 that employs a lens array to be inspected by a lens array inspection apparatus according to an embodiment of the present invention. The projector 100 includes an integrator illumination optical system 110, a color separation optical system 120, a relay optical system 130, an electro-optical device 140, a color synthesis optical system 150, and a projection optical system 160.
[0027]
The integrator illumination optical system 110 includes a light source device 111 including a light source lamp 111A and a reflector 111B, a first lens array 113, a second lens array 115, a reflection mirror 117, and a superimposing lens 119. The light beam emitted from the light source lamp 111A is aligned in the emission direction by the reflector 111B, divided into a plurality of partial light beams by the first lens array 113, and the emission direction is bent by 90 ° by the folding mirror, and then the second lens array. An image is formed in the vicinity of 115. Each partial light beam emitted from the second lens array 115 is incident so that the central axis (principal ray) thereof is perpendicular to the incident surface of the superimposing lens 119 in the subsequent stage, and further, a plurality of parts emitted from the superimposing lens 119. The light beam is superimposed on three liquid crystal panels 141R, 141G, and 141B that constitute an electro-optical device 140 described later.
[0028]
The color separation optical system 120 includes two dichroic mirrors 121 and 122 and a reflection mirror 123, and a plurality of partial light beams emitted from the integrator illumination optical system 110 by the mirrors 121, 122, and 123 are red, It has a function of separating light into three colors of green and blue.
[0029]
The relay optical system 130 includes an incident side lens 131, a relay lens 133, and reflection mirrors 135 and 137, and has a function of guiding the color light separated by the color separation optical system 120, for example, blue light B to the liquid crystal panel 141B. Have.
[0030]
The electro-optical device 140 includes three liquid crystal panels 141R, 141G, and 141B, which use, for example, polysilicon TFTs as switching elements, and each color light separated by the color separation optical system 120 is These three liquid crystal panels 141R, 141G, and 141B are modulated according to image information to form an optical image.
[0031]
The color synthesizing optical system 150 includes a cross dichroic prism 151, and forms a color image by synthesizing images modulated for each color light emitted from the three liquid crystal panels 141R, 141G, and 141B. . In the cross dichroic prism 151, a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are formed in a substantially X shape along the interface of four right-angle prisms. Three color lights are synthesized by the dielectric multilayer film. The color image synthesized by the color synthesizing optical system 150 is emitted from the projection optical system 160 and enlarged and projected on the screen.
[0032]
(2) Lens array structure to be inspected
As shown in FIG. 2, the first lens array 113 employed in the projector 100 described above has a plurality of small lenses 11 arranged in a matrix in M rows and N columns within a plane orthogonal to the light emission direction of each small lens 11. It is comprised by arranging in. Each small lens 11 divides a parallel light beam emitted from the light source device 111 into a plurality of (M × N) partial light beams, and the divided partial light beams are included in the second lens array 115 as described above. Image in the vicinity. Here, the shape of each small lens 11 is set to be substantially similar to the shape of the image forming regions of the liquid crystal panels 141R, 141G, and 141B constituting the electro-optical device 140. For example, if the aspect ratio (ratio between vertical and horizontal dimensions) of the liquid crystal panels 141R, 141G, and 141B is 4: 3, the aspect ratio of each small lens is also set to 4: 3.
[0033]
Similarly to the first lens array 113 described above, the second lens array 115 has a configuration in which the small lenses 11 are arranged in a matrix of M rows and N columns. However, as described above, the second lens array 115 is provided to cause the plurality of partial light beams divided by the first lens array 113 to enter the incident surface of the subsequent superimposing lens 119 perpendicularly, It is not necessary to have the same configuration as the first lens array 113. In short, if the plurality of partial light beams can be perpendicular to the incident surface of the superimposing lens 119, the small lens shape can be set to various shapes. That is, the small lenses constituting the second lens array 115 need not be similar in shape to the aspect ratio of the image forming areas of the liquid crystal panels 141R, 141G, and 141B as in the first lens array 113. Then, for the convenience of manufacturing, the small lenses 11 are arranged in a matrix of M rows and N columns to constitute the second lens array 115.
[0034]
Therefore, since the first lens array 113 and the second lens array 115 have different functions, the measurement items of the small lens 11 by the inspection apparatus 2 described later are also different.
[0035]
The first lens array 113 and the second lens array 115 are formed by pouring molten glass or a resin material into a mold corresponding to the shape of the plurality of small lenses 11, or softening glass into a plurality of small lenses. It is manufactured by press molding with a mold corresponding to the shape of the lens 11 and then slowly cooling. Therefore, due to deformation of each small lens 11 constituting the lens array 113, difference in contraction, etc., the occurrence of a sag 11A at the boundary between the small lenses 11 and the position of the small lens 11 in the lens arrays 113 and 115 Misalignment may occur. Therefore, it is necessary to inspect how much the change in the optical characteristics of the lens arrays 113 and 115 due to these phenomena is different from the designed optical characteristics using an inspection apparatus.
[0036]
(3) Structure of the lens array inspection device
FIG. 3 shows a lens array inspection apparatus 2 that inspects the first lens array 113 and the second lens array 115 described above.
[0037]
The inspection apparatus 2 includes a work holder 21 to which lens arrays 113 and 115 to be inspected are attached, a light source unit 23 that emits a light beam toward the lens arrays 113 and 115 on the work holder 21, a work holder 21 and a light source unit. 23, a measurement object selection unit 27 disposed between the image sensors 23, an image detection unit 29 that detects an image that has passed through the lens arrays 113 and 115, a frame 31 in which these are installed, and an arithmetic processing unit that is provided on the back of the frame 31. As an image processing unit 33. In this inspection apparatus 2, the traveling direction of the light beam emitted from the light source unit 23 is the Z axis, the vertical direction of the inspection apparatus 2 is the Y axis, and the left and right direction (the direction orthogonal to the paper surface of FIG. 1) is the X axis.
[0038]
The work holder 21 is a holding frame to which the lens arrays 113 and 115 to be inspected are attached. A step for moving each axis on the X-axis work stage 211 and the Y-axis work stage 212 installed in the main body of the inspection apparatus 2. It is installed via a motor 213. The work holder 21 can be moved in the X-axis and Y-axis directions by a step motor 213 of each axis, and the drive of each step motor 213 is performed by a mechanical control personal computer 35 disposed below the inspection apparatus 2. It is controlled. As shown in FIG. 4, the work holder 21 is provided along the edge of the opening 21B formed in the frame main body 21A, and includes four holding projections 21C for holding the lens arrays 113 and 115, and the lens array. A movable projection 21D for biasing 113 and 115 in a diagonal direction is provided. Although not shown in the drawing, the contact portions of the projections 21C and 21D with the lens arrays 113 and 115 are configured such that an elastic body is interposed and the lens arrays 113 and 115 are not damaged. Further, the movable protrusion 21D can move in the diagonal direction of the lens arrays 113 and 115, and the work holder 21 also corresponds to the lens arrays 113 and 115 having different sizes.
[0039]
The light source unit 23 is a part that emits a light beam for inspection to the lens arrays 113 and 115, and includes a collimator 231 as a first light source unit and a diffused light source unit 232 as a second light source unit. The collimator 231 emits a parallel light beam to the lens arrays 113 and 115 to be inspected. As shown in FIG. 5, a fiber light source 231 </ b> A and a reference pattern forming unit 25 are provided inside the collimator 231.
[0040]
As shown in FIG. 6, the reference pattern forming unit 25 is a part for forming an inspection reference pattern image, in which a well-shaped inspection reference pattern 253 is formed on the surface of a translucent plate 251. It is. The inspection reference pattern 253 is set to measure the amount of optical axis deviation of the small lenses 11 constituting the lens arrays 113 and 115, and a specific method for measuring the amount of optical axis deviation will be described later. The light beam emitted from the fiber light source 231A of the collimator 231 is passed through the reference pattern forming unit 25 to form an inspection reference pattern image corresponding to the inspection reference pattern 253, and is projected onto the small lens 11 to be measured. It has become so.
[0041]
As shown in FIG. 7, the diffused light source unit 232 includes a case 232A in which an opening for emitting a light beam is formed, a fiber light source 232B serving as a point light source, and a reflection that bends the light beam emitted from the fiber light source 232B by 90 °. A mirror 232C and a diffusion plate 232D that is disposed so as to close the opening of the case 232A and diffuses the emitted light beam are provided. The light beam emitted from the fiber light source 232B is bent in the horizontal direction by the reflection mirror 232C while being diffused, the illuminance distribution is made uniform by the diffusion plate 232D, and is emitted as diffused light from the opening of the case 232A.
[0042]
As can be seen from FIG. 3, such a diffused light source unit 232 is disposed at a position closer to the work holder 21 than the collimator 231. When the collimator 231 is used, the diffused light source unit 232 is arranged in the X-axis direction. The luminous flux emitted from the collimator 231 is supplied to the lens arrays 113 and 115 attached to the work holder 21. The reason why the diffused light source unit 232 is arranged at a position close to the work holder 21 is that diffused light is emitted from the diffused light source unit 232, so that it is separated from the lens arrays 113 and 115 to be inspected. This is because the amount of light flux supplied to the lens arrays 113 and 115 is reduced.
[0043]
The measurement target selection unit 27 selects the small lens 11 to be measured from the plurality of small lenses 11 constituting the lens arrays 113 and 115 held by the work holder 21, and the light source unit 23 is selected only for the small lens 11. The other small lens 11 has a function as a shielding plate that does not supply the light beam.
[0044]
Specifically, as shown in FIG. 8, the measurement target selection unit 27 is configured by overlapping substantially L-shaped plate members 271 and 273 that are cut out from one corner portion of a rectangle. The L-shaped plate members 271 and 273 are overlapped so that the respective substantially L-shaped portions face each other, and a gap surrounded by the approximately L-shaped portions is an opening for supplying a light beam only to the small lens 11 to be measured. Part 275. The plate members 271 and 273 are movable in the X-axis direction and the Y-axis direction, respectively, and the opening amount of the opening 275 is changed by arranging these plate members 271 at desired X-axis positions and Y-axis positions. be able to. The movement of the plate members 271 and 273 in the X-axis direction and the Y-axis direction is omitted in FIG. 8, but is performed by an XY two-axis servo mechanism provided in each of the plate members 271 and 273, and the above-described mechanical control personal computer 35. It is controlled by.
[0045]
The image detection unit 29 is a part that detects a reference pattern image for inspection that has passed through the small lens 11, converts it into an electrical signal, and outputs it. A CCD (Charge Coupled Device) camera 291, which is an area sensor, And an XYZ stage 293 that moves the X axis, the Y axis, and the Z axis. The movement of the CCD camera 291 in the direction of each axis of the XYZ stage 293 is performed by a servo mechanism 37 disposed below the XYZ stage 293. The servo mechanism 37 is operated by a mechanical control personal computer 35 in the same manner as described above. Be controlled. The CCD camera 291 has a zoom mechanism, and zoom adjustment of the CCD camera 291 is also controlled by the mechanical control personal computer 35.
[0046]
The image processing unit 33 is a part that performs image analysis by processing an electrical signal related to the reference pattern image for inspection output from the image detection unit 29 described above, and is a computer that includes a CPU and a storage device. The image analysis of the inspection reference pattern is performed by an image processing program developed on an operating system that controls the image processing unit 33, and a specific processing procedure will be described later.
[0047]
The operation of the image processing unit 33 and the mechanical control personal computer 35 is performed by a keyboard 39 provided on the side surface of the frame 31, and is attached to the work holder 21 by the image analysis result of the image processing unit 33 or the mechanical control personal computer 35. The position of the inspection object, the opening amount of the opening 275 of the measurement object selection unit 27, and the XYZ position of the CCD camera 291 are not shown, but are confirmed by a display installed on the upper part of the inspection apparatus 2. can do. The keyboard 39 is provided so as to be rotatable with respect to the frame 31. When operating, the keyboard 39 is in a horizontal state, and when the inspection apparatus 2 is moved, the keyboard 39 is in a vertical state so as not to obstruct the movement. It has become.
[0048]
Although not shown in FIG. 3, the outer side of the frame 31 can be covered with a shielding plate, and at the time of inspection, the work holder 21, the light source unit 23, the reference pattern forming unit 25, and a measurement target selection The unit 27 and the image detection unit 29 are covered with a shielding plate, and the lens array is inspected in a dark room.
[0049]
(4) Inspection of lens array by inspection device
The inspection of the lens arrays 113 and 115 by the above-described inspection apparatus is performed by previously registering lens array data to be inspected, determining the origin of each axis of the inspection apparatus 2, performing calibration, and the like, and then performing the mechanical control personal computer 35, This is automatically performed by the image processing unit 33. Specifically, the lens arrays 113 and 115 are inspected according to the procedure shown in FIG. 9, and each item will be described in detail below.
[0050]
(4-1) Registration / correction of lens data (processing S1)
This is a process for pre-registering the design optical characteristics of the lens array to be inspected. In automatic measurement (process S7) described later, lens data corresponding to the inspection object is selected from a plurality of lens data registered in this process. And perform automatic measurement. Specific registration contents of the lens data include the name of the lens array, the application (which of the first lens array 113 and the second lens array 115 is used), the type of material of the lens array, and the model name of the projector used. There are design data such as the outer dimensions of the lens array, the number of small lenses, the optical axis coordinates of each small lens, the focal length, the arrangement position on the lens array, and the like. The created lens data is stored as a text file and used by the mechanical control personal computer 35 and the image processing unit 33 as necessary.
[0051]
(4-2) Setting of reference position (Processing S2, S3)
The work holder 21, the measurement object selection unit 27, and the CCD camera 291 that constitute the inspection apparatus 2 are set as reference positions, and reference points are registered. Further, since the diffused light source unit 232 is unnecessary when the collimator 231 is used, the diffused light source unit 232 also registers a retreat point for retreating from the optical path of the light beam emitted from the collimator 231. Further, an image processing command for starting image processing is output from the mechanical control personal computer 35 to the image processing unit 33, a response from the image processing unit 33 is confirmed, and it is confirmed whether the image processing unit 33 is operating normally. To do.
[0052]
(4-3) Lens data selection (processing S4), measurement item selection (processing S5)
After the setting of the reference position is completed, the lens arrays 113 and 115 to be inspected are set on the work holder 21 and the optical characteristic design of the lens arrays 113 and 115 to be inspected from the lens data registered in the process S1. Lens data corresponding to the value is selected (processing S4). Next, a measurement item is selected according to the application of the lens arrays 113 and 115 to be inspected (processing S5). Specifically, in the case of the first lens array 113, the optical axis position, focal length, size, and arrangement position on the lens array of each small lens 11 are selected as measurement items. On the other hand, in the case of the second lens array 115, the optical axis position and the focal length are selected.
[0053]
(4-4) Designation of small lens to be measured (Processing S6)
When the measurement item is selected, which small lens 11 is to be measured among the plurality of small lenses 11 constituting the lens arrays 113 and 115 to be inspected is designated (processing S6). At this time, it is possible to designate only a specific small lens 11 or to designate all the small lenses 11. When selecting a specific small lens 11, there are two methods: a method of clicking a small lens image to be measured with a mouse or the like in a lens array image displayed on the display, and a method of double clicking a corresponding lens position in the list. Can be selected. On the other hand, when all the small lenses 11 are designated, automatic measurement is executed in the order registered in the lens data.
[0054]
(4-5) Automatic measurement (Processing S7)
After the above setting is completed, the measurement of the lens arrays 113 and 115 is automatically started based on the selected lens data (processing S7). For example, when the first lens array 113 is inspected, the automatic measurement is performed based on the flowchart shown in FIG.
[0055]
First, the X-axis work stage 211 and the Y-axis work stage 212 are moved to a position where the center of the small lens 11 to be measured is aligned with the mechanical optical axis (processing S71). Next, the two plate members 271 and 273 of the measurement target selection unit 27 are moved by the servo mechanism, and the aperture amount of the aperture 275 is set to the size of the small lens × the aperture ratio (processing S72). Then, the XYZ stage 293 of the CCD camera 291 is called from the design optical axis position of the small lens 11 in the X-axis and Y-axis directions and from the lens data in the Z-axis direction (the focal point of the small lens 11). It is moved to the position of distance + focal length of CCD camera 291 (process S73). The above-described processes S71 to S73 are controlled by the mechanical control personal computer 35 and can be performed in order, but can also be performed simultaneously.
[0056]
Next, the light source of the light source unit 23 is set to the collimator 231 (process S74), and the focal length measurement (process S75) and the optical axis position measurement (process S76) are performed by the emitted light beam from the collimator 231. Specifically, the focal length measurement and the optical axis position measurement are performed for all of the small lenses 11 specified in the process S6, and the movement of the small lenses 11 is completed until the measurement of all the small lenses 11 is completed (process 77). (Processing S78) and measurement are repeated.
[0057]
When these measurements are completed, the light source is changed from the collimator 231 to the diffused light source unit 232 (process S79), the size (area) measurement of the small lens 11 (process S80), and the arrangement position measurement of the small lens 11 (process S80). Processing S81) is performed. Specifically, as described above, the size (area) measurement and the arrangement position measurement are performed for all the small lenses 11 specified in the process S6, and the measurement of all the small lenses 11 is completed (process). S82) The movement of the small lens 11 (process S83) and measurement are repeated, and when all measurements are completed, the automatic measurement is terminated.
[0058]
Each measurement described above is processed by the image analysis program of the image processing unit 33, and is processed as follows for each measurement.
[0059]
(a) Measurement of focal length (processing S75)
First, as shown in FIG. 11, a plurality of vertical and horizontal detection lines L1 and L2 are set so as to straddle the well-shaped line L0 of the reference pattern image for inspection that has passed through the small lens 11 imaged by the CCD camera 291. . Next, the density of the image is extracted for each detection line. Then, a primary differentiation process is performed on the concentration extracted for each detection line, the absolute values of the differential values are integrated, and an integration result is output. In addition, when outputting the integration result, the vertical pattern and the horizontal pattern of the inspection reference pattern image may be different in focus, so the vertical pattern result and the horizontal pattern result are output separately.
Furthermore, the integration result obtained in this way is sent to the mechanical control personal computer 35, and the position where the integration value is maximized is output as the focal length.
[0060]
(b) Measurement of optical axis position (processing S76)
As in the focus measurement, first, as shown in FIG. 12, a plurality of vertical and horizontal detection lines L3 and L4 are set so as to straddle the well-shaped line L0 of the inspection reference pattern image (detection lines). Setting process), the positions of the lines of the reference pattern image for inspection on the detection lines L3 and L4 are detected. On each of the detection lines L3 and L4, there are two points P1 and P2 that are recognized as the line L0 of the inspection reference pattern image, so the midpoint P3 of these two points is calculated (middle point calculation process). Straight line approximation is performed using the midpoint coordinates calculated at a plurality of locations to obtain a vertical center line LV and a horizontal center line LH (center line calculation process). Finally, as shown in FIG. 13, the coordinates of the intersection point P4 of the vertical and horizontal center lines LV and LH are output as the optical axis position of the small lens 11 (optical axis position setting process). In the present embodiment, the intersection coordinates are obtained in units of 1/10 of the pixel of the CCD camera 291.
[0061]
(c) Small lens size (area) measurement (processing S80)
The shadow line LS generated at the boundary portion of the small lens 11 by the light beam emitted from the diffused light source unit 232 is captured as an image by the CCD camera 291. As shown in FIG. 14, a plurality of detection lines L5 are set radially from the screen center O, and an intersection with the shadow line LS is acquired as an edge. Next, a triangle is set by the two adjacent detection lines L5 and the detected edge, and the area of the triangle is calculated. This is integrated 360 ° around the screen center O, and this area is output as the area of the small lens 11. In order to improve the measurement accuracy of the area of the small lens 11, the number of detection lines L5 set radially from the screen center O may be increased. Further, when the area of the complete small lens 11 is obtained, there is a relationship with the processing time, but a method of adding all the inner portions of the shadow can be employed.
[0062]
(d) Measurement of the position of the small lens (processing S81)
Similarly to the measurement of the size of the small lens, the shadow line LS generated at the boundary portion of the small lens 11 by the light beam emitted from the diffused light source unit 232 is captured as an image by the CCD camera 291 and, as shown in FIG. A plurality of vertical and horizontal detection lines L6 and L7 are set in this image. As can be seen from FIG. 15, when the sag 11A occurs in the small lens 11 (see FIG. 2), the shadow line LS also curves along this sag. By using the set detection lines L6 and L7, the shadow line LS of the small lens 11 is detected as the edge of the small lens 11, and the four edges of the small lens 11 are acquired. Based on the acquired edge coordinates, linear approximation is performed for each side. Intersection points P5 to P8 of the approximate straight lines of the sides constituting the shadow line LS are acquired as coordinates of the four corners of the small lens 11, and as shown in FIG. 16, between the intersection point P5 and the intersection point P7, the intersection point P6 and The diagonal lines L8 and L9 are set between the intersection points P8, and the intersection point of the two diagonal lines L8 and L9 is output as the arrangement position P9 of the small lens 11. The arrangement position data is based on the lower left vertex of the small lens 11 arranged at the lower left of the lens arrays 113 and 115 in FIG. 4 as the origin, the X axis extending in the horizontal direction from the origin, and the Y axis extending in the vertical direction. Are given as (X, Y) coordinate values.
If the coordinates of the intersection points P5 to P8 are compared with the coordinates of the design value, it is possible to calculate the deviation amount with respect to the outer shape of each small lens 11 and to perform more rigorous analysis.
[0063]
(4-6) Save measurement data (Process S8)
When the automatic measurement described above is completed, the obtained measurement data and the selected lens data are stored in the storage device of the mechanical control personal computer 35 as a predetermined data file as necessary. The stored measurement data can be displayed in a list format or output to a printer as necessary.
[0064]
(5) Effects of the embodiment
According to this embodiment as described above, there are the following effects.
Since the light source unit 23, the reference pattern forming unit 25, and the measurement target selection unit 27 are provided, the image detection unit 29 can detect the reference pattern image for inspection that has actually passed through the small lens 11 that is the measurement target. . Therefore, the actual optical characteristics of the small lenses 11 constituting the lens arrays 113 and 115 can be grasped, and the optical characteristics of the lens arrays 113 and 115 can be measured with high accuracy.
[0065]
In addition, since the detection result detected by the image detection unit 29 is processed by the image processing unit 33 serving as an arithmetic processing unit, even if a large number of inspections of the small lens 11 are set, the processing can be easily performed. By collectively processing the optical characteristics of the obtained small lenses, it is possible to accurately grasp the optical characteristics of the entire lens array.
[0066]
Furthermore, since the light source unit 23 includes two types of light sources, that is, the collimator 231 and the diffused light source unit 232, an appropriate light source according to the difference in the measurement items of the small lens 11 can be employed.
[0067]
And since the opening amount of the opening part 275 of the measuring object selection part 27 is comprised variably, the inspection apparatus 2 can be used for the inspection of the lens array which combined the small lens of a different size, The versatility of the inspection apparatus 2 is further improved. Further, since the measurement object selection unit 27 is configured by combining two L-shaped plate members 271 and 273, the size of the opening 275 can be made variable with a simple structure, and the measurement object selection can be made. The structure of the portion 27 can be simplified.
[0068]
In addition, since the image detection unit 29 includes the CCD camera 291, the lens array can be inspected using a highly versatile image processing program, and the cost of the inspection apparatus 2 can be reduced. be able to.
[0069]
Further, automatic measurement S7 includes focal length measurement (focal length measurement step) S75, optical axis position measurement (optical axis position measurement step) S76, lens size measurement (lens area measurement step) S78, and lens arrangement position measurement ( Since the lens position measurement step S79 is provided, the optical characteristics of the entire lens array can be measured with high accuracy by precisely measuring the optical characteristics of the small lenses 11 constituting the lens arrays 113 and 115. .
[0070]
Since the optical axis position measurement S77 includes a detection line setting process, a midpoint calculation process, a center line calculation process, and an optical axis position setting process, the accurate optical axis position of the small lens 11 can be grasped. In addition, the accuracy of the inspection of the lens arrays 113 and 115 can be further increased.
[0071]
(6) Modification of the embodiment
In addition, this invention is not limited to the above-mentioned embodiment, The modification as shown below is also included.
[0072]
In the above-described embodiment, the lens arrays 113 and 115 to be inspected are optical components constituting the integrator illumination optical system 110 of the projector 100. However, the present invention is not limited to this, and the lens arrays used for other purposes are also used. The inspection apparatus according to the present invention may be used for inspection.
[0073]
In the above embodiment, the automatic measurement is performed in the order of the focal length measurement S75, the optical axis position measurement S76, the lens size (area) measurement S80, and the lens arrangement position measurement S81. However, the present invention is not limited to this. . That is, after performing the focal length measurement S75, the order of other measurement items may be set as appropriate. However, the focal length measurement and the optical axis position measurement use a parallel light source, and the lens size (area) measurement and the arrangement position measurement use diffused light. is there.
[0074]
Furthermore, in the above-described embodiment, the measurement data is collectively processed by the inspection apparatus 2 including the image processing unit 33 and the mechanical control personal computer 35. However, the present invention is not limited to this. That is, image analysis and mechanical control may be processed and controlled using a dedicated computer separate from the inspection apparatus main body.
[0075]
In addition, the specific structure, shape, and the like when implementing the present invention may be other structures as long as the object of the present invention can be achieved.
[0076]
【The invention's effect】
According to the present invention as described above, since the lens array inspection apparatus includes the light source unit, the reference pattern forming unit, and the measurement target selection unit, the image detection unit passes through the lens that is actually the measurement target. A reference pattern image for inspection can be detected. Therefore, the actual optical characteristics of the small lenses constituting the lens array can be grasped, and the optical characteristics of the lens array can be inspected with high accuracy.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing the structure of a projector that is an optical apparatus that employs a lens array to be inspected by an inspection apparatus according to an embodiment of the present invention.
FIGS. 2A and 2B are a front view and a side view showing a structure of a lens array in the embodiment. FIGS.
FIG. 3 is a front view showing a structure of a lens array inspection apparatus in the embodiment.
FIG. 4 is a front view showing the structure of the work holder in the embodiment.
FIG. 5 is a horizontal sectional view showing a structure of a first light source unit in the embodiment.
FIG. 6 is a front view illustrating a structure of a reference pattern forming unit in the embodiment.
FIG. 7 is a vertical sectional view showing the structure of the diffuse light source in the embodiment.
FIG. 8 is a front view illustrating a structure of a measurement target selection unit in the embodiment.
FIG. 9 is a flowchart showing an inspection procedure by the inspection apparatus in the embodiment.
FIG. 10 is a flowchart showing an inspection procedure by the inspection apparatus in the embodiment.
FIG. 11 is a diagram for explaining a focal length measurement method in the embodiment.
FIG. 12 is a diagram for explaining an optical axis position measuring method in the embodiment.
FIG. 13 is a diagram for explaining an optical axis position measuring method in the embodiment.
FIG. 14 is a diagram for explaining a measurement method of the size of a small lens in the embodiment.
FIG. 15 is a diagram for explaining a measuring method of the arrangement position of the small lens in the embodiment.
FIG. 16 is a diagram for explaining a measurement method of the arrangement position of the small lens in the embodiment.
[Explanation of symbols]
2 Inspection equipment
11 Lens
21 Work holder
25 Reference pattern forming section
27 Measuring object selector
29 Image detector
33 Image processing unit (arithmetic processing unit)
113, 115 lens array
231 Collimator (first light source unit)
232 Diffused light source unit (second light source unit)
271, 273 Substantially L-shaped plate material
275 opening
291 CCD camera (image sensor)
S75 Focal length measurement step
S76 Optical axis position measurement step
S80 Lens size (area) measurement step
S81 Lens position measurement step

Claims (7)

A lens array inspection apparatus for inspecting optical characteristics of a lens array configured by arranging a plurality of lenses in a matrix,
A work holder attached to the lens array and movable along an arrangement direction of the plurality of lenses;
A light source that emits a light beam toward the lens array on the work holder, and a reference pattern formation that is installed between the work holder and the light source and forms a reference pattern image for inspection based on the light beam from the light source A light source via the reference pattern forming unit is selectively introduced into a lens to be measured among a plurality of lenses of a lens array attached to the work holder. A measurement object selection unit in which an opening to be formed is formed;
An image detection unit for detecting a reference pattern image for inspection through the lens selected by the measurement target selection unit;
An inspection apparatus for a lens array, comprising: an arithmetic processing unit that performs arithmetic processing on a detection result detected by the image detection unit. The lens array inspection apparatus according to claim 1,
A lens array inspection apparatus comprising a second light source unit that emits diffused light. The lens array inspection apparatus according to claim 1 or 2,
2. The lens array inspection apparatus according to claim 1, wherein the measurement object selection unit is configured to be able to vary the size of the opening. The lens array inspection apparatus according to claim 3,
The measuring object selection unit is configured to inspect a lens array, wherein a pair of substantially L-shaped plate members are overlapped so that the substantially L-shaped portions face each other and are relatively movable. apparatus. In the inspection apparatus of the lens array in any one of Claims 1-4,
The lens array inspection apparatus, wherein the image detection unit is an image sensor including a charge coupled device. A lens array inspection method for inspecting optical characteristics of a lens array configured by arranging a plurality of lenses in a matrix,
A pattern image detecting step of projecting a predetermined reference pattern image for inspection on a lens to be measured among a plurality of lenses constituting the lens array, and detecting a reference pattern image for inspection through the lens;
A focal length measuring step for measuring the focal length of the lens based on the reference pattern image for inspection detected in the image pattern detecting step;
An optical axis position measuring step for measuring an optical axis position of the lens;
A lens area measuring step for measuring the area of the lens;
And a lens position measuring step for measuring an array position of the lenses in the lens array. In the inspection method of the lens array according to claim 6,
The inspection reference pattern image is composed of a well-shaped image pattern arranged along a lens center line in a plane orthogonal to the emission direction of the luminous flux of the lens,
The optical axis position measuring step includes a detection line setting process for setting a plurality of detection lines so as to straddle the well-shaped image pattern, and two intersection points of the image pattern detected on each detection line. A midpoint calculation process for calculating points, a centerline calculation process for calculating centerlines that are orthogonal to each other by linear approximation based on a plurality of midpoints calculated from each detection line, and two centerlines that are orthogonal to each other And an optical axis position setting process in which the optical axis position of the lens is set as an optical axis position setting process.

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