JP6273171B2 - Micro lens array - Google Patents

Description

  The present invention relates to a microlens array, and more particularly to a microlens array in which generation of interference fringes is suppressed.

  Conventionally, an optical component using a microlens array that is an aggregate of a plurality of microlenses is known. An optical component using a microlens array divides a light receiving surface into a plurality of minute light receiving surfaces, receives light from each lens portion of the microlens array on each divided minute light receiving surface, and forms an image. To obtain the image. According to this method, the optical component can be greatly reduced in size.

  However, when such an optical component using a microlens array is used in a projector or the like, the microlens array has the same shape and is regularly aligned, and the distribution thereof is formed without any unevenness. Then, interference fringes are generated in the projected image due to regularity. In addition, when coherent light such as laser light is used as the light source, a sharp striped pattern is generated in the image projected on the screen due to the regularity of the light source and the regularity of the microlens array. As a result, the image quality is degraded. Therefore, a microlens array using a processing method for suppressing the occurrence of such a stripe pattern has been proposed in Patent Document 1.

  FIG. 7 shows the structure of a diffuse reflector 900 which is an optical component using the microlens array disclosed in Patent Document 1.

  FIG. 7 is a perspective view showing an example of a concavo-convex film 950 (microlens array) created as the diffuse reflector 900. FIG. On the convex surface of the concavo-convex film 950, there is formed a transfer molding cutting trace 915 formed by transferring the cutting trace on the concave curved surface of the mold. The transfer molding cutting trace 915 includes cutting traces 915a and 915b resulting from cutting in different cutting directions. In the concavo-convex film 950, an undercoat layer 951 having a concavo-convex shape transferred thereon is laminated on a base film (or base material) 952.

  According to the invention disclosed in Patent Document 1, the generation of interference fringes can be suppressed by making the cutting directions of the fine cutting marks 915a and 915b remaining on the diffuse reflector 900 different.

JP 2007-025090 A

  However, the concavo-convex film 950 (microlens array) used in the diffuse reflector 900 disclosed in Patent Document 1 has the following problems.

  In the microlens array used in the diffuse reflector 900, there are lens portions with different cutting directions. However, when the cutting directions are different, the shape of the lens portion varies depending on the cutting direction, and the shape of the lens portion varies. There was a problem that it would. Furthermore, if the shape of each lens part in the microlens array varies, there is a problem that the focal position varies.

  The present invention has been made in view of the actual situation of the prior art, and an object of the present invention is to provide a microlens array that can suppress the occurrence of interference fringes and the occurrence of variations in the shape of the lens portion. Is to provide.

In order to solve this problem, the microlens array of the present invention is a microlens array that is manufactured by molding and has a plurality of lens portions arranged on the same surface, and the plurality of lens portions include: A plurality of protrusions formed by transferring the processing traces of the mold for molding are formed, respectively, and the plurality of lens parts include a first lens part and a second lens part, Each of the plurality of protrusions in the lens part is formed along the same first direction, and is a pitch between the protrusions in the first lens part of the plurality of lens parts. The first pitch is different from the second pitch, which is the pitch between the protrusions in the second lens portion of the plurality of lens portions, and the light transmitted through the first lens portion and the second and light passing through the lens unit Inhibited the formation of interference fringes due to overlapping, it has the feature that.

  In the microlens array configured as described above, since the first pitch in the first lens unit and the second pitch in the second lens unit are different from each other, the fringe pattern due to the interference of light generated from each of the plurality of lens units is generated. Can be suppressed. As a result, generation of interference fringes can be suppressed. At the same time, since the processing directions for all the lens portions are the same, the occurrence of variations in the shape of the lens portions can be suppressed.

  Further, in the above configuration, a first lens unit group in which a plurality of first lens units including a plurality of protrusions having the first pitch are continuously formed in the first direction, and the second pitch. A second lens part group including a plurality of second lens parts each having a plurality of protrusions formed in the first direction, the first lens part group and the second lens part. The group is arranged along the second direction which is a direction orthogonal to the first direction, and the arrangement order of the first lens unit group and the second lens unit group is not repeated. Has characteristics.

  In the microlens array configured as described above, since the pitch of the protrusions can be made random for each lens unit group, the light passing through the first lens unit group and the light passing through the second lens unit group The generation of interference fringes due to the overlapping can be suppressed.

  In the above configuration, the first lens unit and the second lens unit are arranged in parallel along the first direction, and the first lens unit and the second lens unit are The first lens unit and the second lens unit in one direction are arranged side by side so as not to be repeated.

  In the microlens array configured as described above, the pitch of the protrusions can be made random for each lens unit, so that the light passing through the first lens unit and the light passing through the second lens unit overlap each other. The generation of interference fringes due to can be suppressed.

  In the microlens array of the present invention, the first pitch in the first lens unit and the second pitch in the second lens unit are different from each other, so that the fringe pattern due to interference of light generated from each of the plurality of lens units is suppressed. Can do. As a result, generation of interference fringes can be suppressed. At the same time, since the processing directions for all the lens portions are the same, the occurrence of variations in the shape of the lens portions can be suppressed.

It is a schematic diagram which shows the structure of the projector which uses a micro lens array. It is sectional drawing of the metal mold | die for a mold shaping, and a micro lens array. It is a perspective view which shows the external appearance of a micro lens array. It is a top view of the micro lens array of the present invention in a 1st embodiment. It is a top view of the micro lens array of the present invention in a 2nd embodiment. It is a top view of the micro lens array of the present invention in a 3rd embodiment. It is a perspective view which shows the external appearance of the microlens array which concerns on a prior art example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present specification, unless otherwise specified, the X1 side of each drawing is described as the right side, the X2 side as the left side, the Y1 side as the back side, the Y2 side as the near side, the Z1 side as the upper side, and the Z2 side as the lower side. To do.

  First, as an example using the microlens array of the present invention, the configuration of a general liquid crystal projector 90 will be described with reference to FIG.

  The liquid crystal projector 90 has a structure in which a light source unit 91, a liquid crystal panel 92, and a projection lens optical system 93 are arranged in this order along the optical axis. The light emitted from the lamp 94 constituting the light source unit 91 is collected by the reflecting mirror 95 to the front of the component emitted to the rear of the lamp 94 and enters the condenser lens 96. The condenser lens 96 further concentrates the light and guides it to the liquid crystal panel 92 via the incident side polarizing plate 97. The guided light is converted into an image by a liquid crystal panel 92 having a function of a shutter or a light valve and an emission side polarizing plate 98. The displayed image is enlarged and projected on the screen 99 via the projection lens optical system 93.

  In the present invention, a small-sized projector that can be carried is assumed as the liquid crystal projector 90. Therefore, it is necessary to make each component small. The projection lens optical system 93 has a short focal length. Therefore, in the liquid crystal projector 90, a microlens array is used for the projection lens optical system 93, the condenser lens 96, and the like. By using a microlens array that is an aggregate of a plurality of microlenses, optical components such as the projection lens optical system 93 can be greatly reduced in size. The shape of the microlens array used is a circular shape having an outer dimension of about 5 mm or a polygonal shape.

  Next, the configuration of the microlens array 100 according to the first embodiment will be described with reference to FIGS. 2A is a cross-sectional view of a mold 60 for molding, and FIG. 2B is a cross-sectional view of the microlens array 100. FIG. 3 is a perspective view showing the appearance of the microlens array 100, and FIG. 4 is a plan view showing the arrangement of each lens unit group in the microlens array 100. FIG.

  As shown in FIG. 2A, a plurality of groove portions 67 are formed at a predetermined interval by moving the surface of the mold base material 61 by applying a processing tool thereto. As a result, a concave portion 65 corresponding to one lens portion is formed, and a plurality of the concave portions 65 are formed, whereby the mold 60 is manufactured. The microlens array 100 is manufactured by molding using the mold 60.

  As shown in FIGS. 2B and 3, the microlens array 100 has a plurality of lens portions 1 arranged on the same surface. On the surface of the plurality of lens portions 1, a plurality of protrusions 7 formed by transferring the groove portions 67 which are a plurality of processing marks of the mold 60 shown in FIG. 2A are formed. At the same time, the convex portion 5 is formed corresponding to the concave portion 65 of the mold 60. Further, by manufacturing the plurality of groove portions 67 in the same first direction (Y1-Y2 direction), the plurality of protrusions 7 in all the lens portions 1 are respectively as shown in FIG. Are formed along the same direction, that is, the first direction (Y1-Y2 direction). At the same time, the plurality of protrusions 7 in each lens unit 1 are adjacent to each other at a predetermined interval (first pitch P1 or second pitch P2).

  In the microlens array 100 according to the first embodiment of the present invention, the pitch between the protrusions 7 is varied in order to suppress the stripe pattern due to the light interference generated in each of the plurality of lens units 1.

  First, the 1st pitch P1 which is the pitch between the some protrusion part 7 in the 1st lens part 11 shown in FIG.2 (b) among the some lens parts 1 is set to a predetermined | prescribed space | interval. The first pitch P <b> 1 is determined by the pitch of the groove portion 67 in the concave portion 65 corresponding to the first lens portion 11. Next, among the plurality of lens portions 1, a second pitch P2 that is a pitch between the plurality of protrusions 7 in the second lens portion 22 shown in FIG. 2B is set to a predetermined interval. The second pitch P <b> 2 is determined by the pitch of the groove portion 67 in the concave portion 65 corresponding to the second lens portion 22. Here, the first pitch P1 and the second pitch P2 are different. That is, as shown in FIGS. 2B and 3, P1 ≠ P2. In this description, for ease of explanation, it has been described that there are two types of lens units, but the same is true if there are three or more types of lens units.

  In the microlens array 100 according to the first embodiment of the present invention, as shown in FIG. 4, the first lens unit 11 including the plurality of protrusions 7 having the first pitch P1 is in the first direction (Y1-Y2). In the first direction (Y1-Y2 direction). The first lens unit group 10 formed continuously in the direction) and the second lens unit 22 including the plurality of protrusions 7 having the second pitch P2 are arranged in the first direction (Y1-Y2 direction). And a plurality of second lens unit groups 20 formed in succession. And the 1st lens part group 10 and the 2nd lens part group 20 are arranged in parallel along the 2nd direction (X1-X2 direction) which is a direction orthogonal to a 1st direction. Furthermore, a third lens unit group 30 in which a plurality of third lens units 33 each having a plurality of protrusions 7 having a third pitch P3 are continuously formed in the first direction is provided in the second lens unit group 20. Adjacent to each other. Each pitch is P1 ≠ P2, P2 ≠ P3, and P3 ≠ P1. When each lens unit group is configured as shown in FIG. 4, specifically, for example, the first pitch P1 is 5.0 μm, the second pitch P2 is 6.7 μm, the third pitch P3 is 8.0 μm, and the like. Can do.

  The arrangement order in which the first lens unit group 10, the second lens unit group 20, and the third lens unit group 30 are arranged is further repeatedly arranged. For ease of explanation, the description has been given assuming that there are three types of lens unit groups, but the same applies if there are four or more types of lens unit groups.

  Thus, in the microlens array 100, the first pitch P1 that is the pitch between the plurality of protrusions 7 in the first lens unit 11 of the plurality of lens units 1 and the plurality of projections in the second lens unit 22. Since the second pitch P2 that is the pitch between the strips 7 is made different, it is possible to suppress the stripe pattern due to the interference of light generated from each of the plurality of lens units 1. Therefore, generation of interference fringes can be suppressed. At the same time, since the processing directions for all the lens portions 1 are the same, it is possible to suppress the variation in the shape of the lens portion 1 and the variation in the focal length caused by the occurrence of the shape variation.

  Next, the configuration of the microlens array 200 according to the second embodiment will be described with reference to FIG. FIG. 5 is a plan view showing the arrangement of the lens unit groups in the microlens array 200.

  The only difference between the microlens array 100 and the microlens array 200 described above is that the arrangement of each lens unit group in the microlens array 200 is different from the arrangement of each lens unit group in the microlens array 100. Other configurations are the same. Therefore, a part of the description of the same part is omitted.

  In the microlens array 200 according to the second embodiment of the present invention, as illustrated in FIG. 5, the first lens unit 11 including the plurality of protrusions 7 having the first pitch P1 is in the first direction (Y1-Y2). A plurality of second lens portions 22 each including a plurality of protrusions 7 having a second pitch P2 and a plurality of second lens portions 22 formed continuously in the first direction. Second lens unit group 20. And the 1st lens part group 10 and the 2nd lens part group 20 are arranged in parallel along the 2nd direction (X1-X2 direction) which is a direction orthogonal to a 1st direction. Furthermore, the third lens unit group 30 in which a plurality of third lens units 33 including a plurality of protrusions 7 having a third pitch P3 are continuously formed in the first direction (Y1-Y2 direction) is the second lens unit 30. It is arranged adjacent to the lens unit group 20.

  However, in the microlens array 200, the arrangement in which the first lens unit group 10 and the second lens unit group 20 are arranged in that order is not repeated. As shown in FIG. 5, the second lens unit group 20 is arranged on the right side of the leftmost first lens unit group 10, and the third lens unit group 30 is arranged on the right side of the second lens unit group 20. . Next, the first lens unit group 10 is arranged on the right side of the third lens unit group 30, and the second lens unit group 20, not the second lens unit group 20, is arranged on the right side of the first lens unit group 10. The lens unit group 30 is arranged. The second lens unit group 20 is arranged on the right side of the third lens unit group 30. That is, the first lens unit group 10 and the second lens unit group 20 are not arranged in that order. In other words, the arrangement in which the first lens unit group 10 and the second lens unit group 20 are arranged in the same order is not repeated. In the description so far, for ease of explanation, it has been described that there are three types of lens unit groups, but the same is true if there are four or more types of lens unit groups.

  As described above, in the microlens array 200, the arrangement order of the first lens unit group 10 and the second lens unit group 20 is not repeated, so that the pitch of the protrusions 7 can be random for each lens unit group. it can. Therefore, generation of interference fringes due to interference between light passing through the first lens unit group 10 and light passing through the second lens unit group 20 can be suppressed.

  Next, the configuration of the microlens array 300 according to the third embodiment will be described with reference to FIG. FIG. 6 is a plan view showing the arrangement of the lens units 1 in the microlens array 300.

  The difference between the microlens array 100 or the microlens array 200 and the microlens array 300 described above is that the arrangement of each lens unit 1 in the microlens array 300 is different from each lens unit 1 in the microlens array 100 or microlens array 200. However, it is the same as the other arrangement methods. Therefore, a part of the description of the same part is omitted.

  In the microlens array 300 according to the third embodiment of the present invention, as shown in FIG. 6, in one column, for example, the leftmost (X2 side) column, the first pitch P1 is set from the farthest side (Y1 side). The 1st lens part 11 provided with the several protrusion part 7 which has and the 2nd lens part 22 provided with the several protrusion part 7 which has the 2nd pitch P2 are along a 1st direction (Y1-Y2 direction). Side by side. And the 3rd lens part 33 provided with the some protrusion part 7 which has the 3rd pitch P3 is arranged in parallel adjacent to the near side (Y2 side) of the 2nd lens part 22. FIG.

  Further, in the leftmost column (X2 side), the first lens unit 11 is arranged in parallel on the front side (Y2 side) of the third lens unit 33 described above, and further on the front side (Y2 side) of the first lens unit 11. ), The third lens portion 33 is arranged in parallel, and the second lens portion 22 is not arranged in parallel. That is, the first lens unit 11 and the second lens unit 22 are arranged side by side so that the arrangement order of the first lens unit 11 and the second lens unit 22 in the first direction (Y1-Y2 direction) is not repeated. ing.

  In this description, the leftmost column (X2 side) is described as an example, but the same applies to the other columns. Further, in the direction orthogonal to each row, that is, in the second direction (X1-X2 direction), the same lens unit 1, for example, the first lens units 11 or the second lens units 22 are not adjacent to each other. Has been placed. In the present description, for ease of explanation, the description has been made assuming that there are three types of lens unit 1, but the same applies even if there are four or more types of lens unit 1.

  As described above, in the microlens array 300, the first lens unit 11 and the second lens unit 22 are arranged in parallel along the first direction (Y1-Y2 direction), and the first lens unit 11 and the second lens unit 22 are arranged in parallel. Since the lens unit 22 is arranged in parallel so that the arrangement order of the first lens unit 11 and the second lens unit 22 in the first direction is not repeated, the pitch of the protrusions 7 is randomly determined for each lens unit. It can be. Therefore, generation of interference fringes due to interference between light passing through the first lens unit 11 and light passing through the second lens unit 22 can be suppressed.

  As described above, in the microlens array according to the present invention, the first pitch in the first lens unit and the second pitch in the second lens unit are different from each other. Striped patterns can be suppressed. As a result, generation of interference fringes can be suppressed. At the same time, since the processing directions for all the lens portions are the same, the occurrence of variations in the shape of the lens portions can be suppressed.

  As described above, the microlens array 100 to the microlens array 300 according to the embodiment of the present invention have been described. However, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention. Can be implemented.

DESCRIPTION OF SYMBOLS 1 Lens part 5 Convex part 7 Projection part 10 1st lens part group 11 1st lens part 20 2nd lens part group 22 2nd lens part 30 3rd lens part group 33 3rd lens part 60 Mold 61 Mold mother Material 65 Concave part 67 Groove part 90 Liquid crystal projector 100 Micro lens array 200 Micro lens array 300 Micro lens array P1 1st pitch P2 2nd pitch P3 3rd pitch

Claims (3)

A microlens array having a plurality of lens portions manufactured by molding and arranged on the same surface,
The plurality of lens portions are respectively formed with a plurality of protrusions generated by transferring the processing marks of the mold for molding.
The plurality of lens units include a first lens unit and a second lens unit,
The plurality of ridge portions in all the lens portions are respectively formed along the same first direction, and the pitch between the ridge portions in the first lens portion of the plurality of lens portions is the same. A first pitch is different from a second pitch that is a pitch between the protrusions in the second lens portion of the plurality of lens portions, and the light transmitted through the first lens portion and the first pitch are different from each other. 2. A microlens array characterized by suppressing generation of interference fringes due to overlapping of light transmitted through two lens portions. A first lens portion group in which a plurality of first lens portions each having a plurality of ridge portions having the first pitch are formed in the first direction, and a plurality of ridge portions having the second pitch. A second lens part group comprising a plurality of second lens parts continuously formed in the first direction,
The first lens unit group and the second lens unit group are juxtaposed along a second direction which is a direction orthogonal to the first direction, and the first lens unit group and the second lens 2. The microlens array according to claim 1, wherein the arrangement order with the group is not repeated. The first lens part and the second lens part are juxtaposed along the first direction,
The first lens unit and the second lens unit are arranged in parallel so that the arrangement order of the first lens unit and the second lens unit in the first direction is not repeated. The microlens array according to claim 1.

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