JP6580434B2 - Lens barrel, image projection device, and mold for molding - Google Patents

Description

  The present invention relates to a lens barrel, an image projection apparatus using the lens barrel, and a molding die for forming the lens barrel.

  In an image projection device that uses a lens barrel such as a projector, in order to prevent image quality deterioration of the projected image due to flare, ghost, etc., light from the light source that is unnecessary for image projection is removed by the light shielding unit. The structure which performs is known (for example, refer patent documents 1-4).

  However, depending on the lens fixing method and the configuration of the lens barrel part, the light shielding part has to be provided separately from the lens barrel part, and there is a problem that the cost increases due to an increase in the number of parts and an increase in work man-hours. there were.

  The present invention has been made in view of the above problems, and is a light-shielding portion that is integrally formed with a lens barrel portion and restricts emission of unnecessary light generated from a light source into the lens barrel or to a projected image. It aims at provision of a lens barrel provided with.

In order to solve the above-described problems, a lens barrel according to the present invention is provided integrally with a lens barrel portion for supporting at least one lens and the lens barrel portion, and transmits outside the effective radius of the lens. A light shielding portion for restricting the emission of the luminous flux to be emitted, a fixing portion for fixing the lens by thermal caulking, and a gap portion formed on the opposite side of the lens with the fixing portion interposed therebetween. The portion is formed along a direction parallel to the optical axis of the lens, and the surface of the light shielding portion on the optical axis side of the lens is formed so as to be flat with the outer peripheral surface of the gap. Features .

  According to the present invention, it is possible to provide a lens barrel that is integrally formed with the lens barrel portion and includes a light shielding portion that restricts emission of unnecessary light generated from the light source into the lens barrel or to the projection image.

It is a figure which shows an example of a structure of the image projector in embodiment of this invention. It is sectional drawing which shows an example of the whole structure of the lens-barrel shown in FIG. FIG. 3 is an enlarged plan view showing an example of a configuration of an A portion of the lens barrel shown in FIG. FIG. 4 is a schematic diagram illustrating an example of a configuration of a molding die for forming the housing portion illustrated in FIG. 3. It is a top view which shows the procedure of the assembly of the lens-barrel shown in FIG. It is a schematic diagram which shows an example of a structure of the modification with respect to embodiment of this invention. It is a schematic diagram which shows an example of a structure of a prior art example.

As an embodiment of the present invention, an example of the configuration of an image projection apparatus is shown in FIG.
The image projection apparatus 100 includes a light source 101 that emits a projection light beam L, and a spatial light modulation element 102 that planarly displays an image to be projected as image information and modulates the projection light beam L from the light source 101. is doing.
The image projection apparatus 100 includes a lens unit 200 that is a lens barrel for projecting the projection light beam L that has passed through the spatial light modulation element 102 onto the projection surface 104, and spatial light modulation for displaying an image to be projected onto the projection surface 104. And a control unit 109 that controls the element 102.

The light source 101 includes a halogen lamp that is a light source that emits the projection light beam L, and emits white light substantially in parallel. Here, a metal halide lamp, a high-pressure mercury lamp, or an LED may be used as the light source.
Although the light source 101 is a white light source, a plurality of monochromatic light sources such as laser light sources corresponding to basic colors such as R, G, and B may be used.

  The spatial light modulation element 102 is a liquid crystal panel that is an image display means that provides image information by transmitting an incident projection light beam L, applying spatial modulation, and emitting the light. The spatial light modulator 102 may be a reflective spatial light modulator such as a DMD (digital micromirror device).

  The control unit 109 controls the spatial light modulation element 102 to add image information to be projected onto the projection surface 104 to the projection light beam L that passes through the spatial light modulation element 102.

As shown in FIG. 2, the lens unit 200 is a lens unit including a projection optical system that projects the light beam L incident from the light source 101 side toward the image projection direction side, that is, the Z direction downstream side.
Of the lens unit 200, the portion closest to the projection surface 104 is indicated by a two-dot chain line as the A region, and is shown in FIG. 3 as an enlarged view.

As shown in FIG. 3, the lens unit 200 includes three lenses 21, 22, and 23, which are optical members arranged in order from the projection surface 104 side, that is, the downstream side in the Z direction that is the image projection direction, and the lenses 21 and 22. , 23, and a housing portion 10 that is a lens barrel portion for supporting.
The lens unit 200 is also formed integrally with the housing unit 10, and includes a light shielding unit 11 that restricts the emission of unnecessary light L ′, which is a light beam incident from the light source 101 side of the lens unit 200 and emitted from the lens unit 200. Have.
The three lenses 21, 22, and 23 are an imaging optical system that forms an image of the projection light beam L that has passed through the spatial light modulation element 102, and a part of the projection optical system that projects an image on the projection surface 104. It is composed. In particular, when it is necessary to distinguish the lenses 21, 22, and 23, the lens arranged closest to the projection plane 104, that is, the downstream side in the Z direction that is the image projection direction, is the projection side lens 21 that is the first lens. To do.
Similarly, a lens disposed upstream of the projection side lens 21 in the Z direction is referred to as a lens 22 as a second lens, and a lens disposed most upstream in the Z direction is referred to as an incident side lens 23 as a third lens.
The projection light beam L transmitted through the lens unit 200 has effective radii r ₂₁ and r ₂₂ based on the optical design of the projection side lens 21, the lens 22, and the incident side lens 23, as indicated by broken lines in FIG. , so that through the _{r 23,} each position of the lens 21, 22, 23 is adjusted.

The traveling direction of the projection light beam L transmitted through the lens unit 200 is the Z direction, the optical axis O of the lens unit 200 is the Z axis, the vertical axis in FIGS. 2 and 3 is the Y axis, and the Z axis and the Y axis are orthogonal to each other. The axis to be operated is defined as the X axis, and the respective axial directions are defined as the Y direction and the X direction.
Here, the optical axis O which is the lens optical axis of the lens unit 200 coincides with the optical axis of the lens 22. Similarly, the optical axes of the projection side lens 21 and the incident side lens 23 also coincide with the optical axis O.
Hereinafter, in particular, when it is desired to specify the direction, each of the X, Y, and Z directions is indicated by + or −.

In the present embodiment, the projection optical system is formed by the three lenses 21, 22, and 23. However, the lens unit 200 only needs to have at least one lens.
Further, the projection side lens 21 may be an optical member other than the lens, for example, glass having no power.

The housing part 10 includes a caulking part 13 as a fixing part as a first fixing part for fixing the lens 22 and the lens 23 by thermal caulking in a mounting process described later, and a projection side lens for supporting the projection side lens 21. The presser part 12 and the lens receiving surface 14 for supporting the incident side lens 23 are provided.
The casing 10 has a gap 15 that is formed on the opposite side of the lens 22 with the crimping portion 13 interposed therebetween, in other words, is a space 15 formed outside the crimping portion 13 around the optical axis O.
The caulking portion 13 is crushed in the direction of the lens receiving surface 14 by the heat caulking jig inserted into the gap portion 15 so as to be slightly applied to the + Z direction side of the lens 22, whereby the lens receiving surface 14 and the caulking portion 13 The lens 22 and the lens 23 are fixed between them.

The light shielding portion 11 is formed on the + Z direction side of the lens 22, in other words, on the downstream side in the emission direction of the unnecessary light L ′ and outside the effective radius r ₂₂ of the lens 22 along the + Z direction. Part.
The light shielding part 11 is arranged so that the tip end part 11a in the + Z direction occupies a position entering the concave part 21a of the projection side lens 21 supported by the casing part 10 on the + Z direction side from the lens 22.
In addition, the recessed part 21a is a part containing the non-lens surface provided in the projection side lens 21 in this embodiment. Therefore, when the light shielding unit 11 occupies such a position, the unnecessary light L ′ is prevented from entering the non-lens surface of the projection side lens 21.

In addition, the light shielding portion 11 has an inner peripheral surface 11b which is a surface on the lens optical axis O side, which is parallel to the Z direction, and is formed to be flat and smoothly connected to the outer peripheral surface 15b of the gap portion 15.
The term “smoothly and smoothly connected” here means that they are formed so as to be flush with each other, and may include a state in which they are inclined so as to spread toward the + Z direction side, as will be described later.
Further, the inner peripheral surface 11b may be provided with a light-shielding antireflection structure on the surface like so-called embossing.

A method for manufacturing the lens unit 200 having such a configuration will be described.
FIG. 4 shows a schematic diagram of a mold 30 as a molding die that is a resin mold for injection molding for forming the casing 10.
In this embodiment, the mold 30 includes a fixed mold 31 that is a female mold for forming the outer side of the casing unit 10, and a movable mold 32 that is a male mold for forming the inner side of the casing unit 10. is doing.
The movable mold 32 has a light shielding forming portion 33 that is a concave portion for forming the light shielding portion 11 and a gap forming portion 34 that is a convex portion for forming the gap portion 15. A wall surface 33 a on the outer peripheral side of the light shielding forming portion 33 is provided so as to be continuous with a side surface portion 34 a which is a side surface of the gap forming portion 34. In other words, the side surface portion 34a on the outer peripheral side of the gap forming portion 34 and the wall surface 33a on the inner peripheral side of the light shielding forming portion 33 are provided so as to be continuously flat and smooth, that is, flush with each other.

When forming the casing unit 10 using such a mold 30, a resin material that is a material of the casing unit 10 in a state where the fixed mold 31 and the movable mold 32 are fixed so as to face each other, that is, in a fitted state. P is dissolved and poured at high pressure.
The melted resin material P is poured into a space in the shape of the casing 10 between the fixed mold 31 and the movable mold 32, and pressure is applied.
The resin material P is cooled in the mold 30 until it hardens. When the resin material P is hardened, the fitting state of the mold 30 is released by moving the movable mold 32 in the movable direction, that is, in the + Z direction, and the casing 10 as a molded product is taken out.
At this time, the inner peripheral surface 11b is a surface parallel to the Z direction, and is formed so as to be flat and smoothly connected to the outer peripheral surface 15b of the gap portion 15, whereby the side surface of the gap forming portion 34 of the movable mold 32 is obtained. The part 34a is die-cut without being caught by the inner peripheral surface 11b.
Note that the term "flatly connected" here means that they are formed so as to be flush with each other, and include a state in which the die can be removed to a certain extent so as to spread to the + Z direction side, in other words, to the downstream side in the movable direction. Good.
Further, the side surface 34a may be formed with a light-shielding antireflection structure that fits in a pair with the textured surface of the inner peripheral surface 11b on the surface in order to form the textured surface on the inner peripheral surface 11b. good.
After the removal of the housing part 10 is completed, the mold 30 is fitted again, and the above operation is repeated, whereby repeated molding is performed.

  In addition, although injection molding was mentioned here as an example, it is not limited to this molding method, Other molding methods may be used.

As shown in FIG. 5A, the housing 10 molded through the molding process is attached so that the incident side lens 23 comes into contact with the formed lens receiving surface 14.
Next, as shown in FIG. 5B, after the lens 22 is inserted into the casing 10 from the + Z direction side and positioned, the crimping portion 13 is joined by heating, pressing or pressure bonding. That is, by pressing, the lens 22 is fixed to the housing unit 10 by heat caulking.
Specifically, the lens receiving surface 14 and the caulking portion are crushed by the heat caulking jig inserted into the gap portion 15 in the direction of the lens receiving surface 14 so that the caulking portion 13 is slightly applied to the + Z direction side of the lens 22. The lens 22 and the lens 23 are fixed between the lens 13 and the lens 13.
Such a caulking process is an attaching process for attaching the lenses 22 and 23 to the housing unit 10.
In addition, by providing a minute gap between the lens 22 and the housing 10, the fitting length between the housing 10 and the lens 22 is optimized, and interference during assembly is reduced, so that the mounting is simple. It becomes possible.
Finally, the projection side lens 21 is fixed to the housing unit 10 using the projection type lens pressing unit 12 and a sheet metal pressing part (not shown), and the configuration of the lens unit 200 as shown in FIGS. Become.

  A method for projecting an image in the image projection apparatus 100 having the above-described configuration will be described.

White light emitted from the light source 101 enters the spatial light modulation element 102 as a projection light beam L, and color image information is converted by the spatial light modulation element 102 that applies spatial modulation based on the control of the control unit 109. Is granted.
The projection light beam L that has been spatially modulated by the spatial light modulation element 102 passes through the lens unit 200 and is projected onto the projection surface 104 as a projection image.

In order to project a high-quality image in the image projection apparatus 100, specifically, in order to prevent deterioration of the image quality of the projected image due to flare, ghost, etc., the lens 21, 22, 23 is transmitted outside the effective radius. It is important to remove unnecessary light L ′ emitted from the unit 200.
In the image projector 100, generally, the light entering from the traveling direction side of the projection light beam L, that is, the −Z direction side, is set to transmit only the projection light beam L. That is, the unnecessary light L ′ mentioned here can be said to be light that passes outside the effective radii of the lenses 21, 22, and 23 among light that enters the lens unit 200 from the −Z direction side.
The unnecessary light L ′ may include, for example, light scattered on the −Z direction side from the lens 23 and scattered by hitting a lens edge (not shown), light scattered by hitting a lens frame, reflected light between lenses. good. Further, the unnecessary light L ′ may include unnecessary light that may cause ghost or flare when appearing in the projected image even if it passes through the effective diameter.
The unnecessary light L ′ may enter a non-lens portion provided for fixing of the lenses 21, 22, and 23 attached to the lens unit 200, for example, and may have an adverse effect.

In order to remove such unnecessary light L ′, as shown in FIG. 7A as a conventional example, a projection 51 a as a light shielding portion is provided so as to block unnecessary light L ′ entering from outside the effective radius of the lens. The structure to provide has been considered.
In the conventional example shown below, the lenses 21, 22, and 23 may have the same configuration as that described in the embodiment, and thus the same numbers are given and the description thereof is omitted.
By the way, in recent years, there is a strong demand for downsizing and cost reduction of the image projection apparatus, and as for the fixing method of the lenses 21, 22, and 23, there is a demand for a fixing method with high accuracy using caulking or the like and with less man-hours.
However, when the lens 22 disposed in the lens unit 500 is fixed by caulking, a space portion is required between the lens 22 and the lens unit 500. In other words, it is necessary to provide a space 53 in which a caulking tool can be inserted.
When the space 53 is provided and the protrusion 51a is further provided, the protrusion 51a is undercut, so that the mold and the molded product cannot be released simply by moving the mold in the opening direction, that is, the Z direction. . If the mold is moved inward, that is, in the Y direction, the protrusion 51a can be released, but the space 53 cannot be released. Therefore, it is difficult to mold such a part.
Further, if the molded product is caught in the mold, the mold cannot be opened, and if the mold is forcibly opened, the molded product may be destroyed.
In order to solve such a problem, as shown in FIG. 7B, a configuration in which the protruding portion 51b is attached as a separate body after the lens 22 is assembled can be considered. However, the configuration becomes complicated and the number of parts increases. The problem of increasing costs has not been solved.

Therefore, in the present embodiment, the light shielding portion 11 is formed toward the + Z direction along the Z direction parallel to the optical axis O.
With this configuration, the light shielding unit 11 integrally formed with the housing unit 10 restricts the emission of unnecessary light L ′.

In the present embodiment, the light shielding unit 11 is formed on the + Z direction side of the lens 22.
With this configuration, transmission of unnecessary light L ′ that passes outside the effective radius r ₂₂ of the lens 22 is limited.

In the present embodiment, the light shielding part 11 is a convex part convex in the + Z direction, and the tip part 11 a enters the concave part 21 a of the projection side lens 21 supported by the housing part 10 on the + Z direction side of the lens 22. It is arranged so as to occupy the position to be.
With such a configuration, emission of unnecessary light L ′ entering the outside of the concave portion 21 a of the projection side lens 21 from the inside of the housing portion 10 is suppressed or prevented.

In the present embodiment, the housing 10 includes a caulking portion 13 that fixes the lens 22 by thermal caulking, and a gap portion 15 that is formed on the opposite side of the lens 22 across the caulking portion 13.
With such a configuration, the lenses 22 and 23 are fixed by putting a tool in the gap 15 and crushing the caulking portion 13 in the direction of the lens receiving surface 14. This is not accompanied by an increase in cost.

In the present embodiment, the side surface 11 b on the inner peripheral side of the light shielding portion 11 is formed to be flush with the outer peripheral surface 15 b on the outer peripheral side of the gap portion 15 and to be flat and continuous.
With such a configuration, while providing the light shielding portion 11, the structure is simple and the number of parts and man-hours are not increased, and an increase in cost is suppressed.

In the present embodiment, the mold 30 has a fixed mold 31 for forming the outer side of the casing unit 10 and a movable mold 32 for forming the inner side of the casing unit 10. The movable mold 32 has a light shielding forming portion 33 that is recessed in the + Z direction for forming the light shielding portion 11 and is movable in the Z direction.
With such a configuration, the structure of the mold for molding the housing portion 10 is facilitated, and an increase in cost is suppressed.

In the present embodiment, the mold 30 has a fixed mold 31 for forming the outer side of the casing unit 10 and a movable mold 32 for forming the inner side of the casing unit 10. In addition, the movable mold 32 includes a light shielding forming portion 33 that is recessed in the + Z direction for forming the light shielding portion 11 and a void forming portion 34 that is convex in the −Z direction for forming the space 15. It can move in the Z direction.
With such a configuration, the structure of the mold for molding the housing portion 10 is facilitated, and an increase in cost is suppressed.

Further, as a modified example, as shown in FIG. 6, a lens barrel 400 that is asymmetric with respect to the Z-axis using so-called D-cut lenses 41, 42, and 43 may be used.
In such a configuration, the light shielding portion 11 is a convex portion formed only on the + Y direction side.
Since other configurations are the same as those in the above-described embodiment, the same reference numerals are given and description thereof is omitted.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the specific embodiments, and the present invention described in the claims is not specifically limited by the above description. Various modifications and changes are possible within the scope of the above.

  For example, the image projector is a single-plate color projector that provides color image information with a single liquid crystal panel, but is not limited thereto, and may be a three-plate color projector or a monochrome image projector. There may be.

  In the present embodiment, the lens barrel that is axially symmetric with respect to the lens optical axis has been described. However, a lens barrel that is asymmetric with respect to the optical axis using a so-called D-cut lens may be used.

In the present embodiment, one of the three lenses is fixed by caulking, but a plurality of lenses may be fixed by caulking. Moreover, you may fix by fixing methods other than caulking.
Further, the antireflection structure formed in the light shielding portion may be processed other than the texture processing as long as it is for reducing reflected light.

  The effects described in the embodiments of the present invention are only the most preferable effects resulting from the present invention, and the effects of the present invention are limited to those described in the embodiments of the present invention. is not.

10 Lens barrel (housing)
11 light-shielding part 11a tip part 11b optical axis side surface (side surface part)
13 Fixing part (crimping part)
15 gap 15b outer peripheral surface 21 optical member (projection side lens)
21a Concave portion 22 Lens 30 Resin mold (mold)
31 Fixed mold 32 Movable mold 33 Recessed part (light-shielding part)
34 Convex part (gap forming part)
100 image projector 200 lens barrel (lens unit)
L Projected light beam L ′ Light beam that passes outside the effective radius of the lens (stray light)
O Optical axis (Lens optical axis)
P resin material Z direction parallel to the optical axis of the lens

Japanese Patent No. 5599093 JP 2013-068857 A JP 2011-242504 A JP 2005-309289 A

Claims (6)

A lens barrel for supporting at least one lens;
A light-shielding portion that is provided integrally with the lens barrel portion and restricts emission of a light beam that passes outside the effective radius of the lens;
A fixing portion for fixing the lens by heat caulking;
A gap formed on the opposite side of the lens across the fixed portion;
Have
The light-shielding portion is formed along a direction parallel to the optical axis of the lens, and the surface of the light- shielding portion on the optical axis side of the lens is formed to be continuous with the outer peripheral surface of the gap portion. A lens barrel characterized by that . The lens barrel according to claim 1,
The lens barrel, wherein the light shielding portion is formed upstream of the lens in the light beam emission direction. The lens barrel according to claim 1 or 2,
The lens barrel, wherein the light shielding portion is a convex portion. In the lens barrel according to claim 3,
The lens is characterized in that a front end portion in the parallel direction of the light shielding portion occupies a position entering the concave portion of the optical member supported by the lens barrel portion on the downstream side of the light beam emission direction from the lens. A lens barrel. An image projection apparatus comprising the lens barrel according to claim 1. A molding die for forming a lens barrel according to any one of claims 1 to 4,
A fixed mold for forming the outside of the lens barrel;
A movable mold for forming the inside of the lens barrel,
The movable mold has a concave portion for forming the light shielding portion and a convex portion for forming the gap portion,
The mold for molding is characterized in that the movable mold is movable in a direction parallel to the optical axis.

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