JP4761750B2 - Lens holding unit and image display device - Google Patents

Description

  The present invention relates to a lens unit and a lens holding unit suitable for an image display apparatus that enlarges and projects an image displayed on a light valve such as liquid crystal or DMD onto a screen.

In a lens unit used for a camera, a projector device, or the like, a plurality of lenses are held by a cylindrical holder or a lens holding unit and incorporated in the device. In Patent Document 1, a single lens device is configured by using a cylindrical lens holding cylinder and holding a plurality of lenses with the lens held between a contact surface of the lens holding cylinder and a presser ring.
JP 2002-40308 A

  This lens device requires a large number of lens holding cylinders and a large number of presser rings in order to hold a plurality of lenses in a predetermined position, has a large number of parts, and takes time to assemble.

  A rear projector device that projects an image formed by a light modulation device (light valve or image forming device) such as a liquid crystal panel or DMD (digital mirror device) on the screen from the back side using a lens unit is thin and large. Since it can display images, it is attracting attention as a next-generation image display device. In order to obtain a high-resolution image equivalent to that of a conventional high-definition TV using this rear projector device, a lens unit with high optical performance that has high aberration correction performance and little focal distance shift due to temperature or the like is desired. ing. Therefore, the number of lenses constituting the lens unit increases, and a lens holding unit that holds these lenses in a predetermined position is required. On the other hand, in order to provide a large number of rear projector devices as household electrical appliances at low cost, a lens unit having a large number of lenses can be manufactured in a short time at a low cost while maintaining performance. It is necessary.

  Accordingly, an object of the present invention is to provide a lens holding unit that can hold a large number of lenses in a desired position, has a small number of parts, and is easy to assemble. Then, an object of the present invention is to provide an image display device that enables mass production of a lens unit having a large number of lenses with high yield and low cost, and that can display a clear image using the lens unit.

  At present, the lens employed for constituting the lens unit is disk-shaped, and the plurality of lenses are linearly arranged such that the optical axis coincides with the center of the lens. Therefore, the outer peripheral shape of the plurality of lenses arranged in a line in the optical axis direction is symmetric around the optical axis. Therefore, when the lens holding unit that holds the lens is divided by a plane including the optical axis, the divided units have a symmetrical shape, and the divided units can be formed by the same mold. Then, the lens holding unit can be formed by assembling so that the planes of the unit having the same shape face each other. Therefore, in this specification, a unit divided by a plane including the optical axis is referred to as a clamshell unit.

  Since the clamshell unit divided by the plane including the optical axis is configured to cover half of each lens, the lens can be attached to the unit from the direction perpendicular to the optical axis, that is, the radial direction of the lens. . Therefore, a large number of lenses can be held by one or a few clamshell units with little influence on the size or arrangement of the lenses. For this reason, the number of parts of the lens holding unit can be greatly reduced. In addition, a structure for holding individual lenses on the inner surface of the clamshell unit, for example, unevenness, grooves, ribs, etc. are provided, so that a large number of lenses can be held at desired positions simply by inserting the lenses into those positions. It becomes possible. Therefore, by applying the clamshell unit, it is possible to provide a lens holding unit that can hold a large number of lenses in a desired position, has a small number of parts, and is easy to assemble. Then, by using a clamshell unit type lens holding unit, it is possible to mass-produce a lens unit having a large number of lenses with high yield and low cost, and to provide a clear image using the lens unit. it can.

It is also possible to form a lens holding unit for constituting one lens unit by a clamshell unit divided into two. The above-mentioned merit can be obtained by using at least a part of the lens holding unit as a clamshell unit. The lens holding unit is divided into a plurality of subunits in a direction perpendicular to the optical axis for reasons such as size limitation of the mold (mold) for molding the clamshell unit, yield and economy, and one or more of them are divided. Make the sub unit of the clamshell unit type. Furthermore, one aspect of the present invention is a lens holding unit that holds a plurality of lenses arranged in a first plurality of lenses arranged in the optical axis direction and a second optical axis, the first optical It has a plurality of subunits divided by a plane perpendicular to the axis, and the plurality of subunits are connecting subunits assembled by a plurality of clamshell units of the same shape divided by a plane including the optical axis. The first optical axis is bent 90 degrees in the direction of the second optical axis , and one end in the first optical axis direction is connected to another subunit. Each of the plurality of clamshell units of the connecting subunit has a symmetrical shape around the second optical axis, and has connecting portions connected to other subunits at both ends in the first optical axis direction. Only one of the connections is used.

  One method of coupling subunits is to screw the subunits together. When the connecting subunit is screwed to the other subunit at both ends, the first screw hole formed at one end and the first escape hole of a size into which the tool can be inserted at the other end And it is preferable to provide the 1st escape hole formed in the position which opposes a 1st screw hole. Even if the distance between both ends of the connecting subunit is short, it can be screwed. In particular, when the optical axis is bent 90 degrees inside the connecting subunit and the clamshell unit of the subunit is shaped symmetrically around the bent optical axis, both ends are If only the first screw hole is provided, the position of the other end corresponding to the first screw hole at one end also becomes the first screw hole, and it is impossible to pass a screwdriver through the screw hole. Since it is possible, it will be in a state where it cannot be screwed. If the position facing the first screw hole is the first escape hole, the position corresponding to the screw hole at one end of the other end becomes the escape hole. It can be screwed using a screw hole.

  As long as the pitch of the screw holes of the counterpart subunit to be screwed matches, there is basically no restriction on the positional relationship between the first screw hole and the first escape hole at the same end. It is possible to form screw holes and escape holes close to both ends, and a structure in which pairs of screw holes and escape holes are formed at equal angular intervals on both ends of the connecting subunit. This is one of the preferred forms and facilitates positioning and assembly. Moreover, the shape suitable for screwing is to make both ends of a subunit into a flange.

  FIG. 1 shows an outline of a rear projector device 1 provided with a lens unit of the present invention. The rear projector apparatus 1 includes a light source 3, a light modulator (light valve) 4 that forms an image by modulating light from the light source 3 using an image signal, and an image of the light valve 4. It has a lens unit 5 for projecting and a mirror 7 that reflects the projection light 8 and guides it to the screen 9. A screen 9 is arranged on the surface of the housing 2, and the image of the light valve 4 is enlarged and projected from the back side by the lens unit 5 on the screen 9. As the light valve 4, a liquid crystal panel, a DMD panel using a micromirror element, or the like can be adopted.

  FIG. 2 shows an outline of the lens unit 5 for projection. The lens unit 5 includes a plurality of lenses 20, a prism 6 for bending an optical path inside the lens unit 5, and a lens holding unit 10 that stores them. The lens holding unit 10 has an L shape as a whole, and outputs projection light by bending light 90 degrees inside the lens unit 5 by the built-in prism 6. This projection light is projected onto the screen 9 via the mirror 7 of the rear projector device 1 to form an image. The plurality of lenses 20 are arranged separately in a first lens group 21, a second lens group 22, and a third lens group 23 from the screen 9 side. The first lens group 21 is disposed on the screen side of the prism 6, and the second lens group 22 and the third lens group 23 are disposed on the light valve side of the prism 6.

  The lens holding unit 10 of the lens unit 5 stores and holds a cylindrical first shell or first subunit 11 for storing and holding the first lens group 21 and a second lens group 22. A cylindrical second shell or second subunit 12, a cylindrical third shell or third subunit 13 for housing and holding the third lens group 23, and a prism 6. And a connecting shell or subunit 14 whose optical path is bent by 90 degrees. The subunit 14 is connected to the second subunit 12 by a flange 41 or 42, and is connected to the subunit 11 by screws in a direction perpendicular thereto.

  FIG. 3 is a perspective view showing details of the appearance of the lens unit 5. FIG. 4 is a perspective view showing the lens holding unit 10 of the lens unit 5 in a state where the lens holding unit 10 is separated into each subunit. In this example, the second subunit 12, the third subunit 13, and the fourth subunit 14 are holders of a type (clamshell type) in which clamshell units are combined, and are planes including the optical axis. It is composed of two clamshell units of the same shape divided into upper and lower (left and right). Therefore, the second subunit 12 is formed into one substantially cylindrical shape by joining two second clamshell units 32 having the same shape by a method such as screwing. The third subunit 13 is formed by joining two third clamshell units 33 having the same shape by a method such as screwing. The fourth subunit 14 is formed as one subunit by joining two fourth clamshell units 34 having the same shape. The first subunit 11 does not employ a clamshell type because the arrangement of the first lens group 21 is easily inserted from one side. However, like the other subunits, the first subunit 11 can also be a clamshell type holder.

  FIG. 5 shows a perspective view of the second clamshell unit 32, the third clamshell unit 33, and the connecting clamshell unit 34. The second clamshell unit 32 and the third clamshell unit 33 are planes including the optical axis 26 and the substantially cylindrical second subunit 12 and third subunit 13 respectively along the optical axis 26. It has a half-divided shape and is provided with structures 27 and 28 for inserting and holding the edge of the lens inside. As the structures 27 and 28 for holding the lens, it is possible to employ irregularities, grooves or ribs that sandwich the front and rear surfaces of the lens. Accordingly, when the lens unit 5 is assembled, the lenses constituting the second lens group 22 are respectively inserted into one second clamshell unit 32 and the other second clamshell unit 32 is joined. Assemble the subunit 12. At the same time or before and after, the lenses constituting the third lens group 23 are respectively inserted into the third clamshell unit 33, and the other third clamshell unit 33 is joined to the third subclamshell unit 33. Assemble unit 13. The same applies to the other subunits. And these subunits 11-14 are connected.

  Therefore, it is possible to hold a large number of lenses in a desired position by simply inserting the clamshell units 32 and 33 from the radial direction of the lens, and joining the other clamshell units 32 and 33 respectively. Thus, the subunits 12 and 13 can be easily assembled. Since clamshell units of the same shape are manufactured from the same mold, it is economical, and the manufacturing tolerances of the clamshell units are the same. Therefore, the clamshell unit having the same manufacturing tolerance holds the lens from a direction symmetric with respect to the optical axis, so that the tolerance is canceled and the second lens group 22 and the third lens group 23 are moved to the optical axis 26. Can be held in a straight line with high accuracy. The lens unit 5 of this example employing a clamshell unit can easily align the optical axes of a plurality of lenses and hold individual lenses at desired positions, so that a lens unit with high optical performance can be obtained with a high yield. Can be manufactured at low cost.

  In the fourth subunit 14, the optical axis 26 extending from the second subunit 12 is bent 90 degrees inside by the prism 6, and converted into an optical axis 25 extending to the first subunit 11. In this example, the fourth subunit 14 is divided into clam shells 34 that are symmetrical with respect to the bent optical axis 26, and the second subunit 12 is disposed at both ends 43 and 44 that are symmetrical positions. And flanges 41 and 42 that can be connected to each other. Short cylindrical portions 45 and 46 extending along the optical axis 26 are formed at both ends 43 and 44 of the fourth subunit 14 perpendicular to the flanges 41 and 42. On the other hand, the second subunit 12 is formed with a circular groove portion 18 corresponding to the cylindrical portion 45 or 46. Therefore, when connecting the fourth subunit 14 and the second subunit 12, the cylindrical portion 45 or 46 is inserted into the groove portion 18 of the second subunit 12, and the flange 16 of the second subunit 12 is inserted. And fixed by the flange 41 or 42 of the fourth subunit 14. By providing the structure of the cylindrical portion 45 or 46 and the groove portion 18 on the inner side of the flange, even if a slight gap occurs in the flange, external light does not enter the lens holding unit 10. Further, by guiding the surface of the cylindrical portion 45 or 46 with the surface of the groove portion 18 when assembling, the optical axis of the second subunit 12 and the optical axis of the fourth subunit 14 can easily coincide with each other. The lens unit 5 with high optical performance can be provided.

  FIG. 6 is a perspective view showing the appearance of the connecting subunit 14, and FIG. 7 is a perspective view showing a state where the connecting subunit 14 is divided into fourth clamshell units 34. The fourth clamshell unit 34 is a semi-conical shape that forms a triangular prism-shaped storage portion 65 that stores a triangular prism 6 that is an optical element that bends an optical path, and a connection portion 19 into which the first subunit 11 is inserted. , And half-flange portions 56 a and 56 b that form flanges 41 and 42 for connecting to the second subunit 12. The storage portion 65 serves as an optical path in which light incident from the opening 63 facing one side of the flanges 41 and 42 on both sides is bent 90 degrees by the prism 6 and emitted from the opening 64 toward the connection port 19. In this example, one of the clamshell units 34 of the connecting subunit 14 is not used optically. Therefore, the prism 6 is not installed in the optical path 65 of one clamshell unit 34, and the opening 63 of the clamshell unit 34 where the prism 6 is not disposed is shielded from light by an appropriate sealing member 67 such as black tape. .

  Two screw holes 51 and two escape holes 61 are formed in one half flange portion 56a of the clamshell unit 34, and two screw holes 52 and two escape holes 62 are formed in the other half flange portion 56b. Is formed. Then, the screw hole 51 of one half flange portion 56a and the escape hole 62 of the other half flange portion 56b face each other, and the screw hole 52 of the other half flange portion 56b and the relief hole of one half flange portion 56a. Each hole is formed in the position where 61 opposes. Further, the screw holes 51 and 52 are formed at positions where the pitch becomes 90 degrees when the clamshell unit 34 is combined. Therefore, the escape holes 61 and 62 are also formed at positions where the pitch becomes 90 degrees when the clamshell unit 34 is combined. For this reason, the subunit 14 formed by combining the clamshell unit 34 has the flange 16 of the second subunit 12 provided with the screw holes 16 s at a pitch of 90 degrees, regardless of which of the flanges 41 and 42. Can be attached.

  At this time, since the escape holes 62 and 61 are opposed to the screw holes 51 and 52, the tool 53 is inserted from the escape hole 62 or 61 into the screw holes 51 and 52. Can be operated. For this reason, even if the distance between the flanges 41 and 42 is short, the screw can be easily operated by the tool 60.

  FIG. 8 shows a view of the connecting subunit 14 viewed from the outside in the direction of the optical axis 26, and FIG. 9 shows a view of the second subunit 12 viewed from the connecting subunit 14 side. The screw holes and relief holes formed in the half flange portions 56a and 56b of the clamshell unit 34 are paired with the screw holes and relief holes formed in the same half flange portions 56a and 56b. The escape holes are arranged at positions shifted by the same angle in the same direction. In this example, escape holes 61 and 62 are formed at positions shifted by several degrees in the clockwise direction with respect to the screw holes 51 and 52. Screw holes 51 and 52 and relief holes 61 and 62 are formed in each half flange portion 56a and 56b so that a total of four pairs are arranged at a pitch of 90 degrees when combined. On the other hand, the side of the fourth subunit 14 facing the flange 16 of the second subunit 12 has the arrangement shown in FIG. 8 and the mirror arrangement, so that it is counterclockwise with respect to the screw holes 51 and 52. Relief holes 61 and 62 are formed at positions shifted by several degrees. Therefore, as shown in FIG. 9, it is possible to attach the flange on either side of the fourth subunit 14 to the flange 16 of the second subunit 12 in which the screw holes 16s are arranged at a pitch of 90 degrees. At that time, the position of the opening 19 to which the first subunit 11 is attached rotates by an angle between the screw hole and the escape hole. Further, by using the relief holes 61 and 62, the screw 53 attached to the screw holes 51 and 52 on either side can be tightened or removed using the tool 60.

  In the above description, the rear projector apparatus, the lens system and the lens holding unit suitable for the rear projector apparatus have been described. However, the lens holding unit and the lens unit of the present invention can be applied to all systems that project an image. Furthermore, the present invention is not limited to a system that projects an image, and can be applied to an optical device or an optical system that uses a lens.

It is a figure which shows schematic structure of a rear projector. It is a figure which shows schematic structure of the lens unit of this invention. It is a perspective view which shows the external appearance of a lens unit in the state which connected each subunit. It is a perspective view which shows the external appearance of a lens unit in the state which isolate | separated each subunit. It is a perspective view which shows the clamshell unit which comprises each subunit. It is a perspective view which shows the subunit for a connection. It is a perspective view shown in the state where the connecting subunit was divided into clamshell units. It is the figure which looked at the subunit for connection from the other end. It is the figure which looked at the 2nd subunit from the subunit side for connection.

Explanation of symbols

1 Rear projector device 4 Light valve (light modulator)
5 Lens unit 6 Prism 9 Screen 10 Lens holding unit 11 First subunit 12 Second subunit 13 Third subunit 14 Subunit 20 for connection Lens 34 Clamshell unit 41, 42 Flange 51, 52 Screw hole 61, 62 Escape hole

Claims (5)

A lens holding unit for holding a plurality of lenses arranged in the first optical axis direction and a plurality of lenses arranged in the second optical axis direction,
A plurality of subunits divided by a plane perpendicular to the first optical axis;
The plurality of subunits are connecting subunits assembled by a plurality of clamshell units having the same shape divided by a plane including the optical axis, and the first optical axis is the second unit inside. Including a connecting subunit that is bent 90 degrees in the direction of the optical axis of the first optical axis, and one end of the first optical axis direction is connected to another subunit;
Each of the plurality of clamshell units of the connecting subunit has a symmetrical shape around the second optical axis, and is connected to the other subunit at both ends in the first optical axis direction. A lens holding unit in which only one of the connecting portions is used. In Claim 1 , the connecting subunit is a connecting subunit screwed to the other subunit,
Each of the connection portions of the plurality of clamshell units includes a first screw hole formed at one end of the both ends and a first escape hole formed at the other end, And a first clearance hole into which a tool for screwing using the first screw hole is inserted . 3. The lens holding unit according to claim 2 , wherein the one end and the other end are flanges. The lens holding unit according to any one of claims 1 to 3 ,
A lens unit having a plurality of lenses held by the lens holding unit. A lens unit according to claim 4 ;
A light modulator that forms an image to be projected onto the screen through the lens unit;
An image display device comprising the screen.

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