JP2003329831A - Wobbling element unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wobbling element unit having a holding means which can fix the element in a specified position of an optical device with high accuracy. <P>SOLUTION: The unit is equipped with a wobbling element containing a single or a plurality of polarization converting elements and a single or a plurality of birefringent plates adhered to each other along the optical path direction, and with a holding mechanism having the referential face to determine the relative position of the polarization converting elements and the birefringent plates and holding the wobbling element with at least a part of side faces of the wobbling element abutted on the referential face. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wobbling element unit for displaying a high definition image.

[0002]

2. Description of the Related Art Conventionally, in an image display device such as a projection display device, a wobbling element in which a polarization conversion element and a birefringent plate are combined is used in order to produce a high-definition image. For example, in the projection display device of Japanese Patent Laid-Open No. 4-63332, as shown in FIG. 1 of the publication, from the light source side, a light source, a display liquid crystal panel, and a polarization direction control liquid crystal panel (polarization conversion element). , A crystal plate (birefringent plate) and a projection lens system are arranged in order, and an electrical control system connected to the display liquid crystal panel and the polarization direction control liquid crystal panel is used to display a display liquid crystal panel having m × n pixels. A technique for increasing the resolution to double or quadruple is disclosed.

The principle of shifting pixels by utilizing the birefringence of a birefringent plate is described in, for example, Japanese Patent Laid-Open No. 11-32687.
It is disclosed in FIG. When the thickness of the birefringent plate in the z-axis direction orthogonal to the xy coordinates on the display surface of the display liquid crystal panel is d and the separation angle between ordinary and extraordinary rays is θ, the ordinary and extraordinary rays emitted from the birefringent plate are
It will be spatially separated by d × tan θ.

However, Japanese Patent Application Laid-Open No. 4-63332 discloses only a method of installing a wobbling element in a projection display device by disposing a polarization conversion element and a birefringent plate near a display liquid crystal panel. However, no specific method for holding the polarization conversion element and the birefringent plate is disclosed. If the birefringent plate is not perfectly parallel to the liquid crystal panel for display here, it is α in the z-axis direction.
, The birefringent plate thickness is equivalently d / c
becomes osα. Therefore, as a result of increasing the separation amount, the skipped position of the pixel deviates from the normal position, and there arises a problem that pixel interference occurs and the resolution is lowered. Therefore, at least the birefringent plate needs to be fixed in parallel with the display liquid crystal panel with sufficient accuracy.

As a means for attaching the optical element to the optical device with high accuracy, for example, Japanese Patent Laid-Open No. 8-6279 discloses a holding mechanism for holding a flat optical element such as a mirror. This holding mechanism is provided with a recess for mounting an optical element on a plate-shaped base member,
Further, the holding member for sandwiching the optical element is provided, and the optical element is placed in parallel with the base member and fixed by the holding member. However, in order to install the wobbling element in the optical device, it is necessary to hold the wobbling element at a portion that does not block the optical path, so this type of holding mechanism cannot be applied.

Further, Japanese Patent Application Laid-Open No. 4-63332 does not disclose a specific method of joining the polarization conversion element and the birefringent plate, but if the polarization conversion element and the birefringent plate are simply brought into pressure contact with each other, an air layer will be formed. Therefore, problems such as generation of interference fringes occur. To prevent this, it is necessary to bond the polarization conversion element and the birefringent plate with an appropriate adhesive. However, in the case of reliably bonding such an optical component, the protrusion of the adhesive becomes a problem. In order to accurately align the relative position of the polarization conversion element and the birefringent plate, it is necessary to attach the side surface to a jig for positioning, but the amount of adhesive applied to obtain sufficient adhesive strength. When the value is increased, the adhesive that sticks out adheres to the jig and tool, which causes contamination of the optical surface of the wobbling element.

Regarding the method of bonding such optical components,
Japanese Patent Application Laid-Open No. 2000-251781 discloses a method of preventing the adhesive from squeezing out in bonding a glass face plate of an image display device and a front plate that protects the glass face plate. This is characterized in that the adhesive side of the front plate, which is adhered to the front face of the glass face plate, has a convex shape so that the adhesive is less likely to stick out.
However, such a solution cannot be adopted because the optical component of the present invention must be flat.

Further, the polarization conversion element is generally one in which liquid crystal is filled between glass plates. The crystal plate is also a crystal of silicon, and both are optical components that are easily destroyed by stress. Therefore, it is not practical to use a fixing method such as providing a projection for attachment on itself and fixing with a screw. Therefore, some kind of holding means is required to fix the wobbling element to the optical system. In a conventional image display device, an abutting surface or a mounting portion is provided on the device side to be mounted, and the wobbling element must be fixed at a predetermined position by adhesive bonding,
There were many requests to the device side.

[0009]

SUMMARY OF THE INVENTION Therefore, the present invention is intended to provide a wobbling element unit having a holding means capable of being fixed to a predetermined position of an optical device with high accuracy.

[0010]

A wobbling element unit of the present invention includes a wobbling element including one or more polarization converting elements and one or more birefringent plates adhered to each other along the optical path direction, and a polarization converting element. And a holding mechanism for holding the wobbling element in a state where at least a part of the side surface of the wobbling element is in contact with the reference surface. At least a part of the side surface of the wobbling element may be adhered to the reference surface of the holding mechanism.

The holding mechanism is provided on at least a part of the reference surface.
It is possible to provide a receiving portion as a guide for installing the polarization conversion element and the birefringent plate at an appropriate position on the reference surface within a range that does not obstruct the optical path.

The holding mechanism may have grooves or irregularities on the reference surface.

The holding mechanism may have a mounting portion for fixing the wobbling element to the optical device in a portion which does not obstruct the optical path. The mounting portion may be provided with a protruding fitting portion. Further, a screw hole for fixing can be provided in the mounting portion.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a "wobbling element" is an element for displaying an image by performing pixel shifting by wobbling, which is formed by adhesively bonding a polarization conversion element and a birefringent plate. Say The principal surfaces of the polarization conversion element and the birefringent plate are adhered to each other along the optical path direction. Here, examples of the polarization conversion element include a liquid crystal display element such as twisted nematic liquid crystal, ferroelectric liquid crystal or antiferroelectric liquid crystal. The birefringent plate is, for example, quartz (α-SiO ₂ ), lithium niobate (LiNbO ₃ ), rutile (TiO ₂ ), calcite.
(CaCo _3), nitratine (NaNO _3), is configured with a anisotropic crystal such as YVO _4, but is not limited thereto. Wobbling element, depending on the purpose of use,
The polarization conversion element and the birefringent plate may each be composed of one or more arbitrary number and arrangement. In addition, a wobbling element having a desired size can be formed by using a polarization conversion element and a birefringent plate having an arbitrary size according to the purpose of use.

The wobbling element unit of the present invention comprises a wobbling element including a polarization conversion element and a birefringent plate, and a holding mechanism, and at least a part of the side surface of the polarization conversion element and the birefringent plate is a reference surface of the holding mechanism. It is configured so as to be in contact with and adhered and fixed to the holding mechanism. This retention mechanism preferably comprises a mechanical attachment, which allows
The wobbling element unit can be easily installed in the optical device. Therefore, the polarization conversion element and the birefringent plate can be correctly and firmly held at the center of the optical axis of the optical device via the holding mechanism.

Embodiments of the present invention will be specifically described below with reference to the drawings, but the present invention is not limited to these and various modifications can be made without departing from the scope of the invention.

FIG. 1 is a view showing a first embodiment of a wobbling element unit of the present invention, (a) is a perspective view,
(B) is the figure which looked at (a) from the top. The U-shaped holding mechanism 4 has two reference surfaces 5 adjacent to each other inside thereof, and the side surfaces of the polarization conversion element 2 and the birefringent plate 3 are brought into contact with this portion and bonded by using an adhesive. . The holding mechanism 4 is made slightly larger than the polarization conversion element 2 and the birefringent plate 3. Therefore, when the polarization conversion element 2 and the birefringent plate 3 are bonded to the reference surface 5, a gap is created. This is because the holding mechanism of the present invention is configured on the assumption that the polarization conversion element and the birefringent plate are adhesively bonded in the holding mechanism, and the polarization conversion element 2 and the birefringent plate are provided in this gap. When the 3 is bonded, the adhesive that flows out flows out, so that it is possible to prevent the adhesive from protruding into the optical path.

In this embodiment, a mounting portion 6 for positioning in the optical system of the apparatus is provided in a portion of the holding mechanism 4 that does not obstruct the optical path, in a direction perpendicular to the optical axis. The mounting portion 6 is provided with a screw hole 7 so that the wobbling element unit 1 can be fixed easily and robustly by screwing it to a predetermined portion such as a projection display device. By providing the wobbling element unit itself with the mounting portion in this manner, it is not necessary to provide a contact surface or a mounting portion for the polarization conversion element or the birefringent plate on the side of the device to be mounted.

Further, the holding mechanism 4 is provided with a slit 12 for drawing out the FPC 11 for supplying power to the polarization conversion element 2. The strength of the FPC connection portion can be increased by applying an adhesive to the portion where the FPC 11 is pulled out. The positions where the FPC 11 and the slits 12 are provided can be changed as desired. Hereinafter, these may be omitted in the drawings.

2A and 2B are views showing a second embodiment of the wobbling element unit of the present invention. FIG. 2A is a perspective view, and FIG. 2B is a front view of FIG. 2A, which is perpendicular to the optical axis direction. It is the figure seen in the direction. This embodiment is a modification of the first embodiment, and the mounting portion 6 is provided in a direction parallel to the optical axis.

FIG. 3 is a view showing a third embodiment of the holding mechanism of the wobbling element unit of the present invention, (a).
Shows a modification of the first embodiment, and (b) shows a modification of the second embodiment. In the present embodiment, the mounting portion 6
In addition, a protruding fitting portion 8 as shown in (c) is provided. The wobbling element can be easily fixed by fitting the fitting portion 8 into a predetermined position of the device to be assembled.

FIG. 4 is a view showing a fourth embodiment of the holding mechanism of the wobbling element unit of the present invention, (a)
Shows a view of the holding mechanism 4 viewed from the optical axis direction, and (b) shows a view of the holding mechanism 4 viewed from a direction perpendicular to the optical axis direction. In the present embodiment, the receiving portion 9 is provided on a part of the reference surface 5 within a range not obstructing the optical path.
For holding the polarization conversion element 2 and the birefringent plate 3
Use as a guide when bonding to.

FIG. 5 is a view showing a fifth embodiment of the wobbling element unit of the present invention, in which the holding mechanism 4 comprises only two reference surfaces 5. Here, an example in which the mounting portion 6 and the receiving portion 9 are provided is shown. With such a configuration, it is possible to contribute to downsizing of the wobbling element.

FIG. 6 is a view showing a sixth embodiment of the wobbling element unit of the present invention. The polarization converting element 2 and the birefringent plate 3 are provided on the reference plane 5 of the holding mechanism 4 in the fourth embodiment. A supporting boss 10 is provided. In this case, the surface of the boss 10 serves as a substantial reference surface. In this structure,
When the polarization conversion element 2 and the birefringent plate 3 are attached to each other with an adhesive, the excess adhesive can be extruded in the direction of the reference plane 5, so that the wobbling element can be easily manufactured.

FIG. 7 is a diagram showing a seventh embodiment of the wobbling element unit of the present invention, in which a groove 13 is provided in the reference surface 5 of the holding mechanism 4 in the fourth embodiment, and the adhesive is extruded. There is an escape if it happens. With such a structure, since the protruding direction of the adhesive is the entire circumference as in the sixth embodiment, the wobbling element can be easily manufactured.

FIG. 8 is a diagram showing an eighth embodiment of the wobbling element unit of the present invention. (A) is a view of the holding mechanism 4 viewed from the optical axis direction, and (b) is a view of (a) viewed from the front in a direction perpendicular to the optical axis direction.

In the projection display device, the size of the display liquid crystal panel varies depending on the size of the projected image. Therefore, it is preferable to select the wobbling element having an optimum size proportional to the size of the display liquid crystal panel. However, it may be cheaper to make one type of polarization conversion element in large quantities. When preparing various types of wobbling elements in this way, the holding mechanism is provided with a member that supports the polarization conversion element and the birefringent plate at an optimal position according to the specifications, so that the polarization conversion element and the birefringence plate are Even in the case where the outer shapes are different from each other, it is possible to correctly hold each of them in the optical center.

In the present embodiment, the rod-shaped boss 10 is provided only in a portion which is in contact with either the polarization conversion element 2 or the birefringent plate 3 whichever is smaller (here, the birefringent plate 3). With such a structure, the birefringent plate 3 is installed at the center of the optical axis by the boss 10 provided on the reference surface 5. The boss 10 may be provided on only one of the reference planes or on both of the reference planes.

FIG. 9 is a view showing a ninth embodiment of the holding mechanism of the wobbling element unit of the present invention, which is a modification of the eighth embodiment. (A) is a view of the holding mechanism 4 viewed from the optical axis direction, and (b) is a view of (a) viewed from the front in a direction perpendicular to the optical axis direction. According to the respective positions of the polarization conversion element 2 or the birefringent plate 3 to be bonded,
By providing two types of rod-shaped bosses 10 having different lengths from the reference plane 5 on the reference plane 5 in two directions, the polarization conversion element 2
It becomes possible to install each of the birefringent plates 3 in the center of the optical axis.

FIG. 10 is a view showing a tenth embodiment of a holding mechanism for a wobbling element unit according to the present invention, which is a modified example in which the sixth embodiment and the ninth embodiment are combined. Here, a plurality of block-shaped bosses 10 are provided on the reference surface 5. Therefore, the direction in which the adhesive protrudes is the entire circumference, which facilitates the production of the wobbling element.

FIG. 11 is a diagram showing an eleventh embodiment of the wobbling element unit of the present invention, which is a modification of the first embodiment. In this, the holding mechanism 4 is made up of two bodies, an optical element holding portion 41 and a lid 42. (A) is a view as seen from the optical element holding portion side 41 parallel to the optical axis direction, (b) is a view as seen from the front of (a) in a direction perpendicular to the optical axis direction,
(C) is a view seen from the lid 42 side in parallel with the optical axis direction. The optical element holding unit 41 has a configuration in which a surface horizontal to the optical axis direction of the optical element is covered within a range that does not obstruct the optical path, and two to three legs out of four sides are provided. The number of legs can be changed as desired. In this case, the reference surface is the inner surface of the foot. A claw 43 is attached to the tip of each foot, and the claw 43 can be easily fixed by being fitted into a groove provided at a predetermined position of the lid 42. With such a structure, the protruding direction of the adhesive is the entire circumference, and the wobbling element can be easily manufactured. Note that other commonly known methods can be used to fix the lid 42 to the optical element holding portion 41.

The lid 42, like the optical element holder 41,
The optical element is configured to cover a horizontal surface in the optical axis direction of the optical element within a range that does not obstruct the optical path. The lid 42 is provided with a mounting portion 6 for fixing the wobbling element unit 1 to the optical system of the projection display device. (D) is the optical element holding unit 4
1 shows a modified example in which the attachment portion 6 is provided.

FIG. 12 is a diagram showing a twelfth embodiment of the wobbling element unit of the present invention. The holding mechanism 4 in the present embodiment is a U-shaped optical element holding portion 4
It is composed of two members, that is, a cover 42 and a cover 42, and surrounds the optical element. 3 constituting the optical element holding portion 41
Grooves 13 for sliding the glass plate 21 of the optical element are provided on the inner surfaces of the two sides that are in contact with the lid 42.

Here, in the present embodiment, an example in which the polarization conversion element 2 and the birefringent plate 3 are used in common is shown. The polarization conversion element 2 usually has a liquid crystal substance enclosed between two glass plates. However, it is also possible to substitute one of the glass plates by the birefringent plate 3 and enclose the liquid crystal substance 22 between the glass plate 21 and the birefringent plate 3. With such a configuration, it is possible to reduce the adhesive portion 23 when a plurality of polarization conversion elements and a plurality of birefringent plates are stacked, and the adhesive does not extend to the optical path even if it protrudes. By inserting such an element into the optical element holding portion 41 by sliding the glass plate 21 into the groove 13 and fitting a claw provided in the fixing lid 42 into the groove provided in the optical element holding portion 41, A simple and thin wobbling element unit 1 can be constructed. In the present embodiment, the optical element can be fixed to the holding mechanism without using an adhesive.

Next, the material of the holding mechanism of the wobbling element unit of the present invention will be described.

The retaining mechanism is preferably made of metal or plastic. For example, as the metal, aluminum, titanium, iron (painted product), stainless steel, magnesium, copper, or the like can be used. Further, as the plastic, liquid crystal polymer, silicone resin, nylon, polyacetal, polycarbonate, ABS,
A U polymer (polyarylate resin), polysulfone, polyether sulfone, epoxy resin, PPS resin, PCT resin, or the like can be used, but is not limited thereto.

In the wobbling element of the present invention, the optical element is bonded to the holding mechanism. Among the above-mentioned materials, nylon, silicone resin, liquid crystal polymer, polyacetal, PPS resin, etc. are not excellent in adhesiveness and are not suitable as a holding mechanism, but they can be adhered.

Further, the wobbling element of the present invention is exposed to high temperatures when a thermosetting adhesive is used, so it is preferable to use a material having excellent heat resistance and heat dissipation. The above-mentioned materials have sufficient heat resistance, and there is not much difference in heat dissipation between the resins, and heat dissipation by metal is excellent. It should be noted that plastics such as glass and GF (glass filler) can be filled to suppress softening and deformation due to heat. Although metal is superior in strength, the strength can be increased by filling plastic with glass, GF or the like.

[0039]

As described in detail above, according to the present invention,
By providing the wobbling element with the above-mentioned holding means, it is possible to fix the optical device at a predetermined position with high accuracy.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a wobbling element unit according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram of a wobbling element unit according to a second embodiment of the present invention.

FIG. 3 is a schematic diagram of a mounting portion of a holding mechanism in a wobbling element unit according to a third embodiment of the present invention.

FIG. 4 is a schematic diagram of a holding mechanism in a wobbling element unit according to a fourth embodiment of the present invention.

FIG. 5 is a schematic diagram of a wobbling element unit according to a fifth embodiment of the present invention.

FIG. 6 is a schematic diagram of a wobbling element unit according to a sixth embodiment of the present invention.

FIG. 7 is a schematic diagram of a wobbling element unit according to a seventh embodiment of the present invention.

FIG. 8 is a schematic diagram of a wobbling element unit according to an eighth embodiment of the present invention.

FIG. 9 is a schematic diagram of a holding mechanism in a wobbling element unit according to a ninth embodiment of the present invention.

FIG. 10 is a schematic diagram of a holding mechanism in a wobbling element unit according to a tenth embodiment of the present invention.

FIG. 11 is a schematic diagram of a wobbling element unit according to an eleventh embodiment of the present invention.

FIG. 12 is a schematic diagram of a wobbling element unit according to a twelfth embodiment of the present invention.

[Explanation of symbols]

1 ... Wobbling element unit 2 ... Polarization conversion element 3 ... Birefringent plate 4 ... Holding mechanism 41 ... Optical element holder 42 ... Lid 43 ... nails 5 ... Reference plane 6 ... Mounting part 7 ... Screw hole 8 ... Fitting part 9 ... Receiver 10 ... Boss 11 ... FPC 12 ... Slit 13 ... Groove 21 ... Glass plate 22 ... Liquid crystal 23 ... Adhesive part

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G02F 1/13363 G02F 1/13363 2K103 G03B 21/14 G03B 21/14 Z (72) Inventor Shinji Nagano Nagano Prefecture 3-15-1 Shibamiya, Nagaya, Okaya City Incorporated company, Okaya Olympus (72) Inventor Noboru Hayashi F-term, 3-15-1, Shibamiya, Nagaya, Okaya City, Nagano Prefecture (Reference) 2H043 AA03 AA05 AB02 AB32 AD04 AD24 AE02 AE07 AE22 2H049 BA02 BA06 BA42 BB03 BB51 BC12 BC22 2H088 EA12 EA20 EA45 EA47 HA16 HA20 MA16 2H091 FA07X FA19 FD07 FD12 FD25 LA03 LA11 LA12 LA13 LA16 MA07 2H099 A07 2K0 05 AA12 CA05 DA05 2

Claims (7)

[Claims] 1. A wobbling element including one or more polarization conversion elements and one or more birefringent plates adhered to each other along an optical path direction, and a relative position between the polarization conversion element and the birefringent plate. A wobbling element unit having a reference surface, and a holding mechanism for holding at least a part of a side surface of the wobbling element in a state of being in contact with the reference surface. 2. The wobbling element unit according to claim 1, wherein at least a part of a side surface of the wobbling element is adhered to a reference surface of the holding mechanism. 3. The holding mechanism includes a receiving portion as a guide for setting the polarization conversion element and the birefringent plate at an appropriate position on the reference surface, in at least a part of the reference surface, and an optical path. The wobbling element unit according to claim 1, wherein the wobbling element unit is provided within a range that does not interfere. 4. The wobbling element unit according to claim 1, wherein the holding mechanism has a groove or an unevenness on a reference surface. 5. The holding mechanism has a mounting portion for fixing the wobbling element to an optical device in a portion that does not obstruct the optical path.
The wobbling element unit according to claim 1. 6. The wobbling element unit according to claim 1, wherein the mounting portion is provided with a protrusion-shaped fitting portion. 7. The wobbling element unit according to claim 1, wherein the mounting portion is provided with a fixing screw hole.