Optics: image projectors – Composite projected image – Plural projection paths with single light source
Reexamination Certificate
1999-02-10
2001-03-13
Adams, Russell (Department: 2851)
Optics: image projectors
Composite projected image
Plural projection paths with single light source
C353S022000, C353S024000, C353S038000, C349S057000, C349S058000, C349S060000, C359S506000, C362S367000, C362S368000
Reexamination Certificate
active
06199987
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
This invention relates to an optical device incorporating a plurality of optical parts (elements), and to a projection display device including this optical device.
2. Description of Related Art
In a projection display device, in order to increase the usage efficiency of light and obtain a bright projected image, a polarized light illumination optical system and an integrator optical system are utilized. The polarized light illumination optical system is an optical system which utilizes only polarized light having one polarization direction as illuminating light. In this polarized light illumination optical system, a polarizing conversion element for converting non-polarized light (light having random polarization directions) into light having one polarization direction is employed. In addition, the integrator optical system is an optical system which divides light source light into a plurality of fine partial luminous fluxes, and which utilizes the respective partial luminous fluxes as illuminating light. In this integrator optical system, a lens array that includes a plurality of small lenses and that divides light source light into a plurality of partial luminous fluxes is employed. An illumination optical system is normally constructed by a combination of the polarized light illumination optical system and the integrator optical system.
SUMMARY OF THE INVENTION
Hitherto, respective optical parts used in the projection display device have been mounted in guides provided at respective predetermined positions on a chassis for mounting respective components of a projection display device thereon. Therefore, the relative positional accuracy of the respective optical components greatly depends on the relative positional accuracy of the respective guides provided on the chassis. Since the chassis is intended for mounting the respective components employed in the projection display device thereon, a certain large size is required, and the positional accuracy of the respective guides provided on the chassis is not very good. However, in order to increase the usage efficiency of the light by bringing out the functions of the polarized light illumination optical system and the integrator optical system, it is preferable to improve the relative positional accuracy when the optical parts used in these systems, especially, the polarizing conversion element and the lens array mounted on the chassis.
This invention is made to solve the above problem in the conventional art, and an object is to provide a technique for increasing the usage efficiency of the light of optical elements used in a projection display device.
In order to solve at least a part of the above problem, an optical device of the present invention includes:
a lens array having a plurality of small lenses;
a polarizing conversion element array having a plurality of polarization separating films that separate light emitted from the small lenses into two kinds of polarized light and a plurality of reflecting films that reflect one of the two kinds of polarized light separated by the polarization separating films, the polarizing conversion element array converting non-polarized light into one kind of linearly polarized light; and
a jig that detachably incorporates the lens array and the polarizing conversion element array.
This optical device can detachably combine the lens array and the polarizing conversion element array in one. This can improve the relative positional accuracy of the optical parts (elements) included in this optical device. This can increase the usage efficiency of the light of the optical elements included in this optical device. In addition, since the optical device of the present invention is detachable, the optical elements incorporated into this optical device can easily be exchanged.
Here, in the above optical device, it is preferable that the lens array and the polarizing conversion element array have substantially rectangular outer shapes,
that the jig includes:
a frame having substantially a rectangular first open surface and a rectangular second open surface on two sides of the frame, and having a hollow section inside the frame;
a partitioning projection provided on an inner peripheral surface of the frame that partitions the hollow section into a first storage section and a second storage section communicating with the first open surface and the second open surface;
fixing members that detachably fix the lens array, the polarizing conversion element array, and the frame in a state where the lens array and the polarizing conversion element array are stored in the frame; and
that the lens array and the polarizing conversion element array are stored in the first storage section and the second storage section, respectively, from the first open surface and the second open surface.
According to the above jig, since the lens array can be stored in the first storage section from the first open surface, and the polarizing conversion element array can be stored in the second storage section from the second open surface, even if one of the optical element is required to be exchanged, it can be exchanged without removing the other optical element. Therefore, there is the advantage of easy exchange of the parts.
In addition, in the above optical device, it is also preferable that the lens array and the polarizing conversion element array have substantially rectangular outer shapes,
that the jig includes:
a frame having substantially a rectangular first open surface and a rectangular second open surface on two sides of the frame, and having a hollow section inside the frame;
a projection provided close to the first open surface;
a step portion provided on an inner peripheral surface of the frame that divides the hollow section into a relatively small first storage section close to the first open surface and a relatively large second storage section close to the second open surface;
fixing members that detachably fix the lens array, the polarizing conversion element array, and the frame in a state where the lens array and the polarizing conversion element array are stored in said frame; and
that the lens array and the polarizing conversion element array are stored in the first storage section and the second storage section in a predetermined order from the second open surface.
According to the above jig, the lens array and the polarizing conversion element array can be stored in the first storage section and the second storage section in a predetermined order from the second open surface. Therefore, there is the advantage of easy assembly.
Incidentally, the above respective optical devices may consist of a light-shielding plate stored in the frame inserted between the lens array and the polarizing conversion element array that shields at least a part of a light incident surface of the polarizing conversion element array.
By shielding at least a part of a light incident surface of the polarizing conversion element array, the purity (degree of polarization) of one kind of linearly polarized light emitted from the polarizing conversion element can be increased.
In addition, in the above respective optical devices, it is preferable that the polarizing conversion element array is divided into a first array unit and a second array unit, each having substantially a rectangular outer shape, and
that one of the first storage section and the second storage section in which the first array unit and the second array unit are stored includes: positioning projections provided between the first array unit and the second array unit that define positions of the first array unit and the second array unit; and elastic members provided on opposing inner surfaces of the frame to press the first array unit and the second array unit onto the positioning projections, respectively.
In addition, in the above optical device, when the lens array and the polarizing conversion element array are stored in the first storage section and the second storage section in a predetermined order fro
Haba Shinji
Takizawa Takeshi
Adams Russell
Brown Khaled
Oliff & Berridg,e PLC
Seiko Epson Corporation
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