Optical unit and projector using the same

Details Optical unit and projector using the same Optical unit and projector using the same

2001-08-10

2003-10-07

Mai, Huy (Department: 2873)

Optical: systems and elements

Lens

With support

C362S331000, C353S100000

Reexamination Certificate

active

06631039

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to a projector that is used for projecting and displaying an image, and, more particularly, to an illumination optical system used in the projector.
2. Description of Related Art
In a projector, the display of an image is achieved by modulating light that exits from an illumination optical system in accordance with image information (image signals) using, for example, liquid crystal light valves, and projecting the modulated light onto a screen.
Such a projector is formed by combining a plurality of optical parts. In a related art device, a plurality of optical parts of a projector are incorporated in one common base frame, with their positions being subjected to fine adjustments in the incorporated state. This base frame includes a plurality of mounting portions that are suitable for mounting each of the optical parts substantially at its corresponding predetermined location.
SUMMARY OF THE INVENTION
Aligning of a plurality of optical parts included in the illumination optical system affects brightness of an image that is projected and displayed, so that it is necessary to align the optical parts of the illumination optical system more precisely than the optical parts of other types of optical systems.
However, when each of the optical parts of the illumination optical system is mounted to the common base frame for the related art projector mentioned above, there is a problem that it is difficult to align each of the optical parts precisely. This is because, in addition to the difficulty in molding the mounting portions of the base frame precisely, there are difficulties in adjusting each of the optical parts used in the illumination optical system due to the separation of the optical parts by relatively narrow gaps, and in confirming whether or not the adjusted state is proper. Such problems become more noticeable when reducing the size of the illumination optical system.
The present invention addresses the above-described problem in the related art technology, and an object of the invention is to provide a technology that makes it possible to easily align optical parts of an illumination optical system.
In order to address at least part of the above-described problem, a base frame is provided for mounting an illumination optical system. The illumination optical system includes a light source device, a lens array that divides light beams that exit from the light source device into a plurality of partial light beams, and a superimposing optical system that superimposes the plurality of partial light beams onto a predetermined illumination area. The base frame is integrally molded and includes a plurality of mounting portions that define locations of two or more of a plurality of optical parts disposed in a light path extending from the light source device to the superimposing optical system.
When such a base frame is used, it is possible to easily align the optical parts of the illumination optical system when assembling the illumination optical system. The advantage of using this base frame becomes particularly noticeable when reducing the size of the illumination optical system.
In the above-described device, the mounting portions may be recesses or protrusions that are provided at an inner side of the base frame, and each optical part may be secured to the recess or the protrusion.
In this way, when the mounting portions of the base frame are formed into recesses or protrusions, the base frame can be formed with a relatively simple structure.
In the above-described device, the base frame may have a substantially rectangular parallelepiped external shape defining a pair of first to third side surfaces, an opening for light that passes through each of the optical parts may be formed in the pair of first side surfaces, the recesses or the protrusions may be provided so as to form a pair at inner sides of the pair of second side surfaces in a direction perpendicular to the pair of third side surfaces, and at least one of the pair of third side surfaces may open to an exterior of the system.
A second aspect of the present invention provides an illumination optical system for illuminating a predetermined illumination area, the illumination optical system including:
a light source device;
a lens array that divides light beams that exit from the light source device into a plurality of partial light beams;
a superimposing optical system that superimposes the plurality of partial light beams onto the predetermined illumination area; and
a base frame that is integrally molded, and including a plurality of mounting portions that define the locations of two or more of a plurality of optical parts disposed in a light path extending from the light source device to the superimposing optical system.
This illumination optical system includes a base frame that mounts a plurality of optical parts that make up the illumination optical system. In this way, when a base frame for an illumination optical system is separately provided, the optical parts of the illumination optical system can be easily aligned when assembling the illumination optical system. The advantage of using the base frame becomes particularly noticeable when reducing the size of the illumination optical system.
In the above-described device, the mounting portions may be recesses or protrusions that are provided at an inner side of the base frame, and each optical part may be secured to the recess or the protrusion.
In the above-described device, the base frame may have a substantially rectangular parallelepiped external shape defining a pair of first to third side surfaces, an opening for light that passes through each of the optical parts may be formed in the pair of first side surfaces, the recesses or the protrusions may be provided so as to form a pair at inner sides of the pair of second side surfaces in a direction perpendicular to the pair of third side surfaces, and at least one of the pair of third side surfaces may open to the exterior of the system.
In the above-described device, the optical parts may be mounted to the corresponding mounting portions by being sandwiched between corresponding light-incident-surface sides and light-exiting-surface sides thereof.
In the above-described device, the optical parts may be mounted to the corresponding mounting portions so that the mounting portions are in contact with light-incident surfaces or light-exiting surfaces of the optical parts.
In this way, the mounting portions that mount the optical parts of the illumination optical system may be provided so as to sandwich the optical parts or to contact either the light-incident surface or light-exiting surface of each optical part. When the mounting portions are provided as in the latter case, it is possible to increase the degree of freedom of adjusting the locations of the optical parts.
A third aspect of the present invention provides a projector including:
any one of the above-described illumination optical systems;
an electro-optical device that modulates light from the illumination optical system in accordance with image information; and
a projection optical system that projects the modulated light beam that is obtained at the electro-optical device.
Since the illumination optical system is used in this projector, aligning of the optical parts of the illumination optical system can be easily performed.
In the above-described device, the illumination optical system, the electro-optical device, and the projection optical system may be mounted to a common base frame that is different from the base frame.


REFERENCES:
patent: 5760849 (1998-06-01), Omae et al.
patent: 5951136 (1999-09-01), Furuhata et al.
patent: 6053616 (2000-04-01), Fujimori et al.
patent: 6331878 (2001-12-01), Takahara
patent: 6364492 (2002-04-01), Fujimori et al.
patent: WO98/14829 (1998-04-01), None

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