JP2004354924A - Projection display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projection display device which reduces the degradation in light utilization efficiency in a rod type integrator and the degree of deteriorating a projected image by formation of an image of dust or the like in the position of an electrooptical device. <P>SOLUTION: The rod type integrator 6 consisting of the solid rod on which light from a lamp is made incident from an incident focal surface 6a at one end and in which the light is reflected on the inside surface, is guided and is emitted from an exit focal surface 6c on the other end side is used and a parallel glass plate 11 is joined to the exit focal surface 6c. The glass plate 11 has a flanged projecting part 11a projected from the external form of the solid rod. The projecting part is used as a holding part. As a result, the leakage of the light from the outer peripheral surface of the solid rod to the outside is substantially eliminated and there is no more degradation in the light utilization efficiency. Also, the adhesion of dust etc., to the exit focal surface 6c of the solid rod does not occur any more and therefore the projection display device free of the influence on the deterioration of the projected video is obtained. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a projection display device including a rod-type integrator having a rod that internally reflects light incident from an incident surface and emits light from an exit surface.
[0002]
[Prior art]
There is a projection display device such as a projector that projects an image formed by an electro-optical device such as a liquid crystal or a DMD (digital micro device) on a screen based on image data from a personal computer, a video camera, or the like. In this type of projection display device, a rod integrator method is known as a means for making the illuminance distribution of the emitted light beam uniform. In this method, light incident from one end surface of a rod such as a glass rod is internally reflected inside the rod and emitted from an emission surface. The effects of this rod integrator can be increased or decreased by the number of internal reflections in the rod, the F value of the light source, etc., to reduce the rod cross-sectional area, increase the length of the rod, and set the F value of the light source to a small value. Are known.
[0003]
In the rod integrator system, the parallelism of the illumination light is easily increased, and it is easy to cope with miniaturization of an electro-optical device such as a liquid crystal panel. As a rod used in this rod-type integrator, a solid rod such as a glass rod and a hollow rod having an inner surface mirror-finished are employed. According to a solid type rod such as a glass rod, the reflectance of internal reflection inside the rod can be made almost 100%, so that light can be used more efficiently than a hollow type rod. Have been.
[0004]
By the way, in the case of the solid rod described above, if the side surface of the rod becomes dirty or scratched, the total internal reflection condition in the rod is disturbed, and light leaks at that portion, which causes a problem that light utilization efficiency is reduced. . Further, an optical component such as a condenser lens is interposed between the emission surface of the rod and an electro-optical device such as a liquid crystal panel. Since the emission surface of the rod and the liquid crystal panel are in a conjugate relationship with the optical component, If dust or the like adheres to the emission surface of the rod, an image to which the dust or the like adheres is formed at the position of the electro-optical device and further formed on a screen.
[0005]
In order to solve this problem, it is known to cover a side surface portion of a solid rod with a cover member formed of a cylindrical body, and further provide a transparent member on an incident surface and / or an emission surface of the solid rod. (Patent Document 1). In this case, since the side surface of the solid rod is covered with the cover member, intrusion of dust and the like into the rod side surface can be reduced, and therefore, the total reflection of the internal reflection of the solid rod can be maintained, and A decrease in efficiency can be prevented.
[0006]
In Patent Document 1, since a transparent member is provided on the emission surface side, an image such as dust is not formed on a liquid crystal panel in a conjugate relationship, and thus an image such as dust is formed on a screen surface. It is described that it is possible to prevent dust and the like from entering the side surface of the rod and to improve the light use efficiency.
[0007]
[Patent Document 1]
JP 2001-228541 A
[Problems to be solved by the invention]
However, in the device disclosed in the above publication, the solid rod is held in a state where the solid rod does not contact the cover member as much as possible. However, since the solid rod is fixed using a screw, the screw still has a point contact. Since light escapes at the part where light is emitted, light utilization efficiency is reduced. Further, in particular, in the embodiment configuration shown in FIG. 6 of the publication, since a gap in the cover member is located on the emission side end face of the solid rod, dust and the like generated at the time of screw tightening on the emission side end face. In such a case, the dust or the like is formed at the position of the electro-optical device, and the projected image is deteriorated.
[0009]
In the embodiment shown in FIG. 8 of the publication, a condensing lens is joined to the emission-side end face of the solid rod. However, since this end face is to be a focal plane, It is inconvenient to join the condenser lens here, and in the embodiment configuration shown in FIG. 12, the condenser lens is joined to the exit side end face of the tunnel rod. Is located inside the end face of the tunnel rod, and its length is a useless rod.
[0010]
The present invention solves the above-mentioned problem, and the light use efficiency of the rod-type integrator is hardly reduced, and furthermore, an image such as dust is formed at the position of the electro-optical device to deteriorate the projected image. It is an object of the present invention to provide a projection display device capable of reducing the degree of the projection.
[0011]
Means for Solving the Problems and Effects of the Invention
In order to achieve the above object, an invention according to claim 1 is a lamp, and a glass in which light from the lamp is incident from an incident surface on one end side, is internally reflected, is guided, and is emitted from an exit surface on the other end side. A rod-type integrator made of a solid rod made of a material, an electro-optical device for forming an image having an irradiated surface irradiated with light emitted from the integrator, and an electro-optical device modulated by the electro-optical device. An optical component for projecting and displaying an image on a screen, wherein the solid rod has a rectangular cross-section, an emission-side end face being a focal plane, and at least the emission-side end face. A parallel glass plate of a constant thickness made of a material having a refractive index equivalent to that of the solid rod is joined with a light transmitting resin, and the parallel glass plate protrudes from the outer shape of the solid rod. It has a flange-like protrusion, is obtained by the flange-like protrusion and the holding portion for the integrator fixed.
[0012]
According to the above configuration, since the holding member does not come into contact with the outer peripheral surface of the solid rod that internally guides the incident light and guides the light, only the air layer can be brought into contact with the solid rod. And the loss of light used in the integrator is not reduced. Also, if dust or the like adheres to the emission-side focal plane of the solid rod, the image is formed at the position of the electro-optical device and the projected image is degraded. Such is eliminated because the glass plates are joined. Also, no light loss occurs at the joint surface between the solid rod and the parallel glass plate. Note that even if dust or the like adheres to the outer surface of the parallel glass plate, its position is out of the focal plane, so the image on the electro-optical device is out of focus, and there is almost no influence on the deterioration of the projected image. .
[0013]
The invention according to claim 2 is a rod type comprising a lamp, and a solid rod in which light from the lamp is incident from an incident surface on one end side, is guided by internal reflection, and is emitted from an exit surface on the other end side. , An electro-optical device for forming an image having a surface to be irradiated with light emitted from the integrator, and projecting and displaying an image of the light modulated by the electro-optical device on a screen A projection type display device comprising an optical component, wherein the solid rod has an emission-side end face as a focal plane, and a glass plate is bonded to at least the emission-side end face. It has a flange-like protrusion projecting beyond the outer shape of the actual rod, and this flange-like protrusion serves as a holding part for fixing the integrator.
According to this configuration, substantially the same functions and effects as those of the first aspect are obtained except for the function and effect of preventing light loss at the joint surface between the solid rod and the parallel glass plate.
[0014]
According to a third aspect of the present invention, in the projection type display device according to the second aspect, the integrator has a light tunnel configuration having a hollow inner surface instead of a solid rod, and the entrance side end surface has a glass. The plate is tightly fixed, and the inside of the light tunnel has a closed structure.
According to this configuration, the incident light is reflected and guided by the mirror surface of the hollow inner surface of the light tunnel configuration. Except that the reflection efficiency is slightly inferior to the case of the light guide by the internal reflection of the solid rod, the effect similar to that of claim 2 can be obtained, and the dust protection inside the light tunnel can be obtained. Further, the entire length of the light tunnel configuration can be effectively used.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a projection display device according to an embodiment of the invention will be described with reference to the drawings. FIG. 1 shows mainly an optical system of a projection display device (generally called an image display projector) according to an embodiment, and FIGS. 2 and 3 show a rod-type integrator used for the optical system of the device. This projection type display device is based on a lamp 1 as a light source, an electro-optical device 2 such as a DMD (digital micromirror device) for forming an image, and an image formed thereby as a projection engine. An image projection optical system 4 for modulating light from the lamp 1 and projecting it on the screen 3 for display is provided. The image projection optical system 4 includes a rod-type rotating color wheel 5 corresponding to RGB colors and a solid rod for condensing and uniformizing the light from the lamp 1 along the optical axis in order from the lamp 1 side. An optical component including an integrator 6, a lens 7, a mirror 8, a condensing relay lens 9, and a projection lens 10 is provided.
[0016]
The integrator 6 is made of a solid rod made of glass material having a rectangular cross section, and has an incident focal plane 6a at one end where light from the lamp 1 is incident, a rod main body 6b that repeatedly guides the internal surface and guides the light. An emission focal plane 6c at the other end for emitting the emitted light to the outside. The integrator 6 is used to obtain light condensed and uniformized with a relatively short optical path length, and shortens the optical path length to make the image projection optical system compact. The outgoing focal plane 6c is the focal plane of the lens 7.
[0017]
Further, in the integrator 6, a parallel glass plate 11 having a constant thickness and made of a material having a refractive index equivalent to that of the solid rod is joined to the light emission focal plane 6c with a light transmitting resin. As the light transmitting resin, a UV curable adhesive having a refractive index equivalent to that of glass is used. The parallel glass plate 11 has a circular flange-shaped protrusion 11a protruding from the outer shape of the solid rod. The flange-shaped protrusion 11a serves as a holding portion for fixing the integrator. That is, the integrator 6 is fixed by holding the flange-shaped protrusion 11a on the frame 12 of the projection engine, and the outer peripheral surface of the rod body 6b of the integrator 6 comes into contact with only the air layer. The optical axis of the rod body 6b of the integrator 6 and the central axis of the circular flange-shaped protrusion 11a are made to coincide.
[0018]
The image forming surface of the electro-optical device 2 is a surface to be irradiated with light emitted from the integrator 6 via the lens 7, the mirror 8, and the relay lens 9. The image forming surface is rectangular, and the cross section of the integrator 6 is rectangular according to this shape. The light modulated by the reflection on the illuminated surface is projected on the screen 3 via the projection lens 10, whereby an image is displayed. The reflection mirror 8 makes the image projection optical system compact by reflecting the light from the lamp 1 and bending the optical path reaching the electro-optical device 2.
[0019]
FIG. 4 shows the configuration of the parallel glass plate 11 joined to the emission focal plane 6c of the integrator 6. In the parallel glass plate 11, the diameter D of the circular flange-shaped protrusion 11a is determined by the maximum emission angle θ (determined by the critical angle of the integrator 6) at the emission focal plane 6c and the F-number of the lens 7, and The size of the light flux from the outer peripheral end surface of the flange-shaped protrusion 11a is not affected by the light flux from the flange 6c. The thickness t of the parallel glass plate 11 is determined by the ratio of the rectangular diagonal dimension of the rod body 6b to the same dimension of the electro-optical device 2, that is, the magnification, and is opposite to the joint surface of the plate 11 with the integrator 6. Even if dust or the like adheres to the side surface, since the surface is separated from the exit focal plane 6c, which is the focal plane, by the thickness t, the image of the dust irradiated on the electro-optical device 2 becomes out of focus, and the influence is reduced. What is necessary is just to make it almost disappear.
[0020]
In the projection type display device of the present embodiment configured as described above, the holding member does not contact the outer peripheral surface of the solid rod of the rod type integrator 6 that internally reflects the incident light and guides the light. There is almost no loss of light leaking out of the solid rod as compared to a conventional one in which only the layers are in contact and point contact is held with conventional screws. Therefore, the light use efficiency in the integrator 6 does not decrease. Further, if dust or the like adheres to the emission focal plane 6c of the solid rod, the image is formed at the position of the electro-optical device 2 to deteriorate the projected image. 11 is bonded, and even if dust or the like adheres to the outer surface, since the position is out of the focal plane, the image on the electro-optical device 2 becomes out of focus, and there is almost no influence on the deterioration of the projected image. Become. Further, even if the flange-shaped protrusion 11a becomes dirty, the image is not deteriorated, so that the integrator 6 can be easily handled.
[0021]
FIG. 5 shows a light tunnel configuration of an image projection optical system according to another embodiment of the projection display apparatus. In this embodiment, a hollow light tunnel 16 having a mirror-finished inner surface is used in place of the solid rod of the rod-type integrator 6 in the previous embodiment. In this case, the parallel glass plate 11 is closely fixed not only to the outgoing focal plane 6c but also to the incident focal plane 6a, and the inside of the light tunnel 16 has a closed structure. The parallel glass plate 11 may have the same configuration as that of the above embodiment.
[0022]
In this embodiment, the incident light is reflected and guided by the mirror surface of the hollow inner surface of the light tunnel 16, except that the reflection efficiency is slightly inferior to that of the light guide by the internal reflection of the solid rod. The same operation and effect as the above embodiment can be obtained. Further, it also becomes dustproof inside the light tunnel 16, and the entire length of the light tunnel 16 can be effectively used.
[0023]
The present invention is not limited to the configuration of the above embodiment, and various modifications are possible. For example, in the above embodiment, the parallel glass plate is also joined to the incident side end face of the solid rod of the rod type integrator. May be done.
[Brief description of the drawings]
FIG. 1 is a configuration diagram mainly showing an optical system of a projection display device according to an embodiment of the present invention.
2A is a side view of a rod-type integrator used in an optical system of the apparatus, and FIG. 2B is a front view thereof.
FIG. 3 is a perspective view of the rod-type integrator.
FIG. 4 is a configuration diagram of a parallel glass plate bonded to an emission focal plane of a rod-type integrator.
FIG. 5A is a side sectional view of a light tunnel used in an optical system of a projection display device according to another embodiment, and FIG. 5B is a front view thereof.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Lamp 2 Electro-optical device 3 Screen 4 Image projection optical system 6 Rod-type integrator 6a consisting of a solid rod Incident focal plane (incident end face)
6b Rod body 6c Outgoing focal plane (outgoing end face)
7 Lens 10 Projection lens 11 Parallel glass plate 11a Flange-shaped protrusion 16 Light tunnel

Claims (3)

A lamp, a rod-type integrator made of a solid rod made of glass, into which light from the lamp enters from an incident surface on one end, is internally reflected and guided, and exits from an exit surface on the other end; and An electro-optical device for forming an image having an irradiated surface to which light emitted from the device is irradiated, and an optical component for projecting and displaying an image of the light modulated by the electro-optical device on a screen. A projection display device,
The solid rod has a rectangular cross-section, and its exit side end face is a focal plane. At least this exit side end face has a parallel glass plate of a constant thickness made of a material having a refractive index equivalent to that of the solid rod. It is joined with mold resin,
The parallel glass plate has a flange-shaped protrusion protruding from the outer shape of the solid rod, and the flange-shaped protrusion serves as a holding portion for fixing an integrator. A lamp and a rod-type integrator made of a solid rod in which light from the lamp is incident from an incident surface on one end side, is internally reflected, is guided, and exits from an exit surface on the other end, and is emitted from the integrator. Projection display, comprising: an electro-optical device for forming an image having an irradiated surface to which the light is irradiated, and an optical component for projecting and displaying an image of the light modulated by the electro-optical device on a screen. A device,
The solid rod has an emission-side end face as a focal plane, and a glass plate is bonded to at least the emission-side end face,
The glass plate has a flange-like projection projecting beyond the outer shape of the solid rod, and the flange-like projection serves as a holding portion for fixing the integrator. The said integrator is a light tunnel configuration having a hollow inner surface instead of a solid rod, and a glass plate is tightly fixed to the end face on the incident side, and the inside of the light tunnel has a sealed structure. Item 3. A projection display device according to item 2.

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