JPH10321005A - Lighting system and projecting apparatus using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify an entire device and uniformly illuminate the illuminating surface by guiding a light flux which is emitted from a light source having a light-emitting surface of a finite dimension in the light axis direction and reflected and collected with a reflector is guided onto an irradiating surface with a positive lens part through a negative lens part arranged before a light collecting position. SOLUTION: Light, emitted from a light source 5 in the vicinity of one focal point of an elliptical reflector 61 and advancing to the vicinity of the other focal point enters in a concave lens 4, and exits after a light collecting degree is decreased. Light fluxes, which are reflected at optional points 61a, 61b of the elliptical reflector 61 and scattered with the concave lens 4, are piled up on a light bulb 2 through a field lens 3 in the specified position, and illuminate the whole surface. By this one integrator, illumination with respect to the light bulb 2 and a projecting image through a projecting lens 11 are made uniform without uneven brightness. A light source image in a pupil 11a of the projecting lens 11, which is almost conjugate with an incident surface 4a of the concave lens 4 turns into one small doughnut shape, and the use of the projecting lens 11 having a small aperture may be used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device and a projecting device using the same, and more particularly, to an enlarged projection of an image displayed on a display element (liquid crystal panel) using a liquid crystal on a screen by a projection lens (projection optical system). The present invention is suitable for a liquid crystal projector.

[0002]

2. Description of the Related Art Conventionally, an image is displayed using a liquid crystal panel, the liquid crystal panel is illuminated by a light beam from a light source, and an image based on transmitted light or reflected light from the liquid crystal panel is enlarged and projected on a screen by a projection lens. Various liquid crystal projectors have been proposed.

FIG. 5 is a schematic view of a main part of an optical system of a liquid crystal projector proposed in Japanese Patent Application Laid-Open No. 7-181392. In the figure, a light beam from a light source 101 is reflected and condensed by a reflecting mirror 102 and is incident on a first lens plate 301 and a second lens plate 302 which function as an integrator.

The first and second lens plates 301 and 302 are composed of a fly's eye lens in which a plurality of minute lenses are two-dimensionally arranged, and form a plurality of secondary light source images. 107 is a color separation system. Reference numeral 108 denotes a parallelizing lens, which is a color separation system 10.
Each of the light beams from 7 is condensed and illuminates the liquid crystal panel 109 provided on the surface to be irradiated.

A collimating lens 110 guides a light beam from the liquid crystal panel 109 to, for example, a projection lens (not shown). As a result, an image based on the light beam modulated from the liquid crystal panel 109 is projected on a predetermined surface (screen). The illumination system shown in the figure employs a Koehler illumination system in which the exit surface of the second lens plate 302 and the pupil of the projection lens 10 have a conjugate relationship.

[0006] Such first and second lens plates 301, 3
02 is uneven brightness (uneven brightness) of the liquid crystal panel on the irradiated surface
In addition, they have the effect of improving color unevenness, and are widely used in recent projectors of this type.

[0007]

In the liquid crystal projector shown in FIG. 5, a light beam from a reflecting mirror 102 is condensed by a first lens plate 301, and a second lens plate 302 is condensed in the condensed optical path.
Has been arranged. Thus, the surface to be irradiated is uniformly illuminated, and the size of the second lens plate 302, the size of the color separation system 107, and the size of the projection lens are reduced.

However, the use of two integrators to uniformly illuminate the surface to be illuminated tends to complicate the entire apparatus.

According to the present invention, while simplifying the entire apparatus,
It is an object of the present invention to provide an illumination device capable of uniformly illuminating a surface to be irradiated and a projection device using the same.

[0010]

According to the present invention, there is provided a lighting device comprising: (1-1) a reflector for reflecting and condensing a light beam from a light source having a light emitting surface having a finite size in an optical axis direction; It is characterized by having a negative lens portion disposed before the position where the light beam is condensed, and a positive lens portion for guiding the light beam from the negative lens portion onto the irradiated surface.

(1-2) Of the light beams from the light source means having a light emitting surface having a finite size in the optical axis direction, the center line of the light beam emitted from the center of the light emitting surface is substantially parallel to the optical axis direction. A reflector that reflects light, a condensing lens that condenses the light beam from the reflector, a negative lens portion that is disposed in front of a position where the light beam from the condensing lens converges, and a light beam from the negative lens portion. And a positive lens unit for guiding light on the surface to be irradiated.

In particular, in the constitution (1-1) or (1-2), (1-2-1) the light flux which is reflected from an arbitrary point on the reflecting surface of the reflector and is in a divergent state is transmitted to the negative lens portion by a field. It is superimposed on the surface to be illuminated via a lens unit.

(1-2-2) The central portion of the light emitting surface is focused on and / or in the vicinity of the irradiated surface. And so on.

[0014] The projection device of the present invention is characterized in that (2-1) the illumination device having the configuration (1-1) or the configuration (1-2) projects an image based on an image display element provided on the illuminated surface. It is characterized in that it is projected on a predetermined surface by an optical system.

In particular, (2-1-1) the negative lens portion and the pupil position of the projection optical system have a substantially conjugate relationship.

(2-1-2) An image display device using liquid crystal is provided on the surface to be irradiated, and a light beam modulated by the image modulation device is guided to a predetermined surface by the projection optical system. That And so on.

[0017]

FIG. 1 is a sectional view of a main part of a first embodiment of the present invention. In the figure, reference numeral 5 denotes a lamp (light source), the light emitting surface 5a of which extends in a finite size in the optical axis LX direction, and is disposed at one focal point of an elliptical mirror (elliptical reflector) 61 or in the vicinity thereof. . Reference numeral 4 denotes a concave lens (negative lens), which is disposed at or near the other focal point of the elliptical mirror 61, and slightly reduces the degree of condensing the light beam from the reflector 61. Reference numeral 3 denotes a field lens which guides a light beam from the concave lens 4 to a liquid crystal light valve element (light valve) as an image display element.

Reference numeral 11 denotes a projection lens, and the light valve 2
Is projected on a predetermined surface, for example, on a screen (not shown). The position of the concave lens 4 and the pupil position 11a of the projection lens 11 are
And a substantially conjugate relationship via.

In this embodiment, the elliptical reflector 61 is used.
The light beam emitted from the lamp 5 disposed at or near one of the focal points travels so as to be collected at the other focal point of the elliptical reflector 61 or at the vicinity thereof. At this time, the condensed light beam enters the concave lens 4 disposed in front of the other focal point of the elliptical mirror 61. The luminous flux incident on the concave lens 4 is emitted from the concave lens 4 by reducing the degree of convergence of the condensed luminous flux by its diverging action.

At this time, as the concave lens 4 has a shorter focal length,
By arranging the concave lens 4 closer to the other focal point of the elliptical mirror 4, the diameter of the light beam from the concave lens 4 can be reduced.

Actually, each light beam reflected from an arbitrary point of the elliptical reflector 61 has a divergence angle caused by the luminous surface 5a of the lamp 5 having a finite size. For this reason, of the light flux passing through the concave lens 4,
The light beam La from the center point 5a1 of the light emitting surface 5a is slightly diverged and intersects near the irradiated surface 2, and the other light beams spread as the light beam progresses.

Therefore, the light valve 2 and the field lens 3 are arranged at a predetermined distance from the concave lens 4 on the side of the projection lens 11, and an arbitrary point (61
a, 61b}), the divergent light beams are subjected to the diverging action of the concave lens 4, and then spread on the light valve 2 through the field lens 3 while spreading at the diverging angle. The whole is illuminated (the distance between the concave lens 4 and the light valve 2 is determined by the spread angle of the light beam and the size of the light valve 2).

As described above, the divergent light beams reflected from arbitrary points (61a, 61b #) of the elliptical reflector 61 are superimposed on the light valve 2 by the concave lens 4. The so-called integration function is performed. As a result, illumination to the light valve 2 becomes uniform with less luminance unevenness, and a uniform image with less luminance unevenness can be obtained also for a projection image based on the light valve 2 through the projection lens 1.

Further, in the present embodiment, the entrance surface 4a of the concave lens 4 is configured to be substantially conjugate with the pupil 11a of the projection lens 11 by the optical action of the field lens 3, and the entrance surface 4a of the concave lens 4 Is made to be a light source image at the pupil 11a of the projection lens 11. FIG. 4 shows a light source image 5b on the pupil 11a at this time.
FIG.

The light source image 5b in the present embodiment is a relatively small donut type as shown in the figure. However, this donut shape is caused by the light emission angle distribution of the lamp 5.

As described above, in the present embodiment, the light source image 5b at the pupil position 11a of the projection lens 11 is of a small donut type. Therefore, even if the projection lens 11 has a smaller pupil, that is, a smaller aperture. It is possible to configure a desired projector (projection device), and the projection lens 11 is simplified. Furthermore, when configuring a projector that uses a schlieren optical system (strictly, an inverse schlieren system) that requires the use of a projection lens with a small pupil and a scattering mode light valve element, it can significantly improve brightness and contrast. I have to.

In this embodiment, a single light valve 2 is used as the light valve 2. However, this embodiment is not limited to a light valve using a light valve of the transmission type. The present invention can be applied to a projector using a reflection type light valve.

In recent years, attempts have been made to increase the effective aperture ratio by providing a microlens array in a light valve in a projector, but by using the present embodiment as an illumination system in this case, the light source of the illumination system can be improved. The image can be easily accommodated in the actual aperture of the pixel, and the light utilization can be further improved.

FIG. 2 is a sectional view of a main part of a second embodiment of the present invention. In FIG. 2, the same elements as those shown in FIG. 1 are denoted by the same reference numerals.

The present embodiment differs from the first embodiment shown in FIG. 1 in that, when the central light beam La of the light beams from the central portion of the light emitting surface 5a of the light source 5 is reflected by the elliptical mirror 62, it is substantially parallel to the illumination optical axis LX. The difference is that a converging lens 91 is provided in the vicinity of the opening of the elliptical mirror 62 to condense the light beam reflected by the reflector 62 and make it incident on the concave lens 4. It is.

In an actual projector, since a lamp has a limited life, a lamp unit in which a lamp and a reflector are integrated is generally designed to be replaceable. When such a lamp unit is replaced, there is a concern that the illumination optical axis is shifted due to mechanical tolerances and variations of the lamp unit and the mounting portion thereof, and a desired optical effect cannot be exhibited.

Therefore, in the present embodiment, the central light beam among the light beams from the center of the light emitting surface of the lamp unit is made substantially parallel to the optical axis LX, and the position of the lamp unit is slightly perpendicular to the optical axis. Even if it shifts, as long as the optical system on the main body side such as the condenser lens 91 and the concave lens 4 is fixed, it does not affect the optical effect.

FIG. 3 is a sectional view of a main part of a third embodiment of the present invention. In the present embodiment, a case is shown in which image information displayed on a light valve illuminated with each color light is projected onto a predetermined surface by a projection lens using a color separation / color synthesis optical system using a dichroic mirror.

In the figure, reference numeral 12 denotes a projection lens;
Reference numerals 2 and 23 denote liquid crystal light valve elements (light valves) for modulating R, G, and B primary color lights, respectively, and 31R and 31.
G and 31B are field lenses disposed adjacent to the illumination side of each light valve, 71 and 72 are dichroic mirrors for performing color synthesis, 75 and 76 are dichroic mirrors for performing color separation, 73 and 74 are total reflection mirrors, 32 is a collimator lens, 4 is a concave lens, 91 is a condenser lens, 5
Is a lamp, and 62 is a parabolic reflector.

Here, the light emitting surface 5a of the lamp 5 is located at or near the focal point of the parabolic reflector 62. Further, the field lens 31 (31a, 31b, 31c)
And the collimator lens 32, the concave lens 4
And the pupil of the projection lens 12 are conjugate.

In this embodiment, the illumination system from the lamp 5 to the concave lens 4 is exactly the same as that of the second embodiment shown in FIG. Then, the entire spread light beam emitted from the concave lens 4 is converted into a substantially parallel light beam by the collimator lens 32, and R, G, and B are output by the dichroic mirrors 75 and 76.
Are separated into three primary colors of light, and are passed through a mirror 73 and each field lens 31 to each of the R, G, and B light valves 2.
1, 22, and 23 are illuminated with each color light.

The light valve 21 illuminated with this illumination light
Nos. To 23 are uniform illuminations with less unevenness due to the integration effect of the concave lens 4 as described above. When each color light passes through these field lenses 31, it is condensed. Then, each color light subjected to the light modulation by each light valve 21 to 23 is a dichroic mirror 71,
The color is synthesized by the projection lens 1 and the mirror 74.
2 to a screen (not shown).

However, each of the light valves 21 to 23 here
Are emitted by the field lens 31, and are all condensed in the pupil of the projection lens 12.
Due to the conjugate relationship with the pupil, a donut-shaped light source image as described above is formed in the pupil.

Therefore, similarly to the first embodiment, even with the three-plate type projector as in the present embodiment, it is possible to construct a projector that can easily perform uniform illumination even with a projection lens having a smaller pupil, that is, an aperture. Thus, simplification of the projection lens can be achieved.

In general, in a three-panel projector, if there is uneven brightness in the illumination of each light valve, color display is performed by superimposing each color light, so that significant unevenness in color tends to occur. There is.

On the other hand, in the present embodiment, as a result of the integration effect of the concave lens 4, the illuminance unevenness of each light valve is small, and the RGB balance unevenness between the light valves is also small, so that good quality with very little color unevenness is obtained. A full-color projection image is obtained.

Further, when a three-plate type projector using a schlieren optical system (strictly, an inverse schlieren system) and a scattering mode light valve element, which requires the use of a projection lens having a small pupil, is remarkably improved in brightness. In addition, it is possible to improve contrast and eliminate color unevenness.

In this embodiment, three light valves of a transmission type are used for each color light, but the present embodiment is limited to a light valve of a transmission type. Instead, the present invention can be applied to a three-plate type projector using a reflection type light valve.

[0044]

As described above, according to the present invention, it is possible to achieve an illumination device capable of uniformly illuminating a surface to be illuminated and a projection device using the same, while simplifying the entire device. .

In particular, according to the present invention, the integration effect of the illumination light can be obtained, and the light source image formed on the pupil plane of the projection lens can be made one small, and the aperture of the projection lens can be reduced ( Cost reduction) and remarkable improvement in image quality in a projection apparatus using a schlieren optical system can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a main part of a first embodiment of the present invention.

FIG. 2 is a schematic view of a main part of a second embodiment of the present invention.

FIG. 3 is a schematic diagram of a main part of a third embodiment of the present invention.

FIG. 4 is a schematic diagram showing a light source image at a pupil of a projection lens of the projection device of the present invention.

FIG. 5 is a schematic view of a main part of a conventional projection device.

[Explanation of symbols]

10, 11, 12 Projection lens 2, 21, 22, 23 Liquid crystal light valve element (light valve) 3, 30, 31 Field lens 32 Collimator lens 4 Concave lens (negative lens) 5 Arc lamp (light source) 60, 62 Object reflector 101 Light source 102 Reflector 71, 72, 75, 76 Dichroic mirror 73, 74 Total reflection mirror 301 First lens plate 302 Second lens plate 90, 91 Condenser lens 11a Pupil

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] May 25, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 2

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction contents]

(1-2) Of the light beams from the light source means having a light emitting surface having a finite size in the optical axis direction, the center line of the light beam emitted from the center of the light emitting surface is substantially parallel to the optical axis direction. A reflector for collimating the light, a condensing lens for condensing the light beam from the reflector, a negative lens portion disposed before the position where the light beam from the condensing lens condenses, and a light beam from the negative lens portion. And a positive lens unit for guiding light on the surface to be irradiated.

Claims (7)

[Claims] 1. A reflector for reflecting and condensing a light beam from a light source means having a light emitting surface of a finite size in an optical axis direction, a negative lens portion disposed before a position where the light beam from the reflector is condensed, and An illumination device comprising: a positive lens unit that guides a light beam from the negative lens unit onto a surface to be irradiated. 2. A light beam emitted from a light source having a light emitting surface having a finite size in a direction of an optical axis so that a center line of a light beam emitted from a central portion of the light emitting surface is substantially parallel to the optical axis direction. Reflector for reflecting light, condensing lens for condensing light flux from the reflector, negative lens portion disposed before the position where light beam from the condensing lens is condensed, and surface to be irradiated with light beam from the negative lens portion An illuminating device comprising: a positive lens unit for guiding light. 3. A light beam reflected from an arbitrary point on a reflection surface of the reflector and in a divergent state is superimposed on the surface to be illuminated via the negative lens unit and the field lens unit. Item 3. The lighting device according to item 1 or 2. 4. The illumination device according to claim 1, wherein a central portion of the light emitting surface is focused on the surface to be irradiated and / or in the vicinity thereof. 5. An image based on an image display element provided on the surface to be irradiated is projected onto a predetermined surface by a projection optical system using the illumination device according to claim 1. A projection device characterized by the above-mentioned. 6. The projection apparatus according to claim 5, wherein the negative lens unit and a pupil position of the projection optical system have a substantially conjugate relationship. 7. An image display device using liquid crystal is provided on the surface to be illuminated, and a light beam modulated by the image modulation device is guided to a predetermined surface by the projection optical system. 7. The projection device according to claim 5, wherein