JP3408940B2 - Illumination device and projection display device provided with the illumination device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device suitable for a light source of a video device such as a projector and a projection type display device including the lighting device.

[0002]

2. Description of the Related Art A conventional technique will be described below with reference to FIGS. FIG. 4 is a structural conceptual diagram for explaining an example of a conventional lighting device used for a projection, a stepper, etc. In the figure, 1 is a reflecting mirror, 2 is a light source, and 3 is a light source.
Is a rod, 4 is an image forming lens part, 5 is an incident part of the rod, 6
Is the emitting portion of the rod, 7 is the surface to be illuminated, 8 is the projection lens, and 9
Is the screen. FIG. 5 is a diagram for explaining the shape of the main part of the conventional lighting device shown in FIG. 4, in which a conceptual diagram of the structure of the lighting device is shown in FIG. 5A, an enlarged perspective view of the rod is shown in FIG. The shape of the entrance / exit portion is shown in (C), and the shape of the irradiation region on the irradiated surface is shown in (D). In the figure, parts having the same functions as those in FIG. 4 are designated by the same reference numerals as those in FIG.

The structure of the lighting device used here is shown in FIG.
As shown in FIG. 3, the light emitted from the light source 2 is reflected by the reflection mirror 1 and condensed at one point to be incident on the incident portion 5 of the rod 3, and the light emitted from the emission portion 6 of the rod 3 is formed into the imaging lens portion 4. By forming an image on the irradiated surface 7 using
The illuminated surface 7 is illuminated. In liquid crystal projection or the like, a liquid crystal panel is arranged at the position of the illuminated surface 7, and the light transmitted through the liquid crystal panel is projected on the screen 9 by the projection lens 8. In such an illumination system, since the light is scrambled by the rod 3, uneven color and uneven illuminance at the incident portion 5 of the rod are eliminated at the emitting portion 6 of the rod, and as a result, good illumination without unevenness on the illuminated surface 7 is achieved. Is obtained. FIG. 5 shows the shape of the illumination area and the shape of the rod in each part of the illumination system. Usually, the rod 3 has an emitting portion 6 having a shape similar to the irradiated surface 7 as shown in the figure. Therefore, the image forming lens 4 has a good image forming characteristic without distortion, and forms an image of an irradiation region having a shape similar to the emitting portion 6 of the rod 3 on the surface 7 to be irradiated.

[0004]

However, although the conventional illumination system using the rod can provide good illumination in terms of unevenness, it is not possible to freely set the illuminance distribution on the illuminated surface. Normally, with image display devices such as liquid crystal projections, it feels brighter when the central area is brighter than in the surrounding area, rather than when the brightness on the screen is average, so the brightness of the central area is much higher. In many cases, the surrounding illuminance is set at a level of about 50%. In such a case, there is no method for controlling the amount of light in the peripheral part in the conventional illumination system using the rod.

The present invention has been made in view of the above-mentioned circumstances, and an illuminating device capable of freely changing and designing an illuminance distribution on a surface to be illuminated, which cannot be controlled by a conventional rod illumination system. It is an object to be solved to provide a projection type display device using the lighting device.

[0006]

According to a first aspect of the present invention, light from a light source condensed at one point is incident on a rod whose entrance and exit portions are rectangular, and the light emitted from the rod is imaged. In an illuminating device that illuminates the illuminated surface by passing through the lens portion to form an image on the illuminated surface, the distortion of the imaging lens portion is adjusted by adjusting the illuminance distribution within the illuminated surface. In addition to changing the shape, the shape of the entrance portion and the exit portion is given a deformation sufficient to correct the change in the shape of the image formed due to the change in the distortion. The feature is that the illuminance distribution on the illuminated surface, which could not be controlled by the conventional rod illumination method, can be freely changed without causing a decrease in average brightness due to distortion of the illumination range. It is obtained as it is possible to meter.

According to a second aspect of the present invention, in the first aspect of the present invention, the shape of the incident portion and the output portion to which the deformation is applied is a barrel shape in which each side of the rectangle is inflated into a convex shape. The feature is that the peripheral light amount ratio of the illuminance distribution on the illuminated surface can be made lower and the distortion of the illumination range can be suppressed.

According to a third aspect of the present invention, in the first aspect of the invention, the shape of the incident portion and the output portion to which the deformation is applied is a pin shape in which each side of the rectangle is recessed. The feature is that the peripheral light amount ratio of the illuminance distribution on the illuminated surface can be increased and the distortion of the illumination range can be suppressed.

The invention according to claim 4 is characterized by comprising the illuminating device according to any one of claims 1 to 3, a liquid crystal panel and a projection lens, which can be controlled by a conventional rod illumination system. It is possible to obtain a projection type display device provided with an illuminating device capable of freely changing and designing the illuminance distribution on the illuminated surface, which has not been possible, without causing a decrease in average brightness due to distortion of the illumination range.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of a lighting device according to the present invention will be described in detail with reference to the accompanying drawings.
In all of the drawings for explaining the embodiments, parts having the same functions are designated by the same reference numerals and are the same as the conventional example except that they characterize the present invention, and the repeated description thereof is omitted. . FIG. 1 is a diagram for explaining an embodiment of an illuminating device according to the present invention. In FIG. 1, distortion characteristics in an imaging lens unit are shown in (A), the shape and light intensity distribution of a surface to be irradiated are shown in (B), and a rod is shown. (C) shows the shape and light intensity distribution of the emission part of, and (D) is an enlarged perspective view of the rod. FIG. 2 is a diagram for explaining another embodiment of the illumination device according to the present invention, in which the distortion characteristic in the imaging lens unit is (A), the shape of the illuminated surface is the light intensity distribution (B), and FIG. The shape of the emitting part of the rod and the light intensity distribution are shown in (C), and the enlarged perspective view of the rod is shown in (D). FIG. 3 is a diagram for explaining the distortion of the imaging lens unit and the image formation shape on the illuminated surface. A state in which the image formation on the illuminated surface is distorted into a pin shape (pincushion type) is shown in (A), and a barrel shape is shown. The state distorted is shown in (B). Here, a shape in which each side of the rectangle is convex and bulged is called a barrel shape, and a shape in which each side is concave is called a pin shape (pincushion type).

According to the present invention, the light emitted from the light source is reflected by the reflection mirror, condensed at one point and made incident on the incident portion of the rod.
In an illuminating device that illuminates the illuminated surface by forming an image of the light emitted from the emitting portion of the rod on the illuminated surface using an imaging lens, an image is formed in order to change the illuminance distribution of the illuminated surface. It is an illuminating device in which the distortion of the lens is increased and the shape of the rod entering and exiting is shaped to have distortion enough to cancel the distortion.

That is, when it is desired to lower the peripheral light amount ratio of the illuminance distribution on the illuminated surface (to increase the difference between the peripheral and central light amounts), the distortion of the imaging lens is designed to increase toward the periphery. To do. As a result, the density of light on the illuminated surface can be made dense in the central portion and sparse in the peripheral portion. However, if this is left as it is, the illumination range on the illuminated surface will be distorted into a pin shape (pincushion shape), so the shape of the entrance / exit portion of the rod is designed to be a barrel shape so as to correct the distortion. By doing so, the peripheral light amount ratio on the illuminated surface can be lowered without reducing the average brightness. Conversely, if you want to increase the peripheral light intensity ratio on the illuminated surface (smaller light intensity difference between the peripheral and central portions), design the distortion of the illumination lens to decrease toward the periphery, The shape may be pin-shaped so as to correct the distortion.

Also in the illuminating device of the present invention, the basic structure of the device is the same as that of the conventional example shown in FIG. 3, and the light emitted from the light source 2 is reflected by the reflection mirror 1 to be condensed at one point, and the light of the rod 3 is emitted. The light is incident on the incident part 5, and the emitting part 6 of the rod 3
The illuminated surface 7 is illuminated by forming an image of the light emitted from the illuminated surface 7 using the imaging lens unit 4. Here, in the case of designing to reduce the peripheral light amount ratio of the illuminance distribution on the illuminated surface 7, as shown in FIG. 1A, the magnification increases as the distortion characteristics of the illumination / imaging lens unit 4 become closer to the periphery. To design. As a result, as shown in FIG. 1B, the light intensity distribution on the illuminated surface 7 can be made dense in the central portion and sparse in the peripheral portion. At this time, since the illumination range on the illuminated surface is distorted into a pin shape if left as it is, the distortion of the shape of the entrance / exit portion 5 of the rod 3 is corrected as shown in FIGS. 1 (C) and 1 (D). It is designed like a barrel so that it does. With such a configuration, it is possible to illuminate the irradiation surface 7 so that the irradiation area becomes substantially rectangular.

Now, with reference to FIG. 3, it will be described how the rectangular rod emitting portion forms an image on the surface to be illuminated by the distortion of the imaging lens. As shown in FIG. 3A, in the case of a distortion in which the magnification increases toward the periphery of the lens, the image formation on the irradiated surface is pin-shaped. Further, as shown in FIG. 3B, in the case of a distortion in which the magnification becomes smaller toward the lens periphery, the image formation on the irradiated surface is barrel-shaped.

Therefore, when it is desired to increase the peripheral light amount ratio on the irradiated surface as compared with the example shown in FIG. 1, the configuration as shown in FIG. 2 is adopted. That is, as shown in FIG.
The distortion characteristics of the illumination lens are designed so that the magnification becomes smaller toward the periphery, and as shown in FIGS. 1 (C) and 1 (D), the shape of the rod entrance / exit is pin-shaped to correct the distortion. do it. At this time, the light intensity distribution on the illuminated surface is as shown in FIG.

[0016]

【The invention's effect】

Effect of claim 1: It becomes possible to freely change and design the illuminance distribution on the illuminated surface, which could not be controlled by the conventional rod illumination system, without causing a decrease in average brightness due to distortion of the illumination range.

It is possible to reduce the peripheral light amount ratio of the illuminance distribution on the surface to be illuminated and to suppress the distortion of the illumination range.

It is possible to increase the peripheral light amount ratio of the illuminance distribution on the illuminated surface and to suppress the distortion of the illumination range.

Effect of claim 4: The illuminance distribution on the illuminated surface, which cannot be controlled by the conventional rod illumination system, can be freely changed and designed without causing reduction in average brightness due to distortion of the illumination range. A projection type display device including the illuminating device is obtained.

[Brief description of drawings]

FIG. 1 is a diagram for explaining an embodiment of a lighting device according to the present invention.

FIG. 2 is a diagram for explaining another embodiment of the lighting device according to the present invention.

FIG. 3 is a diagram for explaining the distortion of the imaging lens unit and the imaging shape on the illuminated surface.

FIG. 4 is a structural conceptual diagram for explaining an example of a conventional lighting device used for a projection, a stepper, or the like.

FIG. 5 is a diagram for explaining a shape of a main part of the conventional lighting device shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Reflective mirror, 2 ... Light source, 3 ... Rod, 4 ... Imaging lens part, 5 ... Rod entrance part, 6 ... Rod exit part, 7 ...
Irradiated surface, 8 ... Projection lens, 9 ... Screen.

Claims (4)

(57) [Claims] 1. The light source light condensed at one point is made incident on a rod having a rectangular shape of an incident part and an emission part, and the light emitted from the rod is passed through an imaging lens part to be irradiated onto a surface to be irradiated. In an illumination device that illuminates the illuminated surface by forming an image, the in-plane illuminance distribution of the illuminated surface is adjusted by changing the distortion of the imaging lens unit. An illuminating device, characterized in that deformations are imparted to the shapes of the entrance portion and the exit portion so as to correct the change in the shape of the image formed due to the change in the distortion. 2. The illumination according to claim 1, wherein the shape of the incident portion and the emission portion to which the deformation is applied is a barrel shape in which each side of the rectangle is inflated into a convex shape. apparatus. 3. The shape of the incident portion and the emission portion to which the deformation has been applied is a pin shape in which each side of the rectangle is recessed. Lighting equipment. 4. A projection type display device, comprising: the lighting device according to claim 1; a liquid crystal panel; and a projection lens.