JPH10293269A - Projection type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a bright display device where the utilization efficiency of illuminating light is enhanced by providing the 2nd lens array plate with a small circle part consisting of fan-shaped lenses and a circular ring-like part consisting of trapezoidal lenses. SOLUTION: As for the transmitting action of the lenses of the 2nd lens array plate 5; twelve pieces of almost trapezoidal lenses 12 constituting the circular ring-like part 11 form respective arc images 15 by every lens. In the case of such image formation, the arc images 15 are arranged along an almost trapezoidal center line, so that the breadth of the vicinity of both ends of the arc image 15 is completely large. Therefore, owing to such lens shape, the transmitted light quantity in the bright range of the arc image is improved. Meanwhile, in the case of four pieces of almost fan-shaped lenses 14, the circumferences of 'vignetting' at the end near to the center are nearly the same as the conventional lens, but the transmitted light quantity in the bright range of the arc image is improved at the other end similarly to the circumstances of the lens 12. Therefore, the total area of the 'vignetting' part is reduced in the case of considering the 2nd lens array plate 5 as a whole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a projection display device, and more particularly, to an integrator used for illuminating a light valve.

[0002]

2. Description of the Related Art Conventionally, as one method of displaying a large-screen image, a projection display device using a light valve has been known.

FIG. 4 is a schematic diagram showing an embodiment of a projection type display device using two lens arrays (integrators). Reference numeral 1 denotes a lamp formed of, for example, a metal halide lamp or the like. 2 is a luminous body. 3 is a parabolic mirror. 4 is a first lens array plate, and 5 is a second lens array plate. Reference numeral 6 denotes a condenser lens. Reference numeral 7 denotes a light valve composed of a liquid crystal panel or the like. 8 is a projection lens. 9 is a screen. Reference numeral 10 denotes a main optical axis of the projection display device.

First, the operation of a basic projection display device having a configuration excluding a lens array portion will be described. As shown in FIG. 4, the light emitted from the lamp 1 is condensed by the parabolic mirror 3, and is passed through the condenser lens 6 to illuminate the light valve 7 displaying an optical image for enlargement, thereby obtaining the main light. The optical image is magnified and projected by a projection lens 8 on a screen 9 installed perpendicular to the axis 10.

[0005] Incidentally, the basic projection type display device having the above configuration condenses light by using the parabolic mirror 3, so that the main optical axis 10
The luminous flux density in the vicinity is large, and therefore, the enlarged projected image on the screen 9 has a characteristic that the degree of so-called “brightness unevenness” is large such that the brightness in the peripheral portion is insufficient. This characteristic is not preferable for an enlarged projection image. Therefore, as a method for uniformly improving the brightness of illumination light, a configuration called an integrator using a lens array is added to the above-described basic projection display device.

[0006] As shown in FIG. 4, the integrator mainly includes a first lens array plate 4 and a second lens array plate 5 which are vertically mounted on a main optical axis 10. The plate 4 and the second lens array plate 5 are formed by arranging a plurality of lenses, such as 16 4 × 4 lenses, in a two-dimensional matrix.

[0007] The first lens array plate 4 divides a single light beam having large brightness unevenness emitted from the parabolic mirror 3 into the same number of partial light beams as a plurality of lenses constituting itself. The partial luminous flux is superimposed by the second lens array plate 5 and the condenser lens 6, and illuminates the light valve 7 with uniform brightness.

FIG. 3 is a diagram showing a lens shape of a conventional second lens array plate and an arc image of a luminous body formed on the lens. By the way, the parabolic mirror 3 and the first lens array plate 4
As a result, as shown in FIG. 2, an arc image (real image) of the light emitter 2 is formed on the second lens array plate. In this arc image formation, the discharge portions L at both ends have a particularly large luminance as compared with the central portion. When a range in which the luminance is equal to or more than a predetermined value is indicated by, for example, a circle centered at L, the range extends outside the lens. That is, for example, a portion of 20 to 30% of the bright range does not pass through the lens, is not transmitted by so-called "vignetting", and the illumination light is not sufficiently used. There is a problem that the brightness of the image to be reproduced is not sufficient.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to provide a bright projection type display device in which the utilization efficiency of illumination light is enhanced.

[0010]

In order to achieve the above-mentioned object, in a projection display device using an integrator, the second lens array plate of the integrator has a small circle portion and the same center as the center of the small circle portion. A circular ring-shaped portion surrounding the outer periphery of the small circular portion having a plurality of substantially fan-shaped lenses obtained by dividing the small circular portion by diameter, and radiation passing through the center of the circular ring-shaped portion. And a plurality of substantially trapezoidal lenses divided by.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS With the above configuration, FIG.
The second lens array plate includes, for example, four substantially fan-shaped lenses and twelve substantially trapezoidal lenses, and the twelve substantially trapezoidal lenses form an arc image for each lens. It is a lens shape that can form an image and sufficiently increase the area near both ends of the arc image. Therefore, this lens shape (almost trapezoidal lens) increases the amount of transmitted light in the bright range of the arc image. Even when the second lens array plate is viewed as a whole, the total area of the “vignetting” portion can be reduced, so that the amount of transmitted light as a whole increases.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a projection type display device according to the present invention. FIG. 1 is a plan view showing an embodiment of the second lens array plate of the projection display device according to the present invention. Reference numeral 5 denotes a circular second lens array plate of the integrator according to the present invention, which includes a small circular portion 13 and a circular ring-shaped portion 11 surrounding the outer periphery of the small circular portion 13 having the same center as the center of the small circular portion 13. It consists of. In addition, the small circle portion
13 is four almost fan-shaped lenses 14 divided by diameter
And 12 substantially trapezoidal lenses 12 obtained by dividing the circular ring-shaped portion 11 by radiation passing through the center. Reference numeral 15 denotes an arc image formed for each lens.

The transmission operation of the lenses of the second lens array plate of the projection display device according to the present invention will be described with reference to FIG. The 12 substantially trapezoidal lenses 12 constituting the circular ring-shaped portion 11 form an arc image 15 for each lens. In this image formation state, the arc image 15 is arranged substantially along the center line of the trapezoid, so that the area near both ends of the arc image 15 is sufficiently large. Therefore, this lens shape (substantially trapezoidal lens) improves the transmitted light amount in the bright range of the arc image.
On the other hand, the four nearly fan-shaped lenses 14 have the same vignetting state at the end near the center as before, but the other ends have the same arc image as the above-described substantially trapezoidal lens 12. To improve the amount of transmitted light in the bright range. Therefore, even when the second lens array plate 5 is viewed as a whole, the total area of the “vignetting” portion can be reduced.

FIG. 2 is a plan view showing another embodiment of the second lens array plate of the projection display device according to the present invention. FIG.
A description will be given of a portion corresponding to the above-described embodiment by adding a to the number. In this embodiment, the second lens array plate 5a is
13a and an elliptical ring-shaped portion 11a surrounding the outer periphery of the small elliptical portion having the same center as the center of the small elliptical portion,
The small elliptical portion is composed of four substantially fan-shaped lenses 14a divided by diameter, and the elliptical ring-shaped portion is composed of 12 substantially trapezoidal lenses 12a divided by radiation passing through the center. Configured. 15a is an arc image formed for each lens. Note that the transmission operation of the lens is the same as that of the embodiment of FIG.

[0015]

As described above, the present invention provides a projection type display device in which the utilization efficiency of illumination light is improved. Therefore, there is an advantage that the brightness of an image enlarged and projected on the screen of the projection display device is improved. Further, the present invention can be implemented by changing the lens shape of the second lens array plate, so that it can be easily realized. Further, when the second lens array plate is manufactured by heating and pressing, the present invention having an outer diameter of a circle or an ellipse is less likely to cause cooling distortion, which is advantageous for the product yield.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of a second lens array plate of a projection display according to the present invention.

FIG. 2 is a plan view showing another embodiment of the second lens array plate of the projection display device according to the present invention.

FIG. 3 is a diagram showing a lens shape of a conventional second lens array plate and an arc image of a light emitter formed on the lens.

FIG. 4 is a schematic diagram showing an embodiment of a projection display device using two lens arrays (integrators).

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 lamp 2 luminous body 3 parabolic mirror 4 first lens array plate 5 second lens array plate 6 condenser lens 7 light valve 8 projection lens 9 screen 10 main optical axis of projection display device 11 circular ring portion 12 almost base Shaped lens 13 Small circular portion 14 Almost fan-shaped lens 15 Arc image 5a Second lens array plate 11a Elliptical ring-shaped portion 12a Almost trapezoidal lens 13a Small elliptical portion 14a Almost fan-shaped lens 15a Arc image

Claims (2)

[Claims] 1. A projection display device using an integrator, wherein the second lens array plate of the integrator is formed into a small circular portion and a circular ring surrounding the outer periphery of the small circular portion having the same center as the center of the small circular portion. And a plurality of substantially trapezoidal lenses formed by dividing the small circular portion by a diameter and by dividing the circular ring-shaped portion by radiation passing through the center. A projection type display device characterized by comprising. 2. A projection display device using an integrator, wherein the second lens array plate of the integrator is a small elliptical portion and an elliptical ring surrounding the outer periphery of the small elliptical portion having the same center as the center of the small elliptical portion. And a plurality of substantially trapezoidal shapes formed by dividing the small elliptical portion by a diameter and dividing the elliptical ring-shaped portion by radiation passing through the center. A projection display device comprising a lens.