JPS59111136A - Light source device for projection - Google Patents

Abstract

PURPOSE:To obtain easily a laterally long rectangular type wide screen and to improve the utilization rate of luminous flux by allowing light beams from adjacent xenon short arc lamps to overlap each other on the screen. CONSTITUTION:Two xenon short arc lamps 1 are arranged in the lengthwise direction of the screen 5. The 2nd focal points of their elliptic converging mirros 2 are both positioned near the center of a projection lens 4. Therefore, the light from the upper lamp 1 is reflected and converged by the elliptic converging mirror 2 to reach a point between points P and Q on the screen 5 through the projection lens 4. The illuminance distribution on the screen 5 in the lengthwise direction X-X has a sufficiently high-illuminance area. Consequently, the long rectangular type wide screen is obtained easily and the utilization rate of light is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a light source device for projection, and in particular, to a light source device for projection.
The present invention relates to a light source device for projection that can be used to improve illuminance distribution.

As in movies and theaters, old carbon arc lamps were mainly used as the light source for the platform and light source for enlarging and projecting the image on a transmission image film onto a screen using a projection lens, but recently C' 1. Most of them have been switched to short-arc xenon lamps, a major advance in terms of labor-saving and automation.

However, as an optical system for a projection light source device (well, still in the era of carbon arc lamps), the arc light of a single xenon lamp for a light source is
The H-type is used, in which light is focused by a single spheroidal mirror made of aluminum with a reflective film, passed through an image film, and then enlarged and projected onto a screen by a projection lens.

A typical example is shown in FIG. A xenon short arc lamp 1 is placed at the first focal point of an elliptical condenser mirror 2.

A projection lens 4 is arranged near the second focal point of the elliptical condenser mirror 2. There is an aperture V for projection film between the xenon short arc lamp 1 and the projection lens 4. - Frame 3 is placed.

Kill''!Non'J, the light emitted from i7 arc lamp 1 is
While being focused by the elliptical condensing mirror 2, the light passes through the image film located at position 16 of the projection film aperture frame 3, and is reflected by the projection lens 4 onto the screen 5.
is enlarged and projected.

FIG. 2 (8) shows the illuminance distribution on the screen 5 in this case.

As is clear from the figure, the illuminance distribution is point symmetrical with the center of the point 01 where the light ll1lli6 of the projection port 1 optical system intersects with the screen 5, so to speak, a pot-bottom type distribution. Therefore, the isolux curve 7 is shown in FIG. 2(A):
In other words, they form concentric circles centered on the point O.

Now, if a rectangular screen 10 having a point O as the center is set on the screen 50 as shown in FIG. 2, the illuminance distribution in the long side X- , respectively, the curve L1 is shown in (B) and (C) of the same figure.
It will be shown as follows.

Generally, the illuminance of a movie screen is determined by the standard visual acuity of the audience and the standard reflection of the screen. There is a substantially constant lower limit value (for example, 50 lux or more) determined from 1.

JL, within the screen screen 5, the illuminance is
It is desirable to keep it as uniform as possible. For that purpose, the second
In Figures (B) and (C), a portion indicated by diagonal lines cannot be used effectively.

Therefore, the shapes of the film screen, the projection film aperture frame 3, and the screen screen 5 have changed from the standard shape (height is about 70% of the width), which was close to a square, to the horizontally elongated rectangular shape (with the recent shift to wide screens). Width equals height 2
(approximately 7 times) (as the value increases to 7, the drawback that the utilization rate of the luminous flux further decreases) becomes 1 (approximately 1).

Furthermore, the illuminance distribution within the screen screen 5 has been changed to 7i.
i: To filter more ambient light
＼Discarding it outside the frame is a must for 2W. On the other hand, if we try to significantly increase the luminous flux utilization rate, only the central part of the screen screen 5 is bright, and the longitudinal direction, that is, both left and right ends and the four corners are not i:; There was a drawback that only the distribution screen 5 could be obtained.

As shown in the following, it is a natural result derived from the 1"1/1 no 1 of the 1 optical system, and the same as the conventional one (1t, 1 silk light emitting light source and condensing URL etc. are adopted. As long as practical 1 is necessary,
In order to obtain a larger screen 1 non-screen 5 while maintaining the brightness of the screen 5 (J, screen 5
It is said that there is a limit to the size of the projection screen that can be realized with a single xenon lamp, which is directly proportional to the size of the manufacturing process. Ta.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide a light source device for projection that can easily produce a large screen such as a horizontally long rectangular wide screen and that can increase the luminous flux utilization rate. It's about making offerings.

In order to achieve the above object, the present invention includes a plurality of elliptical condensing mirrors, each of which has a second focus 4 near the center of a common projection lens, and a first condenser of each of the elliptical condensers. A plurality of xenon 7.0>'-clamps arranged at the focal point ■ are provided, and the peripheral part of the luminous flux emitted from the adjacent xenon short arc lamp is on the screen screen V! It is constructed in such a way that the middle tatami mats are folded in 7 increments.

The present invention will be described in detail below with reference to the drawings.

FIG. 3 is a partially sectional plan view showing a schematic configuration of the first embodiment of the present invention, and FIG. 4 is a partially sectional side view thereof. In addition, FIG. 5 (A>) shows the screen screen 5 in z6 in this embodiment.
”-, the figure (B) shows the illuminance distribution of screen 5.
(C) shows the illuminance distribution in the long side direction of the screen 5, and (C) shows the illuminance distribution in the short side direction of the screen 5. In these figures, the same reference numerals as in FIGS. 1 and 2 represent the same or equivalent parts.

As can be seen from FIG. 3, in this example, 21t! One Kirenon short arc lamp 1 is arranged side by side in the long side direction of the screen screen 5. Of course, each Kirenon short arc lamp 1 is installed at the first focal point of the corresponding elliptical condenser mirror 2). The second focal point of each elliptical condenser mirror 2 is positioned near the center of the projection lens 4.

Therefore, in the third cause, the light emitted from the upper arc lamp 1 is collected by the (. P
and Q.

In this case, on the screen screen 5, the screen longitudinal direction (×
The illuminance distribution in the -x direction) becomes as shown in FIG. 5 L3, and a high illuminance region with little unevenness is formed over a sufficiently wide range.

Therefore, according to this embodiment, it is possible to easily obtain a horizontal L-9, l) carved "noid screen" without increasing the light output of the Kirenon short arc lamp alone. It is possible to minimize variations in the illuminance of the screen and direct the wasted luminous flux to outside the screen, thereby increasing the luminous flux utilization efficiency.

FIG. 6 (A) is a diagram showing the illuminance distribution on the screen obtained by the second embodiment of the present invention, and the same figure (P, )
11. This is a diagram showing the illuminance distribution along the line x-x (false).

Bar' (Illuminance distribution diagram (Figure 5) in the case of 1st example and glue,
As can be easily understood from the j ratio, in the second embodiment, the set of the Kirenon short arc lamp 1 and the elliptical condensing mirror 2 is 4♀fl.
t's! The intersection points 01 to 0/1 between the optical axis of each silk and the screen are located at each vertex of a square or rectangle on the screen.

In relation to the video screen, if the video screen is divided into four equal parts, top, bottom, and right, the intersection points 01-04 match the center of each divided screen. A silk optical axis is set.

Of course, in this case, each of the optical axes passes through the center of the projection lens 4; II”l
The positional relationship of Tj is set.

Therefore, for the same reason as stated in iC1, this embodiment also allows you to easily obtain a wider screen without reducing the light output of the single non-short arc lamp. Instead, the luminous flux utilization rate a'3
and illuminance distribution can be significantly improved.

As is clear from the above description, according to the present invention, a large square or hammered rectangular screen can be easily obtained without increasing the light output of the xenon short arc lamp alone. Furthermore, variations in illuminance within the screen can be suppressed to a small extent, and the luminous flux discarded to the outside of both sides of the screen can be reduced, thereby increasing the luminous flux utilization rate.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of a conventional projection light source device, FIG. 2 is a diagram showing the illuminance distribution on the screen in FIG. 1, and FIG. 14 is a partially sectional plan view showing the structure, and FIG. 4 is a partially sectional side view thereof.
FIG. 5 is a diagram showing the illuminance distribution on the screen screen shown in FIG. 1 in the first embodiment, and FIG.
It is a figure which shows the illumination rσ distribution on the screen screen in an Example. 1... Kirenon short arc lamp, 2... 4h circular condenser mirror, 3... Aperture frame for projection film, 4... Projection lens, 5... Screen screen, 6... Optical axis 1 ，
7... Isoluminance curve, 10... Rectangular screen 5th
Figure 6

Claims (1)

[Claims] (1) Aberdeley frames for the projection film l\, moecars of the Aberdeley frame for the projection film 11;
a plurality of elliptical condensing mirrors arranged at the rear of the aperture frame and on the opposite side of the screen, each having a second focal point near the center of the aperture lens;
A plurality of xenon short arc lamps are arranged at the first focal position of each of the elliptical condensing mirrors, and the light emitted from the seven adjacent xenon short arc lamps is superimposed on the screen. A light source device for projection that is characterized by: