JPH0333732A - Light source unit for projector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (2) (3) "Industrial Application Field" The present invention relates to a light source for a projector used in a slide projector, a projection projector using a liquid crystal, etc. The present invention relates to a light source for a projector that can efficiently irradiate a target slide or the like with a luminous flux.

"Prior Art" A conventional projection projector includes, for example, a light source lamp 100 made of a halogen lamp or the like, a curved mirror 200 made of an ellipsoid of revolution or a paraboloid, as shown in FIG. 5, for example.
Target 3 includes slide film, liquid crystal elements, etc.
00 and a projection lens group 400. This projection projector focuses a light beam from a light source lamp 1°O onto a curved mirror 200″c′,
The light is irradiated toward the Targutsu l-300 surface.

The light beam that has passed through the target 300 is imaged on a screen or the like by a projection lens group 400. (First method) When the light collection efficiency is further increased or the divergence angle of the emitted light beam is required to have strict characteristics, an illumination light source device as shown in FIG. 6 has been adopted. This illumination light source device was composed of a light source lamp 100, a curved mirror 200, a fly's eye lens 500 made of a glass fiber bundle, and a condenser lens 600. This illumination light source device condenses a light beam from a light source lamp 100 with a curved mirror 200, and a fly's eye lens 500 made of a glass fiber bundle.
It is used to irradiate. Then, the light beam that has passed through the fiber optical path is irradiated onto a condenser lens 600, and a parallel light beam can be obtained by the condenser lens 600. (Second method) ``Problem to be solved by the invention'' However, although the first method described above can achieve a luminous flux utilization rate of about 30 to 50%, it is not satisfactory as a light source for a projection projector. It wasn't possible. This is because, of the radiation scene from the light source lamp 100, the luminous flux of the part surrounded by the curved mirror 200 can be used effectively, but the luminous flux of the part not surrounded is radiated into space and cannot be used effectively. This is because it cannot be done.

To explain this point in detail, if we adopt a light source with a light source distribution as shown in Figure 2 (radiant intensity expressed by line length for each radiation angle), the effective luminous flux portion shown in Figure 3 will be The light is reflected by the curved mirror 200 and is effectively radiated to the target 300, but the ineffective beam portion is not radiated to the target 300. That is, when a small halogen lamp is used, there is a serious problem in that the projected image has insufficient illuminance, and particularly when the magnification of the image projected onto the screen is increased, the image becomes extremely dark. In order to increase the illuminance of the projected image, methods such as using a large-diameter lens or increasing the output of the light source lamp have been considered, but these methods not only increase weight but also result in extremely high costs. Furthermore, if a light source lamp with a large amount of light is used, it becomes difficult to use the light source, and there is a risk of malfunction, especially when the target is a liquid crystal element.

Next, the second method using optical fibers can improve the light collection efficiency, but requires a fiber member in addition to the inexpensive mirror member, which has the problem of high cost.

"Means for Solving the Problems" The present invention has been devised in view of the above-mentioned problems, and includes a first curved surface reflecting member for reflecting the light beam from the light source once and guiding it to the target, and a first curved surface reflecting member for guiding the light beam from the light source to the target. a second curved surface reflecting member for receiving light and focusing the light in front of the light source; and a second curved surface reflecting member disposed near a light focusing position by the second reflective curved surface reflecting member to direct the reflected light flux from the second curved surface reflecting member toward a target. and a third curved reflecting member for dodging.

It is also possible to configure the second curved reflecting member of the present invention from a concave surface having an ellipsoid of revolution, and the third curved reflecting member from a convex surface having a spherical surface.

Furthermore, the light source of the present invention may have a light distribution characteristic in which the amount of light distributed to the sides is greater than the amount to the front.

"Function" In the present invention fitted as described above, the first curved surface reflecting member reflects the light flux from the light source once and guides it to the target, and the second curved surface reflecting member reflects the light flux from the light source to the light source. A third curved surface reflection member arranged in the vicinity of the light collection position of the second curved head reflection member directs the reflected light flux from the second curved surface reflection member toward the target,
It is possible to increase the utilization rate of the luminous flux from the light source.

In particular, if a light source with a light distribution characteristic that distributes more light to the sides than to the front is used, the luminous flux from the light source can be used more effectively.

"Example" An example of the present invention will be described based on the drawings. FIG. 1 is a diagram illustrating the configuration of a light source device 1 for a projector according to this embodiment. The light source device 1 for a projector of this embodiment is as follows:
A light source lamp 2, a pair of first mirrors 3, and a pair of second mirrors
mirror 4, a third mirror 5, a target 6, and a projection lens group 7. The light source lamp 2 corresponds to a light source, and suitable light emitting means such as a halogen lamp can be employed. The first mirror 3 corresponds to a first curved reflecting member, and reflects the luminous flux from the light source lamp 2 once and guides it to the target 6. Honji 7i! The first mirror 3 at fM is composed of an ellipsoid of revolution. The second mirror 4 corresponds to a second curved reflecting member, and focuses the light beam from the light source lamp 2 in front of the light source lamp 2. The second mirror 4 in this embodiment is composed of an ellipsoid of revolution. The third mirror 5 corresponds to a third curved reflecting member, and is arranged near the focal point of the second mirror 4, and guides the reflected light beam from the second mirror 4 toward the target 6. The third mirror 5 in this embodiment has a t
I have been admonished. The target 6 is composed of a slide film, a liquid crystal element, etc.
If you place a positive film with the desired image recorded on it,
Images can be projected onto a screen or the like. The projection lens group 7 is a lens for forming an image on a screen or the like using the light beam transmitted through the target 6.

Next, the operation of this embodiment will be explained. First, the first mirror 3 reflects the light beam from the light source lamp 2 and irradiates the target 6 with the light beam. Note that the light beam incident on the first mirror 3 from the light source lamp 2 is an effective light beam shown in FIG. Of the luminous flux from the light source lamp 2, the luminous flux corresponding to the invalid luminous flux shown in FIG. 3 is incident on the second mirror 4,
The light beam reflected by the second mirror 4 is focused at a specific position on the central axis in front of the light source lamp 2. Then, the third mirror 5 reflects the light beam reflected by the second mirror 4 again and irradiates it onto the target 6.

Here, since the mounting positions of the second mirror 4 and the third mirror 5 are important, they will be explained in detail. The second mirror 4 is formed of a part of an ellipsoid of revolution, and focuses the light emitted from the center of the light source onto a different point. That is, the second mirror 4 is arranged so that the first focal point coincides with the center of the light source, and the light emitted from the center of the light source is focused on the second focal point on the optical axis. The convergence position of the light beam reflected by the second mirror 4 (the second focal point of the second mirror 4) is
The focal length gi (R/2, where R is the third mirror 5)
When the third mirror 5 is arranged so as to match the radius of curvature of the spherical surface (the radius of curvature of the mirror arm), the light beam reflected by the third mirror 5 becomes a parallel ray.

If the focal point of the light beam reflected by the second mirror 4 is closer to the light source than the focal point F of the third mirror 5, one shot is lost. Therefore, in the real rope, the third mirror 5
In order to make the light reflected by the second mirror 4.4 a completely destroyed light that illuminates the entire surface of the target, the light reflected by the second mirror 4.4 is focused at a position slightly closer to the light source lamp 2 than the focal position F of the third mirror 5. Note that the second mirror 4 and the third mirror 5 need to be placed at positions where they do not obstruct the optical path of the light beam formed by the first mirror 3. For this purpose, the second mirror 4 is placed outside the first mirror 3, and the third mirror 5 is placed on the vertex where the light amount distribution of the light source lamp 2 is the lowest.

In this embodiment configured as described above, the luminous flux utilization rate of the light source light amount can be increased to 60% or more simply by using the mirror member, which is an inconvenient component.

In addition, the shapes of the first mirror 3, second mirror 4, and third mirror 5 are usually axially symmetric rotating surfaces, but 3=4 or 3=4 as in slide projectors and liquid crystal projectors. When using a rectangular target such as 4:5, the reflection mirror system can be made rotationally asymmetrical to match the target shape.

Note that if the light emission distribution of the light source lamp 2 is made to be an axially symmetrical radiation distribution as shown in FIG. mirror 4
This has the effect of increasing the luminous flux incident on the light source and increasing the utilization rate of the luminous flux from the light source. Furthermore, the first mirror 3 and the second mirror 4 are shaped into a spherical or aspherical shape, and the third mirror 5 is shaped into a hyperboloid, an ellipsoid, etc.
By combining these, it is possible to achieve uniform illumination conditions. That is, in this embodiment, the optical path from the light source lamp 2 to the target 6 includes an optical path that is reflected once by the first mirror 3 and reaches the target 6, and an optical path that goes from the second mirror 34 to the third mirror 5. There are two optical paths leading to the target 6, which has the effect of increasing the degree of freedom of illumination conditions. Therefore, if the light distribution characteristics of the respective optical paths are combined so as to compensate for each other, it is possible to achieve extremely uniform illumination on the target 6.9 In addition, the first mirror 3 of this embodiment, The second mirror 4 and the third mirror 5 may be formed of a part of a spherical surface, an ellipsoid of revolution, a hyperbolic surface, or a paraboloid.

If this embodiment is applied to the Kakugan allojection lamp light source optical system 700 as shown in FIG. The present invention has the outstanding effect of being able to utilize light flux and providing a light source flux system with extremely high light source utilization efficiency.

"Effects" The present invention configured as described above includes a first curved reflecting member for once reflecting the light beam from the light source and guiding it to the target lens 1-, and a first curved surface reflecting member for receiving the light beam from the light source and a second curved reflection member for condensing light onto the target; and a third curved reflection member disposed near the light collection position by the second curved reflection member for directing the reflected light flux from the second curved reflection member toward the target. Since the first curved surface reflecting member is made up of a
The light can be reflected by the third curved reflecting member and irradiated toward the target via the third curved reflecting member. Therefore, there is an effect that the utilization efficiency of the luminous flux from the light source can be significantly improved.

Furthermore, the component of the present invention is only a simple curved reflective member, and there is an effect that the utilization rate of the luminous flux can be increased without complicating the configuration.

If the second curved reflecting member of the present invention is made of a concave surface having an ellipsoid of revolution, and the third curved reflecting member is made of a convex surface having a hyperbolic surface, the light beam reflected by the second curved reflecting member can be converged. The light position can be made to coincide with the focal point position of the third curved surface reflecting member, and in this case, the reflected light beam of the third curved surface reflecting member can be made into parallel light beams. Furthermore, when the condensing position of the light beam reflected by the second curved surface reflection member is closer to the light source than the focal point position of the third curved surface reflection member, the light beam reflected by the third curved surface reflection member can be made into diverging light. It has an outstanding effect.

Furthermore, if the light source of the present invention has a light distribution characteristic in which the amount of light distributed to the sides is larger than that to the front, the first curved surface reflecting member and the $2
This has the effect of increasing the amount of light that enters the reflective member at curved locations and increasing the utilization rate of the light from the light source.

[Brief explanation of drawings]

The figures show one embodiment of the present invention, and FIG. 1 is a diagram showing the configuration of the light source device for a projector of this embodiment, FIG. 2 is a diagram showing the emitted light distribution of the light source lamp, and FIG. Figure 4 shows the effective and invalid light flux from the light source, Figure 4 shows the square projection light source optical system, Figure 5 shows the conventional technology (first method), and Figure 6 shows the conventional technology (first method). FIG. 2 is a diagram showing a conventional technique (second method).・Light source device for projector ・Light source lamp ・First mirror ・Second mirror ・Third mirror ・Target ・Projection lens group

Claims (3)

[Claims] (1) a first curved reflecting member for reflecting the luminous flux from the light source once and guiding it to the target; a second curved reflecting member for receiving the luminous flux from the light source and focusing it in front of the light source; A light source device for a projector, comprising: a third curved surface reflective member disposed near a light condensing position by the second curved reflective member for directing the reflected light beam from the second curved reflective member toward a target. . (2) The light source device for a projector according to claim 1, wherein the second curved reflecting member is formed from a concave surface having an ellipsoid of revolution, and the third curved reflecting member is formed from a convex surface having a spherical surface. (3) The light source device for a projector according to claim 1, wherein the light source has a light distribution characteristic in which the amount of light distributed is larger to the sides than to the front.