JPH0740994Y2 - Light source - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a light source device for obtaining parallel illumination light for irradiating a chart surface, and in particular, is provided with a reflector in which the opening of the reflecting surface is different from the shape of the chart surface. The present invention relates to a light source device.

[Prior Art] There is known a liquid crystal projector that irradiates a crystal display panel with light from a light source to enlarge and project a television image or the like displayed on the liquid crystal display panel onto a screen.

The light source device of such a liquid crystal projector needs to have a function of illuminating the liquid crystal display panel, which is the chart surface of the irradiation target, from a distance with a predetermined illuminance, and thus is configured to obtain parallel illumination light. Is composed of a light-emitting body and a reflector that reflects the light emitted by the light-emitting body to form parallel illumination light toward the liquid crystal display panel. For the light emitter, a xenon lamp or halogen lamp with high emission brightness is usually used.
The reflector has a reflecting surface formed of a paraboloid of revolution.

[Problem] By the way, in the case of the above-mentioned conventional light source device, the light of the light-emitting body reflected by the reflective surface of the reflector proceeds as it is toward the liquid crystal display panel surface, and the reflective surface opening portion of the reflector is formed on the liquid crystal display panel surface. Is emitted as circular parallel illumination light having a size (area). In this case, the surface of the liquid crystal display panel illuminated by the circular parallel illumination light is generally vertical, for example.
3: Since the reflector has a rectangular shape with a ratio of 4 in the horizontal direction, the reflective surface of the reflector is a circular parallel illumination light having an area such that the size of the opening can illuminate the entire rectangular liquid crystal display panel surface. The size is set to get

However, in the case of irradiating the rectangular liquid crystal display panel surface with the circular parallel illumination light in this way, there are many wasted light rays which do not substantially illuminate the liquid crystal display panel surface in the parallel illumination light (substantially About 50% of the light is radiated outside the liquid crystal display panel surface.) Therefore, the efficiency of utilizing the light beam directed to the liquid crystal display panel surface to irradiate the liquid crystal display panel surface was extremely low.

Further, when trying to obtain parallel irradiation light in the above-mentioned conventional light source device, there is also a problem that the central portion of the parallel illumination light for irradiating the liquid crystal display panel surface is hollowed due to the shadow of the light emitter and the image performance is deteriorated. .

[Purpose of Invention] This invention was made in view of the above circumstances.
It is an object of the present invention to provide a light source device in which the utilization efficiency of light from a light-emitting body is improved and the brightness of light toward a chart surface to be irradiated is substantially uniform.

[Points of Invention] In order to achieve the above-mentioned object, a light source device according to the present invention comprises:
Among the light rays emitted from the light-emitting body or the light rays emitted from the light-emitting body and reflected by the reflector, the optical path of the light ray that goes out of the chart surface of the irradiation target is optically corrected to be a substantially parallel light ray within the chart surface. The main point is to provide a correcting means between the reflector and the chart surface so as to make the light directed toward the chart surface substantially uniform in brightness.

[Embodiment] An embodiment in which the present invention is applied to a light source device used in a liquid crystal projector will be described below with reference to the drawings.

FIG. 1 shows the overall structure of a light source device according to a first embodiment of the present invention.

The light source device 1 includes a light-emitting body 2 formed of a xenon lamp, a light-emitting body 2 mounted on the center of a reflecting surface 3 which is a paraboloid of revolution and forms a cold mirror, and is supported by a cylindrical support 4. The reflector 5 and the light ray traveling position correction prism 6 arranged in front of the reflector 5 so as to face a rectangular liquid crystal display panel surface (not shown) which is a chart surface.

The reflector 5 does not have the circular shape of its reflection surface 3 and has an opening 7
The size (diameter) is set to a size that can be circular parallel illumination light having an area capable of irradiating the light emitted by the light-emitting body 2 on the entire rectangular chart surface.

The light ray traveling position correction prism 6 is for optically correcting the light ray a in a region going out of the chart surface out of the light rays reflected by the reflecting surface 3 of the reflector 5 and going to the chart surface, and moves the light ray a in the vicinity of the optical axis O. It is composed of a first correction prism 8 (see FIG. 2) arranged on the reflector 5 side and a second correction prism 9 (see FIG. 3) arranged on the chart surface side. The first correction prism 8 corrects the light ray a directed to the upper and lower sides of the chart surface, and the second correction prism 9 corrects the light ray a directed to the left and right sides of the chart surface.

The first correction prism 8 and the second correction prism 9 have basically the same structure. FIG. 4 shows the structure, but in the case of this figure, the first correction prism 8
In the figure, the side shape (in contrast, the front shape in Fig. 2)
The second correction prism 9 has a planar shape (in contrast, FIG. 3 shows a front shape). The first correction prism 8 and the second correction prism 9 include a main prism 10 that totally reflects a light ray a in an area extending out of the chart surface in the optical axis O direction, and a light ray a totally reflected by the main prism 10. And a sub-prism 11 for emitting light from the vicinity of the optical axis O. The main prism 10 is a columnar prism having a rectangular basic shape, and has total reflection surfaces 12, 12 on both sides thereof. The sub-prism 11 is a columnar prism having an isosceles triangular shape, two sides of which are total reflection surfaces 13, 13 and are fitted in a V-shaped groove 14 formed in the central portion of the main prism 10. . In this case, the main prism 10 and the sub-prism 11 are glass prisms, but are usually made of glass having different refractive indexes (the sub-prism 11 has a larger refractive index than the main prism 10). When the main prism 10 and the sub-prism 11 are made of glass having the same refractive index, a material layer (for example, an air layer) 15 having a refractive index smaller than that of the main prism 10 and the sub-prism 11 is provided between them as illustrated. Is intervened.

In the first correction prism 8, as shown in FIG. 2, the main prism 10 and the sub prism 11 are installed so as to be horizontal. Therefore, the light ray a in the region which is reflected by the reflecting surface 3 of the reflector 5 and goes out of the chart surface (upper and lower parts) is totally reflected in the optical axis O direction by the total reflecting surfaces 12, 12 of the main prism 10, and The light is totally reflected by the total reflection surfaces 13, 13 of the prism 11, is emitted from the vicinity of the optical axis O, and travels toward almost the center of the chart surface. Further, the light ray a ′ in the area toward the inside of the chart surface passes through the main prism 10 and the sub-prism 11 as it is and travels toward the inside of the chart surface.
In the illustrated example, the length l of the primary prism 10 and the secondary prism 11
Is aligned with the lateral dimension of the chart surface, so that the light ray a traveling to the left and right portions outside the chart surface does not pass through the main prism 10 and the radiation prism 11, and is directly transmitted to the first correction prism 8
The light travels outside and gradually enters the second correction prism 9.

In the second correction prism 9, as shown in FIG. 3, the main prism 10 and the sub prism 11 are installed so as to be in the vertical direction. Therefore, out of the light rays reflected by the reflecting surface 3 of the reflector 5 and traveling toward the chart surface, the light rays travel without passing through the first correction prism 9 and go out of the chart surface (left and right portions).
The light ray a directed toward the total reflection surface 12 of the main prism 10 is totally reflected in the optical axis O direction, and the total reflection surface of the sub prism 11 is
The light is totally reflected by 13, 13 and is emitted from the vicinity of the optical axis O and travels toward almost the center of the chart surface. Also, the first
The optical axis a ′ of the region which is transmitted through the correction prism 9 and enters the chart surface is directly transmitted through the main prism 10 and the sub-prism 11 and proceeds toward the chart surface.

The parallel illumination light reflected by the reflecting surface 3 of the reflector 5 and traveling toward the chart surface is reflected by the first correction prism 8 and the second correction prism.
By passing through the correction prism 9 of the above, the parallel illumination light having the shape (circular shape) and the area of the opening of the reflecting surface 3 is gradually changed to the parallel illumination light having the shape (rectangle) and the area of the chart surface. While being changed, the light ray a in the region going out of the chart surface is corrected so as to sequentially travel near the optical axis O. Therefore, almost all light rays reflected by the reflection surface 3 of the reflector 5 and directed to the chart surface become parallel illumination light that illuminates the inside of the chart surface, and the light rays reflected by the reflection surface 3 of the reflector 5 are not wasted. It is used as parallel illumination light to illuminate a surface. Further, even if parallel illumination light is obtained on the reflecting surface 3 of the reflector 5, the light ray a in the region going out of the chart surface in the first correction prism 8 and the second correction prism 9 travels near the optical axis O. Since it is corrected to, the hollowness due to the shadow of the light emitter does not occur.

FIG. 5 shows the overall construction of the light source device according to the second embodiment of the present invention.

The light source device 1'includes a light-emitting body 16 made of a xenon lamp, a reflector 18 having the light-emitting body 16 mounted at the center of a reflecting surface 17 formed of a paraboloid of revolution and forming a cold mirror,
A front portion of the reflector 18 is provided with a light ray traveling position correction reflector 19 arranged so as to face a rectangular liquid crystal display panel surface (not shown) which is a chart surface.

The reflector 18 has a circular opening 20 on its reflecting surface 17.
The size (diameter) is set to a size that can be circular parallel illumination light having an area capable of irradiating the light emitted from the light-emitting body 16 on the entire rectangular chart surface.

The light ray traveling position correction reflector 19 optically corrects a light ray a in a region directed to the outside of the chart surface out of the light rays reflected by the reflection surface 17 of the reflector 18 and directed to the chart surface, and the optical axis O
It is for advancing the neighborhood. The light ray traveling position correcting reflector 19 has a reflecting surface 21 of a paraboloid of revolution facing the reflecting surface 17 of the reflector 18, and the reflecting surface
An opening 22 is formed in the center of 21. The opening 23 of the reflecting surface 21 is set to the same size (diameter) as the opening 20 of the reflecting surface 17 of the reflector 18, and the shape and area of the opening 22 are the sixth.
It is fitted to that of the rectangular chart surface as shown.

As described above, the light ray traveling position correcting reflector 19 is arranged in front of the reflector 18 so as to face the chart surface. In this case, the light ray a'reflected by the reflecting surface 17 is emitted from the light emitting body 16. It is set so as to pass through a point light source (arc) P and be reflected by the reflecting surface 17 of the reflector 18 to travel in the vicinity of the optical axis O.

In such a light source device 1 ′, the light emitted from the light emitter 16 is reflected by the reflecting surface 17 of the reflector 18 to be circular parallel illumination light directed toward the chart surface, but the light traveling position correcting reflector 19 is used. When passing, the light ray (not shown) in the area toward the chart surface proceeds through the opening 22 toward the chart surface as it is, but the light ray a in the area outside the chart surface is reflected by the reflecting surface 21. , Is returned to the reflector 18 side again, passes through the point light source P, is reflected by the reflecting surface 17 of the reflector 18, travels in the vicinity of the optical axis O, and passes through the opening 22 toward almost the center of the chart surface. Therefore, also in the light source device 1 ', almost all of the light rays reflected by the reflecting surface 17 of the reflector 18 and traveling toward the chart surface become parallel illumination light that illuminates the inside of the chart surface. Therefore, the light rays reflected by the reflecting surface 17 of the reflector 18 are used as parallel illumination light for illuminating the chart surface without waste, and at the same time, the reflector is used.
Even if parallel illumination light is obtained on the reflecting surface 17 of 18, the hollowing due to the shadow of the light emitting body 16 does not occur.

Incidentally, the prism 6 and the reflector 19 used as the light ray traveling position correcting means in the first and second embodiments.
Is not limited to the structure of the embodiment, and various design changes can be made. Further, this invention is not limited to the light source device used in the liquid crystal projector of the embodiment, but can be widely applied to other light source devices.

[Advantages of the Invention] As described above, according to the light source device of the present invention, the light rays in the area going out of the chart surface are made to go into the chart surface, so that the light rays reflected by the reflecting surface of the reflector are reflected. Since all the rays are rays that illuminate the chart surface, the utilization efficiency of the rays is significantly improved, and even when obtaining parallel illumination light, there is an advantage that hollowing due to the shadow of the light emitter does not occur. .

[Brief description of drawings]

Each of the drawings shows an embodiment of the present invention, FIG. 1 is a side view showing an overall configuration of a light source device according to a first embodiment of the present invention, and FIG. 2 is a first correction prism of the same light source device. A front view, FIG. 3 is a front view of a second correction prism constituting the light source device, and FIG. 4 is a view showing configurations of a first correction prism and a second correction prism of the light source device. FIG. 6 is a side view showing the overall structure of a light source device according to a second embodiment of the present invention, and FIG. 6 is a front view of a light beam traveling position correcting reflector which constitutes the light source device. 1, 1 '... Light source device, 3, 17 ... Reflective surface, 5, 18 ...
Reflector, 6 ... Prism for correcting ray traveling position, 7, 20
...... Reflection surface open mouth, 19 ...... Ray travel position correction reflector.

Claims (1)

[Scope of utility model registration request] 1. A light source device comprising a reflector having a reflector opening whose shape is different from that of a chart surface to be irradiated with light, wherein a light beam emitted from a light emitter or a light beam emitted from said light emitter and reflected by said reflector. With the light ray, the optical path of the light ray that goes out of the chart surface is optically corrected to be directed into the chart surface as a substantially parallel light ray, and the correction means that makes the brightness of the light toward the chart surface substantially uniform is provided. A light source device provided between the reflector and the chart surface.