JPH058582Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a light source device that emits parallel light.

[Conventional technology]

For example, a light source device in an optical display device such as a liquid crystal projector consists of a light source lamp and a reflector that reflects the light from the light source lamp.This light source device generally has a light source placed on the focal point of a parabolic mirror reflector. A structure in which the light emitting part of the lamp is positioned, the light from the light source lamp is reflected by a reflector, and parallel light parallel to the optical axis of the reflector is emitted toward the irradiated object (transmissive liquid crystal display panel in the case of liquid crystal projectors). It has been known. The light source lamp used is a high-intensity, high-voltage arc lamp such as a xenon lamp or a halogen lamp, which has terminals at both ends. It is positioned above and along the optical axis of the reflector, and is supported by the reflector by penetrating and fixing the proximal end to the center of the reflector (the center of the reflective surface).

[Problem that the invention attempts to solve]

However, the conventional light source device has a problem in that a shadow is formed at the center of the beam of parallel light reflected by the parabolic mirror reflector and emitted forward. This is because in the above light source device, the base end of the light source lamp is fixed through the center of the reflector, so there is no reflective surface in the center of the reflector, and the terminals at both ends of the light source lamp do not allow light to pass through. This is due to the fact that the terminal at the tip of the light source lamp is in the shadow.In light source devices that use a parabolic mirror reflector to reflect light from the light source, the light reflected by the reflector is parallel light. In order to emit light as In this case, the center of the irradiated object will become dark.

This idea was made in view of the above-mentioned circumstances, and its purpose is to emit parallel light using a parabolic mirror reflector, but the emitted light is To provide a light source device capable of producing light without a shadow in the center.

[Means to solve problems]

The light source device of this invention is provided with a ring-shaped light deflector in front of the outer peripheral edge of the parabolic mirror reflector, which reflects or refracts the light reflected at the outer peripheral edge of the reflector toward the optical axis of the reflector. In addition, a small-diameter center is positioned in front of the light source lamp on the optical axis of the reflector, and refracts or reflects the light from the ring-shaped light deflector forward to make parallel light parallel to the optical axis of the reflector. The device is characterized by being provided with a partial light deflector.

[Effect]

That is, the light source device of this invention reflects or refracts the light reflected at the outer peripheral edge of the parabolic mirror reflector toward the optical axis of the reflector by the ring-shaped light deflector provided in front of the outer peripheral edge of the reflector. At the same time, the light from this ring-shaped light deflector is refracted or reflected forward by a small-diameter central light deflector located in front of the light source lamp and positioned on the reflector optical axis. In this way, the light reflected at the outer periphery of the reflector is emitted as parallel light that is parallel to the reflector. Since the shadow can be eliminated by guiding the light, the light emitted from the light source device can be made to have no shadow in the center of its luminous flux.

〔Example〕

An embodiment of this invention will be described below with reference to the drawings regarding a light source device in a liquid crystal projector.

First, to explain the structure of the liquid crystal projector, in FIG. 1, reference numeral 1 is a case of the liquid crystal projector.The rear half of this case 1 is a light source house 1a, and inside this light source house 1a is a light source device having the structure described later. A is provided. Also, case 1
The front half of the display housing 1b is a display housing 1b, and a transmissive liquid crystal display panel 2 is provided within the display housing 1b. This liquid crystal display panel 2 is
For example, it is a matrix display panel that displays television images (color images), and this liquid crystal display panel 2 is attached to the front surface of the display panel cooler 3 (the surface opposite to the light source house 1a). . The display panel cooler 3 is a sealed container with transparent front and rear surfaces filled with a transparent cooling liquid such as an aqueous ethylene glycol solution, and constantly forcibly cools the heat-sensitive liquid crystal display panel 2. 2. Prevents temperature rise. 4 is display house 1
The projection lens 5 provided on the front surface of b is a condensing lens made of a circular Fresnel lens located between the liquid crystal display panel 2 and the projection lens 4 and provided within the display housing 1b. Also, 6
is a heat insulating wall that partitions the light source house 1a and the display house 1b, and this heat insulating wall 6 is provided with a transparent window 7 that transmits light from the light source device A in the light source house 1a. The transparent window 7 is formed by providing an opening in the heat insulating wall 6 and attaching a transparent plate 8 made of heat-resistant glass or the like to the opening. Although not shown, the case 1 is provided with an intake hole and an exhaust hole for air cooling the inside of the light source part house 1a and the inside of the display part house 1b.

This liquid crystal projector enlarges and projects a display image on a liquid crystal display panel 2 onto an external screen (not shown) placed in front of the projector using a projection lens 4, and the light from the light source device A in the light source house 1a is insulated. The light entering the liquid crystal display panel 2 through the transparent window 7 of the wall 6 and the display panel cooler 3 and transmitted through the liquid crystal display panel 2, that is, the displayed image on the liquid crystal display panel 2, is transmitted to the projection lens 4 by the condenser lens 5. The light is condensed and projected by the projection lens 4 onto the external screen surface as an enlarged image.

Next, the light source device A in the light source house 1a will be explained. In FIG. 1, 10 is a parabolic mirror reflector that reflects light from the light source lamp 11 toward the liquid crystal display panel 2. is supported within the light source box 12 with its reflective surface (inner surface of the reflector) facing the liquid crystal display panel 2. The light source lamp 11 is a high-brightness, high-voltage arc lamp, such as a xenon lamp or a halogen lamp, having terminal portions 12a and 12b at both ends.
The light emitting part 11a is a parabolic mirror reflector 10
is positioned on the focal point of the reflector along the optical axis o of the reflector, and is supported by the reflector 10 by penetrating and fixing its base end to a lamp insertion part 10a provided at the center of the reflective surface of the reflector 10. . Also,
Reference numeral 13 denotes a ring-shaped reflecting plate for changing light, which is provided in front of the outer peripheral edge of the reflector 10, and reference numeral 14 refers to a ring-shaped reflecting plate for changing light, which is provided in front of the light source lamp 11 and positioned on the optical axis o of the reflector. As shown in FIGS. 1 and 2, the ring-shaped reflecting plate 13, which is a central prism, is attached to a square frame 15 and a transparent plate 16 attached perpendicularly to this frame 15 with heat-resistant adhesive. The central prism 14 is fixed with adhesive.
is adhesively fixed to the transparent plate 16 with a transparent heat-resistant adhesive. Note that the transparent plate 16
When the light source lamp 11 overheats and explodes, its fragments scatter and damage electronic equipment (not shown, such as the power supply circuit and display panel drive circuit) inside the case 1.
It also serves as an explosion-proof plate to prevent damage to the
Therefore, this transparent plate 16 is made of high-strength heat-resistant glass.

The ring-shaped reflector 13 reflects the light a' reflected at the outer periphery of the reflector 10, out of the light a reflected by the parabolic reflector 10 as parallel light parallel to the reflector optical axis o, toward the center of the reflector reflected light beam, i.e., the reflector optical axis o, and the inner reflective surface of the ring-shaped reflector 13 is inclined at 45° with respect to the reflector optical axis o. The central prism 14 refracts the light a' reflected by the ring-shaped reflector 14 forward to make it parallel light parallel to the reflector optical axis o, and the central prism 14 is a small-diameter conical prism.
The central prism 14 is provided so that its top faces the light source lamp 11. The diameter of the bottom surface of the central prism 14 is approximately equal to the larger of the diameter of the lamp mounting portion (the portion not forming the reflective surface) at the center of the reflector 10 and the diameter of the terminal portion 12a at the tip side of the light source lamp 11.
The width of the reflecting surface of the central prism 14 is set to allow light to be incident on the peripheral surface (light incident surface) of the central prism 14 over its entire area.
The ring-shaped reflector 13 has an outer diameter that is approximately the same as the diameter of the reflector 10 and an inner diameter that is slightly larger than the diameter of the circle that circumscribes the display area of the liquid crystal display panel 2.

To explain the irradiation of light onto the liquid crystal display panel 2 by this light source device A, the light from the light source lamp 11, which is provided with the light emitting part 11a positioned on the focal point of the parabolic mirror main reflector 10, is It is reflected by the surface mirror reflector 10 as parallel light parallel to the reflector optical axis o, and among this reflector reflected light, the light a that passes inside the ring-shaped reflecting plate 13 provided in front of the outer peripheral edge of the reflector 10 is , the light passes through the transparent plate 16 as it is and is emitted toward the liquid crystal display panel 2. Note that since the ring-shaped reflector 13 has an inner diameter slightly larger than the display area of the liquid crystal display panel 11, the light a that exits through the inside of the ring-shaped reflector 13
The luminous flux has a width that can irradiate the entire display area of the liquid crystal display panel 2. on the other hand,
Light reflected at the outer periphery of the reflector 10
a' is reflected toward the reflector optical axis o by the ring-shaped reflecting plate 13 and enters the center prism 14 provided in front of the light source lamp 11 on the reflector optical axis o. The light is refracted forward by the prism 14, becomes parallel light parallel to the reflector optical axis o, passes through the transparent plate 16, and is emitted toward the liquid crystal display panel 2.

That is, the light source device A reflects the light a' reflected at the outer peripheral edge of the parabolic mirror reflector 10 toward the reflector optical axis o by the ring-shaped reflecting plate 13 provided in front of the outer peripheral edge of the reflector 10. At the same time, the light from this ring-shaped reflecting plate 13
a' is placed in front of the light source lamp 11, and the reflector optical axis o
A small diameter central prism 14 located above
The optical axis of the reflector is refracted toward the front by
The light is emitted as parallel light parallel to the reflector 10, and in this way, the reflector 1
Even if there is a shadow due to the fact that no light is reflected at the center of the reflector or the terminal portion 12a on the tip side of the light source lamp 11 does not pass light, the shadow may include light reflected at the outer periphery of the reflector. We can eliminate the above shadow by guiding light a′. Therefore, according to the light source device, the light emitted from the light source device is made into light with no shadow in the center of the luminous flux,
Since substantially uniform irradiation light can be incident on the liquid crystal display panel 2 over the entire display area with sufficient light intensity at the center, the center of the displayed image on the liquid crystal display panel 2 can be prevented from becoming dark. , the brightness of the displayed image can be made uniform over the entire screen, and a high-quality image without uneven brightness can be projected onto the screen surface.

In the above embodiment, the ring-shaped light deflector that directs the light reflected at the outer peripheral edge of the reflector 10 toward the reflector optical axis o is used as the reflector plate 13, but this ring-shaped light deflector is a prism. In addition, the central light deflection body that directs the light from the ring-shaped light deflection body forward is not limited to the conical prism 14 of the above embodiment, but a reflecting plate may be used. You may.

That is, FIG. 3 shows another embodiment of this invention, in which light reflected at the outer periphery of the parabolic mirror reflector 10 is directed forward of the outer periphery of the parabolic mirror reflector 10. A ring-shaped prism 17 that refracts light a' toward the reflector optical axis o is provided, and is positioned in front of the light source lamp 11 on the reflector optical axis o to direct the light a' from the ring-shaped prism 17 forward. A small-diameter central reflecting plate 18 is provided with a conical reflecting surface that reflects the light into parallel light parallel to the reflector optical axis o. In FIG. 3, parts corresponding to those shown in FIG. 1 are denoted by the same reference numerals and their explanations will be omitted.

Further, in the above embodiment, a light source device in a liquid crystal projector that projects the display image of the liquid crystal display panel 2 onto an external screen has been described. It can be applied to a type of LCD projector that projects the image displayed on an LCD panel, a light source device for a non-projection type optical display device that uses the surface of the LCD panel as its screen, and an optical display that uses an LCD panel. It goes without saying that the present invention can be widely applied not only to devices but also to light source devices such as optical display devices that use a transmissive electrochromic display panel or the like as an irradiated object.

[Effect of idea]

The light source device of this invention is provided with a ring-shaped light deflector in front of the outer peripheral edge of the parabolic mirror reflector, which reflects or refracts the light reflected at the outer peripheral edge of the reflector toward the optical axis of the reflector. In addition, a small-diameter center is positioned in front of the light source lamp on the optical axis of the reflector, and refracts or reflects the light from the ring-shaped light deflector forward to make parallel light parallel to the optical axis of the reflector. Since it is equipped with a partial light deflector, even though it uses a parabolic mirror reflector to emit parallel light, it is possible to make the emitted light light without a shadow in the center of the light flux. .

[Brief explanation of drawings]

Figures 1 and 2 show an embodiment of this invention, with Figure 1 being a longitudinal cross-sectional side view of a liquid crystal projector equipped with a light source device, and Figure 2 showing a ring-shaped reflector and a reflector of the central prism. It is a front view seen from the side. FIG. 3 is a longitudinal sectional side view of a light source device showing another embodiment of this invention. A... Light source device, 2... Liquid crystal display panel (illuminated object), 10... Parabolic mirror reflector, 11...
Light source lamp, 11a... Light emitting part, o... Reflector optical axis, 13... Ring-shaped auxiliary reflector, 14
...Central prism, 16...Transparent plate, 17...
Ring-shaped prism, 18... center reflector.

Claims (1)

[Scope of utility model registration request] In a light source device in which a light emitting part of a light source lamp is positioned on the focal point of a parabolic mirror reflector, light from the light source lamp is reflected by the reflector and parallel light parallel to the optical axis of the reflector is emitted. A ring-shaped light deflector is provided in front of the reflector to reflect or refract the light reflected at the outer peripheral edge of the reflector toward the optical axis of the reflector, and is located in front of the light source lamp on the optical axis of the reflector. The light source is characterized in that a small-diameter central light deflector is provided that refracts or reflects the light from the ring-shaped light deflector forward to produce parallel light parallel to the optical axis of the reflector. Device.