JPH03167520A - Light source device for liquid crystal projection device - Google Patents

Abstract

PURPOSE:To efficiently and effectively use light from a light source by inserting a collected light fiber between a concave mirror or a condenser lens and a liquid crystal display panel. CONSTITUTION:The collected optical fiber 15 obtained by collecting a large number of optical fibers and making them in a bundle state is provided in the middle of the concave mirror 6 and the liquid crystal display panel 3. The optical fiber 15 is housed in a frame or the like and maintained in the bundle state. Besides, the cross section shape thereof as a bundle is demarcated according to the shape of the frame. In such a case, the cross section shape of one end surface 15a of the optical fiber 15 faced to the concave mirror is made circular and the diameter thereof is made almost identical to the aperture 6' of the mirror 6. Simultaneously, the cross section shape of the other end surface 15b faced to the panel 3 is made rectangular whose size is almost identical to the panel 3. Thus, luminous flux projected from the concave mirror or the condenser lens is efficiently used and power consumption is saved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a light source device used in a liquid crystal projection device. [Prior Art] A transmissive liquid crystal projection device is known as a video projector that allows you to enjoy a large television screen. Such a liquid crystal projection device has a structure as shown in FIG. 5 in principle. That is, the light from the projection light source 1 is made into parallel light by the condenser lens 2 and illuminates the transmissive liquid crystal display panel 3, and the light that passes through this is refracted by the projection lens 4 to produce an enlarged image on the screen 5. image.

Next, FIG. 6 shows a liquid crystal projection device for obtaining color images. In this device, light emitted from a projection light source 1 is reflected by a concave mirror 6 and converted into parallel light by a condenser lens 2. Next, this parallel light beam is separated into blue component light, green component light, and red component light by the guichroic mirror 7 according to the following procedure. First, in the white light reflected by the concave mirror 6, some of the blue light is first reflected by the blue color 7b, is bent at a right angle and travels upward in the figure, and the remaining light travels straight and then red light. The light of the red precept is reflected by the mirror 7r and travels downward in the figure at a right angle. The remaining green component light passes through both the puller 7b and the red mirror 7r and travels straight. The reflected blue component light and red component light are each reflected by mirrors 8 and 9 placed at the top and bottom of the figure, and are bent at right angles again to become parallel to the green component light that has traveled straight. Go in the direction.

The light of each color divided in parallel in this way is transmitted to a transmission type liquid crystal display panel 3 r for each color provided at right angles to each optical path.
s 3 g s 3 t), and becomes liquid crystal transmitted light for, log, job having image information of each color. Among these, liquid crystal transmitted light Job, 1 with blue and red information
0r is reflected by the mirrors 11 and 12 and enters the optical path of the liquid crystal transmitted light 10g having green information, and is reflected by the guichroic mirrors 13 and 14 and all the liquid crystal transmitted light 1
0r, 10gt 10b overlap. Here, since the mirrors, liquid crystal display panels, etc. are arranged so that the optical path lengths from each liquid crystal display panel 3r, 3g, 3b to the projection lens 4 are all equal, information on each color incident on the projection lens 4 is stored. The light transmitted through the liquid crystal forms an enlarged color image on the screen 5.

In the above-mentioned liquid crystal projection device, in order to project a bright image on the screen 5, a powerful projection light source is essential, and the light emitted from the light source is used by condensing it into parallel light beams. are doing. For example, in the above-mentioned FIG. 6, parallel light rays are obtained by the concave mirror 6 and the condenser lens. Also, as shown in FIG. 7, a parabolic mirror 6 is used as the concave mirror 6.
Sometimes a is used. This takes advantage of the fact that if a light source is placed at the focal point of a parabola, the light will be focused and parallel rays will be obtained. Furthermore, in FIG. 8, the concave mirror 6
The ellipsoidal surface vL6b is used as the ellipsoidal surface vL6b. That is, a light source l@ is placed at one focal point of the ellipse, and the light beams are once converged at the other focal point, and then converted into parallel beams by the condenser lens 2.

On the other hand, since these projection light sources are powerful, they also generate a large amount of heat, so they can be cooled by a cooling fan or the like (not shown).

[Problem to be solved by the invention]

However, in the above-mentioned prior art, as shown in FIG. 9, a light beam with a circular cross-section along the aperture 6' of the concave mirror 6 comes from the light source, whereas the liquid crystal display panel 3 has a rectangular shape. As a result, a wasted luminous flux was generated that irradiated the outside of the panel 3. If the height-to-width ratio of a typical television screen is 3:4, approximately 40% of the total amount of light emitted from the light source is wasted. Therefore, in the past, the output of the projection light source l was set to be large in order to emit this extra luminous flux, and the cooling load was also large. [Object of the Invention] The present invention has been made in view of the above-mentioned facts, and it is an object of the present invention to propose a light source device for a liquid crystal projection device that can effectively use the light from the light source without wasting it. [Summary of the Invention] In order to achieve the above object, the present invention inserts a collective optical fiber between a concave mirror or a condenser lens and a liquid crystal display panel, and makes the cross-sectional shape of the projection light source side of the collective optical fiber opposite to each other. The liquid product display panel has a circular shape that is approximately the same size as the concave mirror or condenser lens, and the end face on the liquid product display panel side has approximately the same shape as the panel. Due to this ゜ζ
, the light beam coming from the entire surface of a concave mirror or condenser lens as a light source can be received by the circular end face, and the light can be made into a rectangular shape and irradiated onto the LCD screen without leaking to the outside, and the light beam emitted from the light source is not wasted. It can be used without any restrictions.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a projection light source placed at the focal point of a concave mirror 6. In this embodiment, since a parabolic mirror is used as the concave mirror 6, the concave mirror 6 directly reflects parallel light beams. 3 is a transmissive liquid crystal display panel. A collective optical fiber 15, which is a bundle of a large number of optical fibers, is provided between the concave mirror 6 and the liquid crystal display panel 3.

The collective optical fibers 15 are housed in a frame (not shown) to maintain a bundle shape, and the cross-sectional shape of the bundle is defined according to the shape of the frame. Therefore, the cross-sectional shape of one end face 15a facing the concave mirror of the collective optical fiber l5 is made circular so that its diameter is approximately the same as the aperture diameter 6' of the concave mirror 6, and the cross-sectional shape of the end face 15a facing the concave mirror 6 is made approximately the same, and the end face 15a facing the other liquid crystal screen display panel 3 is made circular. The end surface 15b has a rectangular cross-sectional shape that is approximately the same size as the liquid crystal screen display panel 3.

As shown in Figure 2, the optical fiber l6 is a double-layered glass or plastic fiber with a core 1
6a has a higher refractive index than the outside (cladding) 16b. Therefore, a light beam that enters the core 16a from one end of the optical fiber 16 at an incident angle within a predetermined range is
No matter how bent 6 is in the middle, there is no leakage along the way, and it reaches the other end while repeating total reflection.

Furthermore, the core has high transparency. For these reasons, optical path loss within the optical fiber can be ignored.

Therefore, by adopting the structure shown in FIG. 1, the reflected light from the concave mirror 6 can be received by the collective optical fiber 15 without waste, and all of the received light beam can be irradiated onto the liquid crystal display panel 3. Therefore, the output of the projection light source 1 can be lower than that of the conventional one, and the cooling load is reduced accordingly.

Furthermore, since the area of the concave mirror 6 and the area of the liquid crystal display panel 3 need only be made approximately equal, the aperture of the concave mirror 6 can be made small and can be manufactured at low cost. FIG. 3 shows an embodiment using a concave mirror and a condenser lens. An ellipsoidal mirror 6b is used as the concave mirror, and light from a projection light source l placed at one focus of the ellipse is focused on the other focus of the ellipse. By aligning the focal point of the condenser lens 2 with the other focal point of the ellipse, parallel light rays are emitted from the condenser lens 2 and illuminate the liquid crystal display panel 3 through the collective optical fiber 5. In this case, one end surface 15a of the collective optical fiber 15 is formed into a circular shape having approximately the same diameter as the condenser lens 2. The other end surface l5b has the same rectangular shape as in FIG. FIG. 4 shows an embodiment in which only a condenser lens 2 is used without using a concave mirror. The projection light source l is placed at the black spot of the condenser lens 2. In this case as well, one end surface 15a of the collective optical fiber 15 is formed into a circular shape having approximately the same diameter as the condenser lens 2. In the above embodiment, a transmissive type liquid crystal display panel 3 is used, but an anti-1/1 type liquid crystal display panel 3 can also be used.

In addition, concave mirrors include parabolic mirrors, ellipsoidal mirrors, and vI. It can be used regardless of the type. Furthermore, in the present invention, the incident light beam does not need to be a perfectly parallel light beam, but can be either a converging light beam or a divergent light beam, as long as the incident angle is within a range that allows the above-mentioned total reflection to be repeated within the optical fiber 16. It can also be used.

〔Effect of the invention〕

As explained above, according to the present invention, the projected light beam from the concave mirror or condenser lens can be used without wasting it, so the projection light source can be made with a lower output than conventional ones, the cooling load is also reduced, and the power consumption is reduced. You can save consumption. Furthermore, since the concave mirror or condenser lens can be made smaller, the cost of the liquid crystal projection device can be reduced, which is a special effect.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the configuration of a light source device for a liquid crystal projection device according to the present invention, FIG. 2 is a configuration diagram of an optical fiber, and FIG. 3 is another embodiment of the present invention, using a concave mirror and a condenser lens. Fig. 4 is a perspective view showing the structure of an embodiment using only a condenser lens without using a concave mirror; Fig. 5 is a diagram showing the principle of a liquid product projection device; Figure 6 is a diagram showing the configuration of a color liquid crystal projection device, Figure 7 is a diagram showing the configuration of an example of a conventional light source device for a liquid crystal projection device, and Figure 8 is a configuration diagram showing another example of a conventional light source device. 9 are diagrams showing the difference in shape between the liquid crystal screen and the light beam from the projection light source. 1... Projection light source, 2... Condenser lens, 3...
・Liquid crystal display panel, l5... collective optical fiber, 15a
... end face on the light source side, 15b... end face on the liquid crystal display panel side.

Claims (1)

[Claims] Consisting of a projection light source and a concave mirror or condenser lens that receives light from the projection light source, the light from the projection light source is focused by the concave mirror or condenser lens and irradiated onto a liquid crystal display panel,
In a light source device for a liquid crystal projection device that enlarges and projects an image on a liquid crystal display panel onto a screen, a collective optical fiber consisting of a bundle of optical fibers is arranged between the concave mirror or condenser lens and the liquid crystal display panel,
The cross-sectional shape of the collective optical fiber is made into a circle having approximately the same diameter as the concave mirror or condenser lens facing the projection light source side, while the cross-sectional shape of the collective optical fiber is approximately the same shape as the panel at the end facing the liquid crystal display panel. A light source device for a liquid crystal projection device, characterized in that: