JP2000180962A - Projection illuminating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection illuminating device which can improve efficiency for utilizing light in an illumination system. SOLUTION: This projection illuminating device uses a light emitting diode(LED) 1 as a light source. A transparent block 10 is positioned so as to be closely adhered to the light emitting diode(LED) 1. Also, angle distribution of a light beam emitted to the block 10 from the light emitting diode(LED) 1 is 0 to 90 degrees. A shape of the block 10 for taking this all light beams and containing angle distribution of outgoing light within the prescribed angle distribution is a shape of curved surface having spread of a parabolic surface. Also, a cross-sectional shape of an incident end and an outgoing end are similar to a shape of an element to be illuminated (in this case: optical modulation element 8).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a projection lighting device. More specifically, the present invention relates to a projection illuminating device in which a cross-sectional area of an emitting end is larger than a cross-sectional area of an incident end, and an incident end is brought into close contact with a light source to improve light use efficiency in an illumination system. .

[0002]

2. Description of the Related Art The configuration of a conventional projection lighting apparatus using a light emitting diode (LED) as a light source is shown in FIG.
There is an example as shown in FIG. In the figure, a ball lens 2 attached to a light emitting diode (LED) 1 is used for increasing the amount of light emitted from the light emitting diode (LED) 1 into the air. The coupling lens 3 takes in a part of the light beam emitted from the ball lens 2 and collimates (in parallel) to the next integrator (multi-lens array) 5
The incident light beam. Integrator 5
Is to illuminate uniformly on an object to be illuminated by causing each lens of the multi-lens array to function as a light source even if there is unevenness in light emission intensity due to the location of the light source.
The condenser lens 6 is provided to form a light source image at an entrance pupil position of the projection lens 9. Further, the dichroic prism 4 may be located between the integrator 5 and the coupling lens 3 in order to obtain a white color by combining a plurality of light sources.

Here, a description will be given of a ratio of a light beam emitted from a light emitting diode (LED) to enter a coupling lens. The angle distribution of the light beam emitted from the light emitting diode (LED) has a spread of 0 to 90 °. In order to capture all of these rays into the coupling lens, a lens with an infinite aperture is required.

In the configuration shown in FIG. 10, there are ten interfaces between the optical component and the air to the illuminated object. That is, when the dichroic prism 4 is excluded and considered, the interface between the ball lens 2 and air, the interface between the plane side of the coupling lens 3 and air, the interface between the curved surface side of the coupling lens 3 and air, and the multi-portion on the left side of the integrator 5 The interface between the left and right curved surfaces of the lens array and the air, the interface between the left curved surface of the multi-lens on the right side of the integrator 5 and the air, the right curved surface of the left lens of the condenser lens 6 and the air, and the interface of the condenser lens 6 The interface between the left curved surface and the right plane of the right lens and the air, and the interface between the air on the surface of the deflection beam splitter 7 facing the condenser lens 6 and the air.

[0005]

As described above, a lens having an infinite aperture is required to capture all light rays emitted from a light emitting diode (LED) into a coupling lens. However, in a conventional projection illumination device, the numerical aperture (NA) is limited to about 0.9, and the luminous flux that can be captured by the coupling lens is limited to about 80%.

In the configuration shown in FIG. 10, the interface between the optical component and the air up to the illuminated object is ten. In such a case, even when the antireflection treatment is performed, a surface reflection loss of about 15% occurs. Therefore, there is a problem that the light use efficiency of the illumination system is limited to about 65% even if the effects of the dichroic prism and the light absorption of each optical component are excluded.

[0007] The present invention has been made in view of such problems, and an object of the present invention is to provide a projection lighting apparatus capable of improving the light use efficiency in an illumination system.

[0008]

SUMMARY OF THE INVENTION A projection illuminating apparatus according to the present invention has a block in which the cross-sectional area of the exit end is larger than the cross-sectional area of the entrance end, and the entrance end is in close contact with the light source.

According to the projection illumination device of the present invention, the cross-sectional area of the exit end is made larger than the cross-sectional area of the entrance end.
In addition, by bringing the incident end into close contact with the light source, it is possible to efficiently take in the light flux from the light source, collimate, and average out the unevenness of the light source.

Further, in the projection illuminating device of the present invention, the cross-sectional shape of the entrance end and the exit end is made similar to the shape of the object to be illuminated, the cross-sectional area of the exit end is made larger than the cross-sectional area of the entrance end, and Has a block in which is adhered to a light source.

According to the projection illuminating device of the present invention, the above-described configuration is further made similar in cross-sectional shape at the entrance end and the exit end to the shape of the object to be illuminated. Light can be eliminated. it can.

[0012]

Embodiments of the present invention will be described below. Here, an embodiment of the invention relating to a projection lighting device will be described with reference to FIGS. FIG. 1 shows a configuration example of a projection illumination device according to the present invention. The projection lighting device in the figure uses a light emitting diode (LED) 1 as a light source. The light source of the projection lighting device according to the present invention is not limited to a light emitting diode (LED), but can be applied to other light sources such as a laser diode (LD), a lamp such as a metal halide lamp, and a mercury lamp. .

A transparent block 10 is located in close contact with the light emitting diode (LED) 1. In addition, as a material of the block 10, an acrylic resin, glass, or another transparent material can be used. In the block 10, the cross-sectional area of the light-emitting end 10b is larger than the cross-sectional area of the light-entering end 10a. Further, the cross-sectional shapes of the incident end and the output end are circular or similar to the illuminated object (here, the light modulation element 8).

In the case of the embodiment of the present invention, a light source of one light emitting diode (LED) of three colors of red, green and blue (RGB) is synthesized by a dichroic prism 4, and a single reflection type light modulator 8 is formed. Lighting configuration is adopted.

The block 10 is made of a material having substantially the same refractive index as that of the block 10, and is bonded to the light source of the light emitting diode (LED) 1 on the incident end side. The exit end of the block 10 is in close contact with the dichroic prism 4. Also at this time, the block and the refractive index are adhered by a material which is almost the same. This is to suppress light loss due to reflection at the entrance end side and the exit end side of the block 10 due to the difference in refractive index.

Further, a plano-convex lens is adhered to the exit side end face of the dichroic prism 4. Also, a plano-convex lens is closely attached to the incident side of the polarizing beam splitter (PBS) 7. In this case, it is desirable to use a material having substantially the same refractive index for each optical component and to use an adhesive having a close refractive index for close contact.

The optimum cross-sectional shape of the block 10 according to the present invention is represented by a function of the coordinates of the light beam traveling direction. This will be specifically described. The refractive index of the block is smaller than the refractive index of the substrate used for the light emitting diode (LED) 1. The angle distribution of the light emitted from the light emitting diode (LED) 1 to the block 10 has a distribution of 0 to 90 °. As shown in FIG. 2, the shape of the block 10 for capturing all the light rays and for keeping the angular distribution of the emitted light within a predetermined angular distribution is as follows.
The curved surface has a parabolic spread. For example, if a material having a refractive index of 1.5 is used, the width in the X-axis direction at the entrance end is 2, and the maximum angle on the exit end side is 6.6 ° (10 ° in air), the X-axis direction at the exit end Is 8.7. The curved surface shape is represented by the following equation.

[0018]

(Equation 1)

Here, Z and X indicate coordinate axes in FIG. In the case of the above conditions, the constants k1 to k5 are 2.52, 0.23, -3.52, -4.26,
It is 0.01. The critical angle at the interface between a material having a refractive index of 1.5 and air is 42 °, but in this curved shape, all rays refracted at the interface with the light emitting diode (LED) 1 satisfy the total reflection condition.

When the cross-sectional shape of the entrance end and the exit end of the block 10 is circular as shown in FIG. 3, the central axis in the longitudinal direction of the block 10 is set to the Z axis, and an arbitrary straight line orthogonal to the central axis is set to X. Axis.

When the object to be illuminated is rectangular, and as shown in FIG. 4, when the cross-sectional shape of the input end and the output end of the block 10 is a rectangle similar to the object to be illuminated, the curved surface shape is the long side of the rectangle. , Changes on the short side. For example, if the width of the incident end in the X-axis direction is 3.2, the width of the output end in the X-axis direction is 13.9 and the total length is 140. The previous constant k1
To k5 are 4.03, 0.23, −9.01,
-6.81 and 0.01.

Similar to a general rod integrator, by guiding the block 10 of the present invention, this block 1
0 has the function of an integrator. In other words, even when the light source has uneven brightness depending on the location, it can be made uniform on the emission end face.

The degree of uniformity can be increased by increasing the block length while keeping the width of the emission end in the X-axis direction. In designing the shape of the block, the total length can be determined according to the degree of unevenness in brightness.

Since only this block has the functions of efficiently taking in the light flux from the light source, collimating, and averaging the unevenness of the light source among the functions required for the projection lighting apparatus, the number of parts can be reduced.

The reduction in the number of parts means that the number of interfaces with air is also reduced, so that the loss of surface reflection can be suppressed and the overall light use efficiency can be increased. In the case of the configuration shown in FIG. 1, the number of interfaces between the optical component and the air up to the illumination target is two. That is, there are an interface between the left lens and the air in the condenser lens and an interface between the right lens and the air in the condenser lens.

The light loss up to the illuminated object excluding the light absorption of the block material and the reflection loss of the dichroic prism is ideally about 3%. In addition, by making the cross-sectional shapes of the entrance end and the output end of the block similar to the shape of the illuminated object, light emitted from the dichroic prism can be effectively illuminated on the illuminated object, and the cross-sectional shape is reduced. It is possible to eliminate useless light generated in the case of a circular shape.

FIG. 5 and FIG. 6 can be considered as modified examples of the curved surface shape of the block when the cross-sectional shape of the input end and the output end of the block is rectangular. That is, in the example of FIG. 5, the cross section of the block is divided into several taper portions from the incident end side to the output end side and is reduced, and in the example of FIG. It is something to do.

In the example of FIG. 6, a light emitting diode (LED) 1
When the light rays incident from the block are reflected by the side surface of the block, the light does not necessarily satisfy the condition of total reflection, so that a slight light leakage occurs on the side surface, but the collimation function and the integrator function are not impaired. In addition, the curved surface shape modification of the block is not limited to those illustrated in FIGS. 5 and 6. That is, by making the cross-sectional area of the emission end 10b larger than the cross-sectional area of the incident end 10a, the block 10 can ensure efficient light flux capture from the light source, collimation function, and integrator function.

It should be noted that the present invention provides a configuration in which there is no dichroic prism between the block 10 and the condenser lens 6 as shown in FIG. 7 or a dichroic prism by using a light emitting diode (RBG) as shown in FIG. , A configuration using a transmissive light modulation element as shown in FIG. 9, and a configuration not using polarization for the light modulation element, for example, a digital mirror device (DMD), a polymer dispersed liquid crystal (PDLC), or The present invention can be applied to any projection device such as a configuration using a diffraction grating.

Further, the block according to the present invention is not limited to the size used in the above description. That is, the size of the block is of the order of several tens to several μm, and it goes without saying that it can be applied as an element on a semiconductor chip.

As described above, according to the embodiment of the present invention, the light use efficiency in the illumination system can be improved. That is, efficient light flux capture from the light source,
The collimation function and the integrator function can be secured. Further, the number of parts can be reduced, and the cost can be reduced. Further, space saving can be achieved. Further, according to the embodiment of the present invention, the above-described effects can be obtained, and the light use efficiency in the illumination system can be further improved. That is, the light emitted from the dichroic prism can be effectively illuminated on the object to be illuminated, and unnecessary light generated when the cross-sectional shape is circular can be eliminated.

It should be noted that the present invention is not limited to the above-described embodiment, but can adopt various other configurations without departing from the gist of the present invention.

[0033]

The present invention has the following effects. By making the cross-sectional area of the exit end larger than the cross-sectional area of the entrance end and bringing the incident end into close contact with the light source, the light use efficiency in the illumination system can be improved. Further, the cross-sectional shape of the incident end and the outgoing end is made similar to the shape of the illuminated object, the cross-sectional area of the outgoing end is made larger than the cross-sectional area of the incident end,
In addition, by bringing the incident end into close contact with the light source, the above-described effects can be achieved, and the light use efficiency in the illumination system can be further improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the invention relating to a projection lighting device.

FIG. 2 is a cross-sectional view showing a traveling state of light in a block used in the projection lighting device.

FIG. 3 is a perspective view showing an example of a block in a case where a cross-sectional shape of an entrance end and an exit end is circular.

FIG. 4 is a perspective view showing an example of a block in a case where a cross-sectional shape of an entrance end and an exit end is rectangular.

FIG. 5 is a perspective view showing another example of the block when the cross-sectional shape of the incident end and the exit end is rectangular.

FIG. 6 is a perspective view showing another example of the block when the cross-sectional shape of the incident end and the exit end is rectangular.

FIG. 7 is a diagram illustrating an example of a projection device having a configuration in which a dichroic prism is not provided between a block and a condenser lens.

FIG. 8 is a diagram illustrating an example of a projection device having a configuration in which a dichroic prism is not used by using a light emitting diode (RBG).

FIG. 9 is a diagram showing an example of a projection device having a configuration using a transmission type light modulation element.

FIG. 10 is a diagram showing an example of a conventional projection device.

[Explanation of symbols]

1 light emitting diode, 2 ball lens, 3 coupling lens, 4 dichroic prism, 5 integrator, 6 condenser lens, 7 deflection beam splitter, 8 light modulation element, 9 {Projection lens, 10} block, 10a {incident end, 10b}
Emission end, 11 ° transmission type light modulation element

Claims (2)

[Claims] 1. A projection illuminating apparatus comprising: a block having a cross-sectional area of an emitting end larger than a cross-sectional area of an incident end, and having a block in which the incident end is in close contact with a light source. 2. A block in which the cross-sectional shape of the entrance end and the exit end is similar to the shape of the object to be illuminated, the cross-sectional area of the exit end is larger than the cross-sectional area of the entrance end, and the entrance end is in close contact with the light source. A projection lighting device, comprising: