JP2001042431A - Light source device and projector device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a compact light source device using a semiconductor light emitting element such as an LED(light emitting diode) and having both of light quantity and luminance being sufficient for practical use. SOLUTION: A dichroic mirror 19 is constituted so that a light having a specified wavelength area out of the visible light is reflected and the light having the other wavelength area is transmitted. Then, luminous flux 21 and 22 emitted from the LED11 and the LED12 and provided with wavelength (λ1) and (λ2) interposing the selective boundary wavelength (λ0) of the mirror 19 as the peak wavelength are synthesized and outputted by the mirror 19. Since the luminous flux from the plural kinds of LEDs or LED groups can be synthesized without changing the cross section area of the emitted luminous flux, the compact light source device which can emit the high-luminance luminous flux is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source device using a semiconductor light source such as an LED and used for a projector or the like.

[0002]

2. Description of the Related Art An LED element (light emitting diode) generally has a longer life than a bubble lamp, and further has advantages such as high conversion efficiency into light. Therefore, in recent years, in many lighting application fields, it has been studied to replace a light source with a light source using a LED element from a pable lamp.

[0003] A single LED element emits a small amount of light. Therefore, in an application field requiring a relatively large amount of light, such as a light source of a projector device, the light source device 90 shown in FIG.
As described above, a required amount of light is secured by arranging a large number of LED elements 91 in a planar manner. Further, particularly in a projector device, a light source device having a large absolute light emission amount (luminous flux: Q) of a light source and a light amount per unit solid angle, that is, luminous intensity (I), and Requires a light source device having a high luminance, which is a luminous intensity per unit area in a specific direction.Therefore, in such an application field, a light beam emitted from a large number of LED elements 91 as a light emitting source is required. It is necessary to increase the luminance by condensing a light beam having a small cross-sectional area by condensing light with a condensing optical system 95 using a lens, for example, in the light source device 90 shown in FIG. To prevent divergence by further arranging a microlens 92, and converge each light beam thus obtained by a converging positive lens 93.
A condensing optical system 95 for converting a parallel light beam by a negative lens 94 is provided. After using such a large number of lenses to form a condensed light beam of high brightness, the light beam 97 is converted to an LCD.
(Liquid crystal panel) 96 or a light valve such as a DMD (digital micromirror device) is irradiated and modulated to form an image for projection.

[0004] Due to its characteristics, an LED is a light-emitting element that emits a monochromatic light beam having a relatively narrow bandwidth centered on a peak wavelength, has a high on-off response, and has an effect on the life even when it is repeatedly turned on and off. There is almost no. Therefore, LEDs for emitting red (R), green (G), and blue (B) light beams are arranged, light sources of three primary colors are provided, and projection is performed through an LCD that generates an image of each color. A projector that projects a color image on a screen can be configured. Alternatively, a color image can be generated by irradiating one LCD in a time sharing manner with light sources of three primary colors.

[0005] By employing an LED light source, troubles such as a burnout of a light bulb can be eliminated, so that a maintenance-free projector device can be realized. Further, if the LED light source is used, the brightness can be easily adjusted, so that a projector device with stable performance can be provided.

Furthermore, since the amount of heat generated is not large as compared with the halogen lamp, the cooling structure of the light source is greatly simplified. As described above, the advantage obtained by changing the light source from the halogen lamp or the like to the LED light source in the projector device is very large.

[0007]

As described above, a large amount of light required by distributing or dispersing a large number of LED elements along a plane perpendicular to the optical axis of the illumination light (condensed light beam) is required. (Luminous flux) can be secured, and the luminance can be increased by employing a condensing optical system. However, since a large number of LED elements are arranged in a plane according to the amount of light and the luminance, the light source device becomes large. This tendency will be improved if the amount of light emission is increased by improving the LED elements.However, in order to obtain a light amount equivalent to that of the current halogen lamps, a large number of LED elements are required, and these must be arranged on a substrate or the like. Therefore, a larger area such as a halogen lamp is required.

As described above, since the light emission amount of each LED element is small, the luminance of the light emitting portion is low even if the LED elements are arranged in a plane, so that a condensing optical system using a plurality of lenses or microlenses is used. It is necessary to increase the brightness using. For this reason, the size of the light source device including the optical system becomes large. In addition, the cost is increased by adding a microlens or another lens, and cost competitiveness with respect to a light source device such as a halogen lamp cannot be obtained.

Furthermore, various losses occur at the stage of condensing the light beam emitted from the LED element by an optical system or the like, so that the light use efficiency is reduced.

Therefore, the LED element itself is a monochromatic light source having a long life and high luminous efficiency while being small in size and low in cost. Regardless, it has not yet reached a stage where it is generally used as a light source for a projector or other illumination system.

Therefore, the present invention provides a compact light source device capable of emitting light of a single primary color having a sufficient amount of light and luminance sufficient for practical use by using a semiconductor light emitting element such as an LED element having many such advantages. It is intended to be. It is another object of the present invention to realize a low-cost, compact, and high-luminance white light source device using the light source device of the present invention. Another object of the present invention is to provide a projector device that is compact and requires no maintenance using the light source device of the present invention.

[0012]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a plurality of types of LEDs having slightly different emission spectral ranges that emit light within a light spectral range that the human naked eye perceives as a single primary color. A semiconductor light source such as a device is prepared. The light emitted from the semiconductor light-emitting source is synthesized by a wavelength-selective optical element such as a dichroic mirror capable of separating adjacent light-emitting spectrum regions, thereby projecting illumination emitted from the light source device. The cross section of the light beam is prevented from increasing.

That is, the light source device of the present invention reflects an optical element that reflects light in a specific wavelength region of visible light and transmits light in another wavelength region, and a boundary wavelength at which the reflectance characteristic of this optical element changes rapidly. And first and second semiconductor light-emitting sources respectively emitting first and second light fluxes having first and second wavelengths sandwiching the boundary wavelength near the boundary between the first and second semiconductor light sources. 2 is a light source device that combines and emits two light beams by an optical element.

In a semiconductor light source such as an LED, light sources having different peak wavelengths and half widths can be manufactured by changing the components and the like. Therefore, humans perceive as almost a single color, for example, about 10
It is possible to prepare a light source having a plurality of peak wavelengths within a wavelength range (optical spectrum region) of about 0 nm. In the present invention, attention is paid to such characteristics of the semiconductor light source, and luminous fluxes emitted from a plurality of light sources are combined using a delicate difference in the center wavelength (peak wavelength). Therefore, it is possible to combine a plurality of light beams into one with an optical element having wavelength selectivity. For this reason, in the light source device of the present invention, the arrangement of the semiconductor light sources can be divided into a plurality of groups and arranged three-dimensionally, so that the degree of freedom of light source arrangement is increased and the degree of integration can be greatly improved.

Further, since the brightness of a light beam can be increased by a wavelength-selective optical element such as a dichroic mirror, for example, a complicated installation using a combination of a plurality of lenses conventionally used to reduce the cross-sectional area of the light beam. It is not necessary to use a condensing optical system requiring a space. Of course, a lens system may be used to collect a light beam input / output to / from an optical element such as a dichroic mirror, and such a light source device is also included in the present invention.
In the present invention, the brightness of a light beam is not increased by the lens system alone, but is increased by combining the light beam with an optical element having wavelength selectivity. For this reason, in the light source device of the present invention, the arrangement of the semiconductor light source is not limited to fit the system of the light collecting optical system (refractive optical system or geometrical optical system) such as the focal length of the lens. And the degree of integration can be greatly improved. Therefore, it is possible to provide a light source device that is compact, emits a large amount of light, and can emit a light beam with high luminance. Further, since the light-collecting optical system combining a plurality of lenses can be omitted or simplified, the cost can be reduced. In addition, since a light-collecting optical system combining a large number of lenses can be omitted or simplified, a loss associated therewith can be reduced, and a light source device with high light use efficiency can be provided.

Therefore, according to the present invention, it is possible to provide a light source device which is compact, emits a large amount of light, and can emit a light beam of high luminance. Since the physical spread of the light source of the light source device can be small, the light use efficiency when the light beam emitted from the optical device of the present invention is used by the condensing illumination optical system or the like can be increased.

As described above, in the light source device according to the present invention, light beams in narrow emission spectrum regions having different peak wavelengths sandwiching the boundary wavelength of the optical element can be combined and emitted. And a light source device that emits a light beam having a high luminance in substantially a single color, in particular, a single primary color can be provided. By setting the boundary wavelength to a wavelength corresponding to a red, green, or blue spectral region, it is possible to provide light source devices that emit high-luminance luminous fluxes of three primary colors.

Since the light source device of the present invention can increase the luminance, the semiconductor light source is suitable for a light source device using a low-cost LED (light emitting diode). Furthermore, when an SLD (Super Luminescent Diode, Super Emitting Light Emitting Diode) is employed, the light emitting element has a strong directivity of the emitted light, so that the luminance of the emitted light beam can be further improved. Further, even if a light source having a near peak wavelength is selected, the emission spectrum width is narrow, so that a component that causes loss by a wavelength-selective optical element such as a dichroic mirror can be reduced. Further, the first and second semiconductor light sources may be constituted by a single semiconductor light emitting element, but in many cases, a plurality of semiconductor light emitting elements having the same peak wavelength in order to obtain a sufficient amount of light. Are desirably arranged to constitute each semiconductor light source. One of the advantages of the light source device of the present invention employing a semiconductor light source is that a light source having the same wavelength characteristic can be easily obtained.

A dichroic mirror or a dichroic prism is suitable as an optical element having wavelength selectivity and capable of synthesizing a light beam. By transmitting the light beam of one wavelength and reflecting the light beam of the other wavelength by these optical elements, a plurality of light beams can be synthesized without increasing the cross-sectional area of the emitted light beam (synthesized light beam). Further, this kind of optical element is not limited to one, and it is also possible to combine three or more light beams having different wavelengths in a narrow range of a spectral region using a plurality of optical elements.

As described above, in the present invention, it is possible to emit a high-luminance luminous flux of a single color, particularly a single primary color, corresponding to or near the boundary wavelength of an optical element by using a semiconductor light-emitting element such as an LED. . Therefore, the first, second, and third light source devices whose boundary wavelengths correspond to red, green, and blue, respectively, are provided, and a light source device that emits white light by combining and emitting light beams emitted from these light source devices. Can be provided. Since the first, second, and third light source devices emit a light beam with high light intensity and high luminance while being compact, they are combined to form white light, thereby achieving high light intensity with high light intensity while being compact. It is possible to provide a light source device that emits light beams of luminance. This light source device can further emit strong light close to a halogen lamp,
Since the LED is a light emitting source, the light source has characteristics such as low heat generation, low power consumption, and long life, so that it can be used in various applications such as headlights of automobiles.

Further, in the projector, it is possible to employ the first, second and third light source devices as a light source of projection light projected through a light valve. And the light source device using the semiconductor light source of the present invention,
Since a compact and high-intensity light can be emitted, it is possible to provide a compact and bright projector that uses a semiconductor light source and that does not have broken balls and requires no maintenance.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a light source device according to the present invention. The light source device 10R illustrated in FIG. 1 is a light source device that emits a red R light flux 20R. Therefore, two types of LED elements that emit light of slightly different peak wavelengths [lambda] 1 and [lambda] 2 within a visible light spectrum region (generally, a range of about 600 to 700 nm) visible to the eye as red light R (hereinafter referred to as "red light R") LED) 11 and 12 and a dichroic mirror 19 that combines the light beams 21 and 22 emitted from the LEDs 11 and 12 to obtain an emitted light beam 20R.

In the light source device 20R of this embodiment, the dichroic mirror 19 has the characteristic that the transmittance fluctuates abruptly at a wavelength λ0 which is approximately halfway between the wavelengths λ1 and λ2. Of light. Therefore, the light beam 21 from the LED 11 is reflected by the dichroic mirror 19, and the light beam 22 from the LED 12 passes through the dichroic mirror 19. For this reason, by disposing the LED 11 and the LED 12 at positions relatively rotated by 90 degrees, for example, and disposing the dichroic mirror 19 at a 45-degree angle as shown in FIG. Can be synthesized by the dichroic mirror 19 to obtain an emitted light beam 20R. The light source device 20R of the present example further includes
A collimator lens 15 is provided in front of each of the LEDs 11 and 12 for converting a light beam emitted from each of the LEDs 11 and 12 into a parallel light beam and supplying the parallel light beam to the dichroic mirror 19.

FIG. 2 shows the light source device 10R used in the present embodiment.
The wavelength characteristics of the LEDs 11 and 12 are shown.
First, the wavelength characteristic (emission spectrum curve) of the light beam 21 emitted from the LED 11 is as shown by a solid line 21a.
The peak wavelength λ1 is 623 nm, and the half width is 15 nm. The wavelength characteristic (emission spectrum curve) of the light beam 22 emitted from the other LED 12 has a peak wavelength λ2 of 660 nm and a half-value width of 25 nm as shown by a solid line 22a. As such LEDs 11 and 12, for example, TLSE series LEDs (InG
aAlP) and TLUR series LED (G
aAlAs). Therefore, when these LEDs 11 and 12 are used, a light source having a spectral region which is viewed as a substantially single red color and whose light amount is substantially the sum of the light emission amounts of the respective LEDs can be obtained.

The transmission characteristics of the dichroic mirror 19 are as follows:
In FIG. 2, this is indicated by a dashed line 19a. As described above, the dichroic mirror 19 of the present example has a boundary wavelength (selection boundary wavelength) at which the transmission characteristic (or the reflectance characteristic) changes abruptly.
λ 0 is the center wavelength λ 1 and λ 2 of the light beams 21 and 22
640 nm, which is about the middle of
It is designed to be. Therefore, the luminous flux 21
Most of the light is reflected by the dichroic mirror 19, and most of the light flux 22 passes through the dichroic mirror 19. However, each of the luminous fluxes 21 and 2
2 intersects the transmittance curve 19a of the dichroic mirror 19, the peak wavelength .lambda.
The parts of the spectral range opposite to 1 and λ2 are cut off by dichroic mirror 19. However, the portion cut by the dichroic mirror 19 is very small, and the transmittance (or reflectance) of the dichroic mirror 19 can be as high as about 90%, so that the loss due to the dichroic mirror 19 is very small. You can think.

Therefore, the luminous fluxes 21 and 22 are synthesized by the dichroic mirror 19, and a curve 20a shown in FIG.
It is possible to obtain an emitted light beam 20R having a twin-peak wavelength characteristic as shown in FIG. That is, it is possible to obtain a light flux 20R having a center wavelength near the selection boundary wavelength λ0 (640 nm) of the dichroic mirror 19 and two peaks of the emission spectrum each having a width of about 20 nm on both sides. In the light source device 10R of this example, the LED 12
Based on the light beam 22 emitted from the LED 11, the light beam 21 of the LED 11 can be synthesized without changing the cross-sectional area of the projection illumination light (emitted light beam) 20R from the LED 12 viewed from the optical axis direction. Therefore, since the light amount can be approximately doubled without changing the cross-sectional area of the light beam, the luminance of the emitted light beam 20R can be approximately doubled as compared with the case where only the LED 12 is used. Therefore, by supplying the light beam 20R emitted from the light source device 10R of the present example to the LCD 8R that generates a red image, a high-brightness projected image can be formed.

Further, in the light source device 10R of the present embodiment, the LEDs 11 and 12, which are light emitting sources, are arranged not at a plane but at a position turned by 90 degrees. Therefore, the installation area (arrangement area) of the light emitting source when viewed from the axial direction of the emitted light beam 20R is about half that when the LEDs 11 and 12 are arranged on the same plane.

In the light source device 10R of this embodiment, except for the collimator lens 15, a light-collecting optical system combining a large number of lenses is used in order to combine the light beams 21 and 22 from the LEDs 11 and 12. Instead, a plurality of light fluxes 21 and 22 are synthesized only by the dichroic mirror 19. As described above, the light-gathering optical system can be omitted for synthesizing the light beam, and the light-gathering optical system is generally complicated and expensive, and can easily take up space. It can be made compact and can be provided at low cost.

Further, since the light emitted from these LEDs 11 and 12 does not need to be collected and combined by the lens system inside the light source device 10R, there is no loss in the process, and the light emitted from the LEDs 11 and 12 is eliminated. The efficiency of use of the luminous flux can be increased. Therefore,
With the light source device 10R of this example, it is possible to provide a light source device using an LED that is compact, low-cost, and can emit monochromatic light with sufficient light quantity and luminance sufficient for practical use.

FIG. 1 shows an example in which one LED 11 and one LED 12 are arranged one by one.
Plural LEDs having the same characteristics as LED 11 and LED 12
May be arranged in a plane or in a curved state in accordance with the characteristics of a collimator lens or the like. Also, in the example shown in FIG.
D12 is arranged at a position turned by 90 degrees, but the angle formed by each LED11 and LED12, or LE
Multiple LEs showing D11 and LED12 as representatives
The angle (relative angle) formed by the group consisting of D is 90
Not limited to the degree, it is sufficient that the light beam reflected by the dichroic mirror 19 is arranged at an angle that overlaps with another light beam transmitted through the dichroic mirror 19.

For example, as shown in FIG. 4, when the angle θ of the dichroic mirror 19 is larger than 45 degrees with respect to the axial direction of the light beam 22 of the LED 12, the LED 11 and L
The relative angle formed by the ED 12 is greater than 90 degrees,
Further, the area where the light beam 21 of the LED 11 is projected in the direction of the light beam 22 transmitted through the dichroic mirror 19 is reduced. For this reason, the area where the plurality of LEDs 11 are arranged can be increased, the light amount at the time of emission of the light beam 21 can be increased, and the luminance at the combining point can be higher than that at the emitted point. Therefore, the intensity (luminance or light concentration) of the light beam 21 in the combined light beam 20R synthesized by the dichroic mirror 19
Becomes larger than the light flux 22. On the other hand, if the angle θ of the dichroic mirror 19 is smaller than 45 degrees with respect to the axial direction of the light beam 22, the relative angle between the LED 11 and the LED 12 becomes smaller than 90 degrees, and the light beam 21 of the LED 11 moves in the direction of the light beam 22. The projected area increases. Therefore, the luminance of the light beam 21 is synthesized lower than that of the light beam 22. Thus, the dichroic mirror 19
, The arrangement of the LEDs 11 and 12 or a plurality of LEDs represented by them can be freely designed, and the dichroic mirror 19
When the light beams 21 and 22 are combined, the brightness of the light beams 21 and 22 from the LEDs 11 and 12 can be adjusted.

Further, since the positional relationship between the LEDs 11 and 12 with respect to the dichroic mirror 19 changes, this also affects the size of the light source device 10R. For example, if the angle θ of the dichroic mirror 19 is larger than 45 degrees, LE
Since D11 and D11 can be arranged rearward with respect to the emission direction of the light beam 20R, the light source device 10R can be shortened with respect to the emission direction.

Further, as shown in FIG. 5, the LEDs 11 are arranged in two groups, upper and lower, that is, two groups arranged in the directions of plus 90 degrees and minus 90 degrees with respect to the LEDs 12, and emitted from these. The light flux is reduced by a dichroic mirror 19 inclined at 45 degrees in each direction.
It is also possible to combine with the light beam from ED12. By employing such an arrangement, the light source device 10R can be shortened in the emission direction of the light beam 20R.

A dichroic prism is known as an optical element having a boundary wavelength λ0 similarly to the dichroic mirror 19, and the light source device of the present invention can be realized even if a dichroic prism is used instead of the dichroic mirror 19. Multilayer interference film (dichroic film)
By using these optical elements provided with wavelength selectivity by, for example, it is possible to flexibly arrange LEDs.

In the light source device according to the present invention, the LE
D11 and 12, and LE represented by these
The arrangement of the D groups is not limited to the above example.
However, as can be seen from the above example, the arrangement of the LEDs becomes very flexible, and is not limited to a flat surface as in the conventional lighting device. Therefore, it is possible to arrange the number of LEDs required to obtain a luminous flux of a desired light amount and luminance with a high degree of integration,
It is possible to provide a compact semiconductor light source capable of obtaining high-intensity light and high-luminance emission light.

In the above example, the illumination device emits a red R light beam. However, similarly, an illumination device that emits another primary color, that is, a green G light beam or a blue B light beam can be configured. For example, in a light source device that emits green G,
Similarly, by selecting a plurality of types of LED elements having slightly different peak wavelengths in a region of about 490 to 550 nm as a semiconductor light emitting source and using a dichroic mirror having a boundary wavelength λ0 between those peak wavelengths. In addition, it is possible to obtain a green synthetic light beam with high radiance. Further, in a light source device that emits blue light B, by selecting a plurality of types of LED elements having slightly different wavelength peaks in a region of about 430 to 460 nm as a light emitting source, a blue light having a high radiance is similarly obtained. Can be obtained.

Further, in the above description, the light beams emitted from the two types of LEDs are combined. However, if there is an LED having an appropriate emission spectrum, the light beams emitted from the three or more types of LEDs are similarly combined. Is possible. FIGS. 6 to 8 show light source devices for synthesizing light beams emitted from three types of LEDs. The light source device 10R of the present example is also a light source device that emits a red R light beam. In the light source device 10R, as the semiconductor light source, an LED 111 having a peak wavelength λ11 of 636 nm and a half-value width of 17 nm, an LED 112 having a peak wavelength λ12 of 612 nm and a half-value width of 15 nm, and a light source device having a peak wavelength λ2 of 660 nm and a half value of 660 nm. The LED 12 having a value width of 25 nm is used. The dichroic mirror 19 having a boundary wavelength λ01 of about 645 nm
1 and light fluxes 22, 211 and 21 emitted from these LEDs 12, 111 and 112 using a dichroic mirror 192 having a boundary wavelength λ 02 of about 620 nm.
2 are synthesized. As an LED having such an emission spectrum, a TLSU series LED manufactured by Toshiba Corporation is used for the LED 111, and an LED 112 is used for the LED element 112.
The company's TLOU series LED and LED12
Can use TLUR series LED manufactured by the company.

As shown in FIG. 7, in this light source device 10R, three types of light fluxes 22 (spectrum 22a) and 211 (spectrum 21) whose peak wavelength difference Δλ falls within 48 nm.
1a) and 212 (spectrum 212a) are synthesized,
An outgoing light flux 20R (spectrum 20a) having a spectrum as shown in FIG. 8 can be obtained without increasing its cross-sectional area. Therefore, although depending on the amount of light emitted from each of the LEDs 12, 111, and 112, a light flux having a luminance of about three times less than that of a light source device in which a single LED is arranged in a plane can be obtained. Specific LED as above
In the light source device in which the LED 12 is selected, the amount of radiation from the semiconductor light source can be reduced without changing the cross section of the emitted light beam (the cross-sectional area perpendicular to the optical path of the projected illumination light beam) as compared with the case where the LED 12 is used alone. , The radiance of the emitted light beam also increases by about 2.5 times.

Of course, if it is possible to select appropriate LEDs having four or more different peak wavelengths within the wavelength range that can be regarded as the same primary color, those LEDs or Ls can be selected in the same manner as described above.
By combining the light beams emitted from the ED group, a high-intensity and compact light source device can be realized. Further, even in a light source device that synthesizes a light beam from these three or more types of LEDs, the degree of freedom in arranging the LEDs is large, and the arrangement variation described above is of course possible.

Further, the semiconductor light source is not limited to the LED,
An LD element (super-emission light emitting diode element, hereinafter SLD) can also be adopted. As shown in FIG.
LDs have a narrower emission spectrum bandwidth than ordinary LEDs. Therefore, it is possible to select a type with more different peak wavelengths than LEDs in a narrow spectral range, with a single primary emitted from a larger number of semiconductor light sources with slightly different emission spectral ranges. It can be synthesized with a light beam. Therefore, it is possible to provide a light source device that can emit a light beam with higher luminance.

Further, since the divergence angle of the emitted light is small in the SLD, it is easy to increase the light collection and transmission efficiency of the luminous flux emitted from the SLD. Therefore, the light source device itself can be made more compact. In addition, since the emission spectrum bandwidth of each SLD is narrow, the light is cut off by a dichroic mirror or the like when a light beam from an SLD having a peak wavelength adjacent to the boundary wavelength λ0 of a dichroic mirror or a dichroic prism is synthesized. The spectral range becomes very small. Therefore, the light use efficiency is further improved.

As described above, according to the present invention, it is possible to realize a light source device using a compact semiconductor light source, which can emit monochromatic light of high luminance. Semiconductor light sources have high conversion efficiency to light and low heat output. Although it has a long life and has many advantages such as good control response, it has a disadvantage that it is difficult to increase the energy density when seeking high luminance. The problem was solved. Therefore, the light source device according to the present invention can be applied to all application fields in which a halogen lamp or the like is used as a light source, in particular, fields in which heat generation is small and a high-luminance light source is required.

FIG. 10 shows outgoing lights 20R, 20G and 20 of red light R, green light G and blue light B according to the present invention.
Three light source devices 10R, 10G and 1 capable of emitting B
The white light source device 2 using 0B is shown. The light source device according to the present invention can emit high-luminance light even with a light flux of a color other than these three primary colors. However, considering that white or all other colors can be expressed by additive color mixing, a light source device that emits monochromatic light of these three primary colors is the most useful as a light source device to which the present invention is applied.

In the white light source device 2 of this embodiment, the light fluxes from the light sources 10R, 10G and 10B of these three primary colors are dichroic having an appropriate wavelength between red R, green G and blue B as a boundary wavelength. The light is synthesized by the prism 7 and radiated to the outside via the emission lens 5. Of course, it is also possible to combine the light beams from the light source devices 10R, 10G and 10B by other optical systems. For example, if two dichroic mirrors or prisms are used, the light beams from these light source devices can be sequentially combined. The white light source device according to the present invention can of course be applied to general lighting and the like, but can obtain a compact and high-luminance white light flux, so that it can be used for spotlights, car headlamps, and even backlights for liquid crystal displays. Are suitable.

FIG. 11 shows the outgoing lights 20R, 20G and 20B of red light R, green light G and blue light B according to the present invention.
Light sources 10R, 10G and 10 capable of emitting light
1 shows a liquid crystal projector 1 using B. The projector 1 shown in FIG. 11 is of a three-plate type, and has a light flux 20 emitted from the light source devices 10R, 10G, and 10B.
R, 20G and 20B are modulated by corresponding light valves, in this example, LCDs 8R, 8G and 8B, and synthesized by a dichroic prism 7 and then emitted by a projection lens or lens system 6 to project a color image on a screen 9. I do.

In recent years, there has been a demand for a compact, bright and quiet projector device as a presentation device or a large-screen TV device. Since the light source device of the present invention can emit a light beam of a single primary color with high compactness and high brightness, it is suitable for a projector device of such a demand. Furthermore, since a semiconductor light source is employed, the light conversion efficiency is high and the amount of heat generation is small, so that noise due to a cooling fan or the like can be reduced. Since the lamp has a long life, there is no need to worry about broken balls unlike a halogen lamp, and a maintenance-free projector can be provided. Therefore, by employing the light source device of the present invention, a compact and low-cost projector device suitable for home use or portable use can be provided.

The projector employing the light source device according to the present invention is not limited to the one shown in FIG. For example, the light source device 1 of three primary colors is substantially the same as the white light source shown in FIG.
0R, 10G and 10B are arranged to guide the emitted light beam to a common LCD, and these light source devices 10R, 10G and 1B are arranged.
If the lighting of 0B is controlled in a time-division manner and the LCD displays an image for each color in synchronization with it, a single-plate type projector can be configured. In addition, LCD
DMD that forms images by mechanically changing the direction of light reflection using micromachine technology instead of (liquid crystal panels)
It is also possible to provide the light source device of the present invention to a projector using (digital micromirror device) as a light valve. The DMD has a faster response speed than a LCD and can obtain a bright image, and thus is suitable for realizing a more compact, high-brightness, high-quality projector.

[0048]

As described above, the light source device according to the present invention utilizes a plurality of luminous fluxes having slightly different peak wavelengths obtained from a semiconductor light emitting device such as an LED device by utilizing a slight difference between the peak wavelengths. Then, they are synthesized by a wavelength-selective optical element such as a dichroic mirror. Therefore, a semiconductor light source such as an LED element can be three-dimensionally arranged from a planar arrangement to increase the degree of integration, and a compact semiconductor light source device with high luminance and large output can be provided. Furthermore, by using an SLD element instead of an LED element, a light source with higher luminance can be made compact.

As described above, according to the present invention, a semiconductor light emitting device which is a single-color light emitting source which is small in size and low in cost, has a long life, and has high luminous efficiency can be used. Since a compact light source device that can emit light of primary colors can be realized, a high-brightness white light source device and a compact and maintenance-free projector device can be provided by the present invention.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a light source device according to the present invention.

FIG. 2 is a diagram showing wavelength characteristics of the monochromatic light source device shown in FIG.

FIG. 3 is a diagram showing a spectrum obtained by combining light from two light sources in FIG. 2 with a dichroic mirror.

FIG. 4 is a diagram showing another example of the light source device.

FIG. 5 is a diagram showing still another example of the light source device.

FIG. 6 is a diagram showing still another example of the light source device.

FIG. 7 is a diagram illustrating a wavelength characteristic of the light source device illustrated in FIG. 6;

FIG. 8 is a diagram showing spectra obtained by combining light from the three light sources in FIG. 7 with a dichroic mirror.

FIG. 9 is a diagram schematically illustrating a characteristic difference between an LED and an SLD.

FIG. 10 is a diagram showing an example of a white light source device using the light source device of the present invention.

FIG. 11 is a diagram showing an example of a projector using the light source device of the present invention.

FIG. 12 is a diagram showing an example of a light source device using a conventional LED element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Projector 2 White light source device 6 Projection lens (projection lens system) 7 Dichroic prism 8 Liquid crystal light valve (LCD) 9 Screen 10 Light source device 11, 12 LED element 19 Dichroic mirror 20 Outgoing light flux (combined light flux) 21, 22 LED light flux

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H088 EA15 HA13 HA23 HA24 HA28 MA20 5C058 EA01 EA12 EA26 EA27 EA51 5C060 BC01 EA01 HC01 HC09 HC21 HD07 JB06 5F041 AA04 AA14 EE25 FF01

Claims (6)

[Claims] 1. Reflecting light in a specific wavelength region of visible light,
An optical element that transmits light in another wavelength region, and first and second light sources having first and second wavelengths near the boundary wavelength where the reflectance characteristic of the optical element changes abruptly and having the first and second wavelengths interposed therebetween. And a first and a second semiconductor light-emitting source for emitting the respective light beams, and combining and emitting the first and second light beams by the optical element. 2. The light source device according to claim 1, wherein the boundary wavelength is a wavelength corresponding to red, green or blue. 3. The light source device according to claim 1, wherein the semiconductor light emitting source is a light emitting diode or a super-emitting light emitting diode. 4. The light source device according to claim 1, wherein the optical element is a dichroic mirror or a dichroic prism. 5. The light source device according to claim 1, wherein the boundary wavelength is a first light source device having a wavelength corresponding to red, and the light source device according to claim 1, wherein the boundary wavelength is The second light source device having a wavelength corresponding to green, and the light source device according to claim 1, wherein the third light source device has a boundary wavelength corresponding to blue, and the first, second, and third light sources. An optical system that combines the light fluxes emitted from the light source devices and emits white light. 6. The light source device according to claim 1, wherein the boundary wavelength is a first light source device having a wavelength corresponding to red, and the light source device according to claim 1, wherein the boundary wavelength is The second light source device having a wavelength corresponding to green, and the light source device according to claim 1, wherein the third light source device has a boundary wavelength corresponding to blue, and the first, second, and third light sources. 3. A projector device comprising: at least one light valve for modulating a light beam emitted from each of the light source devices of No. 3; and a projection lens for projecting light modulated by the light valve onto a screen.