JP2002099046A - Lighting device and image display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device and an image display having a compact constitution capable of displaying a bright color image with high quality. SOLUTION: A light source section 12 includes point light sources 20R, 20G, 20B emitting color light beams 71R, 71G, 71B that have mutually different wavelengths, and an objective lens 14 making these light beams parallel to each other. The lighting device 10 is constituted so that the light beams 71R, 71G, 71B emitted from the light source 12 are entered into a prism 40 with slightly different angles for the prism 40, and the color light beams 72R, 72G, 72B are emitted from the prism 40 in the identical directions. In this lighting device 10, a plurality of point light sources 20R, 20G, 20B can be located on adjoining positions. Therefore, the compact lighting device with high availability of light and the image display employing this lighting device can be provided at a low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device capable of performing color display using a point light source.

[0002]

2. Description of the Related Art In a conventional image display apparatus, two methods are mainly known for color display. One is a method of modulating each of the three primary colors of light using an image display element or an image display device (light valve) such as an LCD (liquid crystal panel), synthesizing using a dichroic prism, and displaying one image. (First method), such as a three-plate type projector device. The other is a method (second method) in which white light is time-divided into three primary colors using a rotary color filter or the like, and a light valve is modulated for each color in synchronization with the time-division (second method). is there.

[0003]

A projector 90 shown in FIG. 11 schematically shows the first method described above, and includes light sources 91R, 91G and 91B of three colors and light beams from these light sources. An objective lens 93 for collimating
A light valve for modulating light of each color, for example, L
It has CDs 50R, 50G and 50B and a dichroic prism 95 for synthesizing light of these colors. Then, the color image obtained by the color synthesis is converted into the projection lens 52.
Is projected on the screen 55 through the interface, and a desired color image is displayed.

In the projector 90, it is necessary to individually prepare the optical paths of the light of each color, and a large space is required. Further, the number of articles is large, and a complex dichroic prism for color synthesis is required for color synthesis.
Therefore, it is difficult to reduce the size of the projector.
It is also difficult to reduce costs.

On the other hand, the second method uses a common white light source,
Irradiation is performed on the rotary color filter 80 shown in FIG. 12, and the color filter 80 is rotationally driven by a motor (not shown) or the like, thereby performing time division into three primary colors. The color filter 80 includes a disk-shaped filter 82 and a filter 82R, 82G for each color radiating from a shaft hole 81 at the center of rotation.
And 82B are divided and arranged. Therefore,
In the method of displaying white light in a time-division manner by using a color filter, the light path of each color can be made common, and the light paths can be compactly integrated. Further, an expensive dichroic prism for color synthesis is not required.
Therefore, a small-sized and low-cost projector can be provided.

However, as shown by hatching in FIG. 12, when passing through the respective portions 84 near the boundaries of the filters 82R, 82G and 82B, the position of the light beam passing through the filters changes from the area 83a to the area 83c. At this time, when the state becomes like the area 83b, the colors are mixed.
For this reason, while the light beam (light flux) applied to the filters 82R to 82G passes through the areas 83a to 83c,
Image display needs to be turned off. Therefore, the screen is darkened only during the time when the light valve is turned off, and the light use efficiency is reduced. In addition, the color filter 80 also needs a motor for rotating itself, and requires a space therefor. Therefore, in that respect, the color filter 80 cannot be downsized. Noise). Further, since the intensity of the image for each color depends on the area of each color obtained by dividing the filter, it is difficult to perform color correction such as adjusting the intensity for each color depending on the characteristics of the light source and the characteristics of the light valve.

It is another object of the present invention to provide a lighting device and an image display device which can display a bright and high-quality color image at a low cost with a compact structure, high light use efficiency, and low cost. I have.

[0008]

Accordingly, in the present invention, in the optical element such as a prism or a diffraction grating, the property of dispersing white light at different angles depending on the wavelength is used in reverse, and the direction of dispersion is determined. By injecting the light flux of each color from an angle, on the output side of the optical element,
Light beams of different colors are emitted in the same direction or angle. That is, in the lighting device of the present invention,
An optical element for dispersing light from the first direction at an angle for each color corresponding to each wavelength, and a light source capable of entering a light beam having a different wavelength to the optical element at an angle for each color; It is characterized in that the direction of 1 is the light emission direction. In the illumination device of the present invention, light of different wavelengths, that is, light of different colors, is input from an angle of each color to an optical element that disperses light at an angle of each color, so that a common angle is obtained on the emission side. That is, a light beam can be emitted from the first direction.

Therefore, for example, by providing a light source for emitting the light beams of red R, green G and blue B at different angles for the respective colors, the illumination device emits the light beams of the respective colors from the first direction of the optical element. Equipment can be provided. On the other hand, since the difference of the angle (incident angle) of the light beam of each color of RGB with respect to the optical element is small, the light paths of each color are adjacent to each other.
Since the arrangement can be made to almost overlap, the lighting device can be designed to be compact. When the light beams of these colors are input simultaneously, white light can be emitted. On the other hand, when the light beams of red, green, and blue are sequentially incident, the light beams of the colors are sequentially emitted in the same direction. Equipment can be provided. Therefore, the lighting device of the present invention can output light of different wavelengths in the same direction without using an expensive dichroic prism, and further, does not require a rotating color filter to output light of each color. Parts such as are unnecessary. Therefore, a compact illuminating device capable of emitting light beams of different colors in the same direction can be provided at low cost.

Therefore, there is provided an image display device including the illumination device of the present invention, an image display device capable of modulating a light beam emitted from the illumination device, and a lens system for projecting light from the image display device. It is possible to provide a compact image display device at low cost. Further, the illumination device of the present invention, a light guide having a total reflection surface extending in the emission direction of the optical element, an image display device having a switching device for turning on and off light with respect to the total reflection surface, It is possible to provide an image display device having a lens system that projects light from the image display device, and a high-contrast, high-resolution image that can display an image by turning on and off evanescent light leaking from the total reflection surface. The image display device can be made compact and can be provided at low cost. In addition, when the lighting device of the present invention is employed, there is no mechanically moving part, so that there is no problem of noise and vibration. Further, if the timing of the light beams having different colors is controlled on the light source side, no color mixing occurs, so that
It is not necessary to turn off the image display device for a predetermined period in order to avoid color mixing of the image display device, and it is possible to provide an image display device such as a projector with high light use efficiency.

As the optical element, a low-cost optical element can be used as compared with a spectral prism capable of separating white light into monochromatic light, or a dichroic prism such as a diffraction grating capable of separating white light into monochromatic light. Further, by using the diffraction grating, a very thin and compact lighting device with good mass productivity can be provided. Furthermore, since the diffraction grating can improve the wavelength selectivity by blazing the incident surface irradiated with the light beam from the light source, it is possible to provide an illumination device and an image display device with high utilization efficiency.

Also, the lighting device of the present invention can control the color emitted on the light source side, unlike the lighting device in which the color is separated by a rotary color filter. Therefore, it is possible to change the emission time of at least one of the red, green, and blue light beams from the others, and to adjust the color tone according to the intensity characteristics of the light source, the characteristics of the image display device, and the like. Can be flexibly supported.

In the illuminating device according to the present invention, a light source that emits light beams having different wavelengths is provided on a direction normal to a plane of incidence on which light from the light source of the optical element is irradiated and a plane including the optical axis of the light. By arranging, light beams having different colors can be emitted in the first direction through the optical element. And since the difference in angle for each color is not so large, it is possible to compactly arrange a plurality of point light sources respectively emitting light beams having different wavelengths at an angle for each color according to the wavelength of the light beam emitted from these point light sources. Further, even when a lens system for collimating the light beams from them is arranged, one lens system can process the light beams from the point light sources. Therefore, a semiconductor light source such as an LED or a laser can be employed as a light source, and a very compact illumination device and an image display device using the same can be provided.

Further, in the illuminating device of the present invention, since the angle range in which these point light sources are arranged is not so wide, it is possible to arrange these point light sources on a common substrate and further reduce the number of parts. It is possible to provide a compact, low-cost lighting device and image display device that are reduced. Further, in addition to the point light sources, it is also possible to mount driving means for sequentially driving them on a common base, so that the number of parts can be further reduced, and the size and cost can be reduced.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a lighting device 1 according to the present invention.
1 shows a schematic configuration of a projector (image display device) 1 provided with a “0”. The projector 1 includes a lighting device 10 of the present invention and a liquid crystal panel that is an image display device that modulates a red light beam 72R, a green light beam 72G, and a blue light beam 72B sequentially emitted from the lighting device 10 in the same direction. (LCD) 50 and a lens system 52 for irradiating the screen 55 with a light beam 73 modulated by the LCD 50 and forming a color image on the screen.

The illumination device 10 of the present embodiment has a red light beam 71.
R, a light source unit 12 for emitting a green light beam 71G and a blue light beam 71B, and these light beams 71R, 71G and 7
1B is directed toward the LCD 50, and a light beam 72 parallel to the same direction.
A prism-shaped optical element 40 capable of emitting light as R, 72G, and 72B is provided. FIG. 2 shows a lighting device 1 of the present example.
0 is shown enlarged. First, the light source unit 12 emits a light beam having a spectrum having a different wavelength, that is, a red light beam 71.
R or three or three groups of semiconductor lasers 20R, 20G and 20B are arranged as point light sources of monochromatic light emitted from R, green light beam 71G and blue light beam 71B, respectively, by a method such as bonding to the surface substantially linearly. Semiconductor substrate 21 is provided. The semiconductor substrate 21 further includes these semiconductor lasers 20R, 20G and 20B.
Are sequentially driven, and the light fluxes 71R, 71G and 71B are sequentially turned on.
A driving circuit 17 for emitting light is formed, and a point light source and a circuit for driving the point light source are integrated on a substrate 21. Further, the light source unit 12 of the present example includes these point light sources 20R,
The light beams emitted from 0G and 20B, that is, a red light beam 71R indicated by a broken line and a green light beam 7 indicated by a dashed line
1G and a common lens (collimator lens) 14 that converts the blue light beam 71B shown by the solid line into a substantially parallel light beam at each output angle.

The optical element 40 of this embodiment has a triangular cross section.
This is a spectroscopic prism made of glass (SF ₃ ). Light beams 71R, 71G, and 71B converted into parallel light beams by the common objective lens 14 enter the incidence surface 42 of the prism 40 at slightly different angles. ing. These light beams 71R, 71G, and 71B propagate inside the spectral prism 40 and are refracted at angles corresponding to the respective wavelengths.
(Arrow A). That is, the luminous fluxes 71R, 71G of the respective colors incident at slightly different angles.
And 71B are all emitted in the same direction as parallel lights 72R, 72G and 72B by passing through the spectral prism 40 and supplied to the LCD 50.

As described above, in order for the light beams 72R, 72G and 72B of each color to be emitted from the prism 40 at the same angle, the emission direction A of the prism 40 and the emission surface 43
It is necessary to arrange the point light sources 20R, 20G and 20B in a direction or an angle at which the light beam of the color is incident on the incident surface 42. Although the angle differs depending on the luminous flux of each color, the difference depends on the apex angle of the prism 40, but is about several degrees. Conversely, the lasers 20R, 20G and 20B of each color may be installed adjacent to each other. It is also possible to swing the angle as much as possible. Therefore, in the light source unit 12 of the present example, the point light sources 20R, 20G, and 20B are formed by a surface perpendicular to the optical axis of the collimator lens 14,
That is, they are arranged close to the surface 21a of the substrate 21 in this order. Therefore, the light beams 71R, 71G, and 71 of the respective colors converted into parallel light beams by the collimator lens 14.
The angle (incident angle) at which B is incident on the incident surface 42 of the spectral prism 40 is smaller than the incident angle φR of the red light beam 71R.
The incident angle φG of the green light beam 71G becomes slightly larger, and the incident angle φB of the blue light beam 71B becomes slightly larger than this incident angle φG.

Therefore, the laser light sources 20R, 20G and 20B of the respective colors are arranged at appropriate intervals on the surface 21a of the substrate 21.
And further adjusting the angle and the distance between the substrate 21 and the incident surface 42 of the spectral prism 40 so that the luminous fluxes 72R, 72G and 72B of each color for color display are emitted from the prism 40 at the same angle. Can be.
For this reason, in the illumination device 10 of this example, the prism 4
It is possible to arrange the light beams 71R, 71G and 71B of each color so that they pass through almost the same light path on the incidence side of 0, and these light beams can be converted into parallel light beams using the common lens 14. Therefore, the space occupied by the optical path on the input side can be significantly reduced as compared with the system using the dichroic prism described above. further,
The collimator lens 14 can be shared, and the point light source 20
Since R, 20G and 20B can be arranged adjacent to each other, they can be arranged on a common substrate 21,
Can also be provided. For this reason, it is possible to greatly reduce the number of components constituting the lighting device 10, and the space for disposing them can be further reduced. Further, since the number of components is reduced and an expensive dichroic prism is not required, a compact illumination device 10 can be provided at low cost. Further, referring to FIG. The function of the optical element (spectral prism) 40 will be described in detail. In this figure, a prism having a right-angled triangular cross section is used as the optical element 4 in order to simplify the surface on which the light beam is refracted into one.
The example adopted as 0 is shown. Spectral prism 40
Has chromatic dispersion based on the refractive index of the material (glass in this example) that constitutes it, and the refractive index varies depending on the wavelength of light. Therefore, conversely, by entering the light beams (light rays) 71R, 71G, and 71B of each color into the spectral prism 40 at different incident angles φ, the directions of the light beams emitted from the prism 40 can be aligned in the same direction. it can.

The spectral prism 4 having a right-angled triangular cross section according to the present embodiment.
At 0, the emitted light fluxes 72R, 72G, and 72B of each color become the emission surface 43 by the refractive index η and the angle θ when the angle between the bottom surface 44 and the inclined surface (incident surface) 42 is the apex angle.
The condition of the incident angle φ emitted in the direction orthogonal to the direction is given by the following equation (1).

Sin φ = η · sin (90−θ) (1) For example, if the wavelength λR of the red light beam 71R, which is on the long wavelength side in the visible light region, is set to about 656 nm, the refraction of the glass at that wavelength The rate ηR is about 1.73,
Assuming that the apex angle θ of the spectral prism 40 is 70 °, the incident angle φ
R is about 36.3 °. For green and blue light, the incident angle φG is about 36.7 ° and the incident angle φB
Is about 37.4 °. On the other hand, when the vertex angle θ of the spectral prism 40 is 60 °, the incident angle φR is about 26.6 °, the incident angle φG is about 26.9 °, and the incident angle φB is about 27.3 °.

From these results, the luminous fluxes 71R, 7R of each color
1G and 71B are directed to the point light source 2 with respect to the spectral prism 40 such that the respective incident angles φR, φG and φB are within the range of a difference of about 1 ° or several degrees.
It can be seen that by arranging 0R, 20G, and 20B, outgoing light 72R, 72G, and 72B can be emitted in the same direction. Therefore, these point light sources 20R, 20R
It can be seen that, unlike the system using the dichroic prism shown in FIG. 11, G and 20B can be arranged at adjacent positions.

FIG. 4 shows the light source unit 1 of the illumination device 10 of the present embodiment.
2 shows an outline of the substrate 21 employed. Substrate 2
As described above, the point light source 20R, 2
0G and 20B are arranged at adjacent positions in this order. Therefore, these point light sources 20R, 20G
And 20B can be handled as one device. In addition to the space advantage, assembly and maintenance can be easily performed. In addition, in the illumination device 10 of the present example, it is necessary to accurately adjust the incident angle of the light beam of each color with respect to the prism 40, but by arranging these light sources on the same substrate 21, the adjustment can be easily performed. Point light source 20R, 20G
And 20B can be composed of edge emitting lasers or surface emitting lasers, and can also be composed of LEDs. It is possible to mount these light sources on the same silicon substrate or the like, or to directly provide them on a GaAs substrate or the like by a known technique.

Further, by using the semiconductor substrate 21, it is possible to simultaneously mount the circuit 17 for driving the light sources 20R, 20G and 20B on the substrate 21 in addition to the light sources 20R, 20G and 20B. . Then, the point light sources 20R, 20R of the respective colors are supplied to the drive circuit 17.
Drive circuit 18 for turning on and off each of G and 20B
R, 18G and 18B are provided, and the point light sources 20R, 20G and 20B can be sequentially driven as shown in FIG. Therefore, the luminous fluxes 72R, 72G, and 72B of the respective colors can be sequentially emitted from the illumination device 10 toward the LCD 50. For this reason, in the image display device 1, by controlling the LCD 50 which is a light valve so as to form an image of each color in synchronization with the timing at which light rays are emitted from each of the point light sources 20R, 20G and 20B, each color is controlled. An image can be projected on a screen and a multi-color image can be output. Since the light beams 72R, 72G, and 72B of each color can be output in a time-sharing manner on the light source unit 12 side, unlike the case using the color filter shown in FIG. No need to turn off. Therefore,
An image display device 1 with high light use efficiency can be provided.

Further, the lighting device 10 of the present embodiment can easily cope with color breakup. That is, if the same color image is displayed for a long time, the color may look blurred when viewed. To prevent such a phenomenon, it is desirable to display images of different colors in a short time in a time-sharing manner.
As the time division is increased, the loss of light increases, so that it is difficult to deal with color breakup. In contrast, when the lighting device 10 of the present example is adopted,
The time division can be increased or the division time can be shortened irrespective of the light loss. Therefore, the image display device 1 employing the illumination device 10 of the present embodiment can display an image that is color-separated at a high frequency so that color breakup does not easily occur.

In the illumination device 10 of the present embodiment, the time for turning on and off the point light sources 20R, 20G and 20B of each color can be freely adjusted by the driving means 17. For example, as shown in FIG. 5A, the point light sources 20R, 20G, and 20B of each color are turned on and off at the same interval (interval) from time t1 to t4, and the luminous flux of each color at the same irradiation time TR, TG, and TB. 72R, 72G and 72B can be emitted. On the other hand, FIG.
As shown in the figure, the lighting times TR, TG and TB of the respective colors can be changed by appropriately adjusting the lighting times t11 to t15.
It is possible to generate a color image with a more adjusted color tone by reflecting the characteristic of 0 or the like. For example, at present, the output of the blue semiconductor laser is insufficient.
By setting the lighting time TB of the blue point light source 20B to be longer than the lighting times of the light sources of the other colors, the output shortage can be compensated by the lighting time. Substrate 2 instead of lighting time
It is also possible to compensate the output with the number of light sources arranged in one.

Further, in FIG. 5B, at time t1
The time TW during which the three point light sources 20R, 20G, and 20B are simultaneously turned on is provided from 4 to t15, so that the white output light is supplied from the lighting device 10 to the LCD 50. Since this white light beam is also emitted in the same direction as the other single-color light beam 72R, the image display device 1 modulates the image with the common LCD 50, combines the monochrome image with the color image, and combines the monochrome image with the color image. Can be displayed. As described above, by providing a time period during which a white light beam is output, it is possible to display a high-luminance image, and to provide the image display device 1 capable of displaying a clear color image even in a bright indoor environment. it can.

In the lighting device 10 of the present embodiment,
By setting the driving circuit 17, the lighting time of each of the light sources 20R, 20G, and 20B can be flexibly controlled, and the white light beam as described above is irradiated in addition to the irradiation time of each color light beam. It is also possible to flexibly set the time to perform. Furthermore, these light sources 2
It is also possible to turn on any two of 0R, 20G, and 20B at the same time, irradiate the intermediate color light beam to the LCD 50, and display the intermediate color image. Illumination device 1 of this example
In the case of 0, even when mixing colors, the ratio and time can be clearly controlled, so unlike the case where color mixing occurs in the rotating color filter, actively use it for adjusting the color tone of the displayed image, etc. Is possible. In any case, it is possible to eliminate a light amount loss in a region where color mixing occurs by using a color filter, improve light use efficiency, and supply a bright image.

Also, unlike the rotary type color filter, the illumination device 10 of the present embodiment has no components that are driven to rotate, and a space necessary for the components to rotate, and a space for installing a motor to rotate. Can be eliminated, and the device can be compactly assembled, the number of parts can be reduced, and the device can be provided at low cost. In addition, noise generated when driving the color filter can be eliminated,
The quiet lighting device 10 and the image display device 1 can be provided.

As described above, in the illumination device 10 of the present embodiment, the point light sources 20R, 20G and 2
0B can be arranged adjacent to each other, and the light beams 71R, 71G and 71
The optical path of B can be arranged in almost the same space.
The light beams 72R, 72G and 72B emitted from the prism 40 are emitted from the same direction (arrow A) and
And so on. Therefore, the point light sources 20R, 20G
And 20B can be placed close to each other to make them compact, and the light beams 71R, 71G and 71B can be made common to the lenses 14 for converting them into parallel light beams. Then, light of each color can be synthesized without using an expensive dichroic prism. Therefore, it is possible to provide the lighting device 10 which has a small number of parts, is low in cost, and is easy to be compactly assembled.

In the illumination device 10 described above, the spectral prism 40 is used as an optical element having the ability to disperse color. However, another type of optical element may be used. FIG. 6 shows an illumination device 11 employing a diffraction grating 41 as an optical element. In the diffraction grating 41, a surface 41a serving as both an incident surface and an output surface is processed into a lattice shape with irregularities at a pitch d, and the surface 45a of the convex portion 45 that reflects light is blazed to obtain a desired surface. The intensity of the diffracted light in the direction can be increased. Diffraction grating 41
Similarly to the dispersing prism 40, the angle of the diffracted light changes according to the wavelength of the incident light.
Similarly to the case of 0, by appropriately setting the angle of the incident light beam, the emission directions of the light beams of each color can be made uniform. Therefore, as shown in FIG. 6, the light fluxes 71R, 71G, and 71B of the respective colors are incident on the diffraction grating 41 from the light source 12 at slightly different angles, so that different colors in the same direction A are emitted from the diffraction grating 41. Luminous flux 72R, 7
2G and 72B can be emitted, and can irradiate the LCD 50 as a light valve. The diffraction grating 41 of this example is blazed,
The intensity of the diffracted light in the emission direction A can be increased, and the illumination device 11 with high light use efficiency is realized.

FIG. 7 shows an enlarged part of the blazed diffraction grating 41 of this embodiment. Diffraction grating 41 of this example
In the example, the cross section of the protrusions 45 formed at a pitch d so as to form a lattice is blazed and thus has a triangular shape. When the angle (blaze angle) α of the surface 45a of the convex portion 45 is α, the relationship between the incident angle i and the output angle θ of the light beam with respect to the normal L to the surface 41a of the diffraction grating 41 is given by the following equation (2). The relationship between the incident angle i and the output angle θ for obtaining the primary light is given by the following equation (3).

Θ = i−2α (2) sin θ−sini = −λ / d (3) In this equation (3), the direction of the primary light depends on the wavelength λ of the light beam. By setting appropriate incident angles iR, iG, and iB for each color, the emission direction of the primary light of the light flux of each color can be made uniform. In this case, the difference between the incident angles iR, iG and iB is about several degrees. Therefore, in the lighting device 11 of the present example, the point light sources 20R, 20G, and 20B can be disposed adjacent to each other, similarly to the lighting device 10 that employs the prism 40 as an optical element, and is a compact and low-cost lighting device. Can be provided. Further, similarly to the lighting device 10 using the above-described spectral prism 40, a point light source such as a laser can be disposed on the semiconductor substrate 21 to be monolithic, and the drive circuit 17 can be mounted on the substrate 21. Benefits can also be obtained. Further, the driving method of the light source 12 is the same, and the image display device 1 employing the illumination device 11 of the present embodiment can display a high-quality color image with high light use efficiency and a bright and well-tuned color tone. .

Further, the diffraction grating 41 employed in the illuminating device 11 of this embodiment is an optical element which is extremely thin and has high productivity. Therefore, more than the above-mentioned lighting device 10,
A low-cost and compact lighting device 11 can be provided.
Further, by blazing the diffraction grating 41, it is possible to provide the illumination device 11 and the image display device 1 using the illumination device 11, which have higher light use efficiency than the case where a flat surface diffraction grating is employed.

FIG. 8 shows an image display device 2 different from the example shown in FIG. The image display device 2 differs from the image display device 1 shown in FIG. 1 in that an evanescent device 60 is employed as a light valve, and light beams 72R, 72G, and
2B is guided and modulated.

FIG. 9 shows an outline of the evanescent device 60. The device 60 is an image display device which can modulate and emit light using an evanescent wave (evanescent light) which is being developed by the present applicant.
The optical switching device 65 includes a plurality of optical switching elements 100 arranged two-dimensionally, and furthermore, the optical switching device 65 has a substantially flat total reflection surface 101a capable of totally reflecting and transmitting the introduced light 72R and the like. Is mounted. These individual optical switching elements 100 are formed on a substrate 120, and are capable of modulating light by approaching and separating from an upper light guide 101, and an actuator 106 for driving the optical element 103. And The optical switching element 100a shown on the left side of FIG.
0b is off. The optical element 103 includes a surface (contact surface or extraction surface) 103a that is in close contact with a surface (total reflection surface) 101a of the light guide 101, which is a transparent member that functions as a waveguide, and the surface 103a is formed as a total reflection surface 101a. The evanescent wave that leaks out when it comes into close contact is extracted and internally reflected in a direction substantially perpendicular to the light guide 101.
A V-shaped reflecting prism (microprism) 104 and a support structure (supporting portion) 105 for supporting the V-shaped prism 104 are provided.

The actuator 106 includes the optical element 103
Can be electrostatically driven, and the upper electrode 107 to which the support structure 105 of the optical element 103 is mechanically connected.
And a lower electrode 108 facing the upper electrode 107. The lower electrode 108 and the anchor plate 109 of the upper electrode 107 are connected to the uppermost surface 120 of the semiconductor substrate 120.
a. The upper electrode 107 is supported by a post 111 extending upward from the anchor plate 109, and a space is formed between the lower electrode 108 and the upper electrode 107. Therefore, for example, by applying an appropriate voltage to the upper electrode 107 and the lower electrode 108 via the anchor plate 109, the second position where the optical element unit 103 is separated from the light guide 101 and the optical element unit 103
Can be driven to the first position in close contact with the light guide 101.

In the switching element 100a, when the optical element 103 is at the first position in contact with the total reflection surface 101a of the light guide 101, the surface 103 of the optical element 103
By using a, evanescent waves leaked from the total reflection surface 101a can be extracted. Then, V of the optical element 103
Light beam 7 extracted by the letter-shaped microprism 104
The angle of 2R or the like is changed to become the emitted light 72Ra. On the other hand, in the optical switching element 100b, the optical element 103
Is located at the second position away from the light guide 101, the evanescent wave is not extracted by the optical element 103, and the light beam 72R and the like do not exit from the inside of the light guide 101. As described above, even if the evanescent device 60 of the present example is used, the light beam can be modulated and emitted, and the light beams 72R, 72G, and 72B of different colors can be emitted from the image display device 2 employing the evanescent device 60 as well. Are sequentially incident and modulated, so that a color image can be projected on the screen 55.

FIG. 10 shows an enlarged schematic configuration of the illumination device 13 used in the image forming apparatus 2 of this embodiment. The end face 102 of the light guide 101 of the evanescent device 60 is inclined to enter the light beam at a critical angle or less so as to be totally reflected on the total reflection surface 101a. 102 is used as an incident surface of the light beams 71R, 71G and 71B of each color,
Light beams 71R, 71G at slightly different angles from light source unit 12
And 71B, so that the light beams 72R, 72G and 72B of the respective colors can be aligned and supplied in the direction of the total reflection surface 101a. Therefore, in the image forming apparatus 2 of the present example, the end portion of the light guide 101 functions as the prism 40 of the above-described illumination device 10, and conversely, the prism 40 is extended, and the optical switching device 65 is extended. Function as a light guide 101 for supplying illumination light 72R, 72G, and 72B of each color.

Therefore, like the image display device 2 of the present embodiment, the optical switching device 60 is connected to the lighting device 1 of the present invention.
3 and the point light sources 20R and 20G so as to be incident at a slightly different angle toward one spectral prism 40 which also functions as a light guide.
And 20B can be placed adjacent to each other. For this reason, also in the illumination device 13 and the image display device 2 of this example, the illumination device 13 can be very compactly assembled, and the number of components can be reduced and the cost can be reduced. Further, the same effects as those of the above-described illumination device 10 and the image display device employing the same can be obtained, for example, the light use efficiency can be improved, and the light source can be mounted on one monolithic substrate. Further, in the image display device 2 of this example, since the evanescent device 60 capable of turning on and off light mechanically is employed as a light valve, LC
It can be driven at a higher speed than D50 and can display an image with high contrast. Therefore, when used in combination with the illumination device 13 of the present embodiment, it is possible to provide the projector device 2 that can display a clear, high-resolution color image that is brighter and has no problems such as color breakup.

In FIG. 8, the optical switching device 60 for extracting evanescent light is described as an example.
By combining the lighting device of the present invention with another switching device, for example, a micromirror device or the like,
Similarly, it is possible to provide an image forming apparatus such as a projector apparatus which can display a bright, high-quality color image at a high speed at a low cost, with high light use efficiency, and at a low cost.

[0042]

As described above, the illuminating device of the present invention uses optical elements such as a prism or a diffraction grating which chromatically disperses incident light at an angle corresponding to its wavelength, and emits light beams of each color. Are incident at slightly different angles of incidence, so that the luminous flux of each color is emitted in the same direction and at the same angle. Therefore, in the illuminating device of the present invention, a plurality of light sources that output luminous flux of each color can be arranged at adjacent positions, and a light source and an optical path of the luminous flux of a plurality of colors required for color display can be arranged compactly. . Furthermore, an expensive dichroic prism, a rotating color filter and a motor for driving the same are not required, and a compact lighting device capable of emitting a light beam of each color toward a single light valve at a lower cost. Can be provided. Furthermore, in the lighting device of the present invention, white light and intermediate colors, including monochromatic light, can be flexibly emitted by controlling the incoming light beams or light sources of different colors in a time-division manner, such as a liquid crystal panel. In combination with a light valve, an image display device capable of outputting a bright, high-quality, beautiful color image suitable for a projector or the like can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing an outline of a projector using a lighting device of the present invention.

FIG. 2 is a diagram showing an outline of the lighting device shown in FIG.

FIG. 3 is an enlarged view showing a direction of a light beam in the lighting device shown in FIG. 2;

FIG. 4 is an enlarged view showing a light source unit of the illumination device shown in FIG. 2;

FIG. 5 is a diagram illustrating an example of a timing at which a light flux of each color is output in the lighting device illustrated in FIG. 1;

FIG. 6 is a diagram showing an outline of an illumination device different from the illumination device shown in FIG. 1 and an image display device using the illumination device.

7 is a diagram showing a relationship between an incident direction and an outgoing direction in the diffraction grating shown in FIG.

FIG. 8 is a diagram showing an outline of an image display device using an image display device different from the projector shown in FIG.

FIG. 9 is a diagram showing an outline of an evanescent device.

10 is an enlarged view showing a lighting device of the image display device shown in FIG.

FIG. 11 is a diagram showing an outline of a conventional image display device using a dichroic prism.

FIG. 12 is a diagram showing an outline of a conventional color filter used for color display.

[Explanation of symbols]

1, 2 Image display device (projector) 10, 11, 13, 90 Illumination device 12 Light source unit 14 Parallel lens 17 Driving means 18 Point light source circuit 20 Point light source 21 Semiconductor substrate 40 Spectral prism 41 Diffraction grating 50 Liquid crystal panel 52 Projection lens 55 Screen 60 Evanescent device 65 Optical switching device 71R, 71G, 71B Incident light of each color collimated 72R, 72G, 72B Luminous flux (emission light) of each color output from optical element

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 9/31 G02F 1/1335 530 F-term (Reference) 2H052 BA02 BA03 BA09 BA14 2H088 EA13 EA15 EA18 HA13 HA23 HA24 HA28 MA05 MA06 2H091 FA19Z FA21Z FA26X FA26Z FA45Z FD01 GA11 LA15 LA18 5C060 DA04 EA01 GA02 GB01 GB06 HC01 HC09 HD00 HD07

Claims (13)

[Claims] An optical element for dispersing light from a first direction at an angle for each color corresponding to each wavelength, and a light beam having a different wavelength can be incident on the optical element at the angle for each color. And a light source, wherein the first direction is an emission direction of the light beam. 2. The method according to claim 1, wherein the light source is red,
An illumination device that emits green and blue light beams. 3. The lighting device according to claim 2, wherein the red, green, and blue light beams are sequentially emitted. 4. The lighting device according to claim 3, wherein the red, green, and blue light beams have different emission times of at least one color light beam. 5. The optical element according to claim 1, wherein the optical element includes an incident surface to which a light beam from the light source is irradiated, and a direction normal to the incident surface and a direction including a light axis of the light beam. A lighting device in which the light source is arranged. 6. The lighting device according to claim 1, wherein the optical element is a spectral prism that can split white light into monochromatic light. 7. The lighting device according to claim 1, wherein the optical element is a diffraction grating that can separate white light into monochromatic light. 8. The lighting device according to claim 7, wherein the diffraction grating has an incident surface to which a light beam from the light source is irradiated, and the incident surface is blazed. 9. The light source according to claim 1, wherein the light source includes a plurality of point light sources that respectively emit the light beams having different wavelengths, and a lens system that makes the light beams parallel. An illuminating device arranged such that light beams from the respective point light sources enter the optical element at angles corresponding to the colors corresponding to the wavelengths of the light beams emitted from the point light sources. 10. The lighting device according to claim 9, wherein the point light source is disposed on a common substrate. 11. The lighting device according to claim 9, wherein the point light sources and driving means for sequentially driving the point light sources are mounted on the common substrate. 12. An illumination device according to claim 1, an image display device capable of modulating a light beam emitted from the illumination device, and a lens system for projecting light from the image display device. An image display device comprising: 13. The lighting device according to claim 1, a light guide including a total reflection surface extending in an emission direction of the optical element; and a light guide for the total reflection surface. An image display device, comprising: an image display device including a switching device for turning on and off a lens; and a lens system that projects light from the image display device.