JP2003287805A - Illuminator and color wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color recapture type illuminator with high chroma by preventing an output of white light. <P>SOLUTION: A color wheel 40 provided with dichroic films 41R to 41B of each color is arranged at the opening 23 of an emission side of the integrator 20 of the color recapture mode illuminator 10. Reflection films 43 are formed in the adjacent regions 42 of the dichroic films 41R to 41B of each color of the color wheel 40, thereby light 71 is not transmitted but reflected toward the integrator 20 side. Transmission of white light through the color wheel 40 is thus prevented, and the light reflected in the adjacent regions 42 can be reused by the integrator 20, thereby light use efficiency is improved. A projector to display the high chroma and a high contrast color image is provided without sacrificing brightness by adopting the illuminator 10. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color wheel used for a color recapture type illumination device.

[0002]

2. Description of the Related Art An image display device such as a so-called single-plate type projector having an optical system for time-divisionally modulating light from one light source is a rotary type color filter.
It is equipped with a color wheel (color filter) that selectively transmits or absorbs white light and time-divides it into three primary colors, and an integrator that makes the intensity distribution of light uniform, and a time-divided light flux is a micromirror. Color modulation is performed with a light valve such as a device, and the result is projected on a screen to synthesize a color image.

[0003]

On the other hand, 200
1 year SID color recapture type optical system 4
0.2 "Sequential Color Recapture and Dynamic Fil
tering A method of Scrolling color ”has been proposed. In the color recapture type optical system, instead of a color filter, a semi-transmissive dichroic film (mirror) that transmits a specific color and reflects light of another color is combined in an appropriate shape such as a spiral shape. A color wheel is used. The dichroic film of each color performs color separation and reflects the light that does not pass through to the incident side. Therefore,
By arranging an integrator equipped with a reflective structure that re-irradiates the color wheel on the light source side of the color wheel, light that does not pass through the dichroic film (filter) of the color wheel is returned to the integrator without being discarded.
It is reflected multiple times in the integrator and is irradiated again on the color wheel. Then, at that time, if the dichroic films of different colors are transmitted and output, the light that does not pass through the color wheel is used. Therefore, the loss of light is reduced, and the light utilization efficiency can be improved compared to the optical system using the conventional color filter.By adopting the color recapture type optical system, it becomes clearer and brighter. It is possible to provide an image display device that displays various multi-color images.

FIG. 20 is an enlarged view of a state of the color wheel 140 arranged so as to face the opening 23 on the exit side of the integrator 20 of the color recapture type illumination device 100. A white light 71W propagating inside the integrator 20 is color-separated by the color wheel 140, output, and emitted to the light valve 52 through the relay lens 51, whereby a multi-color image can be displayed. At this time, in the boundary or adjacent portion 142 of the dichroic films 141R, 141G and 141B of the respective colors of the color wheel 140, the dichroic films 141R to 141B are adjacent to each other, but as shown in FIG. The gap W is formed so that the end portions of the films do not overlap. Therefore, the end portions of the dichroic films 141R to 141B are formed in an edge shape. Since the light 71W is also output to the adjacent portion 142 from the emission side opening 23 of the integrator 20, the light 71W passing therethrough is not color-separated, that is, is supplied to the light valve 52 as white light and projected. This causes a reduction in the saturation of the image. Further, since a color image cannot be obtained even when white light is switched, it is a factor that substantially reduces the aperture ratio of the light valve 52. Therefore, even if the color recapture type illuminating device 100 is adopted, it is difficult for an image display device to display a clear color image that makes the most of the advantage of high light utilization efficiency.

Further, as shown in FIG. 22, considering the wavelength characteristics (transmission amount) of the dichroic films 141R, 141G and 141B of the respective colors, the dichroic films 14 of the respective dichroic films 14R, 141G and 141B are considered.
Since the central portion of 1R to 141B is formed to have a predetermined uniform film thickness, as shown by the solid line, a very high color separation performance of about 95 to 99% is achieved with respect to a light beam passing through that portion. Show. However, in the adjacent region 142, the edge of the dichroic film has an edge-like thin portion 141R.
Since light passes through t, 141Gt, and 141Bt, even if they are color-separated, as shown by the alternate long and short dash line,
Only a low color separation performance of 50% or less can be obtained. And
Light passing through the gap W is not color-separated at all. Therefore, the light 71 is output without being color separated in the gap W, and passes through the color wheel 140 without being clearly separated at the ends of the dichroic films 141R to 141B and is reflected by the color wheel 140. The amount of light returned to the integrator 20 is reduced. Thus, due to the effect of the border or adjacent area 142, less light is available at the light valve 52 and less light is recaptured. Therefore, the processing of the adjacent region 142 becomes an important factor for further improving the light utilization efficiency in the color recapture type optical system.

Therefore, in the present invention, in the illumination device or the image display device using the color recapture method,
An object of the present invention is to provide an illuminating device and a color wheel capable of displaying a bright, high-saturation, high-quality color image with higher light utilization efficiency.

[0007]

Conventionally, in a color filter that performs color separation in an optical system, it is necessary to increase the area through which light is transmitted as much as possible in order to increase the light utilization efficiency. The design is being done.
On the other hand, in the color wheel of the color recapture method, even if the light is not transmitted, if the light is reflected in the direction of the integrator, the utilization efficiency of the light is not significantly lowered. Therefore, considering that the efficiency of use of light is substantially reduced by emitting unusable light with insufficient white or color separation, without outputting light with insufficient white or color separation,
The efficiency of light utilization is improved by reflecting the light. Therefore, in the present invention, the adjacent regions of the semi-transmissive portions of the respective colors are formed so that the adjacent semi-transmissive portions are overlapped or covered with a reflective material so that the reflectance is high. White light or light with insufficient color separation that cannot be used or cannot be used efficiently by the light valve is output from the adjacent area.

That is, the color recapture type illumination device of the present invention includes a rod integrator, a light source for supplying light to an opening on the incident side of the rod integrator,
The output side of the rod integrator has a semi-transmissive part that transmits one of the three primary colors of light and reflects the other color of the light of the three primary colors. The semi-transmissive part of each color is the emission side of the integrator. And a color wheel which is rotated so as to divide the opening of the semi-transparent portion and has a higher reflectance in the area adjacent to the semi-transmissive portion than in the semi-transmissive portion. The rod integrator may be hollow and has a reflective inner peripheral surface, may be totally reflected by the peripheral surface of a waveguide such as glass, or may be covered with a reflective film. Therefore, in the present invention, the color wheel is disposed in the opening on the exit side of the rod integrator, and is a semi-transmissive type that transmits one of the three primary colors and reflects the other colors. And a semi-transmissive part of each color is rotated so as to divide the output side opening of the rod integrator,
Provided is a color wheel in which a reflectance of a region adjacent to the semi-transmissive portion is higher than that of the semi-transmissive portion. The present invention also includes a method of manufacturing a color wheel having a processing step of forming the reflectance of a region adjacent to the semi-transmissive portion of each color higher than that of the semi-transmissive portion.

In the color wheel of the present invention, since the reflectance of the adjacent region is higher than that of the semi-transmissive portion, the amount of light transmitted through the adjacent region is small or almost nonexistent. Therefore, as described above, white light is hardly output from the adjacent area, or light with insufficient color separation is hardly output, and the substantial aperture ratio of the light valve is reduced or the saturation of the color image is reduced. Can be prevented from decreasing. On the other hand, since the light reflected by the area adjacent to the color wheel is returned to the inside of the rod integrator and is reused, the light utilization efficiency of the lighting device is hardly reduced. Therefore, an illumination device having the color wheel of the present invention, a light valve that forms image data based on the luminous flux of each color output from the device, and a lens system that projects light from the light valve are provided. Thus, in an image display device such as a projector that displays a bright, uniform color image of high quality, multi-color display with high saturation and high contrast is possible. Further, since the color recapture type illumination device is adopted, a compact and bright image display device can be provided.

In order to increase the reflectance in the adjacent area, it is possible to overlap the semi-transmissive films forming the respective semi-transmissive portions in the adjacent area. This makes it possible to allow adjacent semi-transmissive films such as dichroic films to transmit only the common wavelength region in the adjacent region, so that if the transmissive properties of the semi-transmissive films do not overlap, it is almost 100%.
It is possible to form an adjacent region having a reflectance close to.

Further, in the adjacent area, the semi-transmissive films forming the semi-transmissive portion can be overlapped so that the total thickness is the same as that of the other semi-transmissive portions, and the thickness of the color wheel can be made uniform. , It is possible to suppress rotation noise and prevent surface wobbling. Color wheels equipped with such adjoining regions can be used for photolithography, gray masks with varying shades (transmittance or reflectance), gradation masks, etc., which are suitable for fine processing in mask film forming methods and semiconductor manufacturing technologies. Can be manufactured using.

Further, the reflectance may be improved by forming a reflection film such as an aluminum film or a silver film in the adjacent region. The reflectance of the adjacent region can be surely increased regardless of the characteristics of the semi-transmissive film.

In the color recapture type optical system, the light reflected in the adjacent region is reused, but the width of the adjacent region is 0.5 μm to 100 μm in consideration of the decrease in output.
It is desirable to form it to a certain degree, and it can be realized by manufacturing using a glass mask or the like. Further, it is desirable that the width of the adjacent region is formed to be about 0.1 μm to 100 μm. This size can be realized by photolithography technology or lift-off processing.

Then, the lower limit of the width of the adjacent region is set to 0.5 μm.
When the color wheel according to the present invention is used for a projector or the like, by setting the above value, or 1 μm or more, it is possible to suppress the chromatic aberration due to the relay lens or the like and the crossing of the colors on the light valve due to the diffusion of the color light rays, and the saturation can be reduced. It can contribute to improvement.

Further, in the illuminating device using the color wheel according to the present invention, the integrator has a rectangular cross section, and the length in the first direction is larger than the length in the second direction. It is also possible to arrange the adjacent regions so as to extend in the second direction. That is, in the image display device, a horizontally long screen size is often adopted. However, by arranging the adjacent area across the screen in the vertical direction as compared with the arrangement in which the adjacent area crosses the screen in the horizontal direction, It is possible to reduce the ratio of the adjacent area to, and it is possible to display a brighter image.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of a projector 1 using an illuminating device 10 according to the present invention. The projector 1 of the present example also includes a color recapture type illumination device 10 and a relay lens that transmits the luminous fluxes 71R (red), 71G (green), and 71B (blue) of the respective colors that are color-separated and output from the illumination device 10. 51, a transmissive light valve 52 such as a liquid crystal that modulates the light beams 71R to 71B from the lens 51 with image data, and a display light 74 output from the light valve 52 is projected on a screen 58 to display a color image. Projection lens 5 to be formed
3 and 3.

The color recapture type illumination device 10 of this embodiment also has a light source section 12 for outputting white light 71 from a xenon lamp, a hollow inner reflective surface 24 and a reflective surface 21 for recapturing light rays. The rod integrator 20 serving as a prismatic integrator having the above and the color wheel 40 that time-divides the white incident light 71 are provided, and these are arranged in order. Therefore, also in the illumination device 10 of this example, the intensity distribution of the white light flux 71 emitted from the light source unit 12 is made uniform by the rod integrator 20 according to the shape of the light valve 50.
It is output from the color wheel 40 in a state of being temporally and spatially color-divided. That is, the color wheel 40
Is a semi-transmissive dichroic film (mirror) 41R, 41G and 41 that transmits a specific color and reflects light of another color.
Since B is combined in an appropriate shape such as a spiral shape, the respective color lights 71R to 71B are separated in time and space and output. Then, the light that does not pass through the color wheel 40 is returned to the integrator 20 and is recaptured (taken away). Therefore, the lighting device 10 is a color recapture type lighting device.

FIG. 2 is an enlarged schematic sectional view of the color wheel 40 of this embodiment. The color wheel 40 of this example is arranged with an appropriate gap so as to face the opening 23 on the emission side of the integrator 20. The color wheel 40 includes a semi-transmissive portion 41R formed of a dichroic film that transmits red light and reflects light of other colors, and a dichroic film that transmits green light and reflects light of other colors. A semi-transmissive portion 41G formed by
A semi-transmissive portion 41B formed of a dichroic film that transmits blue light and reflects light of other colors is formed in a spiral shape. Therefore, by arranging the integrator 20 so as to face an appropriate position in the circumferential direction of the color wheel 40, the opening 23 on the emission side of the integrator 20 is approximately ⅓ by the semi-transmissive portions 41R to 41B of each color. , And the order can be changed over time by rotating the color wheel 40.

In the color wheel 40 of this example, a disk-shaped glass substrate 91 is adopted as a supporting member, and an AR coat (antireflection coating) 92 is provided on the back surface side thereof, that is, the side facing the light valve 52. It has been subjected. On the other hand, on the surface side of the glass substrate 91, that is, on the side facing the opening 23 on the exit side of the integrator, thin film dichroic films 41R to 41B are coated so as to be spirally continuous. It is a so-called Archimedean spiral.

As shown in FIGS. 3 (a) to 3 (c), the opening 23 on the output side of the integrator is formed by the color wheel 40.
Shows how the colors are divided. The opening 23 on the output side of the integrator has a rectangular shape in which the length in the horizontal direction H is longer than the length in the vertical direction V according to the size of the image or the size of the light valve. The side opening 23 is arranged such that its horizontal direction H crosses the semi-transmissive portions 41R to 41B. That is, the semi-transmissive portions 41R to 41B move in the opening 23 while extending in the vertical direction V, which is shorter than the horizontal direction H. The opening 23 of the integrator can be arranged in a region where these dichroic films 41R to 41B are arranged in parallel in the vertical direction, but by adopting the arrangement shown in FIG. Since the length of the region adjacent to the portions 41R to 41B is shortened, the light utilization efficiency is higher in the arrangement as in this example.

With such an arrangement, the color wheel 40 is different from the arrangement in which the adjacent region 42 extends in the horizontal direction H.
Adjacent regions 4 of each of the dichroic films 41R to 41B of
The area of 2 can be reduced by about 2.5%, and the light utilization efficiency can be improved by about 1.8%.

As the color wheel 40 rotates, as shown in FIGS. 3 (a), 3 (b) and 3 (c), the dichroic films 41R-41B are used to open the aperture 2.
3 is roughly divided into three, and the semi-transmissive regions 41R to 41B that pass each color and reflect the other colors sequentially move in the left-right direction. Therefore, the light fluxes 71R to 71B of the respective colors are emitted from the color wheel 40 in a region and temporally separated state (space and time-separated state), and are output as the color wheel 40 rotates. Therefore, by dividing the side of the light valve 52 into areas of the color of the emitted light and controlling them at time-separated timings, a multi-color image can be displayed.

In the color wheel 40 of this embodiment, as schematically shown in FIG. 2, in the adjacent region 42 which is a boundary between the dichroic films 41R to 41B, the edges of the adjacent dichroic films 41R to 41G of different colors are formed. 44 are stacked on top of each other. Further, a reflective film 43 made of aluminum or the like is formed on the superposed surface (on the integrator side).
Are formed. Therefore, in the adjacent area 42, all the light emitted from the integrator 20 is reflected, and the dichroic films 41R to 41G have a higher reflectance.

Therefore, as shown in FIG.
The white incident light 71W emitted from the inside enters from the opening 22 of the incident side 20a of the integrator 20 to the inside of the surrounding reflective inner peripheral surface 24. Then, the incident light W reflected by the inner peripheral surface 24 travels toward the opening 23 on the emission side 20b,
The green dichroic film 41G of the color wheel 40 is reached. Here, in the white light 71W, only the light flux 71G including the green wavelength is transmitted and is output to the light valve 52 side as the green light 71G.

On the other hand, the luminous fluxes of colors (71R and 71B) not emitted from the dichroic film 41G of the color wheel 40 are reflected back to the inside of the integrator 20 and reflected on the recapture reflecting surface 21 to be reflected by the color wheel 40 side. When it reaches the opening 23 next time, it is output if it hits the dichroic film that transmits the light flux of that color, and if it does not hit, it is returned to the inside of the integrator 20 again.

On the other hand, the dichroic film 41R-
The incident light 71W applied to the adjacent area 42 of 41G is reflected by the reflection film 43 provided on the surface of the adjacent area 42, and the light 71W of all color components returns to the integrator 20 side. That is, without passing through the color wheel 40,
No white light is output. And again integrator 2
0 on the inner peripheral surface 24 is reflected multiple times and the opening 2 on the outlet side 20b
3 and, for example, when reaching the green dichroic film 41G of the color wheel 40, the green luminous flux 71G
Is transmitted and output to the light valve 52. Then, the light fluxes containing other colors that have not been transmitted, in this example, the red light flux 71R and the blue light flux 71B are reflected and returned to the integrator 20. Therefore, the integrator 20
Is reflected by the recapture reflection surface 21 and further reflected by the reflective inner peripheral surface 24, proceeds to the opening 23 on the outlet side 20b again, and then reaches the blue dichroic film 41B, the blue light flux 71B is transmitted. And output to the light valve 52.

Further, the red luminous flux 71R which is not output even at this stage is returned to the integrator 20 and reaches the red dichroic film 41R while being reflected by the inner peripheral surface 24 and the recapture reflecting surface 21 thereof. After passing through, the red luminous flux 71R is output to the light valve 52.

As described above, even the light 71W reflected by the adjacent region 42 is returned to the integrator 20 to be given an opportunity to be recaptured, and the light source 12 is repeatedly reflected several times. 71W white light from
Can be output in a state of being separated into three colors without waste. Therefore, it is possible to prevent the white light 71W from leaking and the light with insufficient color separation to be leaked, and it is possible to improve the light utilization efficiency of the light valve. In addition, since the light reflected by the adjacent region 42 is reused, the recapture efficiency in the color recapture type optical system can be improved. Therefore, the utilization efficiency of the light incident on the integrator 20 is improved, and according to the simulation by the inventors, the utilization efficiency can be improved by about 13%. Therefore, the image display device using the illumination device 10 of the present example can output a bright color image with high saturation.

4A to 4C and 5A to 5C.
A manufacturing process of the color wheel 40 of this example is shown in (c). First, as shown in FIG. 4A, a green dichroic film 41G is multi-layered in a thin film by vapor deposition on the surface of a glass substrate 91 to form a resist layer 9
After patterning 9, C, as shown in FIG.
RI using HF ₃ or fluorine-based gas as an etchant
E (Reactive Ion Etching)
To process. Since the green dichroic film 41G was formed at this stage, the characteristic evaluation is performed. By evaluating the green dichroic film at this stage, improve the quality,
It is possible to reduce manufacturing waste and improve yield. It is possible to form the dichroic film for any color, but since it is difficult to control the characteristics of the green dichroic film 41G, it is necessary to form the green film 41G first in order to improve the yield. desirable.

In FIG. 4C, a red dichroic film 41R is formed next to the green dichroic film 41G on the surface of the glass substrate 91. At this time, the sacrificial layer 9 is formed so as to cover the surface of the green dichroic film 41G next to the existing green dichroic film 41G (on the right side in the figure, a region where the blue dichroic film 41B will be formed later).
8 is provided. The sacrificial layer 98 is not formed in the adjacent region 42 of the edge 44G of the green dichroic film 41G. The sacrificial layer 98 is coated with a red dichroic film 41R. Therefore, the red dichroic film 41R is overlaid on the green dichroic film 41G with the sacrificial layer 98 partially sandwiched therebetween.

Then, as shown in FIG. 5 (a), CHF
RIE is performed using ₃ or O ₂ as an etchant to process the red dichroic film 41R. At this time, the adjacent portion 42 is formed by the edge 44G of the green dichroic film 41G.
The red dichroic film 41R is formed so as to be overlapped on the portion of, so that there is no gap. Similarly, a blue dichroic film 41B is formed next to the green dichroic film 41G (on the right side in this figure).

Further, as shown in FIG. 5 (b), the dichroic films 41R to 41R including the overlapping adjacent portions 42 are included.
On the surface of 1G, for example, lift-off resist MS
-230C is formed as a peeling layer 98, and 0.1 is formed thereon.
An aluminum layer 97 of a reflection film is formed to a thickness of about μm, and a resist layer 99 is patterned on the adjacent portion 42. Next, as shown in FIG. 5C, when the aluminum layer 97 is etched, an aluminum layer, that is, the reflection film 43 is formed on the surface of the adjacent portion 42, and the color wheel 40 as shown in FIG. 2 is manufactured. To be done.

In the adjacent area 42, the lights 71R to 71R of the respective colors are
Since none of B is transmitted, increasing the area of the region 42 reduces the aperture ratio. Therefore, the width W of the adjacent region 42 is preferably 0.5 μm or more and 500 μm or less, and more preferably 1.0 μm or more and 100 μm or less. Considering the manufacturing tolerance of the above method, it is possible to sufficiently control up to about 5 μm.

Then, the lower limit of the width of the adjacent region is set to 0.5 μm.
When the color wheel 40 is used in the projector 1, the relay lens 5 has a thickness of 1 μm or more.
The color aberration on the light valve 52 due to the chromatic aberration due to 1 or the like and the diffusion of the color light rays can be suppressed, and the color saturation can be improved.

Further, as shown in FIG. 6A, in the color wheel 40 of this example, each dichroic film 41 is formed.
Instead of overlapping the adjacent portions 42 of R, 41G, and 41B with each other, a reflecting member 43 such as aluminum may be provided directly on the adjacent portions 42 to increase the reflectance of the adjacent portions 42. The reflecting member 43 is made of aluminum alloy, Al
Nd, etc., Ag, Ag alloy, etc. can be used. Further, SiO ₂ and Ta are used as a reflecting member on the adjacent portion 42.
Materials having different refractive indexes may be laminated in multiple layers to form a multilayer film.

Alternatively, as shown in FIG. 6B, the reflecting member 43 may be provided so as to be embedded between the dichroic films 41R and 41G of different colors in the adjacent portion 42. Further, the end side of the reflecting member 43 of the adjacent portion 42 can be provided so as to overlap the dichroic films 41R and 41G to 41B. In this way, the adjacent portion 4
It is possible to reliably improve the reflectance without forming a gap in 2.

FIG. 7 shows a different example of the present invention. The color wheel 61 includes an end 44 of each of the dichroic films 41R, 41G and 41B formed in a spiral shape.
R, 44G, and 44B are formed so as to be stacked on the dichroic films 41R to 41B of different colors in the respective adjacent regions 42. In the color wheel 61, by overlapping the dichroic films having a plurality of characteristics, the adjacent area 4
2 is provided with a reflecting function so that the recapture efficiency can be improved without outputting the white light 71W as in the color wheel 40 described above. The color wheel 61 can be manufactured by using photolithography technology or the like, and the dichroic films 41R to 4R of the respective colors are manufactured.
By superimposing a film of a different color, that is, a film having a different dichroic characteristic, on the slightly adjacent portion 42 of 1B, the reflectance of this region 42 is increased, and it is possible to manufacture relatively easily.

8 to 10 show the results of simulating the characteristics of the adjacent portions where the dichroic films 41R to 41B of the respective colors overlap with each other. FIG. 8 shows a characteristic in which the red dichroic film 41R is overlaid on the green dichroic film 41G, and as can be seen from this graph,
Since these dichroic films 41G and 41R do not include a common transmission wavelength range, light in almost all wavelength ranges is reflected without being transmitted.

FIG. 9 shows a green dichroic film 41G.
The characteristics of the blue dichroic film 41B are shown in FIG. The dichroic films 41G and 41B of these colors which are usually used include a common transmission wavelength region, and in the common region, light is almost transmitted but the ripple becomes large. On the other hand, independent transmission wavelength range (non-common wavelength range)
Then, it acts as a reflection film. Therefore, the blue dichroic film 41B or the green dichroic film 4 is
It is desirable to shift the wavelength region of 1 G so that the overlap is small. For example, in the vicinity of 490 nm, the green dichroic film 41G and the blue dichroic film 4 are formed.
By dividing into 1B, the reflectance of the adjacent region 42 can be increased. Alternatively, the adjacent area 4 that has this combination
Only 2 may be provided with a reflection film made of aluminum or the like.

FIG. 10 shows a red dichroic film 41R.
The characteristics of the blue dichroic film 41B are shown in FIG. Similar to the case shown in FIG. 8, since the common transmission wavelength region is not included, light in almost all wavelength regions is reflected without being transmitted.

As shown in FIGS. 4 and 5, the color wheel 61 is formed by photolithography, and at the stage of FIG. 5A, the dichroic films of the respective colors are overlapped with each other. It can also be manufactured by finishing.

Alternatively, as shown in FIGS. 11A to 11C, it can be manufactured by lift-off processing. Lift-off processing is a method used for patterning a non-etchable thin film. In the lift-off process, a reverse pattern of the intended pattern is formed on the substrate by a metal photoresist or the like. Then, a thin film layer to be the dichroic film 41B or 41R of the desired color is deposited. Then, after the vapor deposition, the unnecessary portion is removed together with the metal and the photoresist, and the desired pattern is left.

More specifically, referring to the drawings, as shown in FIG. 11A, first, on the front surface side of the glass substrate 91 having the AR coating film 92 formed on the back surface side,
A green dichroic film 41G is formed. Therefore, a lift-off resist layer 98a is formed around the region where the green dichroic film 41G is formed by ZRN-1100 manufactured by Nippon Zeon Co., Ltd. This resist layer 9
It is also possible to use aluminum or copper for 8a. 30 seconds for forming resist layer, 300 rp
The existing dichroic film 41 is spin-coated at about m.
A lift-off resist layer 98a is formed with a film thickness d2 of about 4 μm so as to be thicker than G. Then, a dichroic film 41G is formed on those surfaces, and the unnecessary portions are removed together with the resist layer 98a by etching with a stripping solution. It is also possible to remove a metal layer such as aluminum or copper by using an acid solution such as dilute sulfuric acid as a stripping solution after sputtering or vapor deposition.

Next, as shown in FIG. 11 (b), when the blue dichroic film 41B is manufactured, a lift-off resist layer 98a is formed on a region except the region where the blue dichroic film is desired to be formed, and the lift-off resist layer 98a is formed thereon. On dichroic film 4
1B is formed into a film. Then, by removing the resist layer 98a, a part of the blue dichroic film 41B is overcoated on the end of the green dichroic film 41G, and these two dichroic films 41 are overlapped.
G and 41B are generated. Similarly, it is possible to form a red dichroic film 41R, as shown in FIG.
As shown in (c), the adjacent region 42, which is the boundary region of the dichroic film, has the same thickness of 2 as shown in FIG.
It is possible to manufacture the color wheel 61 in which dichroic films of different types are laminated.

FIG. 13 shows an example of an illuminating device 10 using a different color wheel 63 of the present invention.
FIG. 14 is an enlarged view of a part of the color wheel 63.
It is shown in. In the color wheel 63 of this example, only the thinned portions of the ends of the dichroic films 41R to 41B are stacked as the adjacent region 42.
The thickness t of the dichroic film laminated on No. 3 does not change in the central portion and the adjacent region. Therefore, the end portions of the dichroic films 41R to 41B of the respective colors are processed into an edge shape or a taper shape, and the overlapping portions are formed to have complementary cross-sectional shapes. By laminating the dichroic films 41R to 41B having different transmission characteristics in this way, the adjacent region 42 can be made reflective as in the above. And this color wheel 6
When it is 3, since the thickness of the dichroic film is uniform over the entire surface, surface wobbling is less likely to occur when the color wheel 63 is rotated, and noise is less likely to occur. Therefore, it is possible to provide a compact lighting device with low noise and high output.

As described above, the thin dichroic film 4 is formed.
In order to form 1R to 41B without changing the total thickness of the adjacent portion 64 and forming a gap, it is necessary to control the boundary positions of the dichroic films 41R to 41B with high accuracy. For example, in the mask film formation method, it is necessary to create a highly accurate mask, perform highly accurate positioning, and control a mask displacement due to mask expansion due to a temperature rise during film formation.

Therefore, the mask 20 as shown in FIG.
0 is provided with two reference planes 202, placed on the tray 301 of the film forming apparatus 300 as shown in FIG. 16 and FIG. 17, and pressed by the spring 305 against the guide 302 serving as the reference plane. Position accuracy is secured. To position in this way, the mask 2
A structure in which 00 can withstand a load of 5 N or more is required.
For this reason, the patterning of the thin-film mask 200 and the mask housing 203 having mask strength are integrally formed while maintaining the placement accuracy of the mask 200 with respect to the reference plane 202.

As a material for the mask housing, if glass is used for the substrate 91 to be film-formed and stainless steel or aluminum which is a general mask material is adopted, 300 ° C.
At a film forming temperature of about a certain degree, a positional shift due to thermal expansion occurs. Therefore, it is effective to use a mask material having a coefficient of linear expansion equivalent to that of the material to be film-formed, as a method of controlling the positional deviation. For example, silicon 3.5, silicon 3.5, tantalum 6.8, nickel steel (64Fe,
36Ni) 5.1, glass 2.8-10, etc. are used as the mask material. These linear expansion coefficients are about 2.8 to 10, and are almost the same because the linear expansion coefficient of the glass substrate is about 4. As a result, it is possible to suppress positional deviation due to temperature changes during film formation.

Next, the thickness of the mask 200 is 1 near the film formation.
In the case of a thickness of mm, a thickness distribution occurs in the vapor deposition film on the substrate 91 due to the influence of the mask 200, and uniform dichroic characteristics cannot be obtained. Therefore, in order to reduce the influence of the mask 200 as much as possible, as shown in a sectional view in FIG.
The mask edge 201 is 0.1 mm to 0.
The film thickness distribution is reduced by thin film processing to 5 mm or processing into a tapered shape. Here, 0.1 mm is
The thickness is necessary to maintain the edge strength of the mask 200. 0.5 mm is the maximum thickness that can suppress the influence of the mask 200. At this time, the edge 201 allows the laser light to enter the surface of the mask 200 obliquely as shown by an arrow 208, so that the edge 201 can be formed to have a uniform film thickness. FIG. 19 is a cross-sectional view of a different example of a mask 200 manufactured for the same purpose.

Such a mask 200 is a mask 200.
The reference plane 202 and the mask pattern are indexed to the reference point of, and can be manufactured by a method of cutting with a diamond tool with a high-performance NC processing machine (for example, Robo Nano manufactured by Finac Co.). Alternatively, it is possible to form a mask by patterning and etching as described above by utilizing a laser processing of high performance NC neodymium YAG or the like or utilizing a photolithography technique. Further, a gray level mask or a gradation mask can be used to form a tapered shape by etching.

As described above, the color wheel of the present invention is provided with an Archimedean spiral pattern and
For the purpose of improving the recapture effect, by increasing the reflection coefficient of the adjacent region 42, it is possible to prevent the white light from being transmitted, and further, the light reflected from the color wheel can be collected by the color recapture method. it can. Therefore, the utilization efficiency of light as the illumination device 10 is high, and even when it is adopted in an image display device such as a projector, the utilization efficiency of light in the light valve can be improved. Further, by adopting the illumination device 10 of this example, the contrast and saturation of the color image modulated by the light valve can be improved, and a brighter and higher quality color image can be displayed. .

Although a hollow rod integrator has been described above as an example, the present inventors have confirmed that the same effect can be obtained with a solid rod integrator. As the image display device (light valve), a transmissive liquid crystal device has been described as an example, but a reflective mirror switching device, an image display device that turns on and off by using evanescent light by a movement of the wavelength level, etc. It is also possible to combine with other types of light valves. Further, the illumination device of the present invention can be applied not only to a projector but also to a direct-view type display device that requires color-separated light, a printer, and the like.

[0053]

As described above, in the color recapture type illumination device of the present invention, white light is prevented from being transmitted by increasing the reflectance of the adjacent regions of the respective semi-transmissive portions of the color wheel. Further, it is possible to further improve the recapture efficiency of the color recapture type optical system, and it is possible to provide an illuminating device and an image display device having a color recapture type with higher light utilization efficiency.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of a projector using an illumination device of a color recapture method according to the present invention.

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

FIG. 3 is a diagram showing a state in which the color wheel shown in FIG. 2 crosses an emission side opening of an integrator.

FIG. 4 is a diagram showing a manufacturing process of the color wheel shown in FIG.

5 is a diagram showing a manufacturing process of the color wheel shown in FIG.

FIG. 6 is a diagram showing a different example of the color wheel shown in FIG.

FIG. 7 is a diagram showing still another example of the color wheel according to the present invention.

8 is a graph showing a characteristic of a dichroic for an adjacent region of the color wheel shown in FIG. 2, and is a graph showing a characteristic of a red dichroic film overlaid on a green dichroic film.

9 is a graph showing a dichroic characteristic relating to an adjacent region of the color wheel shown in FIG. 2, and is a graph showing a characteristic in which a blue dichroic film is superposed on a green dichroic film.

10 is a graph showing a dichroic characteristic relating to an adjacent region of the color wheel shown in FIG. 2, and is a graph showing a characteristic in which a blue dichroic film is superposed on a red dichroic film.

FIG. 11 is a diagram showing a manufacturing process of the color wheel shown in FIG. 7.

FIG. 12 is a diagram showing a state in which an adjacent region of the color wheel shown in FIG. 11 is enlarged.

FIG. 13 is a diagram showing still another example of the color wheel according to the present invention.

FIG. 14 is a diagram showing a state in which an adjacent region of the color wheel shown in FIG. 13 is enlarged.

FIG. 15 is a diagram showing an outline of a mask forming a color wheel according to the present invention.

16 is a diagram showing an outline of the film forming apparatus for the mask shown in FIG. 15 as seen from above.

17 is a diagram showing a state of the film forming apparatus for the mask shown in FIG. 18, as viewed from the side surface side.

FIG. 18 is a diagram schematically showing a cross section of the mask shown in FIG. 15.

19 is a diagram schematically showing patterns having different cross sections of the mask shown in FIG.

FIG. 20 is a diagram showing an outline of a color wheel of a conventional color recapture type illumination device.

21 is an enlarged view showing an adjacent portion of the dichroic film of each color of the color wheel shown in FIG.

FIG. 22 is a graph showing dichroic characteristics.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 projector 10 illuminating device 12 light source unit 20 integrator 20a surface 20b on the incident side surface 21 on the emitting side recapture reflection surface 22 opening on the incident side 23 opening on the exit side 24 inner peripheral surface 40, 61, 63, 140 color wheel 41R, 41G, 41B Dichroic film 42 of each color 42 Adjacent portion 42 Reflective film 44 Edge of dichroic film 51 Relay lens 52 Light valve 53 Projection lens 58 Screen 71W Light flux of white light (incident light) emitted from a light source 71R, 71G, 71B Color separation Specified light flux (emitted light) 91 Glass substrate 92 AR coat film 200 Mask forming device 200 Mask 201 Mask edge 202 Mask reference plane 203 Mask housing 300 Mask film forming device 301 Tray 302 Guide 305 Spring

Continued front page    F-term (reference) 2H041 AA21 AB10 AC01 AZ01 AZ08                 2H088 EA12 EA15 HA10 HA12 KA01                       KA03 MA01 MA02 MA05 MA06                 2H091 FA02X FA15X FA23X FA41Z                       FD01 FD06 FD11 FD21 FD24                       FD26 LA15 LA16 LA17 LA18                       LA20 LA30 MA07                 2K103 AA01 AA05 AB04 BA04 BC26                       BC35

Claims (25)

[Claims] 1. A rod integrator, a light source for supplying light to an entrance-side opening of the rod integrator, and an exit-side opening of the rod integrator for transmitting light of one of three primary colors of light. A semi-transmissive portion that reflects light of another color is provided, and the semi-transmissive portion of each color is rotated so as to divide the opening on the emission side of the rod integrator, and the reflectance of the area adjacent to the semi-transmissive portion is A color recapture illumination device having a color wheel higher than the semi-transmissive portion. 2. In claim 1, in the adjacent area,
A lighting device in which a semi-transmissive film forming the semi-transmissive portion is superimposed. 3. The adjacent region according to claim 1,
An illuminating device in which semi-transmissive films forming the semi-transmissive portion are stacked with the same thickness. 4. The adjacent region according to claim 1,
An illumination device in which a semi-transmissive film forming the semi-transmissive portion is stacked so that the total thickness is the same as that of the semi-transmissive portion. 5. The lighting device according to claim 1, wherein a reflective film is formed in the adjacent region. 6. The lighting device according to claim 1, wherein a width of the adjacent region is 0.5 μm or more and 500 μm or less. 7. The lighting device according to claim 1, wherein the widths of the adjacent regions overlap each other in a range of 1 μm or more and 100 μm or less. 8. The rod integrator according to claim 1, wherein a cross section of the rod integrator is rectangular and a length in a first direction is larger than a length in a second direction, and the rod integrator has a region adjacent to the color wheel. A lighting device arranged to extend in the second direction. 9. A color wheel arranged at the exit side opening of a rod integrator, comprising a semi-transmissive portion for transmitting light of one color and reflecting light of another color of light of three primary colors. A color wheel in which the semi-transmissive portion of each color rotates so as to divide the opening on the exit side of the rod integrator, and the reflectance of a region adjacent to the semi-transmissive portion is higher than that of the semi-transmissive portion. 10. The color wheel according to claim 9, wherein a semi-transmissive film forming the semi-transmissive portion is overlapped in the adjacent region. 11. The color wheel according to claim 9, wherein in the adjacent region, the semi-transmissive films forming the semi-transmissive portion are stacked with the same thickness. 12. The color wheel according to claim 9, wherein, in the adjacent region, a semi-transmissive film forming the semi-transmissive portion is laminated so that a total thickness thereof does not change from that of the semi-transmissive portion. 13. The color wheel according to claim 9, wherein a reflective film is formed in the adjacent region. 14. The color wheel according to claim 9, wherein the width of the adjacent region is 0.5 μm or more and 500 μm or less. 15. The color wheel according to claim 9, wherein the width of the adjacent region is 1 μm or more and 100 μm or less. 16. A color wheel arranged in the exit side opening of a rod integrator, comprising a semi-transmissive portion for transmitting light of one color and reflecting light of another color of light of three primary colors. , A method of manufacturing a color wheel in which the semi-transmissive portion of each color rotates so as to divide the opening on the emission side of the rod integrator, wherein the reflectance of a region adjacent to the semi-transmissive portion is greater than that of the semi-transmissive portion. A manufacturing method of a color wheel having a processing step of forming high. 17. The method of manufacturing a color wheel according to claim 16, wherein, in the processing step, the adjacent region is formed by superimposing a semi-transmissive film forming the semi-transmissive portion. 18. The method of manufacturing a color wheel according to claim 16, wherein in the processing step, the adjacent regions are formed by superposing semitransparent films forming the semitransparent portion with the same thickness. 19. The collar according to claim 16, wherein, in the processing step, the adjacent region is formed by superimposing a semi-transmissive film forming the semi-transmissive portion so that a total thickness of the semi-transmissive film is not changed. Wheel manufacturing method. 20. The method of manufacturing a color wheel according to claim 16, wherein in the processing step, a reflective film is formed in the adjacent region. 21. The method of manufacturing a color wheel according to claim 16, wherein in the processing step, a width of the adjacent region is 0.5 μm or more and 500 μm or less. 22. The method of manufacturing a color wheel according to claim 16, wherein in the processing step, the width of the adjacent region is 1 μm or more and 100 μm or less. 23. The method of manufacturing a color wheel according to claim 16, wherein in the processing step, each of the semi-transmissive portions of the adjacent region is processed into a tapered shape or an edge shape. 24. The method of manufacturing a color wheel according to claim 16, wherein in the processing step, the adjacent region is formed by a gradation mask. 25. The lighting device according to claim 1, a light valve that forms image data based on the luminous flux of each color output from the device, and a light from the light valve is projected. A projector having a lens system.