JP3591220B2 - Projector device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a projector device that projects a multi-gradation image using a single two-dimensional spatial light modulator, and in particular, has a high light use efficiency, a bright display screen, a small size, low power consumption, and a light source life. Related to a long projector device.
[0002]
[Prior art]
In recent years, with the advent of high-definition television (HDTV) and the spread of personal computers and the use of multimedia, there has been a demand for high-definition, large-screen image display of tens of inches to 200 inches used by multiple people and reduction in size and weight. The demand is increasing, and various types of products are being developed to meet the demand. Conventionally, there is a flat display such as a liquid crystal display, a plasma display, and a light emitting diode display to meet this demand.
[0003]
In recent years, the size of a liquid crystal display has been increased from a 14-inch desktop type to a 25-inch liquid crystal display in which two liquid crystal spatial light modulators are laminated. However, in the case of a liquid crystal display, the process of manufacturing a liquid crystal spatial light modulator is complicated and long, and there are essential problems such as the inability to produce a large-sized one and high price. Even if it is done, since it is made by laminating several liquid crystal spatial light modulators, it is unavoidable that the joint becomes a problem and the price becomes high.
[0004]
2. Description of the Related Art Plasma displays have recently emerged and are attracting attention as large-screen displays that compete with the liquid crystal displays. The plasma display has a simple structure, the manufacturing process is short, it is easy to make a large screen, and the development of a phosphor suitable for excitation by ultraviolet light from plasma enables a display with good color reproducibility. It depends on what happened. However, in the case of a plasma display, there is a problem that a large input of about 300 W is required even at 40 inches due to poor luminous efficiency, and a high withstand voltage driving circuit is required because the discharge voltage is as high as 200 to 300 V. . In addition, even if it is a flat display, it is actually about 10 cm thick including the housing, weighs about 40 inches and is tens of kilograms heavy, and special work is required to use it as a wall-mounted type .
[0005]
2. Description of the Related Art A light-emitting diode display has been developed in which a pixel is formed by combining a recently developed high-luminance and high-efficiency green or blue light-emitting diode with an existing high-efficiency red light-emitting diode. In this case, since one pixel is composed of three light emitting diodes, about 900,000 light emitting diodes are required even with the number of pixels (480 × 600) of a normal personal computer. Therefore, even if the price of a light emitting diode is reduced to about 10 yen in the future, the cost of the light emitting diode alone becomes as high as about 10 million yen, which is not suitable for use in homes and small conference rooms.
[0006]
A projector device is known as a device that avoids the above-described problems of the flat display. Conventionally, various types of projector devices have been developed depending on the type of light source, spatial light modulator, and optical system for separating and synthesizing three primary colors. As the spatial light modulator, a transmission type or a reflection type is used. There are various types such as a liquid crystal spatial light modulator and a two-dimensional micro deflection mirror array. In this projector device, it is sufficient that the image display unit has a screen or a white wall for projecting image light, and the image display unit can be reduced in weight, and the screen size can be freely changed according to the area of use. There are advantages. In addition, since the image light formed by the spatial light modulator is enlarged and projected several tens times using a projection lens, the spatial light modulator itself is a very small device of 2 to 3 inches as compared with a normal display. It can be said that it is a device that has the possibility of lowering the price.
[0007]
FIG. 9 shows a conventional projector device using a single two-dimensional micro-deflection mirror array as a spatial light modulator (Projection Display II, P.193, 1996: Proceedings of SPIE, Vol. 2650). The projector device 100 includes a lamp 101 such as a xenon lamp, a halogen lamp, and a metal halide lamp that emits white light, and a parabolic reflector 102 that once collects output light from the lamp 101 and then reflects the light in a predetermined direction. Light source unit 103, a cold mirror 104 for removing infrared components from the output light of the light source unit 103, and red, green, and blue (R, G, B, (Abbreviated.) Condenser lens 106 that condenses light on filters 105r, 105g, and 105b of three colors, and a mirror that returns light of three colors Lr, Lg, and Lb of R, G, and B separated by filters 105r, 105g, and 105b. And a three-color light Lr of R, G, and B from the return mirror 108. A two-dimensional micro-deflection mirror array 109 that deflects Lg and Lb to output R, G, and B three-color image signal lights 109r, 109g, and 109b, and image signal lights 109r, 109g, A total reflection prism 110 for separating the three color lights Lr, Lg, and Lb of R, G, and B from the folding mirror 108 and image signal lights 109r, 109g, and 109b from the two-dimensional micro deflection mirror array 109 are not shown. A projection lens 111 for projecting the image on a screen.
[0008]
In this projector device 100, the output light 103 a of the light source unit 103 is collected by the condenser lens 106 after the infrared component is removed by the cold mirror 104, and the R, G, and B filters of the rotating filter plate 105 are filtered. The light passes through 105r, 105g, and 105b. The rotation speed of the rotation filter plate 105 is equal to the frame display speed of the image, and is 60 rotations per second. During the one rotation, the transmitted light (103a) of the rotating filter plate 105 is time-divisionally separated into R, G, and B three-color lights Lr, Lg, and Lb by filters 105r, 105g, and 105b. The light enters the two-dimensional micro deflecting mirror array 109 via the 108 and the total reflection prism 110. The R, G, and B three-color lights Lr, Lg, and Lb incident on the two-dimensional micro-deflection mirror array 109 are deflected based on image signals of the respective colors, and are formed as image signal lights 109r, 109g, and 109b. The image signal lights 109r, 109g, and 109b are projected onto a screen (not shown) by the projection lens 111. The area ratio of the R, G, and B filters 105r, 105g, and 105b slightly varies depending on the intensity of the R, G, and B lights, but the duration of each of the R, G, and B lights is 5.6 milliseconds on average. is there. The deflection time constant of each micro-deflection mirror in the two-dimensional micro-deflection mirror array 109 is 5 microseconds, which is 1/1000 of the above-mentioned duration. By adjusting the deflection time of the micro-deflection mirror, each of R, G, and B is adjusted. It is possible to give a gradation of 8 bits or more. By using a single two-dimensional micro deflecting mirror array 109 in this manner, it is possible to realize a projector device that is small in number of parts, small in size and low in cost, and is suitable as a home display device.
[0009]
[Problems to be solved by the invention]
However, the conventional projector device 100 has the following problem.
[0010]
(1) Light utilization efficiency is poor.
Since a xenon lamp, a halogen lamp, and a metal halide lamp are used as the light source, the life of the light source is short and on / off modulation cannot be performed, so that the light is continuously lit. Since the R, G, and B lights are modulated in a time-division manner as described above, the R, G, and B lights are cut by the filters 105r, 105g, and 105b while modulating the other color lights. . For this reason, the light use efficiency is reduced correspondingly, and is reduced to about 1/3 as compared with the method of individually modulating the R, G, and B lights using three micro deflection mirror arrays. On the other hand, a light source such as a halogen lamp or a xenon lamp used in a projector device is enclosed in a glass bulb several centimeters in size for discharge, and the size of the reflector is limited by the size and cannot be reduced so much. Is shaped into a parallel light having a size of 10 to 20 mm, the light collection efficiency is low, and is 50% or less. Aluminum can be used for the deflecting mirror and the reflectivity is 90%, but the total light use efficiency is as small as 10% in consideration of blurring and absorption by other optical systems. In the case of a metal halide lamp, the light intensity of the R color spectrum is weak. Therefore, in order to improve the color balance, the light intensities of the other G and B colors must be reduced. descend. A projection light beam of a projector device using a single-plate type micro-deflection mirror array that is currently being developed has a light emission efficiency of at most about 300 lm at most even with a light source electric input of 300 W.
[0011]
(2) The power consumption is large and the device becomes large.
Since the light use efficiency is low, a high-luminance light source such as a metal halide lamp must be used, which results in a large power consumption of 300 W. As the power supply unit becomes larger, the projector becomes larger. .
[0012]
(3) The life of the lamp is short, and frequent lamp replacement is required.
Since a xenon lamp, a halogen lamp, or a metal halide lamp is used as a light source, the life of the light source is short and on / off modulation cannot be performed, so that the light source is continuously lit. Therefore, frequent lamp replacement is required. For example, in the case of a metal halide lamp, the time required for the central intensity to decrease by 50% is 1,000 hours (Journal of the Illuminating Engineering Institute, Vol. 77, No. 12, P. 748, 1993). This has a service life of about 4 months at a usage frequency of 8 hours / day, and frequent lamp replacement is required. However, since the lamp surface is hot, there is a risk that the lamp will explode if there is any dirt, and if the lamp is misaligned, there will be problems such as a decrease in light collection efficiency and a decrease in image quality. Lamp replacement is difficult and is being replaced by specialized technicians (for example, if 10 million lamps are spread, 100,000 lamp replacements will occur per day, requiring 10,000 or more technicians) ).
[0013]
(4) Other
Light that is not used for display among the transmitted light of the rotary filter plate 105 is absorbed by the filters 105r, 105g, and 105b, and the heat at this time heats the filters 105r, 105g, and 105b and the inside of the device 100, thereby lowering the reliability of the device. And an air-cooling fan is required.
[0014]
These are the major reasons that, besides being expensive, the projector device is not easily spread to homes, small conference rooms and the like.
[0015]
Accordingly, it is an object of the present invention to provide a projector device with a bright display screen, which improves light use efficiency.
Another object of the present invention is to provide a projector device which can achieve low power consumption and is downsized.
It is another object of the present invention to provide a projector device having a longer life of a light source.
[0016]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a plurality of semiconductor light emitting devices. Are arranged in parallel with each other, from the plurality of semiconductor light emitting elements Multiple output lights of different colors Parallel to each other A plurality of light emitting element arrays that emit in time series, and the plurality of output lights emitted from the plurality of light emitting element arrays are shaped into parallel light plural Shaping optics and said plural From shaping optics A plurality of dichroic mirrors for reflecting or transmitting the plurality of parallel lights in a predetermined direction; and a plurality of dichroic mirrors provided in the predetermined direction, and provided from the plurality of dichroic mirrors. Said plural A single unit that performs spatial modulation according to the image signals of the different colors on the parallel light and outputs a plurality of image signal lights in time series Two-dimensional polarizing mirror array And said Two-dimensional polarizing mirror array A projection optical system for projecting the plurality of image signal lights from the projector onto a screen.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a projector device according to a first embodiment of the present invention. The projector device 1 includes a light emitting element array unit 2 that emits three primary color lights Lr, Lg, and Lb of R (red), G (green), and B (blue) in a time series, and a light emitting element array unit 2. A shaping optical system 3 for shaping the three primary color lights Lr, Lg, Lb into parallel light, a synthesis optical system 4 for synthesizing the three primary color lights Lr, Lg, Lb shaped into parallel light, and a synthesized three primary color light Lr , Lg, and Lb are subjected to time-series processing (spatial modulation) in which the amount of reflected light changes according to the image signals Sr, Sg, and Sb of the respective colors, and output as R, G, and B image signal lights 5r, 5g, and 5b. A spatial light modulator 5 and a projection optical system 7 such as a projection lens for enlarging and projecting the R, G, and B image signal lights 5r, 5g, and 5b from the spatial light modulator 5 on a screen 6 in time series. A light emitting element array driver 8 for driving the light emitting element array 2; 5, a spatial light modulator driver 9 for driving the light emitting element 5, and a controller 10 for controlling the light emitting element array driver 8 and the spatial light modulator driver 9 based on the R, G, B image signals Sr, Sg, Sb. In the first embodiment, a light emitting diode (hereinafter, referred to as “LED”) as a semiconductor light emitting element is used for the light emitting element array section 2.
[0018]
The light emitting element array unit 2 includes a red LED array 20R that emits red light Lr, a green LED array 20G that emits green light Lg, a blue LED array 20B that emits blue light Lb, and each of the LED arrays 20R, 20G, 20B.
[0019]
The shaping optical system 3 includes a two-dimensional microlens array 30 for shaping the three primary color lights Lr, Lg, Lb from the light emitting element array unit 2 into parallel light, and three primary color lights Lr, Lg shaped by the microlens array 30. , Lb in accordance with a pixel range of a two-dimensional micro-deflection mirror array 50 of the spatial light modulator 5 which will be described later, and a reduction optical device 33 configured by combining a convex lens 31 and a concave lens 32. Note that, instead of the microlens array 30, a homogenizer having a fine uneven surface made of a transparent medium such as glass may be used. In this case, the incident light from the LED arrays 20R, 20G, and 20B is scattered by the minute uneven surface, and the minute uneven surface functions as a secondary light source surface. Be shaped.
[0020]
The combining optical system 4 reflects the red light Lr from the light emitting element array section 2 and transmits the blue light Lb from the dichroic mirror 4B and the green light Lg from the dichroic mirror 4G, and a dichroic mirror 4R and a light emitting element array section. A dichroic mirror 4G that reflects the green light Lg from the light source 2 and transmits the blue light Lb from the dichroic mirror 4B, and a dichroic mirror 4B that reflects the blue light Lb from the light emitting element array unit 2.
[0021]
The spatial light modulator 5 applies a two-dimensional micro deflection mirror array 50 for spatially modulating the three primary color lights Lr, Lg, Lb from the dichroic mirrors 4R, 4G, 4B for each pixel, and enters the two-dimensional micro deflection mirror array 50. And a stopper 51 for receiving the invalid reflected light of the three primary color lights Lr, Lg, Lb of R, G, B.
[0022]
Next, details of the light emitting element array section 2 and the shaping optical system 3 will be described with reference to FIGS.
[0023]
FIG. 2 shows the directivity of the output light of the LED, and FIG. 3 shows the relationship between the light emitting element array unit 2 and the shaping optical system 3. Each of the LED arrays 20R, 20G, and 20B has a two-dimensional 192 LED array having a size of 3 mmφ having an output light quantity distribution 22a as shown in FIG. (12 × 16) LEDs are arrayed, the array size is about 48 × 64 mm, the LEDs 22 are wired in series in row units (16), and each row is wired in parallel. By arranging the LEDs 22 two-dimensionally, a necessary light flux can be obtained. Further, by setting the aspect ratio of the size of each of the LED arrays 20R, 20G, and 20B to 3: 4 and matching the pixel range of the two-dimensional micro deflection mirror array 50, the light use efficiency can be further increased. The output light of the semiconductor light emitting element (here, the LED 22) has a high directivity and a small light emitting area, so that the light collection efficiency is high. In addition, since the semiconductor light emitting device outputs monochromatic light having a relatively narrow spectrum width of several tens nm or less, the color combining efficiency is increased.
[0024]
As shown in FIG. 3, the mask 21 is configured so that the peripheral portion of the output light 22a of each LED 22 is cut by the opening 21a and only the output light 22b at the central portion is transmitted.
[0025]
As shown in FIG. 3, the microlens array 30 has a plurality of square microlenses 30a arranged two-dimensionally with no gap so as to coincide with the optical axis of each LED 22 of the LED arrays 20R, 20G, and 20B. The focal length 30a is set to the distance D between the LED arrays 20R, 20G, 20B and the microlens array 30. ₁ Is almost equal to. Further, the numerical aperture W of each micro lens 30a of the micro lens array 30 is made to correspond to the spread angle (about 30 degrees) θ of the output light 22b at the center of the LED 22. Thereby, the output light 22b of the LED 22 becomes a parallel light 30b having a substantially uniform light intensity distribution.
[0026]
FIG. 4 shows details of the reduction optical device 33. The reduction optical device 33 reduces the parallel light 30b from each micro lens 30a of the micro lens array 30 by the convex lens 31 and the concave lens 32, and converts the parallel light 30a into a two-dimensional micro deflection mirror array via the dichroic mirrors 4R, 4G, and 4B as parallel light 33a. 50. The reduction ratio of the reduction optical device 33 is a value (for example, 0.16 / 1) slightly smaller than the ratio of the size of the two-dimensional micro deflection mirror array 50 and the size of the LED arrays 20R, 20G, and 20B. Thereby, the two-dimensional micro-deflection mirror array 50 can be irradiated with the parallel light 30b from the microlens array 30 as the parallel light 33a again almost uniformly.
[0027]
FIG. 5 shows details of the spatial light modulator 5. The two-dimensional micro deflection mirror array 50 is configured by arranging a plurality of square micro deflection mirrors 52 of about 16 μm on a semiconductor substrate 53 in a two-dimensional array by pivots 54. Here, the number of pixels (the number of mirrors) of 480 × 640 dots and the pixel range of about 7.7 × 10.2 mm are used. Each of the micro-polarizing mirrors 52 deflects based on an electrostatic force generated when a transistor (not shown) formed in an array on the semiconductor substrate 53 is turned on by driving the spatial light modulator driver 9, and the LED arrays 20 R, 20 G , 20B, the micro deflecting mirror 52 is arranged in the state shown by the solid line in FIG. 5, and the three primary color lights Lr, Lg, Lb are projected by the projection optical system 7. In the case where the light is sequentially reflected and the reflected light is invalid, the micro deflecting mirror 52 is arranged in the state shown by the broken line in FIG. 5 so that the three primary color lights Lr, Lg, Lb are sequentially reflected to the stopper 51. Each micro-deflection mirror 52 projects the R, G, and B image signals Sr, Sg, and Sb according to the magnitude of the pixel signals constituting the image signals Sr, Sr, and Sb by driving the spatial light modulator driver 9 under the control of the controller 10. The reflection time (4.5 milliseconds at the maximum and 17.6 microseconds at the minimum) to the optical system 7 is controlled, and the amount of reflected light changes at 256 gradations (8 bits).
[0028]
6A shows the operation timing of each part of the device 1, FIG. 6B shows the dependency of the applicable current of the LED 22 on the pulse duty ratio, and FIG. 6C shows the output characteristics of the LED 22 with respect to the input current. Is shown. As shown in FIG. 3A, when the R, G, B image signals Sr, Sg, Sb are input, the control unit 10 synchronizes the LED arrays 20R, R in one frame with the input timing. The lighting control for the light emitting element array unit driver 8 is performed so that the light emitting elements 20G and 20B are lighted in time series at a predetermined duty ratio (about 1/3), and the two-dimensional micro deflection mirror array 50 deflects light in time series. The light amount control for the spatial light modulator driver 9 is performed as described above. This light amount control enables multi-tone (full color) image display. The control unit 10 controls the light emitting element array unit driver 8 so that the LED arrays 20R, 20G, and 20B are turned off during the horizontal and vertical blanking periods in the two-dimensional micro deflection mirror array 50.
[0029]
As is clear from FIG. 6B, by reducing the duty ratio from 100% (continuous input (CW)) to about 1/3, the applicable current can be increased 2.5 times and the output can be increased. The proportion can be increased by a factor of three or more. This is because the applied current and output of the LED 22 are mainly limited by the amount of heat generated, so that the applicable current can be increased in inverse proportion to the lighting time, and the output can be increased in proportion to this or more. This is because it can be increased.
[0030]
As is clear from FIG. 6 (c), the output with respect to the input current shows a saturation tendency as the input current increases in the case of CW (broken line), whereas the output with the pulse input (duty ratio 30% ) Increases in proportion to the input current up to 60 mA. The rated current value of the LED 22 is about 20 mA in the case of CW. Therefore, the output can be increased three times or more by reducing the duty ratio to about 30%. In other words, it can be seen that the total output can be made equal to or greater than that of the CW even if the R, G, and B lights are divided in time series. Further, by turning off all the LEDs 22 during the horizontal and vertical blanking periods of the image frame, the pulsed light output can be further increased. In the case of the NTSC signal, the blanking period is 20% of the entirety. During this period, since all the LEDs 22 can be turned off, the duty ratio of each LED 22 is reduced to 27%. As a result, when the pulse electric input is CW, And the output can be increased to about 3.5 times, and the light use efficiency can be further improved.
[0031]
Next, the operation of the projector device 1 according to the first embodiment having the above configuration will be described.
The control section 10 controls the light emitting element array section driver 8 in synchronization with the image signals Sr, Sg, Sb of each color, and lights the LED arrays 20R, 20G, 20B in time series. That is, as shown in FIG. 6A, the control unit 10 turns on the red LED array 20R when the R image signal Sr is input, and turns on the green LED array when the G image signal Sg is input. 20G is turned on, and when the B image signal Sb is input, the blue LED array 20B is turned on. The red light Lr, the green light Lg, and the blue light Lb emitted from each of the LED arrays 20R, 20G, and 20B have their peripheral portions cut by the mask 21 and then form the microlenses 30a that form the microlens array 30 of the shaping optical system 3. And is reduced by the reduction optical device 33 and is incident on each dichroic mirror 4R, 4G, 4B of the combining optical system 4. The red light Lr from the red LED array 20R is reflected by the dichroic mirror 4R, and the green light Lg from the green LED array 20G is reflected by the dichroic mirror 4G, passes through the dichroic mirror 4R, and is blue from the blue LED array 20B. The light Lb is reflected by the dichroic mirror 4B, passes through the dichroic mirror 4G and the dichroic mirror 4R, and enters the two-dimensional micro deflection mirror array 50 of the spatial light modulator 5 respectively.
On the other hand, the control unit 10 controls the spatial light modulator driver 9 in synchronization with the image signals Sr, Sg, Sb of each color, and the two-dimensional micro deflection mirror array 50 of the spatial light modulator 5 controls R, G, B. The three color lights Lr, Lg, Lb are spatially modulated in time series. That is, when the three primary color lights Lr, Lg, and Lb from the LED arrays 20R, 20G, and 20B are used as the effective reflected light, the control unit 10 outputs the image signal to the red light Lr when the R image signal Sr is input. The two-dimensional micro-deflection mirror array 50 performs spatial modulation in which the amount of reflected light changes according to the pixel signals constituting Sr for each pixel, and when the G image signal Sg is input, the image signal Sg is converted to green light Lg. The two-dimensional micro-deflection mirror array 50 performs spatial modulation in which the amount of reflected light changes according to the constituent pixel signal for each pixel, and when the B image signal Sb is input, forms the image signal Sb in the blue light Lb. Spatial modulation in which the amount of reflected light changes according to the pixel signal is performed by the two-dimensional micro deflection mirror array 50 for each pixel. At this time, when the three primary color lights Lr, Lg, Lb from the LED arrays 20R, 20G, 20B are used as effective reflected light, the two-dimensional micro deflection mirror array 50 uses the three primary color lights Lr, Lg, Lb as a projection optical system. In the case where the light is reflected by the light 7 and becomes invalid reflection light, the three primary color lights Lr, Lg, Lb are reflected by the stopper 51. The R, G, and B image signal lights 5r, 5g, and 5b spatially modulated as effective reflected light by the two-dimensional micro deflection mirror array 50 are enlarged and projected on the screen 6 by the projection optical system 7. Thus, the full-color image is displayed on the screen 6 on a large screen.
[0032]
Next, effects of the projector device 1 according to the first embodiment will be described.
(B) The light use efficiency is improved, and a bright display screen is obtained.
Since light sources for each of the colors R, G, and B are used, color separation becomes unnecessary, and light loss at the time of color separation can be avoided. For this reason, the product of the light collection efficiency and the color synthesis efficiency can be increased to 0.77, which is three times or more the conventional light source. Further, since the light can be collected with good directivity, the projection efficiency of the projection optical system 7 can be increased to 85% or more. As a result, the light transmission efficiency in the optical system of the device 1 is 90% in the light emitting element array unit 2 and the shaping optical system 3, 85% in the combining optical system 4, and the reflectance of the two-dimensional micro deflection mirror array 50 is 90%. Since the projection optical system 7 is 85%, the total light use efficiency is about 58%, which is about six times or more that of the conventional one. The wavelength, chromaticity coordinates, and pulse light output of the output light of the R, G, and B LEDs 22 are 650 nm: (0.7, 0.28): 30 mW, and 520 nm: (0.17, 0.7). ): 10.5 mW, 450 nm: (0.13, 0.075): 6 mW, so that the chromaticity coordinates of the synthesized white light are (0.36, 0.37) and slightly yellowish white, The brightness of about 650 lm was obtained for all the arrays 20R, 20G, and 20B, and 380 lm was obtained as the image signal lights 5r, 5g, and 5b as the projection light flux. The center of the chromaticity coordinates can be changed by slightly changing the lighting time of each of the R, G, and B LEDs 22. For example, it is possible to shift to the center (0.33, 0.33) of the chromaticity coordinates by increasing the time of the B light.
[0033]
(B) Low power consumption can be achieved and downsizing can be achieved.
The power consumption per LED (22) is 120 mW, 165 mW, 210 mW (current is 60 mA each) for each of R, G, and B, and the lighting duty ratio of each array 20 R, 20 G, and 20 B is 27%. The power consumption is 30 W or less, which is 1/10 of the conventional power consumption. The operating voltage per LED (22) is 2 to 3.6 V. In order to suppress the operating voltages and currents of the LED arrays 20R, 20G, and 20B to easy-to-handle values (<100V, <1A), the LED array 20R is used. , 20G, and 20B are wired in rows (16 units) in series and each row is wired in parallel, so that the operating voltage and current for each of the arrays 20R, 20G, and 20B are 40 to 80 V, respectively. , 0.5 A. The LED arrays 20R, 20G, and 20B were turned off during the period of horizontal blanking (about 13% in NTSC signal) and vertical blanking (8%). As a result, about 20% of the power and the amount of heat generation are reduced, and the total power consumption of the LED arrays 20R, 20G, and 20B can be further reduced. Further, since a single spatial light modulator is used, the size of the projector device can be reduced.
[0034]
(C) The life of the light source can be extended.
The life of the LED 22, which is the light source, is 10,000 hours or more, which is 10 times or more that of halogen lamps, etc., so that the life of the light source can be significantly extended, and the usage frequency is about 8 hours / day and it is used for almost 4 years. Will be possible.
[0035]
(D) Cost reduction can be achieved.
The price of the LED 22 is 10 to several tens of yen / piece, and the whole array is several thousand yen to 10,000 yen, which is slightly more expensive than the conventional light source (thousands of hundreds of yen). Considering that there is no light source, that the power consumption is 1/10 and that safety is considered, even if the cost of the light source is higher by an order of magnitude, it is sufficient.
[0036]
In the above embodiment, a single two-dimensional micro-deflection mirror array is used as the spatial light modulator. However, the same applies when a reflective or transmissive spatial light modulator using ferroelectric liquid crystal is used. Needless to say, the effect is obtained. Also, in a reflection type or transmission type spatial light modulator using a nematic liquid crystal or a dispersion type liquid crystal, since the modulation speed is as slow as several tens of milliseconds, the image flickers, but the same effect can be obtained. . In the above embodiment, the light emitting element array that emits R, G, and B output light is used. However, two or more of these may be used in combination. When two colors of output light are used, the image signal light may be displayed in time series with two colors and a mixed color thereof.
[0037]
Figure 7 Shows a projector device according to a second embodiment of the present invention. In a projector device 1 according to the second embodiment, a surface emitting laser (VCSEL) that emits linearly polarized red laser light Lr ′, green laser light Lg ′, and blue laser light Lb ′ is provided in a light emitting element array section 2. The array 24R, 24G, and 24B are used, and the shaping optical system 3 uses a magnifying optical device 34. The other configuration is the same as that of the first embodiment.
[0038]
In the VCSEL array 24, 191 (12 × 16) VCSEL elements having a diameter of 15 μm are arranged in a two-dimensional array at an arrangement pitch of 60 μm on a single GaAs substrate, and the array size is about 5.5 × 7. 5 mm. Further, in general, each VCSEL element in the VCSEL array is formed so that the cathode is common and the anode has an individual electrode. However, the VCSEL array 24 of the present embodiment is configured such that the anodes of the VCSEL elements are connected in series in row units. And each row is connected in parallel.
[0039]
FIGS. 8A and 8B show a G VCSEL array 24G. The VCSEL array 24G for G has a two-dimensional array of VCSEL elements 241 formed of a GaInP-based compound semiconductor on a GaAs substrate 240, as shown in FIG. , VCSEL elements 241 are connected in series on a row-by-row basis by striped Au wiring, and a p-type electrode 242 is formed to connect the rows in parallel. A light emitting hole 242a is formed in the p-type electrode 242 at a position corresponding to each VCSEL element 241. In the VCSEL array 24G, as shown in FIG. 3B, an n-type electrode 243 serving as a common cathode of each VCSEL element 241 is formed below the GaAs substrate 240, and an n-type electrode 243 is formed on the GaAs substrate 240. A mirror layer 244, an n-type cladding layer 245, an active layer 246, a p-type cladding layer 247, a p-type mirror layer 248, and a proton injection region 249 are formed. In this figure, reference numeral 250 denotes a wire bonding pad, which is directly bonded to an aluminum alloy holder (not shown) also serving as a heat radiation fin, thereby improving heat radiation characteristics.
[0040]
In the case of VCSEL arrays for G and B (not shown), the VCSEL elements are formed of a GaInN-based compound semiconductor, and sapphire is used for the substrate. Since this material is insulative, the cathode of each element was connected for each row by an Au wiring like the anode. Similar to the VCSEL array for G, the heat radiation characteristics are enhanced by directly bonding to an aluminum alloy holder also serving as a heat radiation fin. In a VCSEL for parallel signal processing, the anode of each element is individually connected to an electrode outside the array via a pad because each element must be driven independently. Since the elements are turned on and off at the same time, it is possible to connect each row in this manner, thereby making it possible to reduce the wiring area, narrow the element interval, and reduce the wiring resistance. In this application, since the power consumption per element is larger than that for signal processing, this is important for preventing heat generation and improving reliability.
[0041]
The shaping optical system 3 includes a two-dimensional microlens array 30 for shaping R, G, and B laser beams Lr ', Lg', and Lb 'from the VCSEL arrays 24R, 24G, and 24B into parallel light, and a microlens array 30. A concave lens 32 for enlarging the R, G, B laser beams Lr ', Lg', Lb 'shaped according to the pixel range (7.7 × 10.2 mm) of the two-dimensional micro deflection mirror array 50; And a magnifying optical device 34 configured by combining the convex lenses 31. The distance between the microlens array 30 and the VCSEL arrays 24R, 24G, 24B is approximately equal to the focal length of each microlens of the microlens array 30, and is 1.4 mm. Note that a homogenizer may be used instead of the microlens array 30.
[0042]
As shown in FIG. 6A, the control unit 10 synchronizes with the input timings of the R, G, and B image signals Sr, Sg, and Sb, as shown in FIG. The lighting control for the light emitting element array section driver 8 is performed so that the VCSEL arrays 24R, 24G, and 24B are lit in a time series at a predetermined duty ratio (about 1/3) during one frame, and the two-dimensional micro deflection is performed. The light amount control for the spatial light modulator driver 9 is performed so that the mirror array 50 deflects in time series. This light amount control enables multi-tone (full color) image display. The control unit 10 controls the light emitting element array unit driver 8 so as to turn off the VCSEL arrays 24R, 24G, and 24B during the horizontal and vertical blanking periods in the two-dimensional micro deflection mirror array 50. When the spacing between each VCSEL element in the VCSEL array is sufficiently larger than the oscillation region, the maximum output is suppressed by increasing the order of the transverse mode. However, if the spacing between the elements is reduced to about three times the oscillation region. Rather, the effect of heat generation becomes stronger. In the case of a VCSEL, since it is manufactured on a GaAs substrate or a GaInN substrate, it is preferable to reduce the cost and reduce the device spacing to increase the device yield. Since it is not necessary, the element interval can be reduced. Therefore, also in the VCSEL arrays 24R, 24G, and 24B, the light output is practically suppressed by heat generation, and ON / OFF lighting is effective for improving output efficiency and increasing light output. In the case of the edge-emitting laser, the maximum output is suppressed by optical damage (catastrophic optical damage) of the end face forming the resonator. With a pulse having a duty ratio of 20 to 30%, the output is much lower than that of the CW. No increase is expected.
[0043]
Next, an operation of the projector device 1 according to the second embodiment having the above configuration will be described. The R, G, and B laser beams Lr ', Lg', and Lb 'emitted in time series from the VCSEL arrays 24R, 24G, and 24B are enlarged to the pixel range of the two-dimensional micro-deflection mirror array 50 by the enlargement optical unit 34. Then, after being synthesized by the dichroic mirrors 4R, 4G, and 4B, the light is incident on the spatial light varying unit 5. The image signal lights 5r, 5g, 5b deflected in accordance with the image signals Sr, Sg, Sb of each color in the spatial light varying section 5 are enlarged and projected on the screen 6 by the projection optical system 7.
[0044]
Next, effects of the projector 1 according to the second embodiment will be described.
(B) The light use efficiency is improved, and a bright display screen is obtained.
The light transmission efficiency in the optical system of the device 1 is 90% in the VCSEL arrays 24R, 24G, 24B and the shaping optical system 3, 85% in the combining optical system 4, and the reflectance of the two-dimensional micro deflection mirror array 50 is 90%. Since it is 85% in the projection optical system 7, the overall light use efficiency is about 58% as in the first embodiment. The wavelength, chromaticity coordinates, and pulsed light output of the output light of the R, G, and B VCSEL elements are respectively 650 nm: (0.7, 0.28): 30 mW, and 520 nm: (0.17, 0). .7): 30 mW, 450 nm: (0.13, 0.075): 30 mW, and the chromaticity coordinates of the synthesized white light are (0.34, 0.35), a white color close to the standard, and a VCSEL array. The brightness of 1200 lm was obtained with 24R, 24G, and 24B, and the brightness of 700 lm was obtained with the image signal lights 5r, 5g, and 5b as the projection light flux. In the VCSEL, the light output is limited by the multi-beam in the transverse mode in addition to the influence of heat generation. This is because the supply of carriers to the center of the beam cannot keep up with the increase in the optical output, and the gain in that part becomes lower than the gain in the peripheral part. This is because the mode easily oscillates.
[0045]
(B) Low power consumption can be achieved and downsizing can be achieved.
The operating voltage per VCSEL element is 2.5 to 3 V, the operating current value is about 80 mA, and the total power consumption is suppressed to about 40 W or less. Since the anodes of the VCSEL elements of the VCSEL array 24 are connected in series on a row-by-row basis, and each row is connected in parallel, the total current and voltage are set to appropriate values (1 A or less, 100 V or less) as in the first embodiment. Below). Further, similarly to the first embodiment, the VCSEL arrays 24R, 24G, and 24B are turned off during the horizontal and vertical blanking periods. As a result, power consumption and heat generation can be reduced by about 20% as in the first embodiment, and the power consumption of the VCSEL array 24 is reduced to 30 W, which is about 1/10 of the conventional power consumption. Further, since the light source area can be reduced and a single spatial light modulator is used, the size of the projector device can be reduced.
[0046]
(C) The life of the light source can be extended.
As in the first embodiment, the life of the VCSEL element, which is the light source, is 10,000 hours or more, which is ten times or more that of the conventional VCSEL. It became.
[0047]
(D) Cost reduction can be achieved.
Even if a 3-inch wafer is used, about 100 VCSEL arrays can be manufactured from one wafer, and the cost can be reduced to several thousand yen or less.
[0048]
When a laser diode is used for image display, the coherence length of the output light is long, so that speckle noise and light condensing on the retina by an eyeball pose a problem. Works as a phase shifter for the laser beams Lr ', Lg', and Lb ', and the coherence between pixels is reduced. In this embodiment, a two-dimensional surface-emitting laser array is used. However, in the case of a small projector device, even if a one-dimensional surface-emitting laser array is used, the output light is two-dimensionally output by a cylindrical lens or the like. This can be realized by enlarging.
[0049]
【The invention's effect】
As described above, according to the present invention, since the output light of the light source has directivity, the light use efficiency can be significantly improved, a bright display screen can be obtained, and the light source has the light emission efficiency. Since a high semiconductor light emitting element is used, low power consumption can be achieved. In addition, since the light use efficiency is increased and power consumption is reduced, the life of the light source can be extended. Further, since a single spatial light modulator is used, the size can be reduced. As a result, it can be spread to homes, small meeting rooms, and the like.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a projector device according to a first embodiment of the present invention.
FIG. 2 is a diagram illustrating directivity of output light of the LED according to the first embodiment.
FIG. 3 is a diagram illustrating a relationship between a light emitting element array unit and a shaping optical system according to the first embodiment.
FIG. 4 is a diagram illustrating details of a reduction optical device according to the first embodiment.
FIG. 5 is a diagram illustrating details of a spatial light modulator according to the first embodiment.
6A is a diagram showing the operation timing of each unit of the present device, FIG. 6B is a diagram showing the dependency of the applicable current of the LED on the pulse duty ratio, and FIG. 6C is a diagram showing the output characteristics of the LED with respect to the input current. It is.
FIG. 7 is a configuration diagram of a projector device according to a second embodiment of the present invention.
8A is a front view of a VCSEL array for G according to a second embodiment, and FIG. 8B is a cross-sectional view thereof.
FIG. 9 is a configuration diagram of a conventional projector device.
[Explanation of symbols]
1 Projector device
2 Light-emitting element array
20R red LED array
20G green LED array
20B Blue LED array
21 Mask
21a opening
22 LEDs
22a Light intensity distribution
22b Output light
23 Substrate
24R, 24G, 24G surface emitting laser (VCSEL) array
240 GaAs substrate
241 VCSEL device
242 p-type electrode
242a light emitting hole
243 n-type electrode
244 n-type mirror layer
245 n-type cladding layer
246 active layer
247 p-type cladding layer
248 p-type mirror layer
249 Proton injection region
250 Wire bonding pad
3 Shaping optical system
30 micro lens array
30a micro lens
30b, 33a Parallel light
31 convex lens
32 concave lens
33 Reduction optics
34 Magnifier
4 Synthetic optical system
4R, 4G, 4B dichroic mirror
5 Spatial light modulator
50 Two-dimensional micro deflection mirror array
51 Stopper
52 micro deflection mirror
53 Semiconductor substrate
54 pivots
5r, 5g, 5b Image signal light
6 screen
7 Projection optical system
8 Light emitting element array driver
9 Spatial light modulator driver
10 control unit
D ₁ distance
Lr red light
Lr 'red laser light
Lg green light
Lg 'green laser light
Lb blue light
Lb 'blue laser light
Sr, Sg, Sb image signal
W numerical aperture
θ Spread angle

Claims (12)

A plurality of light emitting element arrays that are arranged in parallel with a plurality of semiconductor light emitting elements and emit a plurality of output lights of different colors from the plurality of semiconductor light emitting elements in time series in parallel with each other ,
A plurality of shaping optical systems for shaping the plurality of output lights emitted from the plurality of light emitting element arrays into parallel light,
A plurality of dichroic mirrors for reflecting or transmitting the plurality of parallel lights from the plurality of shaping optical systems in a predetermined direction,
A single unit that is provided in the predetermined direction and outputs a plurality of image signal lights in time series by performing spatial modulation according to the image signals of the different colors on the plurality of parallel lights from the plurality of dichroic mirrors A two-dimensional polarizing mirror array ,
A projector device comprising: a projection optical system that projects the plurality of image signal lights from the two-dimensional polarizing mirror array onto a screen. The projector device according to claim 1, wherein the plurality of light emitting element arrays emit the plurality of output lights of red, green, and blue. The projector device according to claim 1, wherein the plurality of semiconductor light emitting arrays have a configuration in which the plurality of semiconductor light emitting elements are two- dimensionally arranged. The projector device according to claim 1, wherein the light emitting element array has a configuration using a surface emitting laser diode array. The projector device according to claim 1, wherein the light emitting element array has a configuration using a light emitting diode array. Before SL plurality of semiconductor light emitting elements, the two-dimensional polarization said in mirror array spatial modulation of the horizontal and vertical projector device according to claim 3, wherein the off structure for a blanking period. Before SL plurality of semiconductor light-projector according to claim 3, wherein the structure the aspect ratio as the aspect ratio and comparable screen projected on the screen. Before SL plurality of semiconductor light emitting elements are connected in series in a row unit, and a projector apparatus according to claim 3, wherein the structure each row are connected in parallel. The light emitting element array is a surface emitting laser diode array in which the plurality of surface emitting laser elements are arranged one-dimensionally or two-dimensionally, and at least one of the positive and negative electrodes of the plurality of surface emitting laser elements is connected in series in a row unit. 2. The projector device according to claim 1, wherein the plurality of rows are connected in parallel with each other. The projector device according to claim 1, wherein the shaping optical system shapes the output light of the plurality of semiconductor light emitting elements into the parallel light having a uniform light intensity distribution. The shaping optical system is disposed on a front surface of the light emitting element array so as to face the plurality of semiconductor light emitting elements, and a plurality of micro-shaped optical light emitted from the plurality of semiconductor light emitting elements is shaped into the parallel light. The projector device according to claim 1, wherein the projector device includes a lens. The projector device according to claim 1, wherein the shaping optical system is configured to enlarge or reduce the output light emitted from the plurality of semiconductor light emitting elements by two lenses to shape the parallel light into the parallel light.

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