JP2005049453A - Image projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image projector which can be miniaturized especially as a picture projecting device which radiates light to a projection panel transmitting or reflecting light in accordance with a picture and emits the light transmitted through or reflected from the projection panel. <P>SOLUTION: The image projector (1) includes a 1st light emitting element (11a) provided on an optical axis and emitting the light of a 1st wavelength component to the projection panel (14), a 2nd light emitting element (11b) provided on an axis orthogonal to the optical axis and emitting the light of a 2nd wavelength component in a direction orthogonal to the optical axis, a 3rd light emitting element (11c) provided in parallel with the 2nd light emitting element (11b) and emitting the light of a 3rd wavelength component, a 1st dichroic mirror (12g) arranged at a position where the optical axis and the light from the 2nd light emitting element (11b) are orthogonally crossed, and a 2nd dichroic mirror (12h) arranged at a position where the optical axis and the light from the 3rd light emitting element (11c) are orthogonally crossed, and reflecting the light from the 3rd light emitting element (11c) to the projection panel (14) side, transmitting the light supplied from the 1st dichroic mirror (12g) and reflecting the light from the 3rd light emitting element (11c) toward the projection panel (14). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image projection apparatus, and more particularly to an image projection apparatus that irradiates light onto a projection panel that transmits or reflects light according to an image and emits the transmitted or reflected light of the projection panel.
[0002]
[Prior art]
FIG. 7 is a block diagram showing an example of a conventional image projection apparatus.
[0003]
The conventional image projection apparatus 100 is configured to include a light source 101, a color separation unit 102, liquid crystal panels 103r, 103g, and 103b, an image synthesis unit 104, a projection lens 105, and a control system 106.
[0004]
The light source 101 includes a halogen lamp, a metal halide lamp, a xenon lamp, and the like, and generates light. Light emitted from the light source 101 is supplied to the color separation unit 102. The color separation unit 102 is separated into three primary colors of RGB.
[0005]
The R component light separated by the separation unit 102 is supplied to the liquid crystal panel 103r. In the liquid crystal panel 103r, the amount of transmission is controlled for each pixel based on the image by the control system 106, and an R component image is generated. The G component light separated by the separation unit 102 is supplied to the liquid crystal panel 103g. The transmission amount of the liquid crystal panel 103g is controlled for each pixel based on the image by the control system 106, and a G component image is generated. Further, the B component light separated by the separation unit 102 is supplied to the liquid crystal panel 103b. The transmission amount of the liquid crystal panel 103b is controlled for each pixel based on the image by the control system 106, and an image of the B component is generated.
[0006]
The images for the respective colors generated by the liquid crystal panels 103r, 103g, and 103b are supplied to the image composition unit 104. The image synthesis unit 104 synthesizes the images for each color generated by the liquid crystal panels 103r, 103g, and 103b and outputs a color image.
[0007]
The color image synthesized by the image synthesis unit 104 is supplied to the projection lens 105. The projection lens 105 enlarges the color image supplied from the image composition unit 104 and projects it on the screen.
[0008]
[Problems to be solved by the invention]
However, since conventional image projection devices such as projectors are spatially synthesized, it is necessary to create an image with each of the separated colors after the light source is separated into three primary colors, and then to compose again, so the optical system is complicated. there were. In addition, halogen lamps, metal halide lamps, xenon lamps, and the like are used as light sources. These halogen lamps, metal halide lamps, and xenon lamps are relatively large in size and generate a large amount of heat, so it is generally necessary to provide a cooling fan. It was. For this reason, it was difficult to reduce the size of the apparatus. In addition, noise was generated by the operating sound of the cooling fan.
[0009]
The present invention has been made in view of the above points, and an object thereof is to provide an image projection apparatus that can be miniaturized.
[0010]
[Means for Solving the Problems]
The present invention is directed to an image projection apparatus (1) for emitting light transmitted through a projection panel (14) after changing the amount of light transmitted by a projection panel (14) provided with a display surface orthogonal to the optical axis. The first light emitting element (11a) provided on the optical axis and emitting light having the first wavelength component in the direction of the projection panel (14), the second light emitting element (11a) provided on the axis orthogonal to the optical axis, and the second A second light emitting element (11b) that emits light having a wavelength component in the direction perpendicular to the optical axis, and a second light emitting element (11b) on the image output side of the optical axis on the axis perpendicular to the optical axis. And a third light emitting element (11c) that emits light having a third wavelength component in a direction perpendicular to the optical axis, and emitted from the optical axis and the second light emitting element (11b). The light having the second wavelength component emitted from the second light emitting element (11b) at a position where the light is orthogonal to the optical axis direction Is arranged so as to be reflected on the projection panel (14) side, transmits light of the first wavelength component emitted from the first light emitting element (11a), and is emitted from the second light emitting element (11b). The first dichroic mirror (12g) that reflects the second component light in the direction of the projection panel (14) on the optical axis, and the position where the optical axis and the light emitted from the third light emitting element (11c) are orthogonal to each other. Are arranged so as to reflect the light of the third wavelength component emitted from the third light emitting element (11c) toward the projection panel (14) in the optical axis direction, and supplied from the first dichroic mirror (12g). The light having the first wavelength component and the second wavelength component transmitted is transmitted, and the light having the third wavelength component supplied from the third light emitting element (11c) is projected on the optical axis (14). Second dichroic mirror reflecting in the direction And having a (12h).
[0011]
According to the present invention, the image projection apparatus includes at least a first light emitting element (11a), a second light emitting element (11b), a third light emitting element (11c), and a first dichroic mirror (12g). And the second dichroic mirror (12h), the three light components constituting the color image can be supplied to the projection panel (14) with the minimum necessary optical system. In addition, the loss of light can be minimized and a high-quality projection image can be obtained.
[0012]
In addition, the said reference code is a reference to the last, This does not limit a claim.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a perspective view of one embodiment of the present invention, and FIG. 2 is a block diagram of the main part of one embodiment of the present invention.
[0014]
The image projection apparatus 1 according to this embodiment is a so-called front type projector, and includes a holder 10, light emitting diodes 11 a, 11 b, 11 c, an illumination optical system 12, an optical element 13, a liquid crystal panel 14, a projection lens 15, and a control system 16. The storage space S including the case 17 and the cover 18 is stored.
[0015]
The holder 10 fixes and holds optical systems such as the light emitting diodes 11a, 11b, and 11c, the illumination optical system 12, the optical element 13, the liquid crystal panel 14, and the projection lens 15.
[0016]
The light emitting diode 11 a is composed of a red light emitting diode, and emits red light by a drive current from the control system 16. The light emitting diode 11 b is composed of a blue light emitting diode, and emits blue light by a drive current from the control system 16. The light emitting diode 11 c is composed of a green light emitting diode, and emits green light by a drive current from the control system 16. At this time, the light emitting diodes 11a, 11b, and 11c are configured to emit light sequentially without being simultaneously emitted under the control of the control system 16. The light emitted from the light emitting diodes 11a, 11b, and 11c is supplied to the illumination optical system 12.
[0017]
The illumination optical system 12 includes collimator lenses 12a, 12b, and 12c, lenses 12d, 12e, and 12f, and dichroic mirrors 12g and 12h, and is attached to the holder 10 and fixed.
The collimator lens 12a guides the light emitted from the light emitting diode 11a toward the dichroic mirror 12g so as not to be wasted. The light guided by the collimator lens 12a passes through the dichroic mirror 12g and is supplied to the lens 12d. The lens 12d collects light from the dichroic mirror 12g. The light emitted from the lens 12d passes through the dichroic mirror 12h and is supplied to the lens 12e. The lens 12 e supplies the light from the dichroic mirror 12 h to the optical element 13.
[0018]
The collimator lens 12b guides the light emitted from the light emitting diode 11b in the direction of the dichroic mirror 12g so as not to be wasted. The light guided by the collimator lens 12b is reflected by the dichroic mirror 12g, supplied to the lens 12d, and supplied to the optical element 13 through the lens 12d, the dichroic mirror 12h, and the lens 12e in the same manner as the light from the light emitting diode 11a. Is done.
[0019]
Further, the collimator lens 12c guides the light emitted from the light emitting diode 11c toward the dichroic mirror 12h so as not to be wasted. The light guided by the collimator lens 12c is collected by the lens 12f, then reflected by the dichroic mirror 12h, and supplied to the lens 12e. The lens 12e supplies the light reflected by the dichroic mirror 12h to the optical element 13.
[0020]
At this time, the light emitted from the light emitting diode 11a is supplied to the optical element 13 through the collimator lens 12a, the dichroic mirrors 12g and 12h, and the lenses 12d and 12e. The light emitted from the light emitting diode 11b is supplied to the optical element 13 through the collimator lens 12b, the dichroic mirrors 12g and 12h, and the lenses 12d and 12e. Furthermore, the light emitted from the light emitting diode 11c is supplied to the optical element 13 through the collimator lens 12c, the lens 12f, the dichroic mirror 12h, and the lens 12e.
[0021]
At this time, the light emitting diodes 12a, 12b, and 12c are arranged so that the optical path lengths La, Lb, and Lc of the light emitted from the light emitting diodes 12a, 12b, and 12c become equal, that is, La = Lb = Lc. . As described above, the optical system can be easily adjusted by making the optical path lengths La, Lb, and Lc equal for red light, blue light, and green light.
[0022]
The light emitted from the light emitting diode 11a and the light emitted from the light emitting diode 11b are both supplied to the optical element 13 through one collimator lens, two dichroic mirrors, and two lenses. Therefore, the attenuation amount of the red light emitted from the light emitting diode 11a and the attenuation amount of the blue light emitted from the light emitting diode 11b are substantially equal. The green light emitted from the light emitting diode 11c is supplied to the optical element 13 through one collimator lens, one dichroic mirror, and one lens, and compared with light from the other light emitting diodes 11a and 11b. The amount of attenuation is reduced by one dichroic mirror. The green light emitted from the light emitting diode 11c has a large contribution to brightness in human vision. By reducing the attenuation of the green light emitted from the light emitting diode 11c and increasing the amount of light, the illuminance of the projected image is increased. Can be improved.
[0023]
Here, the reason why the illuminance of the image can be improved by reducing the attenuation of the green light emitted from the light emitting diode 11c and increasing the light amount will be described.
[0024]
FIG. 3 is a diagram showing the relationship between the wavelength and the relative visibility coefficient.
[0025]
As shown in FIG. 3, the relative visibility shows a characteristic having a peak at a wavelength of 555 nm, which is green light.
[0026]
For this reason, the illuminance ratio of red R, green G, and blue B is as follows when trying to produce white having a color temperature of 5500K.
R: G: B = 38.5: 100.0: 5.0 (1)
The color temperature is generally used to represent a white color. The higher the color temperature, the bluish white, and the lower, the reddish white. 5500K is the color temperature of sunlight. Further, the ratio of R, G, and B is an example of the illuminance ratio of each of R, G, and B when using the spectrum (wavelength) distribution of a certain light emitting diode.
[0027]
As shown in Equation (1), it can be seen that the brightness of green light is most important for improving the illuminance. Therefore, when it is desired to increase the brightness, it is most efficient to increase the brightness of the green light if it is allowed to slightly deviate from the target color temperature. This is because the specific luminous efficiency coefficient of green light is the largest.
[0028]
Conversion from W (watt), which is a radiation quantity (physical quantity), to lumen Lm, which is a photometric quantity (physiological quantity for humans), is performed by the following equation.
[0029]
Lm = 683 × W × V (2)
V: Specific visibility coefficient (coefficient representing human visual brightness)
Lm = illuminance (lx) × area (mm ^ 2)
It is represented by Thus, even if R, G, and B each have the same radiation amount W and output, the overall brightness Lm looks brightest when the output of green G light is increased.
[0030]
Therefore, in this embodiment, as shown in FIGS. 1 and 2, the light emitting diode 11c that emits green light is arranged, and the number of times of passing through the dichroic mirror which is a reflection / transmission optical system is set to red light, blue It is possible to improve the brightness by reducing the attenuation of green light emitted from the light emitting diode 11c by reducing the light emitting diodes 11a and 11b that emit light.
[0031]
The optical element 13 is an element that makes the outer shape of incident light substantially coincide with the outer shape of the liquid crystal panel 14 and refracts the light so that its intensity is substantially uniform over the entire surface of the liquid crystal panel 14, for example, a microlens array. Or it comprises a micro optical element such as a microprism.
[0032]
The microlens array has a structure in which a large number of microlenses are arranged on the entire surface, and the cross-sectional shape of incident light by varying the size of each microlens and the curved surface shape according to the position on the surface. The incident light is refracted and emitted so as to substantially match the outer shape of the liquid crystal panel 14 and the intensity thereof is substantially uniform over the entire surface of the liquid crystal panel 14.
[0033]
FIG. 4 is a diagram for explaining the operation of the optical element 13. 4A shows a cross-sectional shape of incident light and outgoing light of the optical element 13, and FIG. 4B shows a light intensity distribution.
[0034]
The light incident on the optical element 13 is light conforming to the light emitted from the light emitting diodes 11a, 11b, and 11c, is circular as shown by a broken line in FIG. 4A, and the spatial distribution of light intensity is shown in FIG. B) shows a Gaussian distribution as indicated by a broken line. The optical element 13 has a rectangular shape that substantially matches the outer shape of the liquid crystal panel 14 as shown by the solid lines in FIGS. 4A and 4B. Thus, the light is shaped and emitted so that its intensity becomes substantially uniform over the entire surface of the liquid crystal panel 14.
[0035]
The light shaped by the optical element 13 is supplied to the liquid crystal panel 14. The liquid crystal panel 14 is composed of a large number of pixels arranged in an n number in the vertical direction and m in the horizontal direction, and is driven in accordance with an image signal from the control system 16. Each pixel of the liquid crystal panel 14 is controlled to increase the light transmission amount if the display luminance is high, and to decrease the light transmission amount if the display luminance is low.
[0036]
As described above, the light incident on the liquid crystal panel 14 is transmitted through the liquid crystal panel 14 according to the display image by changing the transmission amount of the light for each pixel. Light corresponding to the image transmitted through the liquid crystal panel 14 is supplied to the projection lens 15. The projection lens 15 enlarges the light from the liquid crystal panel 14 and projects it on a screen (not shown).
[0037]
Here, the control system 16 will be described.
[0038]
FIG. 5 is a block diagram of the control system 16.
[0039]
The control system 16 includes a video signal processing unit 21, a switching unit 22, a switching signal generating unit 23, and a light emission control unit.
[0040]
A video signal is supplied to the video signal processing unit 21 from the video input port P0. The video signal processing unit 21 separates and generates an R component signal, a G component signal, and a B component signal from the video signal supplied from the video input port P 0, and supplies the separated signal to the switching unit 22.
[0041]
The switching unit 22 includes switches SW1 and SW2. The switch SW1 is supplied with the R component signal and the G component signal from the video signal processing unit 21, and selects the R component signal when the first switching signal from the switching signal generating unit 23 is at the high level, and the low level. At this time, switching is performed so as to select the G component signal.
[0042]
The switch SW2 is supplied with the selection output signal of the switch SW1 and the B component signal from the video signal processing unit 21, and when the second switching signal from the switching signal generation unit 23 is at the high level, the selection output signal of the switch SW1. Is switched so that the B component signal is selected when the level is low. The switching signal generation unit 23 generates first and second switching signals according to the synchronization signal of the video signal processed by the video signal processing unit 21. The first and second switching signals generated by the switching signal generation unit 23 are supplied to the switching unit 22 and the light emission control unit 24.
[0043]
The switching unit 22 outputs an R component signal when the first switching signal and the second switching signal from the switching signal generation unit 23 are both at a high level, the first switching signal is at a low level, and the second switching signal. When the signal is high level, the G component signal is output, and when both the first switching signal and the second switching signal are low level, the B component signal is output. In addition, when both the first switching signal and the second switching signal are at a high level, the light emission control unit 24 supplies a driving signal to the light emitting diode 11a that emits R component light, and the first switching signal is at a low level. When the level and the second switching signal are at the high level, a drive signal is supplied to the light emitting diode 11c that emits light of the G component, and when both the first switching signal and the second switching signal are at the low level, the B component A drive signal is supplied to the light emitting diode 11b that emits the light.
[0044]
FIG. 6 is a diagram for explaining the operation of the control system 16. 6A is a first switching signal generated by the switching signal generator 23, FIG. 6B is a second switching signal generated by the switching signal generator 23, and FIG. 6C is a switching unit. 22 shows the selected output and the light emitting states of the light emitting diodes 11a, 11b, and 11c.
[0045]
In the period T11, when both the first switching signal and the second switching signal generated by the switching signal generation unit 23 become high level as shown in FIGS. 6A and 6B, FIG. As shown, an R component signal is output from the switching unit 22. At this time, as shown in FIG. 6D, the light emitting diode 11 a is driven, and R component light is emitted and incident on the liquid crystal panel 14.
Next, in the periods T12 and T21, when the first switching signal becomes low level as shown in FIG. 6A and the second switching signal becomes high level as shown in FIG. 6B, FIG. As shown in C), the G component signal is output from the switching unit 22. At this time, as shown in FIG. 6D, the light emitting diode 11c is driven, G component light is emitted, and is incident on the liquid crystal panel.
[0046]
Further, when both the first switching signal and the second switching signal generated by the switching signal generation unit 23 become low level in the period T13 as shown in FIGS. 6A and 6B, FIG. B component signal is output from the switching unit 22 as shown in FIG. At this time, as shown in FIG. 6D, the light emitting diode 11b is driven, B component light is emitted, and is incident on the liquid crystal panel.
[0047]
As described above, the image displayed on the liquid crystal panel 14 and the light component incident on the liquid crystal panel 14 are sequentially switched in the order of the R component, the G component, and the B component. By sequentially projecting the G component video and the B component video, the R component video, the G component video, and the B component video are combined to display a color video.
[0048]
According to the present embodiment, it is possible to reduce the size of the device by using the light emitting diodes 11a, 11b, and 11c that are small and have high luminance as the light source. In addition, the optical element 13 changes the shape of the light emitted from the light emitting diodes 11a, 11b, and 11c from a circular shape to a rectangular shape corresponding to the liquid crystal panel, and converts the light distribution from a Gaussian distribution to a surface uniform distribution. By improving the utilization efficiency, it is possible to prevent a decrease in the brightness of the projected image, improve the unevenness of the projected image, and improve the image quality. Further, since the cooling fan provided in the conventional projector is unnecessary, noise such as an operating noise of the fan does not occur. In this embodiment, the apparatus can be reduced in size by comprising a single liquid crystal panel 14 and synthesizing RGB images temporally.
[0049]
In the present embodiment, the optical element 14 is disposed immediately before the liquid crystal panel 14, but may be disposed immediately after the light emitting diodes 11a, 11b, and 11c.
[0050]
In this embodiment, one light emitting diode for each of RGB is used as the light source. However, the present invention is not limited to this, and laser light may be used as the light source. In this case, if the emitted laser light is generated using a semiconductor laser or the like, it can contribute to miniaturization.
[0051]
Furthermore, in the present embodiment, the image is expressed by transmitting light to the liquid crystal panel 14, but the image may be expressed by using a reflective projection panel such as a DMD (digital micro-mirror device). Good.
[0052]
【The invention's effect】
As described above, according to the present invention, the image projection apparatus includes at least the first light emitting element, the second light emitting element, the third light emitting element, the first dichroic mirror, and the second dichroic mirror. Since the three light components that make up the color image can be supplied to the projection panel by using the minimum necessary optical system, it is possible to reduce the size and minimize the loss of light with high quality. The projection image can be obtained.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an embodiment of the present invention.
FIG. 2 is a block diagram of a main part of an embodiment of the present invention.
FIG. 3 is a diagram illustrating a relationship between a wavelength and a relative visibility coefficient.
4 is an operation explanatory diagram of the optical element 13. FIG.
FIG. 5 is a block configuration diagram of a control system 16;
6 is an operation explanatory diagram of a control system 16. FIG.
FIG. 7 is a configuration diagram of an example of a conventional image projection apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Image projector 11a, 11b, 11c Light emitting diode, 12 Illumination optical system 13 Optical element, 14 Liquid crystal panel, 15 Projection lens, 16 Control system 21 Video signal processing part 22 Switching part, 23 Switching signal generation part, 24 Light emission control part

Claims (8)

In the image projection apparatus for emitting the transmitted light of the projection panel after changing the light transmission amount by the projection panel provided with the display surface orthogonal to the optical axis,
A first light emitting element that is provided on the optical axis and emits light having a first wavelength component toward the projection panel;
A second light emitting element that is provided on an axis perpendicular to the optical axis and emits light having a second wavelength component in a direction perpendicular to the optical axis;
Provided in parallel with the second light emitting element on the image output side of the optical axis on an axis orthogonal to the optical axis, and emits light having a third wavelength component in a direction orthogonal to the optical axis. A third light emitting element;
Light having the second wavelength component emitted from the second light emitting element at a position where the light emitted from the second light emitting element is orthogonal to the optical axis toward the projection panel in the optical axis direction The light having the second wavelength component emitted from the second light emitting element is transmitted, and the light having the second wavelength component emitted from the first light emitting element is transmitted. A first dichroic mirror that reflects in the direction of the projection panel on the optical axis;
The light having the third wavelength component emitted from the third light emitting element at a position where the optical axis and the light emitted from the third light emitting element are orthogonal to each other on the projection panel side in the optical axis direction The first light component is transmitted from the first light emitting element and transmits the light having the first wavelength component and the second wavelength component supplied from the first dichroic mirror, and is supplied from the third light emitting element. An image projection apparatus comprising: a second dichroic mirror that reflects light having a wavelength component of 3 toward the projection panel on the optical axis. 2. The image projection according to claim 1, wherein the first light emitting element, the second light emitting element, and the third light emitting element are arranged to have the same optical path length to the projection panel. apparatus. A first lens that is provided between the first dichroic mirror and the second dichroic mirror on the optical axis, and that collects light supplied from the first dichroic mirror;
2. A second lens that is provided between the third light emitting element and the second dichroic mirror and collects light emitted from the third light emitting element. Or the image projector of 2. A third lens is provided between the second dichroic mirror on the optical axis and the projection panel, and irradiates the projection panel with light emitted from the second dichroic mirror. The image projection apparatus according to claim 1. 5. The image projection apparatus according to claim 1, wherein each of the first light emitting element, the second light emitting element, and the third light emitting element includes a light emitting diode. 6. The image projection apparatus according to claim 1, wherein the first light emitting element, the second light emitting element, and the third light emitting element are configured by laser light generating elements. . In the first period, the first light emitting element is caused to emit light, the second light emitting element and the third light emitting element are extinguished, and an image of the first component is displayed on the projection panel,
When the second light emitting element is caused to emit light and the first light emitting element and the third light emitting element are extinguished in a second period different from the first period, Display the image of the two components,
The projection panel when the third light emitting element is caused to emit light and the first light emitting element and the second light emitting element are turned off in a third period different from the first and second periods. A control unit that displays an image of the third component in
The image projection apparatus according to claim 1, wherein a color image is projected by sequentially repeating the first to third timings by the control unit. The third light emitting element emits light of a green component of the three primary colors as the third wavelength component,
The first light emitting element emits light of any one of a red component and a blue component among the three primary colors as the first wavelength component,
The second light emitting element emits light of a component different from the first component emitted from the first light emitting element, of the three primary colors, the red component or the blue component, as the second wavelength component. The image projection apparatus according to claim 1, wherein the image projection apparatus is an image projection apparatus.

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