JP2008003270A - Illumination device and projection-type image display device using the same - Google Patents

Abstract

By detecting a change in the light amount of the light source and a change in the emission main wavelength caused by a change in the ambient temperature condition and the light source drive condition, and controlling the drive of the light source according to the detection result, the entire color reproduction range is detected. Provided are an illumination device and a projection-type image display device that always realize stable brightness and chromaticity.
A light emitting element having a plurality of colors, a color combining optical system for color combining light beams emitted from the light emitting elements of the plurality of colors, a rod integrator at a subsequent stage of the color combining optical system, and a light for forming an image A condensing lens that is composed of a bulb and a projection lens and that is arranged between the color synthesis optical system and the rod integrator has a light branching part that emits part of the illumination light outside the effective area of the illumination optical path in close contact or in the vicinity, Furthermore, a detection element capable of detecting the emission intensity of the emitted light is provided.
[Selection] Figure 1

Description

  The present invention relates to an illumination device and a projection type image display device using the same.

  In recent years, as a backlight light source for LCD (Liquid Crystal Device), which is an image display device, or as a backlight light source for an LCD TV, or as an illumination light source for a projector, which is a projection-type image display device, it has been replaced with a conventional cold cathode tube or an ultra-high pressure mercury lamp. Using a light emitting diode (LED) or a semiconductor laser, the color reproduction range is expanded.

  In the case of a semiconductor light source such as an LED or a laser, its emission spectrum is different from that of a cold cathode tube or an ultrahigh pressure mercury lamp, and has a characteristic concentrated in a relatively narrow wavelength range, and R (Red) as a light source for illumination. ), G (Green), and B (Blue) in many combinations.

  It is known that such a semiconductor light source has a light emission output that changes depending on a temperature change of the surrounding environment, a temperature change of the light source itself, or a driving condition, that is, a driving current amount. The light emission output here is a light amount, that is, brightness and a light emission dominant wavelength. As these change, the chromaticity and luminance of each primary color change, and the luminance and color temperature of the entire screen, that is, the chromaticity of white changes.

  Therefore, for example, Patent Document 1 proposes a technique for particularly stabilizing the chromaticity of white by performing feedback control using a photodetector.

Specifically, a first configuration in which reflected light of light projected on the screen from the projection lens is detected by a common sensor, and a light branching unit is provided between the projection lens and the light valve that modulates the image. A second configuration for detecting by the sensor, a third configuration for detecting by each color sensor having a light branching unit between the light valve for each color for modulating the image and each light source, the direction of the projection lens or the projection A projection-type image display apparatus using a fourth configuration that includes a DMD element in which movable mirrors that reflect in a direction other than the lens are arranged in a matrix form as a light valve, and that detects light reflected in a direction other than the projection lens. Proposed.
JP 2004226663 A

  In the first detection configuration of the conventional projection type image display apparatus shown above, it is necessary to project white color on a screen after eliminating the influence of general illumination light and making a dark room. There is a problem that it is easily affected by the light distribution characteristics of the light, that is, the reflection characteristics of the projected colors.

  One of the second detection configurations uses a prism as a light branching portion between the projection lens and the light valve, and it is necessary to take a long back focus of the projection lens, so that a large projected image can be obtained at a short distance. It will be disadvantageous. Further, in the second detection configuration using the diffraction element as the light branching portion, the second detection configuration is limited to a light valve that modulates polarized light, and further causes deterioration in resolution and contrast.

  In the third detection configuration, a diffractive element is used between the light source and the light valve. However, variations in the diffractive elements for the respective colors and variations in accuracy of the sensors for the respective colors are problems.

  Further, in the second and third detection configurations, since it is necessary to input a signal for displaying white in an image or to provide it as an internal signal, adjustment while displaying an image other than white is impossible. is there.

  Further, in the fourth detection configuration, since the incident angles from the light sources of the respective colors to the DMD are different, the light distribution characteristics of the light sources need to be ideally uniform, which is not practical, and further in directions other than the projection lens. In order to detect from the description of reflected light, it is necessary to display black on the screen, and in order to detect automatically, a black display must be inserted during video display.

  The present invention solves the above-described conventional problems, and a detection configuration that performs feedback control using a photodetector for improving color uniformity and luminance uniformity while suppressing an increase in cost. An object of the present invention is to provide an illumination device and a projection-type image display device provided.

  In order to achieve the above object, the illumination device of the present invention includes a plurality of light emitting elements of each color, a color combining optical system for color combining light beams emitted from the plurality of light emitting elements of each color, and the color combining optical system. A rod integrator is provided at the latter stage, and a light branching unit that emits a part of the color-combined white light beam outside the effective optical path is closely attached to the condenser lens disposed between the color combining optical system and the rod integrator. Or a detection element provided in the vicinity and capable of appropriately detecting the light emission intensity of the light beam emitted from the light branching portion.

  The illumination device according to the present invention includes a plurality of light emitting elements of each color, a color combining optical system for color combining light beams emitted from the plurality of light emitting elements of each color, and a first stage after the color combining optical system. An integrator optical system composed of a lens array and a second lens array is configured, and light that causes a part of the color-combined white light beam to be emitted outside the effective range of the illumination light path to the lens group constituting the first lens array And a detection element capable of appropriately detecting the light emission intensity of the light beam emitted from the light branching unit.

  The projection-type image display apparatus according to the present invention includes a plurality of light emitting elements of each color, a color combining optical system that combines light beams emitted from the plurality of light emitting elements of each color, a light valve that forms an image, and the light A projection lens for projecting an image formed on the bulb; and a rod integrator at a rear stage of the color synthesis optical system; and the color synthesis on the condenser lens disposed between the color synthesis optical system and the rod integrator. A light branching part that emits a part of the white light beam emitted outside the effective range of the illumination light path is provided in close contact or in the vicinity thereof, and a detection element capable of appropriately detecting the light emission intensity of the light beam emitted from the light branching part. It is characterized by.

  Further, the projection type image display apparatus of the present invention includes a plurality of light emitting elements of each color, a color combining optical system for color combining light beams emitted from the light emitting elements of the plurality of colors, a light valve for forming an image, An integrator optical system comprising a projection lens for projecting an image formed on the light valve and a first lens array and a second lens array downstream of the color synthesis optical system is configured, and the first lens array And a detection element capable of appropriately detecting the light emission intensity of the light beam emitted from the light branching portion, and a light branching portion that emits a part of the color-combined white light beam outside the effective optical path area. It is characterized by having.

  According to the present invention, a change in the light amount of the light source caused by a change in the ambient temperature condition or the light source driving condition, and a change in the emission main wavelength are appropriately detected, and the light source driving is controlled in accordance with the detection result, so that the color Stable brightness and chromaticity can always be achieved over the entire reproduction range. Further, there is a feature that it is not necessary to input an adjustment signal or the like as an internal signal.

  The color synthesizing optical system of the illumination device or the projection type image display device of the present invention is constituted by a dichroic mirror without using an expensive color synthesizing prism, and the condensing lens system is constituted by a plurality of lenses. As a result, it is possible to easily ensure mechanical holding accuracy for improving color uniformity and luminance uniformity while suppressing an increase in cost.

  The illumination device or the projection type image display device according to the present invention is characterized in that a detection element capable of appropriately detecting the emission intensity of the combined light is disposed in the subsequent stage of the color combining optical system. According to this configuration, since the light emitted from each color light source can detect light passing through the same optical path at the same detection position, variation due to the optical path and detection elements for each color are used. Variations in the detection element can be eliminated.

  In the illumination device or the projection type image display device of the present invention, it is desirable to provide a rod integrator at the rear stage of the light branching unit. Alternatively, it is desirable that the light branching unit is provided in addition to the effective part of the integrator made of a lens array. According to this configuration, it is possible to suppress unevenness in the luminance of the screen that is caused by taking out part of the projection light at the light branching portion. Further, the light diffusing means may be frosted glass or plastic whose surface is processed into frosted glass, glass or plastic provided with an opal layer on the substrate surface, glass, film or plastic provided with randomly arranged uneven patterns. It is characterized by that. According to this configuration, it is possible to suppress variation in the amount of light incident on the sensor by diffusing even light with uneven intensity.

  The illumination device or the projection type image display device according to the present invention is characterized in that at least red, blue, and green semiconductor light emitting elements are arranged as the light emitting elements of a plurality of colors.

  Moreover, it is preferable that at least one of the first dichroic mirror and the second dichroic mirror has an optical film thickness changed in one direction in the plane. According to this configuration, even when the incident angle to the dichroic mirror changes uniformly from the optical axis to the peripheral portion, color unevenness and luminance unevenness can be prevented.

  Moreover, it is preferable that at least one surface of the condenser lens disposed between the semiconductor light emitting element and the dichroic mirror has an aspherical shape. According to this configuration, aberration correction becomes easy.

  The semiconductor light emitting element is preferably a light emitting diode element, an electroluminescence element, or a semiconductor laser element.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a conceptual diagram of an optical system of a projection type image display apparatus according to Embodiment 1. FIG. 2 is an enlarged conceptual diagram of the light detection unit 3 shown in FIG. In the figure, 1-G is a green semiconductor light emitting element, 1-R is a red semiconductor light emitting element, and 1-B is a blue semiconductor light emitting element. Examples of the semiconductor light emitting element include a light emitting diode element, an electroluminescence element, and a semiconductor laser element.

  Reference numerals 101 to 104 denote a condensing lens system that creates light source images of the semiconductor light emitting elements in the vicinity of the incident surface 9a of the rod integrator 9 described later, from the light emitted from the semiconductor light emitting elements of the respective colors. 101 is a first condenser lens, 102 is a second condenser lens, 103 is a third condenser lens, and 104 is a fourth condenser lens. Reference numeral 2 denotes a light branching unit, which is composed of a lens having an effective portion at a position shifted from the apex position, and is in close contact with the fourth condenser lens 104. Reference numeral 3 denotes a light detection unit, and FIG. 2 shows an enlarged top view and an enlarged front view. In FIG. 2, 4 is a sensor, and 5 is a diffusion means. Reference numeral 10 denotes a first dichroic mirror, and 11 denotes a second dichroic mirror. 9 is a rod integrator. Reference numeral 12 denotes a total reflection mirror.

  201 is a first relay lens, 202 is a second relay lens, and 203 is a field lens. 7 is a total reflection prism, 8 is a reflection type light valve, and 6 is a projection lens.

  In FIG. 1, the first condenser lens 101 and the second condenser lens 102 are provided between the semiconductor light emitting element 1 -G and the first dichroic mirror 10, and between the semiconductor light emitting element 1 -R and the first dichroic mirror 10. And between the semiconductor light emitting element 1 -B and the total reflection mirror 12.

  The third condenser lens 103 is disposed between the first dichroic mirror 10 and the second dichroic mirror 11 and between the total reflection mirror 12 and the second dichroic mirror 11.

  In the example of FIG. 1, the total reflection mirror 12 is disposed between the second condenser lens 102 and the third condenser lens 103 that collect the semiconductor light emitting element 1 -B for the purpose of downsizing. However, the structure which excluded this may be sufficient.

  The first dichroic mirror 10 is disposed between the second condenser lens 102 and the third condenser lens 103. The first dichroic mirror 10 has a characteristic of transmitting green and reflecting red.

  Further, the first dichroic mirror 10 changes the optical film thickness in one direction within the surface. That is, the optical film thickness changes according to the incident angle that changes as the distance from the optical axis increases. As a result, the spectral characteristics of the peripheral portion where the incident angle is different from 45 degrees are made as close as possible to the spectral characteristics on the optical axis at the incident angle of 45 degrees.

  By configuring in this way, even if the incident angle to the first dichroic mirror 10 changes uniformly from the optical axis to the peripheral portion, the optical film thickness is changed accordingly, so that color unevenness, Brightness unevenness can be prevented.

  The second dichroic mirror 11 is disposed between the third condenser lens 103 and the fourth condenser lens 104. The second dichroic mirror 11 has a characteristic of transmitting green and red and reflecting blue.

  The second dichroic mirror 11 changes the optical film thickness in one direction within the surface. That is, the optical film thickness changes according to the incident angle that changes as the distance from the optical axis increases. As a result, the spectral characteristics of the peripheral portion where the incident angle is different from 45 degrees are made as close as possible to the spectral characteristics on the optical axis at the incident angle of 45 degrees.

  By configuring in this way, even if the incident angle to the second dichroic mirror 11 changes uniformly from the optical axis to the peripheral part, the optical film thickness is changed accordingly, so that color unevenness, Brightness unevenness can be prevented.

  That is, there is no difference in color between light detected by the light detection unit 3 described later and projection light.

  However, since the second dichroic mirror 11 is often closer to parallel light than the light beam passing through the first dichroic mirror 10, the mirror whose optical film thickness is always changed in one direction in the plane as described above. May not be used. Furthermore, since the arrangement of blue, green, and red of the semiconductor light emitting element is not limited, the specification of the dichroic mirror may be changed in accordance with the arrangement.

  In addition, the first condenser lens 101 and the second condenser lens 102 can also be configured by a single aspheric lens having an aspheric shape on at least one of the surfaces.

  The number of condensing lenses is not limited to the example of FIG. 1, but it is necessary to create a light source image of the semiconductor light emitting element in the vicinity of the incident surface 9 a of the rod integrator 9.

  Here, in the present embodiment, the condensing lens system is composed of a plurality of lenses, and the focal length of each lens is increased by adopting a configuration in which a color synthesizing system composed of a dichroic mirror is inserted between the condensing lenses. Therefore, it is easy to ensure the component accuracy and the holding accuracy by avoiding sensitivity to color unevenness and brightness unevenness.

  Next, the operation of the present embodiment will be described with reference to FIG. The green and red luminous fluxes emitted from the semiconductor light emitting elements 1-G and 1-R of the respective colors are condensed by the first condenser lens 101 and the second condenser lens 102 and enter the first dichroic mirror 10. . The first dichroic mirror 10 color-combines the green light emitted from the semiconductor light emitting element 1 -G and the red light emitted from the semiconductor light emitting element 1 -R, and the second light is transmitted through the third condenser lens 103. Is incident on the dichroic mirror 11.

  On the other hand, the light emitted from the semiconductor light emitting element 1-B is condensed by the first condenser lens 101 and the second condenser lens 102, and the second dichroic is passed through the total reflection mirror 12 and the third condenser lens 103. Incident on the mirror 11. The second dichroic mirror 11 synthesizes green, red, and blue into white. Further, a light source image of the semiconductor light emitting element is formed in the vicinity of the incident surface 9 a of the rod integrator 9 by the condensing lens system of the first condensing lens 101 to the fourth condensing lens 104.

  The light beams of the respective colors synthesized in white are incident on the rod integrator 9, and the light source image of the semiconductor light emitting element is appropriately reflected on the inner surface of the rod integrator 9 and formed in a divided manner, and the incident light flux has a non-uniform illuminance distribution. Even so, it is emitted as an illumination light beam with excellent uniformity. The light beam emitted from the rod integrator 9 illuminates the reflective light valve via the first relay lens 201, the second relay lens 202, the field lens 203 and the total reflection prism 7.

  The reflective light valve 8 emits modulated light that forms an optical image. The light flux from the reflective light valve 8 reaches the projection lens 6 through the total reflection prism 7. The projection lens 6 projects the optical image formed by the reflective light valve 8.

  The reflective light valve 8 is composed of a digital mirror device that is an aggregate of fine mirrors, and displays an image by an electric signal output from a drive circuit (not shown). The image displayed on the reflection type light valve 8 is enlarged and projected through the total reflection prism 7 and the projection lens 6 and projected onto a screen (not shown).

  On the other hand, part of the light beam synthesized in white by the light branching unit 2 provided in close contact with the fourth condenser lens 104 is emitted toward the light detection unit 3. In addition, since the projection effective light beam partially branched is emitted by the rod integrator 9 as an illumination light beam having excellent uniformity, the non-uniformity of the projection light caused by partial branching is eliminated. Furthermore, the light detection unit 3 is provided outside the effective range of the projected light beam.

  In addition, the light beam emitted from the light branching unit 2 is diffused by the diffusing unit 5 in FIG. 2, and the light distribution characteristics are not steep, and detection variations due to positional deviation can be suppressed. The light beam emitted from the diffusing unit 5 enters the sensor 4. The sensor 4 is, for example, a photosensor in which a color filter is attached to a photodiode, and outputs a signal indicating the amount of light. In addition, the control unit 30 compares the output signal value with the signal value when the white balance is adjusted by changing the R, G, and B light amounts in advance, so that the difference between the light sources is reduced. By changing the driving gain, feedback control is performed so as to maintain a desired light amount of each color. By continuously and periodically performing the feedback, white chromaticity and luminance are kept constant, and a stable white balance can be obtained.

  In the present embodiment, an example of a projection type image display apparatus has been described. However, if an apparatus including at least a configuration from a semiconductor light emitting element of each color to a field lens 203 is used as a lighting apparatus in the order in which light travels, high luminance and An illumination device that can irradiate uniform light can be realized. The same applies to the following embodiments.

(Embodiment 2)
FIG. 3 is a conceptual diagram of an optical system of the projection type image display apparatus according to the second embodiment. Components having the same configuration as that of the projection type image display apparatus shown in FIG.

  In the present embodiment, unlike the condenser lens system of the first condenser lens 101 to the fourth condenser lens 104 having the configuration shown in FIG. 1, the condenser of the first condenser lens 105 to the fourth condenser lens 108 is used. The light beam emitted from the optical lens system is substantially parallel light. This is to improve the performance of the integrator using the lens array described later.

  Here, in the present embodiment, as in the first embodiment, the condensing lens system is configured by a plurality of lenses, and a color synthesizing system including a dichroic mirror is inserted between the condensing lenses. By increasing the focal length of each lens so as not to be sensitive to color unevenness and brightness unevenness, it is easy to ensure component accuracy and holding accuracy.

  Further, the first dichroic mirror 13 has an optical film thickness changed from the optical axis to the peripheral portion as in the first embodiment. By configuring in this way, even if the incident angle to the dichroic mirror changes uniformly from the optical axis to the peripheral part, by changing the optical film thickness accordingly, color unevenness and brightness unevenness can be reduced. Occurrence can be prevented. The optical film thickness of the second dichroic mirror 14 is also changed in one direction within the surface. That is, the optical film thickness changes according to the incident angle that changes as the distance from the optical axis increases. As a result, the spectral characteristics of the peripheral portion where the incident angle is different from 45 degrees are made as close as possible to the spectral characteristics on the optical axis at the incident angle of 45 degrees.

  By configuring in this way, even if the incident angle to the second dichroic mirror 14 changes uniformly from the optical axis to the peripheral part, the optical film thickness is changed accordingly, so that color unevenness, Brightness unevenness can be prevented.

  That is, the color difference between the light detected by the light detection unit 3 described later and the projection light is prevented.

  However, since the second dichroic mirror 14 is often closer to parallel light than the light beam passing through the first dichroic mirror 13, the mirror whose optical film thickness is always changed in one direction in the plane as described above. May not be used. Furthermore, since the arrangement of blue, green, and red of the semiconductor light emitting element is not limited, the specification of the dichroic mirror may be changed in accordance with the arrangement.

  A light beam emitted from the fourth condenser lens 108 as substantially parallel light is converted into a light beam incident on the first lens array 90 by a lens array integrator composed of the first lens array 90 and the second lens array 91. Even with a non-uniform illuminance distribution, it is superimposed on a reflective light valve 9 described later, and as a result, an illumination light beam with excellent uniformity can be obtained. The light beams emitted from the first lens array 90 and the second lens array 91 illuminate the reflective light valve 8 via the first relay lens 204, the field lens 205, and the total reflection prism 7. Thereafter, as described in the first embodiment, the image is enlarged and projected via the projection lens 6 and projected onto a screen (not shown).

  On the other hand, by providing the light branching unit 20 including a lens having an effective portion at a position shifted from the apex position outside the effective range of the first lens array 90, a part of the light beam synthesized in white is detected by the light detecting unit 3. It is injected towards. Although the effective area of the light beam emitted from the fourth condenser lens 108 is circular, the lens array is composed of a rectangular lens group, and therefore there is an area that cannot be used in the peripheral portion. It is intended to detect the light flux in that region and does not affect the projection system. Further, the light detection unit 3 is installed outside the effective range of the second lens array 91.

  The light beam emitted by the light branching unit 20 is diffused by the diffusing unit 5 in FIG. 2, and the light distribution characteristics are not steep, and detection variations due to misalignment can be suppressed.

  Further, the light beam emitted from the diffusing unit 5 enters the sensor 4. The sensor 4 is, for example, a photosensor in which a color filter is attached to a photodiode, and outputs a signal indicating the amount of light. In addition, the control unit 30 compares the output signal value with the signal value when the white balance is adjusted by changing the R, G, and B light amounts in advance, so that the difference between the light sources is reduced. Feedback control is performed so as to maintain a desired light amount of each color by changing the drive gain. By continuously and periodically performing the feedback, white chromaticity and luminance are kept constant, and a stable white balance can be obtained.

  In the present embodiment, an example of a projection type image display apparatus has been described. However, if an apparatus including at least a configuration from a semiconductor light emitting element of each color to a field lens 203 is used as a lighting apparatus in the order in which light travels, high luminance and An illumination device that can irradiate uniform light can be realized.

(Embodiment 3)
FIG. 4 is a conceptual diagram of an optical system of the projection type image display apparatus according to the third embodiment. Components having the same configuration as that of the projection type image display apparatus shown in FIG. 1 of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the present embodiment, unlike the condenser lens system of the first condenser lens 101 to the fourth condenser lens 104 having the configuration shown in FIG. 1, the first condenser lens 301, the second condenser lens 302, and the first condenser lens It is composed of three condensing lenses 303. By making the curved surface of the condensing lens an aspherical surface, the condensing efficiency can be made almost equal, and the condensing efficiency can be reduced. However, the number of lens curved surfaces to be aspherical is not limited. On the other hand, the luminous flux of each color is a color composition in which the first dichroic mirror 16 and the second dichroic mirror 17 inserted between the second condenser lens 302 and the third condenser lens 303 are crossed and arranged in an X shape. Color synthesis is performed by an optical system. According to the color composition configuration, the color composition system can be reduced to about ½ of the color composition system described in the first and second embodiments. With the above configuration, the condenser lens system and the color composition system can be reduced.

  The color-combined light beams of the respective colors enter the rod integrator 9, and the light source image of the semiconductor light emitting element is appropriately reflected and divided by the inner surface of the rod integrator 9, and the incident light flux has a non-uniform illuminance distribution. Even so, it is emitted as an illumination light beam with excellent uniformity. The light beam emitted from the rod integrator 9 illuminates the reflective light valve via the first relay lens 201, the second relay lens 202, the field lens 203 and the total reflection prism 7.

  The reflective light valve 8 emits modulated light that forms an optical image. The light flux from the reflective light valve 8 reaches the projection lens 6 through the total reflection prism 7. The projection lens 6 projects the optical image formed by the reflective light valve 8.

  The reflective light valve 8 is composed of a digital mirror device that is an aggregate of fine mirrors, and displays an image by an electric signal output from a drive circuit (not shown). The image displayed on the reflection type light valve 8 is enlarged and projected through the total reflection prism 7 and the projection lens 6 and projected onto a screen (not shown).

  On the other hand, a part of the color-combined light beam is emitted toward the light detection unit 3 by the light branching unit 21 provided in close contact with the third condenser lens 303. In addition, since the projection effective light beam partially branched is emitted by the rod integrator 9 as an illumination light beam having excellent uniformity, the non-uniformity of the projection light caused by partial branching is eliminated. Furthermore, the light detection unit 3 is provided outside the effective range of the projected light beam.

  In addition, the light beam emitted from the light branching unit 21 is diffused by the diffusing unit 5 in FIG. 2, and the light distribution characteristic is not steep, so that detection variations due to misalignment can be suppressed. The light beam emitted from the diffusing unit 5 enters the sensor 4. The sensor 4 is, for example, a photosensor in which a color filter is attached to a photodiode, and outputs a signal indicating the amount of light. In addition, the control unit 30 compares the output signal value with the signal value when the white balance is adjusted by changing the R, G, and B light amounts in advance, so that the difference between the light sources is reduced. By changing the driving gain, feedback control is performed so as to maintain a desired light amount of each color. By continuously and periodically performing the feedback, white chromaticity and luminance are kept constant, and a stable white balance can be obtained.

  In the present embodiment, an example of a projection type image display apparatus has been described. However, if an apparatus including at least a configuration from a semiconductor light emitting element of each color to a field lens 203 is used as a lighting apparatus in the order in which light travels, high luminance and An illumination device that can irradiate uniform light can be realized.

  As described above, according to the present invention, even when there is a change in the amount of light and a change in the emission main wavelength in the semiconductor light emitting device, it is possible to control the driving of the light source according to the detection result. It is useful as a lighting device or a projection type image display device that always realizes stable brightness and chromaticity over the entire reproduction range.

1 is a conceptual diagram of an optical system of a projection type image display apparatus according to Embodiment 1 of the present invention. Enlarged conceptual diagram of the photodetecting unit according to Embodiments 1, 2, and 3 of the present invention Conceptual diagram of an optical system of a projection type image display apparatus according to Embodiment 2 of the present invention. Conceptual diagram of an optical system of a projection type image display apparatus according to Embodiment 3 of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1-R Red semiconductor light emitting element 1-G Green semiconductor light emitting element 1-B Blue semiconductor light emitting element 2, 20, 21 Light branching part 3 Photodetection part 4 Sensor 5 Diffusing means 6 Projection lens 7 Total reflection prism 8 Reflection type light valve 9 Rod integrator 9a Rod integrator incident surface 10, 13, 16 First dichroic mirror 11, 14, 17 Second dichroic mirror 12, 15 Total reflection mirror 30 Control unit 90 First lens array 91 Second lens array 101, 105 , 301 First condenser lens 102, 106, 302 Second condenser lens 103, 107, 303 Third condenser lens 104, 108 Fourth condenser lens 201, 204 First relay lens 202 Second relay lens 203, 205 Field lens

Claims (22)

A plurality of light emitting elements of each color;
A color synthesizing optical system for color synthesizing light beams respectively emitted from the light emitting elements of the plurality of colors;
A light branching unit that emits a part of the color-combined white light beam outside the effective optical path area after the color combining optical system;
An illumination device, comprising: a detection element capable of appropriately detecting the light emission intensity of the light beam emitted from the light branching unit. A rod integrator is provided at the subsequent stage of the color synthesis optical system,
The illumination device according to claim 1, wherein the light branching portion is provided in close contact with or in the vicinity of a condenser lens disposed between the color synthesis optical system and the rod integrator. An integrator optical system composed of a first lens array and a second lens array is formed after the color synthesis optical system,
The lighting device according to claim 1, wherein the optical branching unit is provided in a lens group constituting the first lens array. The lighting device according to any one of claims 1 to 3, wherein the light branching unit is any one of a lens, a prism, a total reflection mirror, and a diffraction element. The illumination device according to any one of claims 1 to 4, further comprising a light diffusing unit in a stage preceding the detection element common to each color. For the light diffusing means, either frosted glass or plastic whose surface is processed into frosted glass, glass or plastic provided with an opal layer on the substrate surface, glass provided with randomly arranged uneven patterns, film or plastic The lighting device according to claim 5, further comprising: 5. The color synthesis optical system includes at least two dichroic mirrors of a first dichroic mirror and a second dichroic mirror in order from the light emitting element side. Lighting equipment. 5. The illumination device according to claim 1, wherein in the color synthesis optical system, the first dichroic mirror and the second dichroic mirror intersect each other and are arranged in an X shape. 9. The optical film having a film thickness changed in one direction in the plane is provided on at least one dichroic mirror of the first dichroic mirror and the second dichroic mirror. Lighting equipment. The lighting device according to claim 1, wherein the light emitting elements of the plurality of colors are red, blue, and green semiconductor light emitting elements. The lighting device according to claim 10, wherein the light emitting element is any one of a light emitting diode element, an electroluminescence element, and a semiconductor laser element. A plurality of light emitting elements of each color;
A color synthesizing optical system for color synthesizing light beams respectively emitted from the light emitting elements of the plurality of colors;
A light valve that forms an image;
A projection lens that projects an image formed on the light valve;
A light branching unit that emits a part of the color-combined white light beam outside the effective optical path area after the color combining optical system;
A projection type image display apparatus comprising: a detection element capable of appropriately detecting the light emission intensity of the light beam emitted from the light branching unit. A rod integrator is provided at the subsequent stage of the color synthesis optical system,
13. The projection type image display device according to claim 12, wherein the light branching unit is provided in close contact with or in the vicinity of a condenser lens disposed between the color synthesis optical system and the rod integrator. An integrator optical system composed of a first lens array and a second lens array is formed after the color synthesis optical system,
The projection image display apparatus according to claim 12, wherein the optical branching unit is provided in a lens group constituting the first lens array. The projection image display apparatus according to claim 12, wherein the light branching unit is any one of a lens, a prism, a total reflection mirror, and a diffraction element. 16. The projection type image display apparatus according to claim 12, further comprising a light diffusing unit in front of the detection elements common to the respective colors. For the light diffusing means, either frosted glass or plastic whose surface is processed into frosted glass, glass or plastic provided with an opal layer on the substrate surface, glass provided with randomly arranged uneven patterns, film or plastic 17. The projection type image display device according to claim 16, further comprising: 16. The color synthesis optical system includes two dichroic mirrors, a first dichroic mirror and a second dichroic mirror, in order from the light emitting element side. Projection-type image display device. The projection type image display apparatus according to claim 12, wherein the color synthesis optical system includes a first dichroic mirror and a second dichroic mirror intersecting each other and arranged in an X shape. 20. The projection according to claim 19, wherein an optical film whose film thickness is changed in one direction in a plane is provided on at least one dichroic mirror of the first dichroic mirror and the second dichroic mirror. Type image display device. 21. The projection image display apparatus according to claim 12, wherein the light emitting elements of the plurality of colors are red, blue, and green semiconductor light emitting elements. The projection image display apparatus according to claim 21, wherein the light emitting element is any one of a light emitting diode element, an electroluminescence element, and a semiconductor laser element.

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