JP5283572B2 - Video display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a video display device which includes a light source switching function and is high in the utilization efficiency of light rays. <P>SOLUTION: The video display device includes a first light source 1 and a second light source 2, and dichroic mirrors 4r, 4g, and 4b respectively reflecting an R light component, a G light component and a B light component of light emitted from the first and second light sources 1 and 2. The first light source 1 and the second light source 2 are switched by changing the direction of each of the dichroic mirrors 4r, 4g and 4b. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an image display device that displays an image by transmitting or reflecting light from a light source to a light valve, and more particularly, to a switching mechanism that switches to another light source when the light source is turned off or its luminance is reduced due to a failure or a lifetime. Is.

  Video display that displays light by transmitting or reflecting light from a light source such as a discharge lamp or semiconductor light emitting device (eg, LED, laser generator) to a light valve such as a liquid crystal or DMD (digital micromirror device) The device is widely known. Normally, such a video display device cannot normally display an image when the light source is turned off or its brightness decreases due to a failure or a lifetime, but at that time, the image is continued by switching to another new light source. Some of them can be displayed (for example, Patent Document 1 below).

JP-A-2-257192

  The projection display device of Patent Document 1 has two light source units and a switching mirror for switching between them, and by changing the direction of the switching mirror, which light of the two light source units is transferred to the light valve. Switching between sending or not. For example, when the first light source unit is used, the switching mirror is fixed in a direction in which the light from the first light source unit is reflected in the direction of the light valve (specifically, the light reflected by the switching mirror). Is split into red, green, and blue components using three dichroic mirrors before entering the light valve). When the second light source unit is used, the switching mirror is fixed in a direction in which the light from the second light source unit is reflected in the direction of the light valve.

  According to the display device of Patent Document 1, since the use can be continued by switching to the spare light source without performing the work of replacing the light source, even when the light source is unexpectedly turned off or the luminance is lowered, the video display is interrupted for a long time. Can be avoided.

  However, the display device of Patent Document 1 (FIG. 1 of the same document) provides light between the light source and the light valve, as compared with the conventional display device (the same document and FIG. 3), because the switching mirror is provided. There is one more mirror that reflects the light. Since the reflectance of the mirror is not 100%, the use efficiency of light decreases (the loss of light increases) when the number of mirrors existing in the light path (optical path) increases.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide an image display device having a light source switching function and high light use efficiency.

Image display apparatus according to a first aspect of the present invention includes a plurality of light sources, and reflecting the light from said plurality of light sources, Ri wavelength of light reflected respectively Do different, linked to work by a plurality of dichroic A mirror, a display unit that displays an image using light reflected by the plurality of dichroic mirrors, a drive mechanism that changes the orientation of the plurality of dichroic mirrors, and a luminance sensor that detects the amount of light incident on the display unit And a control circuit that controls the drive mechanism based on the change in the amount of light detected by the luminance sensor and switches the plurality of light sources by changing the direction of the plurality of dichroic mirrors. .

The video display device according to the second aspect of the present invention includes a plurality of first light sources that generate first light having a first wavelength and a plurality of second light sources that generate second light having a second wavelength. A light source, a first dichroic mirror that reflects the first light, a second dichroic mirror that reflects the second light and is coupled to be linked to the first dichroic mirror, and A display unit that displays an image using light reflected by the first and second dichroic mirrors, a drive mechanism that changes the orientation of the first and second dichroic mirrors, and the first and the incident light incident on the display unit A brightness sensor that detects the amount of light of each second light, and the drive mechanism is controlled based on a change in the amount of light of the first and second lights detected by the brightness sensor to switch the first light source. The first dichroic Done by changing the direction of Kkumira, the switching of the second light source, in which a control circuit carried out by changing the orientation of the second dichroic mirror.

  Since the switching of the plurality of light sources is performed by changing the direction of the plurality of dichroic mirrors, it is not necessary to separately provide a mirror for switching the light sources. Therefore, no light loss is caused by the light source switching mirror, and the light use efficiency is increased. Further, since a light source switching mirror is unnecessary, it is possible to contribute to reduction of manufacturing costs.

3 is a plan view of a main part of the video display device according to Embodiment 1. FIG. 6 is a diagram for explaining an operation of the video display apparatus according to Embodiment 1. FIG. 6 is a plan view of a main part of a video display device according to Embodiment 2. FIG. FIG. 6 is a side view of a main part of a video display device according to Embodiment 2. 6 is a perspective view of a dichroic mirror driving mechanism of a video display device according to Embodiment 2. FIG. 6 is a bottom view of a dichroic mirror driving mechanism of a video display device according to Embodiment 2. FIG. 10 is a diagram for explaining an operation of the video display apparatus according to Embodiment 2. FIG. FIG. 6 is a top view of a main part of a video display device according to a second embodiment. FIG. 6 is a front view of a main part of a video display device according to a second embodiment. FIG. 6 is a side view of a main part of a video display device according to Embodiment 2. 6 is a cross-sectional perspective view of a main part of a video display device according to Embodiment 2. FIG. 6 is a perspective view of a main part of a video display device according to Embodiment 3. FIG. FIG. 10 is a perspective view of a dichroic mirror drive mechanism according to a third embodiment. 6 is a cross-sectional perspective view of a main part of a video display device according to Embodiment 3. FIG. FIG. 6 is a cross-sectional plan view of a main part of a video display device according to Embodiment 3. 10 is an enlarged cross-sectional view of a main part of a video display device according to Embodiment 3. FIG. 10 is a diagram for explaining an operation of the video display apparatus according to Embodiment 3. FIG. 10 is a diagram for explaining an operation of the video display apparatus according to Embodiment 3. FIG. FIG. 10 is a rear view of the main part of the video display device according to Embodiment 3.

<Embodiment 1>
FIG. 1 is a plan view of the main part of the video display apparatus according to Embodiment 1 of the present invention. The video display device has a light source switching function for switching between two light sources.

  The first light source 1 and the second light source 2 are lamps that generate white light by arc discharge, and are disposed to face each other. Three spectroscopic dichroic mirrors 4r, 4g, and 4b are disposed between the first light source 1 and the second light source 2. Each of the dichroic mirrors 4r, 4g, and 4b reflects only light having a specific wavelength.

  The red dichroic mirror 4r reflects only red light (R light), the green dichroic mirror 4g reflects only green light (G light), and the blue dichroic mirror 4b reflects only blue light (B light). . In this embodiment, as shown in FIG. 1, the blue dichroic mirror 4b, the green dichroic mirror 4g, and the red dichroic mirror 4r are arranged in this order from the first light source 1 side to the second light source 2 side. Has been established.

  The R light reflected by the red dichroic mirror 4r is reflected by the reflecting mirror 5a, then passes through the red light valve 6r for generating a red image, and enters the dichroic prism 7. The G light reflected by the green dichroic mirror 4g passes through the green light valve 6g for generating a green image and enters the dichroic prism 7. The B light reflected by the blue dichroic mirror 4 b is reflected by the reflection mirror 5 b, then passes through the blue light valve 6 b that generates a blue image, and enters the dichroic prism 7. The dichroic prism 7 combines the R light, G light, and B light to generate color image light. The image light is magnified through the projection lens 8 and projected onto the screen 9.

  As shown in FIG. 1, the blue dichroic mirror 4 b is fixed to the gear 10, the green dichroic mirror 4 g is fixed to the gear 11, and the red dichroic mirror 4 r is fixed to the gear 12. The gears 10, 11, and 12 are engaged with a rack 13 that moves to the left and right according to the rotation of the pinion 14. When the pinion 14 is rotated, the gears 10, 11, and 12 are rotated, and the dichroic mirrors 4r, 4g, and 4b fixed to the gears 11 and 12 change their directions in conjunction with each other. That is, the dichroic mirrors 4r, 4g, 4b are connected via the gears 10, 11, 12 and the rack 13 so that they are interlocked.

  In the video display device of the present embodiment, switching between the first light source 1 and the second light source 2 is performed by changing the direction of the three dichroic mirrors 4r, 4g, 4b. Although not shown, the video display device includes a luminance sensor that detects the amount of light emitted from the first light source 1 and the second light source 2, and the pinion 14 and the first light source 1 and the second light source according to the light amount. A control circuit for controlling the light source 2 is provided. The control circuit automatically rotates the pinion 14 to change the direction of the dichroic mirrors 4r, 4g, and 4b when the first light source 1 or the second light source 2 is turned off or the brightness is reduced due to a failure or the like. Switching between the light source 1 and the second light source 2 is executed. Hereinafter, the switching operation will be specifically described.

  For example, when the first light source 1 is used, the control circuit turns on the first light source 1 and adjusts the directions of the dichroic mirrors 4r, 4g, 4b as shown in FIG. 1 to thereby adjust the dichroic mirrors 4r, 4g, 4b. However, the light from the first light source 1 is reflected by the dichroic mirrors 4r, 4g, 4b so as to be directed to the light valves 6r, 6g, 6b and the dichroic prism 7.

  In this state, the B light included in the light from the first light source 1 is reflected by the blue dichroic mirror 4b, further reflected by the reflection mirror 5b, and transmitted through the blue light valve 6b to the dichroic prism 7. Incident. The G light passes through the blue dichroic mirror 4b, is reflected by the green dichroic mirror 4g, passes through the green light valve 6g, and enters the dichroic prism 7. The R light is transmitted through the blue dichroic mirror 4b and the green dichroic mirror 4g, then reflected by the red dichroic mirror 4r, further reflected by the reflective / reflecting mirror 5a, and transmitted through the red light valve 6r and transmitted through the dichroic prism 7 Incident to. As a result, image light using the light from the first light source 1 is projected onto the screen 9 through the projection lens 8.

  It is assumed that the first light source 1 is unexpectedly turned off while the first light source 1 is in use. When the luminance of the first light source 1 falls below a predetermined level, the luminance sensor detects this, and accordingly the control circuit rotates the pinion 14 clockwise (CW direction) using a motor. Then, the rack 13 moves in the right direction (arrow A), the gears 10, 11, and 12 rotate counterclockwise (CCW direction), and the dichroic mirrors 4r, 4g, and 4b also rotate in the CCW direction. At this time, the dichroic mirrors 4r, 4g, and 4b are controlled to rotate by approximately 90 °.

  As a result, the dichroic mirrors 4r, 4g, 4b are fixed in a direction in which the light from the second light source 2 is reflected to the light valves 6r, 6g, 6b and the dichroic prism 7 as shown in FIG.

  Subsequently, the control circuit turns on the second light source 2. In this state, the R light included in the light from the second light source 2 is reflected by the red dichroic mirror 4r, further reflected by the reflecting mirror 5a, and transmitted through the red light valve 6r to the dichroic prism 7. Incident. The G light passes through the red dichroic mirror 4r, then is reflected by the green dichroic mirror 4g, passes through the green light valve 6g, and enters the dichroic prism 7. The B light is transmitted through the red dichroic mirror 4r and the green dichroic mirror 4g, then reflected by the blue dichroic mirror 4b, further reflected by the reflection mirror 5b, and transmitted through the blue light valve 6b to the dichroic prism 7. And incident. As a result, the image light using the light from the second light source 2 is projected onto the screen 9 through the projection lens 8.

  As described above, by automatically switching from the first light source 1 to the second light source 2, the period during which video display is interrupted can be shortened. Thereafter, the user may replace the first light source 1 that has reached the end of its life (for example, after viewing a series of images).

  Although the switching operation from the first light source 1 to the second light source 2 has been described above, the switching operation from the second light source 2 to the first light source 1 is substantially the same. That is, when the second light source 2 is turned off in the state of FIG. 2, the control circuit rotates the pinion 14 counterclockwise (CCW direction), so that the dichroic mirrors 4r, 4g, 4b are moved in the CW direction. The first light source 1 may be turned on by rotating it approximately 90 ° to the state shown in FIG.

  According to the present embodiment, the light source is switched by changing the direction of the dichroic mirrors 4r, 4g, 4b, and it is not necessary to separately provide a light source switching mirror. That is, the function can be realized by using the same number of mirrors as a conventional video display device that does not have a light source switching function (for example, FIG. 3 of Patent Document 1). Therefore, an image display device having a light source switching function and high light use efficiency (low loss) can be obtained.

  Further, the light source switching device (dichroic mirror drive mechanism) in the present embodiment can be configured with inexpensive parts such as gears 10, 11, 12, rack 13, pinion 14, and motor (not shown). In addition, since the dichroic mirrors 4r, 4g, and 4b are linked so as to move in conjunction with each other, only one motor is required to drive the three dichroic mirrors 4r, 4g, and 4b, and no light source switching mirror is required. For this reason, it is possible to contribute to a reduction in manufacturing cost of a video display device having a light source switching function.

<Embodiment 2>
3 to 11 are diagrams for explaining a video display apparatus according to the second embodiment. FIG. 3 is a plan view of the main part of the video display device, and FIG. 4 is a side view thereof.

  The video display apparatus of the first embodiment uses a white light source, but the video display apparatus of the present embodiment displays an image using a plurality of light sources that generate light of different wavelengths. It is. The video display device includes a first blue light emitting element 21b and a second blue light emitting element 22b that are semiconductor light emitting elements that generate B light, and a first red light emitting element 21r that is a semiconductor light emitting element that generates R light. And a second red light emitting element 22r, and a first green light emitting element 21g and a second green light emitting element 22g, which are semiconductor light emitting elements that generate G light.

  A blue dichroic mirror 24b that reflects only B light is disposed between the first blue light emitting element 21b and the second blue light emitting element 22b. A red dichroic mirror 24r that reflects only R light is disposed between the first red light emitting element 21r and the second red light emitting element 22r. A green dichroic mirror 24g that reflects only the wavelength of the G light is disposed between the first green light emitting element 21g and the second green light emitting element 22g. Further, a collimator lens 23 is disposed between each light emitting element and the dichroic mirror to refract the single wavelength light emitted from the light emitting element into a parallel light beam.

  As shown in FIG. 3, a first blue light emitting element 21b, a second red light emitting element 22r, and a first green light emitting element 21g are disposed on one side of the dichroic mirrors 24b, 24r, and 24g. On the other side, a second blue light emitting element 22b, a first red light emitting element 21r, and a second green light emitting element 22g are disposed.

  The video display device according to the present embodiment includes a first light source unit including a first blue light emitting element 21b, a first red light emitting element 21r, and a first green light emitting element 21g, a second blue light emitting element 22b, The second light source unit composed of the second red light emitting element 22r and the second green light emitting element 22g has a function of switching by changing the direction of the dichroic mirrors 24b, 24r, 24g. Therefore, the video display device includes a luminance sensor 35 that detects the light emission state of each light emitting element, a dichroic mirror 24b, 24r, 24g, and a control circuit (not shown) that controls each light emitting element according to the detection result. Yes.

  For example, when the first light source unit is used, the control circuit turns on the first blue light emitting element 21b, the first red light emitting element 21r, and the first green light emitting element 21g, and turns on the dichroic mirrors 24b, 24r, and 24g. Fix in the orientation shown in FIG. Further, the second red light emitting element 22r, the second green light emitting element 22g, and the second blue light emitting element 22b are all turned off.

  In this state, the B light emitted from the first blue light emitting element 21b is converted into a parallel light beam by the collimator lens 23, reflected by the blue dichroic mirror 24b, and transmitted through the red dichroic mirror 24r and the green dichroic mirror 24g. Then, the light enters the condenser lens 25. The R light emitted from the first red light emitting element 21r is converted into a parallel light flux by the collimator lens 23, reflected by the red dichroic mirror 24r, transmitted through the green dichroic mirror 24g, and incident on the condenser lens 25. . The G light emitted from the first green light emitting element 21g is converted into a parallel light beam by the collimator lens 23, reflected by the green dichroic mirror 24g, and incident on the condenser lens 25.

  The light beam composed of R light, B light, and G light that has passed through the condenser lens 25 enters the rod integrator 26, is reflected many times along the rectangular inner surface of the rod integrator 26, and is orthogonal to the optical axis 27. It becomes white light of a uniform rectangular shape in the plane to be. The white light is refracted by the relay lens 28 to become a substantially parallel light beam. Then, the light is reflected by the first reflecting mirror 29 and the second reflecting mirror 30, and enters the light valve 33 through a prism 31 that refracts or transmits light according to the incident angle of the light. The light valve 33 is mounted on the circuit board 32 without a lead wire.

  By synchronizing the video signal output from the circuit board 32 and the light emission cycle of each light emitting element, the attitude angle of the micromirror inside the light valve 33 is controlled, and the light valve 33 is controlled according to the video signal. Generate color images. The color image is projected onto a screen (not shown) through the projection lens 34 by the light incident on the light valve 33.

  The luminance sensor 35 is mounted on a part of the circuit board 32 (the same surface as the mounting surface of the light valve 33) as shown in FIG. The luminance sensor 35 generates a current corresponding to the intensity (light quantity) of light of a specific wavelength, and detects the light quantity of each of R light, G light, and B light from slight transmitted light of the reflection mirror 30. . By directly mounting the luminance sensor on the circuit board 32, a dedicated substrate, lead wires, connectors, and the like for the luminance sensor can be omitted, which can contribute to reduction in manufacturing cost and downsizing of the apparatus.

  5 and 6 are diagrams showing a configuration of a dichroic mirror driving mechanism that changes the direction of the dichroic mirrors 24b, 24r, and 24g in the video display device according to the second embodiment. FIG. 5 is a perspective view of the dichroic mirror driving mechanism, and FIG. 6 is a bottom view thereof.

  As shown in FIG. 5, the base 39 that holds the red dichroic mirror 24 r is mounted on a gear 40, and a rotational movement of a pinion 37 attached to the rotation shaft of the motor 36 is received by the gear 40. Is transmitted through.

  A base 46 for holding the blue dichroic mirror 24 b is mounted on the scissor gear unit 41 engaged with the gear 40. The base 48 holding the green dichroic mirror 24g is mounted on the scissor gear unit 42 engaged with the gear 40 on the opposite side of the scissor gear unit 41. Each of the scissor gear units 41 and 42 is formed by connecting two gears with springs (springs 43 and 44 shown in FIG. 6), and can always apply tension to the engaged gear 40 by the force of the springs. . Thereby, backlash between the gear 40 is prevented.

  As the scissor gear units 41 and 42 are engaged with the gear 40 in this manner, the dichroic mirrors 24b, 24r, and 24g are coupled to each other. The gear 40 and the scissor gear units 41 and 42 are provided with the same number of teeth so that the angular velocities when rotating are the same. However, the rotation direction is reversed between the scissor gear units 41 and 42 and the gear 40.

  Here, it is assumed that one of the first light source units (the first blue light emitting element 21b, the first red light emitting element 21r, and the first green light emitting element 21g) is extinguished due to a failure or the like. In the luminance sensor 35, any of the detection currents of the R light, the G light, and the B light decreases, and thereby the control circuit detects a failure of the first light source unit.

  Then, the control circuit stops supplying current to the first light source unit, and this time, the second light source unit (second red light emitting element 22r, second green light emitting element 22g, and second blue light emitting element 22b). Supply current to and turn it on.

  At the same time, the control circuit rotates the pinion 37 using the motor 36 to rotate the gear 38 and the gear 40. At this time, the control circuit controls the rotation speed of the motor 36 so that the gear 40 rotates by 90 ° in the CCW direction when viewed from above. Since the scissor gear units 41 and 42 rotate in reverse at the same angular velocity as the gear 40, they rotate by 90 ° in the CW direction.

  As a result, the blue dichroic mirror 24b mounted on the scissor gear unit 41 is 90 ° in the CW direction, the red dichroic mirror 24r mounted on the gear 40 is 90 ° in the CCW direction, and for green mounted on the scissor gear unit 42. The dichroic mirror 24g rotates 90 ° in the CW direction, and the respective directions change to the state shown in FIG.

  In this state, the B light emitted from the second blue light emitting element 22b is converted into a parallel light beam by the collimator lens 23, reflected by the blue dichroic mirror 24b, and transmitted through the red dichroic mirror 24r and the green dichroic mirror 24g. Then, the light enters the condenser lens 25. The R light emitted from the second red light emitting element 22r is converted into a parallel light beam by the collimator lens 23, reflected by the red dichroic mirror 24r, transmitted through the green dichroic mirror 24g, and incident on the condenser lens 25. To do. The G light emitted from the second green light emitting element 22g is converted into a parallel light beam by the collimator lens 23, reflected by the green dichroic mirror 24g, and incident on the condenser lens 25. As a result, the image light using the light from the second light source unit is projected onto the screen (not shown) through the projection lens 34.

  By automatically switching from the first light source unit to the second light source unit in this way, the period during which video display is interrupted can be shortened. Thereafter, the user may replace the first light source unit that has reached the end of its life (for example, after viewing a series of images). Of course, if the first light source unit can replace the first blue light emitting element 21b, the first red light emitting element 21r, and the first green light emitting element 21g independently, replace only the defective one. Also good.

  Although the switching operation from the first light source unit to the second light source unit has been described above, the switching operation from the second light source unit to the first light source unit is substantially the same. That is, when the second light source unit is turned off during use of the second light source unit in the state of FIG. 7, the control circuit rotates the pinion 37 in the CW direction, and the red dichroic mirror 24r is moved 90 ° in the CW direction. The blue dichroic mirror 24b and the green dichroic mirror 24g may be rotated by 90 ° in the CCW direction to the state shown in FIG. 3, and the first light source unit may be turned on.

  According to the present embodiment, since the light source is switched by changing the direction of the dichroic mirrors 24b, 24r, and 24g, it is not necessary to separately provide a light source switching mirror. Therefore, an image display device having a light source switching function and high light use efficiency (low loss) can be obtained.

  Further, the light source switching device (dichroic mirror driving mechanism) can be constituted by inexpensive parts such as the pinion 37, the gears 38, 40, 41, and 42, and the motor. Further, since the dichroic mirrors 24b, 24r, and 24g are connected so as to move in conjunction with each other, only one motor is required to drive the three dichroic mirrors 24b, 24r, and 24g, and no light source switching mirror is required. This also contributes to a reduction in manufacturing cost of the video display device having a light source switching function.

  Particularly in the present embodiment, as shown in FIG. 3, among the first blue light emitting element 21b, the first red light emitting element 21r, and the first green light emitting element 21g constituting the first light source unit, One red light emitting element 21r is disposed on the opposite side of the other two with the dichroic mirrors 24b, 24r, and 24g interposed therebetween. Similarly, the second blue light emitting element 22b and the second blue light emitting element 22b constituting the second light source unit are arranged. Of the red light emitting element 22r and the second green light emitting element 22g, the second red light emitting element 22r in the middle is disposed on the opposite side of the other two with the dichroic mirrors 24b, 24r, and 24g in between.

  Due to this arrangement, when switching between the first light source unit and the second light source unit, the middle red dichroic mirror 24r out of the other two dichroic mirrors 24b, 24r, and 24g is rotated in the reverse direction. Since this operation can be realized by directly engaging the gears 40, 41, and 42 on which the dichroic mirrors 24b, 24r, and 24g are mounted, the above arrangement contributes to a reduction in the number of parts of the dichroic mirror driving mechanism. If it is necessary to rotate all the dichroic mirrors 24b, 24r, and 24g in the same direction, it is necessary to provide a reverse gear or the like.

  Further, the arrangement of each light emitting element is also effective from the viewpoint of heat dissipation of the light emitting element. This will be described below.

  8 is a top view of the main part including the cooling mechanism of the video display device according to the second embodiment, FIG. 9 is a front view of the portion shown in FIG. 8, FIG. 10 is a side view, and FIG. FIG.

  As described above, the set of the first blue light emitting element 21b, the second red light emitting element 22r, and the first green light emitting element 21g, the second blue light emitting element 22b, the first red light emitting element 21r, and the second The green light emitting element 22g is disposed at a position sandwiching the dichroic mirrors 24b, 24r, and 24g. Although omitted in FIG. 8, a set of the first blue light emitting element 21b, the second red light emitting element 22r, and the first green light emitting element 21g, the second blue light emitting element 22b, and the first red light emitting element. Dichroic mirrors 24b, 24r, and 24g are disposed in a space between the pair of 21r and the second green light emitting element 22g.

  As shown in FIGS. 8 to 11, the substrates 50 b, 50 r, and 50 g on which the first blue light emitting element 21 b, the second red light emitting element 22 r, and the first green light emitting element 21 g are mounted are fixed to the heat radiating plate 51. Is done. Cooling fans 52 and 53 are disposed in front of the heat radiating plate 51 in order to enhance the cooling effect. The substrates 54b, 54r, and 54g on which the second blue light emitting element 22b, the first red light emitting element 21r, and the second green light emitting element 22g are mounted are fixed to the heat radiating plate 55. Cooling fans 56 and 57 are disposed in front of the heat radiating plate 55.

  When the first light source unit is used, the first blue light emitting element 21b, the first green light emitting element 21g, and the first red light emitting element 21r emit light, and the substrates 50b, 54r, and 50g generate heat. That is, in the heat sink 51, heat is generated at the contact portions with the substrates 50b and 50g, but heat is not generated at the contact portions with the substrate 50r. Therefore, the contact portion of the heat radiating plate 51 with the substrate 50r functions as a part of the heat radiating region. Further, in the heat radiating plate 55, heat is generated at the contact portion with the substrate 54r, but heat is not generated at the contact portions with the substrates 54b and 54g. Therefore, the contact portion of the heat radiating plate 55 with the substrates 54b and 54g functions as a part of the heat radiating region.

  On the other hand, when the second light source unit is used, since the second blue light emitting element 22b, the second green light emitting element 22g, and the second red light emitting element 22r emit light, the substrates 54b, 50r, and 54g generate heat. That is, in the heat sink 51, heat is generated at the contact portion with the substrate 50r, but heat is not generated at the contact portions with the substrates 50b and 50g. Therefore, the contact part with the board | substrates 50b and 50g in the heat sink 51 acts as a part of heat dissipation area | region. Further, in the heat radiating plate 55, heat is generated at the contact portions with the substrates 54b and 54g, but heat is not generated at the contact portions with the substrate 54r. Therefore, the contact portion of the heat radiating plate 55 with the substrates 54b and 54g functions as a part of the heat radiating region.

  Thus, since all the three light emitting elements used at the same time are not fixed to the same heat sink, the heat generated in the light emitting elements can be dissipated by the plurality of heat sinks, so that the cooling efficiency is increased. As a result, the air volume of the cooling fans 52, 53, 56, and 57 can be reduced, which can contribute to noise reduction of the video display device.

  In this embodiment, among the three light emitting elements used at the same time, the R light emitting element is fixed to a heat radiation plate different from the B light and G light emitting elements, so that the cooling efficiency of the R light emitting element is improved. Is the highest. In general, since a semiconductor light emitting element that generates R light has a large wavelength drift accompanying a temperature change, increasing the cooling efficiency of the R light emitting element is effective in that the wavelength drift can be reduced. In addition, in order to increase the cooling efficiency of the R light emitting element, it is not necessary to use a heat sink or cooling fan dedicated to the R light emitting element, which can contribute to a reduction in the number of parts.

  Or you may comprise so that the thing with the largest emitted-heat amount among the three light emitting elements used simultaneously may be fixed to the heat sink different from another thing. The cooling efficiency of the light emitting element having the largest heat generation amount can be maximized, and thereby the temperature of each light emitting element can be made uniform. Also in this case, since a heat sink and a cooling fan dedicated to the light emitting element having the largest amount of heat generation are unnecessary, it is possible to contribute to a reduction in the number of parts.

<Embodiment 3>
FIG. 12 is a perspective view of the main part of the video display apparatus according to Embodiment 3 of the present invention. In the second embodiment, the configuration includes two light emitting elements for each color. However, the video display device of the present embodiment includes three light emitting elements for each color.

  As shown in FIG. 12, the video display device includes first, second, and third blue light emitting elements 21b, 22b, and 23b that are semiconductor light emitting elements that generate B light, and a semiconductor light emitting element that generates R light. And first, second and third red light emitting elements 21r, 22r and 23r, and first, second and third green light emitting elements 21g, 22g and 23g which are semiconductor light emitting elements generating G light. doing. The first, second, and third blue light emitting elements 21b, 22b, and 23b are disposed so as to surround the blue dichroic mirror 24b that reflects only the B light, and the first, second, and third red light emitting elements. 21r, 22r, and 23r are disposed so as to surround the red dichroic mirror 24r that reflects only R light, and the first, second, and third green light emitting elements 21g, 22g, and 23g reflect only G light. The green dichroic mirror 24g is disposed so as to surround it.

  Although omitted in FIG. 12, a collimator lens is provided between each semiconductor light emitting element and the dichroic mirror for refracting the single wavelength light emitted from the semiconductor light emitting element so as to be a parallel light beam. Has been.

  In the present embodiment, only the light source of the video display device and the switching device portion thereof will be described, but the other portions are the same as those shown in FIGS. That is, the light reflected by the dichroic mirrors 24b, 24r, and 24g in FIG. 12 is the same as in FIGS. 3 and 4, and the condensing lens 25, the rod integrator 26, the relay lens 28, and the first and second reflecting mirrors 29. 30, 30, and incident on the light valve 33 through the prism 31, and then projected onto the screen through the projection lens 34.

  In FIG. 12, when the side on which the condenser lens 25 and the like are disposed (the side on which the light indicated by the arrow is directed) is defined as the front side, the first blue light emitting element 21b is the right side of the blue dichroic mirror 24b when viewed from the front side. The second blue light emitting element 22b is disposed on the left side of the blue dichroic mirror 24b, and the third blue light emitting element 23b is disposed on the lower side of the blue dichroic mirror 24b. The first red light emitting element 21r is disposed below the red dichroic mirror 24r, the second red light emitting element 22r is disposed on the right side of the red dichroic mirror 24r, and the third red light emitting element 23r is disposed on the left side of the red dichroic mirror 24r. Established. The first green light emitting element 21g is disposed on the left side of the green dichroic mirror 24g, the second green light emitting element 22g is disposed on the lower side of the green dichroic mirror 24g, and the third green light emitting element 23g is disposed on the right side of the green dichroic mirror 24g. Established.

  In other words, the first blue light emitting element 21b, the second red light emitting element 22r, and the third green light emitting element 23g are disposed on the right side of the dichroic mirrors 24b, 24r, and 24g when viewed from the front side, and also on the left side. , A second blue light emitting element 22b, a third red light emitting element 23r, and a first green light emitting element 21g are disposed. Similarly, on the lower side, the third blue light emitting element 23b, the first red light emitting element 21r and the first red light emitting element 21r are arranged. Two green light emitting elements 22g are disposed.

  The video display device according to the present embodiment switches the first to third blue light emitting elements 21b to 23b and changes the first to third red light emitting elements by changing the individual directions of the dichroic mirrors 24b, 24r, and 24g. It has a function of automatically switching between 21r to 23r and switching between the first to third green light emitting elements 21g to 23g. Therefore, the image display apparatus also controls the luminance sensor 35 for detecting the light emission state of each light emitting element, and the dichroic mirrors 24b, 24r, 24g and each light emitting element according to the detection result, as in FIGS. A control circuit (not shown) is provided.

  For example, when the first blue light emitting element 21b, the first red light emitting element 21r, and the first green light emitting element 21g are used, the control circuit lights them, and the dichroic mirrors 24b, 24r, and 24g are shown in FIG. Fix in the direction. Other light emitting elements are turned off.

  In this state, the B light emitted from the first blue light emitting element 21b is reflected by the blue dichroic mirror 24b toward the optical axis 60, and is transmitted through the red dichroic mirror 24r and the green dichroic mirror 24g to be condensed. The light enters the lens 25 (not shown). The R light emitted from the first red light emitting element 21r is reflected in the direction of the optical axis 60 by the red dichroic mirror 24r, passes through the green dichroic mirror 24g, and enters the condenser lens 25. The G light emitted from the first green light emitting element 21 g is reflected in the direction of the optical axis 60 by the green dichroic mirror 24 g and enters the condenser lens 25. As a result, image light using light from the first blue light emitting element 21b, the first red light emitting element 21r, and the first green light emitting element 21g is projected onto a screen (not shown).

  FIG. 13 is a perspective view of the dichroic mirror driving mechanism of the third embodiment. 14 is a cross-sectional perspective view of the main part of the video display device including the dichroic mirror driving mechanism, and FIG. 15 is a cross-sectional plan view. FIG. 16 is an enlarged cross-sectional view of a region where the first to third blue light emitting elements 21b to 23b and the blue dichroic mirror 24b are disposed in the main part.

  As shown in these drawings, the dichroic mirrors 24b, 24r, and 24g are fixed in cylinders 39b, 39r, and 39g held by the base 64, respectively.

  Guide grooves 62b and 63b into which semicircular guide portions 64b and 65b protruding inside the base 64 are fitted and a gear portion 40b are formed on the side surface of the cylinder 39b. The rotational movement of the pinion 37b attached to the rotation shaft of the motor 36b is transmitted to the gear portion 40b via the gears 38b and 61b. Therefore, when the motor 36b rotates, the cylinder 39b rotates along the guide portions 64b and 65b. The cylinder 39b is positioned so that its rotational axis coincides with the optical axis 60 shown in FIG.

  Further, on the side surface of the cylinder 39r, guide grooves 62r and 63r into which semicircular guide portions 64r and 65r protruding inside the base 64 are fitted, and a gear portion 40r are formed. The rotational movement of the pinion 37r attached to the rotation shaft of the motor 36r is transmitted to the gear portion 40r via the gears 38r and 61r. Therefore, when the motor 36r rotates, the cylinder 39r rotates along the guide portions 64r and 65r. The cylinder 39r is also positioned so that its rotation axis coincides with the optical axis 60 shown in FIG.

  Similarly, guide grooves 62g and 63g into which semicircular guide portions 64g and 65g protruding inside the base 64 are fitted and a gear portion 40g are formed on the side surface of the cylinder 39g. The rotational movement of the pinion 37g attached to the rotation shaft of the motor 36g is transmitted to the gear portion 40g via the gears 38g and 61g. Therefore, when the motor 36g rotates, the cylinder 39g rotates along the guide portions 64g and 65g. The cylinder 39g is also positioned so that its rotation axis coincides with the optical axis 60 shown in FIG.

  On the side surfaces of the cylinders 39b, 39r, and 39g, openings 67b, 67r, and 67g for taking in light from the respective light emitting elements are formed. Also, an opening 68b is formed on the front side of the cylinder 39b so that the light (optical axis 60) reflected by the dichroic mirrors 24b, 24r, and 24g is not blocked, and an opening is formed on the front side and the back side of the cylinder 39r, respectively. Portions 68r and 69r are formed, and openings 68g and 69g are formed on the front side and the back side of the cylinder 39g, respectively.

  For example, the B light from the first blue light emitting element 21b in FIG. 12 enters the cylinder 39b through the opening 67b and is reflected by the blue dichroic mirror 24b, and then the openings 68b and 69r, the cylinder 39r, and the opening. The light enters the condenser lens 25 on the front side through the portions 68r, 69g, the cylinder 39g, and the opening 68g. The R light from the first red light emitting element 21r enters the cylinder 39r through the opening 67r and is reflected by the red dichroic mirror 24r, and then passes through the openings 68r and 69g, the cylinder 39g and the opening 68g. Then, the light enters the condenser lens 25. The G light from the first green light emitting element 21g enters the cylinder 39g through the opening 67g, is reflected by the green dichroic mirror 24g, and then enters the condenser lens 25 through the opening 69g.

  For example, it is assumed that the first blue light emitting element 21b is turned off due to a failure or the like during use of the first blue light emitting element 21b, the first red light emitting element 21r, and the first green light emitting element 21g. In the luminance sensor 35, the detection current of the B light decreases, and thereby the control circuit detects a failure of the first blue light emitting element 21b.

  Then, the control circuit stops supplying the current to the first blue light emitting element 21b and supplies the current to the second blue light emitting element 22b to cause it to emit light. Further, the motor 36b is rotated to rotate the cylinder 39b approximately 180 ° in the CCW direction (see FIG. 13). The blue dichroic mirror 24b is oriented as shown in FIG.

  As a result, the B light emitted from the second blue light emitting element 22b passes through the opening 67b on the side surface of the cylinder 39b and is reflected in the direction along the optical axis 60 by the blue dichroic mirror 24b in the cylinder 39b. The light passes through the red dichroic mirror 24r and the green dichroic mirror 24g in the green dichroic mirror 24g, and enters the condenser lens 25. That is, switching from the first blue light emitting element 21b to the second blue light emitting element 22b is performed.

  It should be noted that a manufacturing error related to the position of the frame 66 holding the blue dichroic mirror 24b inside the cylinder 40b, or a deviation between the rotation axis of the cylinder 39b and the optical axis 60 shown in FIG. 12 (this is the guide grooves 62b and 63b). Or due to a manufacturing error related to the positions of the guide portions 64b and 65b), the path of the B light is shifted when switching from the first blue light emitting element 21b to the second blue light emitting element 22b. The amount of light incident on the rod integrator 26 may decrease. In this case, the control circuit finely adjusts the rotation angle of the cylinder 39b so that the amount of B light detected by the luminance sensor 35 is maximized when switching from the first blue light emitting element 21b to the second blue light emitting element 22b. adjust. Thereby, the deviation of the path of the B light can be suppressed, and the shortage of light amount and the deterioration of color balance can be prevented.

  Subsequently, it is assumed that, for example, the first red light emitting element 21r is turned off due to a failure or the like during use of the second blue light emitting element 22b, the first red light emitting element 21r, and the first green light emitting element 21g. In the luminance sensor 35, the detection current of the R light decreases, and thereby the control circuit detects a failure of the first red light emitting element 21r.

  Then, the control circuit stops the supply of current to the first red light emitting element 21r and supplies the current to the second red light emitting element 22r to cause it to emit light. Further, the motor 36r is rotated to rotate the cylinder 39r approximately 90 ° in the CW direction (see FIG. 13). The red dichroic mirror 24r is oriented as shown in FIG.

  As a result, the R light emitted from the second red light emitting element 22r passes through the opening 67r on the side surface of the cylinder 39r, and is reflected in the direction along the optical axis 60 by the red dichroic mirror 24r in the cylinder 39r. The light passes through the green dichroic mirror 24 g in the dichroic mirror 24 g and enters the condenser lens 25. That is, switching from the first red light emitting element 21r to the second red light emitting element 22r is performed. Also at this time, the control circuit finely adjusts the rotation angle of the cylinder 39r so that the amount of R light detected by the luminance sensor 35 is maximized.

  Thereafter, the first green light emitting element 21g is turned off due to a failure or the like while the second blue light emitting element 22b, the first red light emitting element 21r, and the first green light emitting element 21g are in use. In the luminance sensor 35, the G light detection current decreases, whereby the control circuit detects a failure of the first green light emitting element 21g.

  Then, the control circuit stops supplying current to the first green light emitting element 21g and supplies current to the second green light emitting element 22g to cause it to emit light. Further, the motor 36g is rotated to rotate the cylinder 39g by approximately 90 ° in the CW direction (see FIG. 13). The green dichroic mirror 24g is oriented as shown in FIG.

  As a result, the G light emitted from the second green light emitting element 22g passes through the opening 67r on the side surface of the cylinder 39g and is reflected in the direction along the optical axis 60 by the green dichroic mirror 24g in the cylinder 39g. The light enters the optical lens 25. That is, switching from the first green light emitting element 21g to the second green light emitting element 22g is performed. Also at this time, the control circuit finely adjusts the rotation angle of the cylinder 39g so that the amount of G light detected by the luminance sensor 35 becomes maximum.

  Through the above operation, all of the dichroic mirrors 24b, 24r, and 24g are oriented as shown in FIG. 17, and all of the first blue light emitting element 21b, the first red light emitting element 21r, and the first green light emitting element 21g Thus, the second blue light emitting element 22b, the second red light emitting element 22r, and the second green light emitting element 22g are switched to each other.

  After that, when the second blue light emitting element 22b, the second red light emitting element 22r, and the second green light emitting element 22g are turned off due to failure or the like, the third blue light emitting element is operated by the same operation as above. Switching to 23b, the third red light emitting element 23r, and the third green light emitting element 23g is performed.

  For example, when the second blue light emitting element 22b is extinguished due to a failure and the luminance sensor 35 detects it, the control circuit turns on the third blue light emitting element 23b and drives the motor 36b to set the cylinder 39b to CW. The blue dichroic mirror 24b is turned to the direction shown in FIG. Thereby, the B light from the third blue light emitting element 23 b is reflected by the blue dichroic mirror 24 b and enters the condenser lens 25.

  When the second red light emitting element 22r is extinguished due to a failure, the control circuit turns on the third red light emitting element 23r and rotates the cylinder 39r approximately 180 ° in the CCW direction to cause the red dichroic mirror 24r. In the direction shown in FIG. Accordingly, the R light from the third red light emitting element 23r is reflected by the red dichroic mirror 24r and enters the condenser lens 25.

  When the second green light emitting element 22g is extinguished due to a failure, the control circuit turns on the third green light emitting element 23g and rotates the cylinder 39g by approximately 90 ° in the CW direction to thereby turn the green dichroic mirror 24g. In the direction shown in FIG. Thus, the G light from the third green light emitting element 23g is reflected by the green dichroic mirror 24g and enters the condenser lens 25.

  As described above, in the video display device according to the present embodiment, the light emitting elements of the respective colors can be switched independently. Accordingly, it is possible to obtain an image display device that can use each light emitting element to the end of its lifetime and can display for a long time. Theoretically, the displayable time is a value close to the product of the average lifetime of the light emitting elements and the number of switchable light emitting elements (three in this embodiment).

  On the other hand, when all three color light emitting elements are switched simultaneously as in the video display device of the second embodiment, the other two colors of light emission that can still be turned off according to the lifetime of the light emitting element that cannot be turned on first. Since the elements are also forcibly switched, each light emitting element cannot be used until the end of its lifetime.

  In other words, the first blue light emitting element 21b, the second red light emitting element 22r, and the third green light emitting element 23g are disposed on the right side of the dichroic mirrors 24b, 24r, and 24g when viewed from the front side, and also on the left side. , A second blue light emitting element 22b, a third red light emitting element 23r, and a first green light emitting element 21g are disposed. Similarly, on the lower side, the third blue light emitting element 23b, the first red light emitting element 21r and the first red light emitting element 21r are arranged. Two green light emitting elements 22g are disposed. This arrangement is also effective from the viewpoint of heat dissipation of the light emitting element. This will be described below.

  FIG. 19 is a rear view of the main part of the video display apparatus according to Embodiment 3. As shown in FIGS. 14, 15 and 19, the substrates 50b, 50r and 50g on which the first blue light emitting element 21b, the second red light emitting element 22r and the third green light emitting element 23g are mounted are respectively It is fixed to the heat sink 70. Cooling fans 52 and 53 are disposed in front of the heat radiating plate 70 in order to enhance the cooling effect. The substrates 54b, 54r, and 54g on which the second blue light emitting element 22b, the third red light emitting element 23r, and the first green light emitting element 21g are mounted are fixed to the heat radiating plate 71, respectively. Cooling fans 56 and 57 are disposed in front of the heat radiating plate 71. The substrates 54b, 54r, and 54g on which the third blue light emitting element 23b, the first red light emitting element 21r, and the second green light emitting element 22g are mounted are fixed to the heat radiating plate 71. Cooling fans 56 and 57 are disposed in front of the heat radiating plate 71.

  As described above, the B light source is switched in the order of the first blue light emitting element 21b, the second blue light emitting element 22b, and the third blue light emitting element 23b, and the R light source is the first light emitting element 21b. The red light emitting element 21r, the second red light emitting element 22r, and the third red light emitting element 23r are switched in this order, and the light source for G light is the first green light emitting element 21g, the second green light emitting element 22g, and the third light emitting element. The green light emitting elements 23g are switched in this order. In other words, on each of the heat sinks 70, 71, 72, it is configured so that one of the three light emitting elements is turned on and the other two are turned off (the state shown in FIG. 12, FIG. 17, or FIG. 18). Due to variations in the lifetime of the light emitting elements, there may be a period in which two light emitting elements are lit on one heat sink).

  In this state, the heat generated by the light emitting elements of the respective colors is radiated by the heat radiating plates 70, 71, 72, so that the cooling efficiency is highest. As a result, the air volume of the cooling fans 52, 53, 56, 57, 74, and 75 can be reduced, which can contribute to the noise reduction of the video display device.

  The cooling fans 52, 53, 56, 57, 74, and 75 have a function of adjusting the cooling capacity of each of the heat radiating plates 70, 71, and 72 according to the air volume. In a state where only one of the three light emitting elements is lit on each of the heat sinks 70, 71, 72, the three light emitting elements being lit are adjusted by adjusting the cooling capacity of the heat sinks 70, 71, 72. The temperature control can be performed independently. Therefore, it becomes easy to suppress the wavelength shift in the light of each color, and an image display device with high luminous efficiency can be obtained. Further, since the temperature control becomes easy, the number of necessary cooling fans can be reduced, which can contribute to cost reduction.

  INDUSTRIAL APPLICABILITY The present invention is effective for a display device (for example, a projection projector or the like) having a business light source switching function (light source changer function) where it is desired to increase the continuous lighting time of the light source or the durability of the light source.

  1 First light source, 2 Second light source, 4b Blue dichroic mirror, 4g Green dichroic mirror, 4r Red dichroic mirror, 6 light bulb, 6b Blue light valve, 6g Green light valve, 6r Red light Bulb, 7 dichroic prism, 8 projection lens, 21b first blue light emitting element, 21g first green light emitting element, 21r first red light emitting element, 22b second blue light emitting element, 22g second green light emitting element, 22r second red light emitting element, 23b third blue light emitting element, 23g third green light emitting element, 23r third red light emitting element, 24b blue dichroic mirror, 24g green dichroic mirror, 24r red dichroic mirror, 25 Condenser lens, 26 Rod integrator, 28 Relay lens, 2 9 first reflection mirror, 30 second reflection mirror, 31 prism, 32 circuit board, 33 light valve, 34 projection lens, 35 brightness sensor.

Claims (5)

Multiple light sources;
Reflects light from the plurality of light sources, a plurality of dichroic mirrors which wavelength of light Ri Do different, linked to interlocked to reflect respectively,
A display unit that displays an image using light reflected by the plurality of dichroic mirrors ;
A drive mechanism for changing the orientation of the plurality of dichroic mirrors;
A luminance sensor for detecting the amount of light incident on the display unit;
A control circuit that controls the drive mechanism based on the change in the amount of light detected by the brightness sensor , and switches the plurality of light sources by changing directions of the plurality of dichroic mirrors. A video display device characterized by the above. A plurality of first light sources that generate first light of a first wavelength;
A plurality of second light sources for generating second light of a second wavelength;
A first dichroic mirror that reflects the first light;
A second dichroic mirror that reflects the second light and is coupled to interlock with the first dichroic mirror;
A display unit for displaying an image using light reflected by the first and second dichroic mirrors;
A drive mechanism for changing the orientation of the first and second dichroic mirrors;
A luminance sensor for detecting the amount of each of the first and second lights incident on the display unit;
Switching the first light source is performed by changing the direction of the first dichroic mirror by controlling the drive mechanism based on a change in the amount of the first and second light detected by the brightness sensor. And a control circuit that switches the second light source by changing the direction of the second dichroic mirror.
A video display device characterized by that. Further comprising first and second heat sinks;
One of the plurality of first light sources and one of the plurality of second light sources are fixed to the first heat radiating plate adjacent to each other,
Another one of the plurality of first light sources and the other one of the plurality of second light sources are fixed to the second heat radiating plate adjacent to each other,
The control circuit includes:
The plurality of first light sources and the plurality of second light sources are controlled so that adjacent light sources on the same heat sink are not lit simultaneously.
The video display device according to claim 2. Further comprising first and second heat sinks;
One of the plurality of first light sources and one of the plurality of second light sources are fixed to the first heat radiating plate adjacent to each other,
Another one of the plurality of first light sources and the other one of the plurality of second light sources are fixed to the second heat radiating plate adjacent to each other,
The control circuit includes:
Independently control the heat dissipation capability of the first and second heat sinks.
The video display device according to claim 2. The luminance sensor is mounted on the same circuit board as the light valve of the display unit, and includes a rod integrator that converts light from the first light source and the second light source into rectangular light, and It is arranged at a position where a small amount of transmitted light that passes through the reflecting mirror arranged between them can be detected.
The video display device according to claim 2.

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