JP2013025130A - Video display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a video display device which can get along with multiple kinds of reflective display devices having different angles at which minute mirrors are driven, without having adversely affecting display video.SOLUTION: A circuit board 33 can be installed in a regularly directed state and in a reversely directed state, which are different for two kinds of DMDs having different driving angles. A position of a light detecting element 15 in the regularly directed state and a position of the light detecting element 15 in the reversely directed state bear relation of point symmetry with respect to a reference point SP being a central point of a reference line connecting screw holes 35, 36, and are located apart from the reference point SP by distance L. In addition, an optical axis center line of off-light 17a and an optical axis center line of off-light 17b have relation where a median line ML of them passes through the reference point SP.

Description

  The present invention is an image display for projecting an image by reflecting light from an illumination light source of a semiconductor light emitting element such as a high pressure mercury lamp or LED by arc discharge to a reflective semiconductor device such as a DMD (digital micromirror device). It relates to the device.

  Conventionally, in a projector having a reflective display device such as a DMD display unit using a reflective light modulation element, deterioration over time of a light source, a color wheel, etc., or changes in luminance and white balance that occur when these are replaced, In many cases, detection is always performed by detecting off-light from the DMD display unit, and correction is automatically performed. In this case, the light detection element does not interfere with the on-light that is the actual screen light, and thus does not affect the projection screen. For example, there is a project disclosed in Patent Document 1 as such a projector.

JP 2007-298798 A

  However, in a conventional projector (image display device), when the display is made to correspond to a plurality of types of reflective display devices with different angles driven by the fine mirror, the area of the transmissive diffusion plate is set to correspond to the plurality of types of reflective display devices. It was necessary to enlarge. When the area of the transmissive diffuser increases, the amount of off-light reflected without passing through the transmissive diffuser increases, and the reflected off-light enters the projection lens and reduces the contrast of the displayed image. There was a problem that would adversely affect.

  The present invention has been made to solve the above-described problems, and an image display apparatus capable of supporting a plurality of types of reflective display devices having different angles driven by a fine mirror without adversely affecting the displayed image is obtained. With the goal.

  In the image display device according to claim 1 of the present invention, the illumination light emitted from the light source is changed in the reflection direction by driving the plurality of fine mirror portions at a predetermined drive angle in each of the positive direction and the negative direction. A reflection type display device that generates reflected light in the positive direction and the negative direction; and a light detection unit that has a light detection element that receives the reflected light in the negative direction and can detect the amount of light. The photodetecting element can be set to one of a first arrangement and a second arrangement, and the first arrangement is configured such that the predetermined driving angle of the reflective display device is the first driving angle. The second arrangement includes an arrangement capable of detecting first negative direction reflected light that is reflected in the negative direction, and the second arrangement is configured such that the predetermined driving angle of the reflective display device is larger than the first driving angle. At the drive angle of 2 A second negative reflected light is definitive the negative direction of the reflected light comprises a detectable arrangement.

  In the video display device according to the first aspect of the present invention, the light detection unit can selectively set the light detection element to one of the first and second arrangements. The first arrangement includes an arrangement capable of detecting the first negative direction reflected light that is the negative direction reflected light when the predetermined driving angle of the reflective display device is the first driving angle. The arrangement includes an arrangement in which the reflective display device can detect the second negative reflected light in the negative direction at the second driving angle.

  Therefore, the photodetecting unit has a photodetecting element that is used as the reflective display device so that the photodetecting unit is adapted to a device having the first and second driving angles (first and second reflective display devices). By setting to one of the first and second arrangements, the first and second negative direction reflected lights from the first and second reflective display devices can be appropriately detected by the light detection element.

  As a result, the photodetecting unit positions the photodetecting element in the first or second arrangement regardless of which of the first and second reflective display devices having different driving angles by the plurality of fine mirrors is used. As a result, the first and second negative direction reflected lights can be accurately received by the photodetecting element, so that a video display device with high versatility of the photodetecting unit can be obtained.

It is a perspective view which shows the principal part structure of the video display apparatus which is embodiment of this invention. It is a side view which shows DMD which is the principal part of the video display apparatus shown in FIG. 1, and its peripheral region. It is explanatory drawing which shows typically the cross-section of DMD which has a some fine mirror with a drive angle in the embodiment in the +/- 12 degree | times. It is a perspective view which shows the principal part cross-section of the video display apparatus of embodiment. It is sectional drawing which shows the principal part sectional structure of the video display apparatus of embodiment. It is explanatory drawing which computed the luminance distribution by the change of the distance of the off-light reflected from DMD by simulation. It is explanatory drawing which decomposes | disassembles and shows the holding structure of the photon detection element which shows embodiment of invention. It is explanatory drawing which shows the outline of the cross-section of DMD which has a some fine mirror with a drive angle of +/- 14 degree in embodiment. It is a top view which shows the planar structure (forward direction state) of the circuit board which mounted the photon detection element. It is a top view which shows the planar structure (reverse direction state) of the circuit board which mounted the photon detection element. It is a perspective view which shows the principal part cross section of the video display apparatus of embodiment at the time of attaching a photon detection unit in a reverse direction state. It is sectional drawing which shows the principal part cross-section of a video display apparatus at the time of attaching a photon detection unit in reverse direction. An image display device using a DMD having a plurality of fine mirrors with a drive angle of ± 14 degrees and an optical path for off-light when a DMD having a plurality of fine mirrors with a drive angle of ± 12 degrees are used are superimposed. It is explanatory drawing which shows a partial cross section structure. It is a perspective view which shows the structure of the conventional project. It is explanatory drawing which showed typically the example of arrangement | positioning of the conventional photon detection element by superimposing the optical path of DMD driven about ± 12 degree | times, and DMD driven about +/- 14 degree | times.

<Prerequisite technology>
FIG. 14 is a perspective view showing the structure of a conventional project. The projector shown in FIG. 14 corresponds to the projector disclosed in Patent Document 1, for example.

  As shown in the figure, single-wavelength light emitted from the LED light sources 1R, 1B, and 1G is condensed into parallel light beams by the collimator lenses 2R, 2B, and 2G, and reflected or transmitted by the dichroic mirror 3. The light is condensed by the condenser lenses 4 and 5 and enters the rod integrator 6. The light incident on the rod integrator 6 is repeatedly reflected several times by the reflecting surface that forms the periphery of the rod integrator 6, and unevenness in the in-plane luminance distribution of the LED light sources 1R, 1B, and 1G emitting surface light from the emission end is to some extent. It is emitted as light with improved uniformity. The emitted light is modulated by a digital micro device (DMD) 14 that is a reflective display device via lenses 10a, 10b, and 10c, mirrors 11 and 12, and a prism 13, and becomes image light, which is not shown. It is magnified by the projection lens and projected onto the screen.

  The DMD 14 is composed of a collection of fine reflecting mirrors (hereinafter referred to as “fine mirrors”), and changes the angle of the fine mirror corresponding to the pixels constituting the image to change the direction of the projection lens and the direction other than the projection lens 1R. , 1B, and 1G, a color image is generated by switching the reflection direction of the colored light.

  The light sources 1R, 1B, and 1G are actually arranged by arranging a light detecting element 15 whose output voltage changes according to the amount of received light of an arbitrary monochromatic wavelength in light reflected in a direction other than the projection lens (hereinafter abbreviated as “off light”). The color balance is controlled by detecting the light quantity balance of red, blue, and green reaching the DMD 14 and controlling the current supplied to each light source.

  In addition, a diffusion transmission plate 56 is disposed between the light detection element 55 and the DMD 14 so that an appropriate color balance can be obtained even if there is uneven color in the plane of the off-light 57, and the diffusion transmission plate 56 extends from the DMD 14 to the diffusion transmission plate. The light diffused and transmitted through 56 is averaged, and the light detection element 55 detects the amount of light.

  Further, the fine mirror constituting the DMD 14 increases the angle between the light reflected in the direction of the projection lens (hereinafter abbreviated as “on light”) and the off light 57 without the projection lens reducing the contrast of the on light 58. Since a wide image can be captured and a bright image can be projected on the screen, it is desirable to set the attitude control angle (drive angle) of the fine mirror as large as possible.

  However, since the angle of the fine mirror is changed at a high speed as the image to be displayed changes, if the drive angle is too large, the rotation fulcrum that changes the angle of the fine mirror causes metal fatigue due to repetitive operation, and the life is shortened. In recent years, the structure of this rotation fulcrum has been improved, and the (reflection type) display device that has been driven ± 10 degrees from the horizontal direction has shifted to ± 12 degrees and the direction in which the driving angle of the fine mirror is gradually increased to ± 14 degrees. Driven display devices are also being commercialized.

  For example, it is possible to drive ± 14 degrees during the manufacturing and production of an image display device comprising a configuration of an illumination optical path using a DMD 14a having a plurality of fine mirrors that are driven ± 12 degrees and a position where the photodetecting element 55 is attached. Assume that the life of the DMD 14b having a fine mirror is improved and becomes usable. In this case, in addition to reconfiguring the optical path that is incident on the DMD 14b from the DMD 14a, the mounting angle of the light detection element 55 that receives the off-light 57 reflected from the DMD 14b and the diffuse transmission plate 56 also changes. Therefore, between the DMD 14a driven by ± 12 degrees (with the fine mirror) and the DMD 14b driven by ± 14 degrees, the configuration of the video display apparatus is the main optical components (light detection element 55, diffuse transmission plate 56, etc.) For example, two types of molds can be produced to increase the cost of mold production, or holes for mounting screws can be processed at different positions to manage similar parts. The problem of becoming complicated arises.

  FIG. 15 is an explanatory diagram schematically showing an arrangement example of the conventional photodetecting element 55 by superposing the optical paths of the DMD 14a driven by ± 12 degrees (by the fine mirror) and the DMD 14b driven by ± 14 degrees. As shown in the figure, the shape of some optical components, such as a DMD prism 13a driven ± 12 degrees and a DMD prism 13b driven ± 14 degrees, and the structural parts holding the optical parts are changed. Consider a case in which a video display device capable of sharing the DMD 14a whose fine mirror is driven ± 12 degrees and the DMD 14b driven ± 14 degrees is manufactured. In this case, the angles of the off-light 57a reflected by the DMD 14a driven ± 12 degrees and the off-light 57b reflected by the DMD 14b driven ± 14 degrees are different.

  For this reason, the diffusing and transmitting plate 56W for transmitting and diffusing the entire light beams of both off lights 57a and 57b diffuses and transmits the entire light beams of the off lights 57a and 57b reflected from the DMDs 14a and 14b, respectively. It is necessary to form a larger area than the diffuse transmission plate, which is sufficient if only one of the off lights 57a (57b) is transmitted.

  For this reason, the material cost of a permeation | transmission diffusion plate becomes expensive. Further, when the area of the diffusing and transmitting plate 56W is increased, the amount of off-light 57a (57b) that is reflected by a few percent without being transmitted through the transmitting and diffusing plate 56W also increases, and the prisms 13a and 13b, DMDs 14a and 14b are increased. Then, there arises a problem that the reflected stray light enters the projection lens and reduces the contrast of the display image.

  In consideration of such a problem of the base technology, an image display apparatus (projector) that can handle a plurality of types of reflective display devices with different angles driven by a fine mirror without adversely affecting the displayed image will be described below. This will be described as an embodiment.

<Embodiment>
FIG. 1 is a perspective view schematically showing a main configuration of a video display apparatus (projector) according to an embodiment of the present invention. FIG. 2 is a side view showing a DMD, which is a main part of the video display device shown in FIG.

  As shown in these drawings, each of the semiconductor light emitting modules 1R, 1G, and 1B is mounted on the basis of a semiconductor light emitting element that emits light of an arbitrary wavelength such as an LED or a laser. The semiconductor light emitting module 1R emits red single wavelength light (hereinafter abbreviated as “R light”), and the semiconductor light emitting module 1G emits green single wavelength light (hereinafter abbreviated as “G light”). The module 1B emits blue single wavelength light (hereinafter abbreviated as “B light”).

  A dichroic mirror 3B that reflects only the wavelength of B light from the light emitting surface of the semiconductor light emitting module 1B is disposed, and a dichroic mirror 3R that reflects only the wavelength of R light from the light emitting surface of the semiconductor light emitting module 1R is disposed. Has been.

  Further, between each semiconductor light emitting element 1R, 1G, 1B and the dichroic mirror 3, a collimator for refracting the single wavelength light emitted from the semiconductor light emitting elements 1R, 1G, 1B to become a parallel light beam. Lenses 2R, 2G, and 2B are provided.

  Therefore, the B light emitted from the semiconductor light emitting module 1B is refracted into a parallel light beam by the collimator lens 2B, reflected by the dichroic mirror 3B, transmitted through the dichroic mirror 3R, and refracted by the condensing lenses 4 and 5 into convergent light. The rod integrator 6 is entered. The R light emitted from the semiconductor light emitting module 1R is refracted into a parallel light beam by the collimator lens 2R, reflected by the dichroic mirror 3R, transmitted through the dichroic mirror 3B, and refracted by the condensing lenses 4 and 5 into convergent light. Incident on the rod integrator 6. Further, the G light emitted from the semiconductor light emitting module 2G is refracted into a parallel light beam by the collimator lens 3G, passes through the dichroic mirrors 3B and 3R, is refracted into convergent light by the condenser lenses 4 and 5, and enters the rod integrator 6. .

  The rod integrator 6 is formed by bonding four reflecting mirrors with an adhesive, and the three color beams incident on the rod integrator 6 are reflected many times along the rectangular shape of the inner surface. The emitted light beam becomes uniform rectangular illumination light 9a in a plane orthogonal to the optical axis 9, and is further refracted into a substantially parallel light beam by the relay lenses 10a, 10b, and 10c, and the first reflection mirror 11 and the second reflection mirror 11 The light is reflected by the reflection mirror 12 and enters a DMD 14 (14a, 14b) provided as a display device via a prism 13a that refracts or transmits light depending on the incident angle of the light.

  The video signal output from the video generation circuit (not shown) and the light emission period of each single-wavelength semiconductor light emitting device 1R, 1G, 1B are synchronized by signal transmission between the video generation circuit and the control circuit described above, The color image generated by controlling the attitude angle of the micromirror inside the DMD 14 (14a in FIG. 2) mounted on the generation circuit is enlarged by the projection lens 19 shown in FIG. 2 and projected onto a screen (not shown). Is done. For example, when a plurality of video display devices are arranged to display one large video image, the relevance to the illumination light 9a actually irradiated on the screen in order to make the brightness of the video image displayed by each video display device uniform. The light detection element 15 detects the off-light 17b having The light detection element 15 is disposed at a position where the light amount of the off-light 17a (first negative direction reflected light) is substantially directly proportional to the light amount of the illumination light 9a. Hereinafter, DMD 14a and DMD 14b are generically referred to as DMD 14, prism 13a and prism 13b are generically referred to as prism 13, and off-light 17a and off-light 17b are generically referred to as off-light 17 and fine mirror 20a and fine mirror 20b. In this case, it is expressed as a fine mirror 20.

  Since the shadow of the light detection element 15 is reflected on the screen when the light detection element 15 is arranged between the DMD 14a and the projection lens 19, the shadow of the light detection element 15 is not reflected on the screen as shown in FIG. The light detection element 15 is disposed at a position where it can receive off-light 17 a having a light amount substantially equivalent to the on-light 18. The electromotive current generated by receiving light by the photodetecting element 15 is digitized by a control circuit (not shown), and is used as, for example, a value for aligning the brightness of each video display device. Further, the light detection element 15 is provided with R, G, B filters, and the values for independently detecting the respective light amounts of the R light, G light, and B light in the illumination light 19a and adjusting the color balance. Can also be used.

  FIG. 3 is an explanatory diagram schematically showing a cross-sectional structure of a DMD 14a having a plurality of fine mirrors with a drive angle of ± 12 degrees in the embodiment. In the figure, the DMD 14a generates an image by changing the angle of the internal fine mirror 20a ± 12 degrees from the horizontal direction by a video signal circuit (not shown). The illumination light 9a is incident on the fine mirror 20a by the prism 13a at an angle of 66 degrees from the horizontal direction. Here, when the CW (ClockWise) direction is “−” and the CCW (CounterClockWise) direction is “+”, when the fine mirror 20a is tilted by +12 degrees, the relative angle between the fine mirror 20a and the illumination light 9a is 66 degrees. The illumination light 9a is reflected in the direction of the projection lens 19 at an angle of 78 degrees from the plane of the fine mirror 20a in the direction opposite to the direction incident on the fine mirror 20a. That is, the illumination light 9a is reflected in the vertical direction, transmitted through the projection lens 19, and becomes the on-light 18 that is enlarged and projects an image on the screen.

  Similarly, the illumination light 9a incident on the fine mirror 20a by the prism 13a at an angle of 66 degrees from the horizontal direction is such that when the fine mirror 20a is inclined by -12 degrees, the relative angle between the fine mirror 20a and the illumination light 9a is 66. The difference value obtained by subtracting 12 degrees from the degree is 54 degrees, and the illumination light 9a is at an angle of 54 degrees from the plane of the fine mirror 20a in the direction opposite to the direction incident on the fine mirror 20a. That is, the illumination light 9a is reflected in a direction different from the projection lens 19 at an angle of 42 degrees from the horizontal direction. This reflected light becomes off-light 17a that does not display the illumination light 9a on the screen.

  FIG. 4 is a perspective view schematically showing a cross-section of the main part of the video display apparatus according to the embodiment. FIG. 5 is a cross-sectional view showing a main-part cross-sectional structure of the video display device according to the embodiment.

  As shown in these drawings, the off-light 17a that is reflected by the DMD 14a and transmitted through the prism 13a further includes the opening hole 22x of the light shielding plate 22 (outside unit light shielding plate) and the light shielding plate 23 (inside unit light shielding plate). After passing through the opening hole 23x), the light passes through the transmission diffusion plate 16 and enters the light detection element 15 in which the output current changes according to the amount of received light. Then, the light detection element 15 detects the luminance variation of the illumination light 9a by detecting the light amount of the received off-light 17a.

  Generally, a method is adopted in which the entire interior surface 21 of the upper case 40 is painted black to suppress stray light due to the reflected light of the off-light 17a to the interior surface 21 of the mirror. However, in this method, the amount of light in the portion irradiated with the off-light 17a in the upper case 40 is large. Therefore, in a commercial video display device used for 5 to 10 years, the mirror in the range irradiated with the off-light 17 is used. As the distance from the DMD 14a to the wall surface irradiated with the off-light 17a is closer, the indoor surface 21 tends to increase the fading speed of the black paint due to secular change. In FIG. 5, VL is a normal line indicating the vertical direction with respect to the light detection element 15.

  In the present embodiment, a light shielding plate 22 is disposed between the prism 13a and the transmission diffusion plate 16 in order to suppress the off light 17a that hits the transmission diffusion plate 16 and is reflected by the prism 13a. The light shielding plate 22 is subjected to a black surface treatment with high light resistance, such as plasma alumite, which generates a ceramic film by reacting a large amount of oxygen plasma generated by plasma electrolysis with an aluminum alloy, for example. Therefore, the light shielding plate 22 disposed close to the prism 13a does not fade even when strong light is irradiated for a long time. Similarly, the light-shielding plate 23 provided on the surface of the transmission diffusion plate 16 is subjected to a surface treatment with high light resistance. The light shielding plates 22 and 23 are formed with opening holes 22x and 23x, respectively, and the off-light 17a passes through the opening holes 22x and 23x and diffuses through the transmission diffusion plate 16 to reach the light detection element 15. . Accordingly, the off-light 17 is not irradiated on the surface 21, and the entire surface treatment of the mirror interior surface 21a does not require a special surface treatment with particularly excellent light resistance. Therefore, the surface area constituting the mirror interior surface 21a is large. The process and cost of surface treatment of parts can be suppressed.

  FIG. 6 is an explanatory diagram in which the luminance distribution due to the change in the distance of the off-light 17 reflected from the DMD 14 is calculated by simulation. In the figure, (a) to (d) show off-light luminance distributions 25 to 28 when LEDs are used as light sources (semiconductor light emitting modules 1R, 1G, 1B). The off-light luminance distribution 25 is the luminance distribution of the off-light 17 at a position 20 mm away from the upper surface 13S of the prism 13, and the off-light luminance distribution 26 is the luminance distribution of the off-light 17 at a position 40 mm away from the upper surface 13S. The light luminance distribution 27 shows the luminance distribution of the off-light 17 at a position 80 mm away from the upper surface 13S, and the off-light luminance distribution 28 shows the luminance distribution of the off-light 17 at a position 1000 mm away from the upper surface 13S.

  In FIG. 6, (e) to (h) show off-light luminance distributions 29 to 32 when a high-pressure mercury lamp light source is used as the light source (semiconductor light emitting modules 1R, 1G, 1B). The off-light luminance distribution 29 is the luminance distribution of the off-light 17 at a position 20 mm away from the upper surface 13S, the off-light luminance distribution 30 is the luminance distribution of the off-light 17 at a position 40 mm away from the upper surface 13S, and the off-light luminance distribution 31 is The luminance distribution of the off-light 17 at a position 80 mm away from the upper surface 13S and the off-light luminance distribution 32 indicate the luminance distribution of the off-light 17 at a position 1000 mm away from the upper surface 13S.

  As shown in FIG. 6, when a high-pressure mercury lamp that emits light by arc discharge is used as a light source, the position of the arc discharge changes between electrodes due to an excessive change in the electrode shape of the arc discharge, or the LED is used as a light source. In such a case, a shadow or the like at the junction of the dichroic mirror 3 disposed in the middle of the optical path appears as an image, resulting in a difference in the in-plane luminance distribution. In this way, the inner surface is reflected a plurality of times by the rod integrator 6 and focused by the DMD 14, and the unevenness in luminance due to the above-described change over time is made uniform on the reflecting surface of the DMD 14. As the distance from 13S (DMD 14) increases, the in-plane luminance distribution has a non-uniformity.

  In the present embodiment, the transmission diffusion plate 16 is brought close to the vicinity of the projection lens 19, and the transmission diffusion plate 16 is disposed, for example, at a position approximately 26 mm away from the upper surface 13 </ b> S of the prism 13. Therefore, the off-light 17 incident on the transmissive diffusion plate 16 has relatively little luminance unevenness due to the temporal change of the light source, and the off-light 17 diffused through the transmissive diffusion plate 16 has a more uniform luminance distribution. Therefore, the difference in the amount of received light due to the variation in the mounting position is small even if the mounting position accuracy of the light detecting element 15 is not individually adjusted. Even in an apparatus using a high-pressure mercury lamp as a light source, the amount of light received by the light detection element 15 varies little due to a change in the arc discharge position due to a change over time. Therefore, the off-light 17 taken into the photodetecting element 15 is the off-light that becomes the reflected light of the illumination light 9 a irradiated to the approximate center of the DMD 14 without receiving and averaging the entire illumination light 9 a irradiated to the DMD 14. By receiving only the center of 17, it is possible to suppress variations in the amount of received light due to variations in mounting of the light detection element 15 and arc movement. Therefore, the area of the transmissive diffusion plate 16 can be reduced.

  FIG. 7 is an explanatory view showing the holding structure of the photodetecting element 15 in an exploded manner according to the embodiment of the invention. Note that FIG. 7 corresponds to a drawing viewed from the opposite direction with FIG. 5 turned upside down.

  In the figure, the light detection element 15 is mounted (fixedly arranged) on the mounting plane (predetermined mounting plane) of the circuit board 33, and the holding member 34 sandwiches the transmissive diffusing plate 16 and further covers the entire diffusing transmissive plate 16. The light-shielding plate 23 is screwed and fixed so as to cover it. Further, the holding member 34 is fixed to the circuit board 33 with screws. Screw holes 35 and 36 are provided in the circuit board 33, and a connector 38 (see FIG. 4) having a detachable portion 37 (see FIG. 4) is mounted on the surface opposite to the surface on which the light detection element 15 is mounted, In the connector 38, a lead wire for energizing an electromotive current generated when the light detection element 15 receives light to another control circuit (not shown) is joined to the detachable portion 37.

  As described above, the light detection unit 39 is formed by a structure including the light detection element 15 holding structure including the light detection element 15, the transmission diffusion plate 16, the light shielding plate 23, the holding member 34, and the connector 38. The light detection unit 39 is screwed and fixed to the upper case 40 holding the projection lens 19, but the connector 38 is inserted through a square hole 41 formed in the upper case 40 and is illustrated from the outside of the upper case 40. It is joined to the lead wire that is omitted. In addition, a flat mounting surface 42 is formed around the square hole 41, and the square hole 41 is formed with dimensions smaller in length and width than the outer shape of the circuit board 33. Accordingly, when the circuit board 33 is screwed and fixed so as to be in close contact with the mounting surface 42, dust entering the inside of the square hole 41 from the outside of the square hole 41 is shielded by the circuit board 33 and is inside the upper case 40, that is, the prism 13a. Do not enter the interior of the mirror holding the optical parts.

  FIG. 8 is an explanatory diagram showing an outline of a cross-sectional structure of a DMD 14b (second reflective display device) having a plurality of fine mirrors with a driving angle of ± 14 degrees, which shows an embodiment. In the figure, the DMD 14b generates an image by changing the angle of the internal fine mirror 20a by ± 14 degrees from the horizontal direction by a video signal circuit (not shown). The illumination light 9b is incident on the fine mirror 20b at an angle of 62 degrees from the horizontal direction by the prism 13b (prism 13b corresponding to the DMD 14b). As described above, when the CW direction is “−” and the CCW direction is “+”, when the fine mirror 20b is tilted by +14 degrees, the relative angle between the fine mirror 20b and the illumination light 9b is increased by 14 degrees to 62 degrees. The illumination light 9b is reflected in the direction of the projection lens 19 at an angle of 76 degrees from the plane of the fine mirror 20b in the direction opposite to the direction incident on the fine mirror 20b. That is, the light is reflected in the vertical direction, transmitted through the projection lens 19, and becomes the on-light 18 that is magnified and projects an image on the screen.

  Similarly, the illumination light 9b incident on the fine mirror 20a by the prism 13b at an angle of 62 degrees from the horizontal direction is such that when the fine mirror 20b is inclined by -14 degrees, the relative angle between the fine mirror and the illumination light 9b is 62 degrees to 14 degrees. The difference value obtained by subtracting the degree is 48 degrees, and the illumination light 9b has an angle of 48 degrees from the plane of the fine mirror 20b in the direction opposite to the direction incident on the fine mirror 20b. That is, the illumination light 9b is reflected in a direction different from the projection lens 19 at an angle of 34 degrees from the horizontal direction, and becomes off-light 17b (second negative direction reflected light) that does not display the illumination light 9b on the screen.

  FIG. 9 is a plan view showing a planar structure (a normal orientation state) of the circuit board 33 on which the photodetector 15 is mounted. FIG. 10 is a plan view showing a planar structure (opposite state) of the circuit board 33 on which the light detection element 15 is mounted on the mounting plane. In FIG. 9, the screw holes 35 and 36 are separated from each other by a distance L symmetrically about the light detection element 15. The center point of the reference line L35 connecting the center points between the screw holes 35 and 36 becomes the reference point SP, and the distance from the reference point SP to the center point of the light detection element 15 becomes L.

  The circuit board 33 shown in FIG. 9 can also be attached to the upper case 40 with the screw holes 35 and the screw holes 36 in the opposite directions so that the left and right are reversed. That is, as shown in FIG. 10, the circuit board 33 can be rotated 180 degrees around the reference point SP so that the positional relationship between the screw hole 35 and the screw hole 36 can be replaced.

  9, the center point C15 of the light detection element 15 is present at a positive distance L in the Y direction with respect to the reference point SP. On the other hand, in the planar position shown in FIG. 10 (in the reverse direction (second state)), the center point C15 of the light detection element 15 is present at a negative distance L in the Y direction with respect to the reference point SP. As described above, the positional relationship between the light detection element 15 in the forward direction of the circuit board 33 and the light detection element 15 in the reverse direction is axisymmetric with respect to the reference point SP. 2, 4, 5, and 9 show examples in which the light detection unit 39 is mounted in a forward orientation so as to correspond to the DMD 14 a.

  FIG. 11 is a perspective view schematically showing a cross section of the main part of the video display device of the embodiment when the light detection unit 39 is mounted in the reverse direction. That is, FIG. 11 shows a cross section of the main part when the light detection unit 39 is mounted in the reverse direction so as to correspond to the DMD 14b, and corresponds to FIG.

  FIG. 12 is a cross-sectional view showing the cross-sectional structure of the main part of the video display device when the light detection unit 39 is mounted in the reverse direction. That is, FIG. 12 shows a structure in the case where the light detection unit 39 is attached in the reverse direction so as to correspond to the DMD 14b, and corresponds to FIG.

  As shown in these figures, the light shielding plate 22 is fixed to the upper case 40 at a position different from the case where the DMD 14a is used so that the center of the optical axis of the off light 17b is transmitted through the opening hole 22x.

  FIG. 13 shows the optical path of the off-light 17a when the DMD 14a having a plurality of fine mirrors having a drive angle of ± 12 degrees is used in an image display device using the DMD 14b having a plurality of fine mirrors having a drive angle of ± 14 degrees. It is explanatory drawing which shows typically the superimposed principal part cross-section.

  In the figure, the light detection element 15 generally has high sensitivity of light received from a substantially vertical direction (normal line VL) with respect to the light receiving surface of the light detection element 15. On the other hand, when FIG. 3 is compared with FIG. 8, the difference in angle between the off-light 17a and the off-light 17b is 8 degrees.

  Therefore, for the middle line ML shown in FIG. 13 in which the angle difference of 8 degrees between the off-light 17a (the optical axis center line) and the off-light 17b (the optical axis center line) is equally divided into two, FIG. As shown in FIG. 10, it is set so that the middle line ML passes through the reference point SP which is the center point of the reference line L35 between the screw holes 35 and. That is, as shown in FIG. 13, the distance from the mounting position (indicated by a broken line) on the circuit board 33 of the photodetecting element 15 in the positive direction provided corresponding to the off-light 17a is twice as long as L. The light detection element 15 in the reverse direction provided corresponding to the off-light 17b is disposed at the position.

  Therefore, as shown in FIGS. 5 and 12, even when the light detection element 15 is either the off-light 17a or 17b, the center optical axis of the off-light 17a or 17b is that of the light detection element 15 indicated by the normal line VL. Light is received with an inclination of 4 degrees in the vertical direction. At this time, light perpendicular to the optical axis center of the off-light 17 can be received by setting the diffusivity so that the diffusing angle of the transmission diffusing plate 16 is expanded by 8 degrees or more. As a result, the light detection unit 39 remains in an assembly in which the components are assembled in the same direction using the same member, and the drive angle is ±± by changing the direction of the circuit board 33 fixed to the upper case 40 by 180 degrees. It can be used in common for both the video display device using the 12-degree DMD 14a and the video display device using the DMD 14b having a drive angle of ± 14 degrees.

  In addition, since the diffuse transmission plate 16, the light shielding plate 23, and the like in the light detection unit 39 are also connected and attached to the circuit board 33, the light detection is performed regardless of the state of the circuit board 33 (forward direction state, reverse direction state). The relative positional relationship with respect to the element 15 does not change.

  In addition, the upper case 40 that forms the mirror chamber in the interior needs to be formed of a high-precision and high-rigidity material in order to mount a projection lens or the like, and is dedicated to aluminum die-casting, magnesium die-casting, engineering plastics, etc. Since the mold is manufactured and molded by injection molding, a dedicated mold cost is incurred.

  However, by providing a plurality of types of screw holes 43, 44, 45, and 46 in advance so that the light shielding plate 22 can be screwed to different locations in the upper case 40 to which the light detection unit 39 is attached, The video display device using the DMD 14a having a drive angle of ± 12 degrees and the video display device using the DMD 14b having a drive angle of ± 14 degrees can be used with a common structure.

  Specifically, referring to FIGS. 7, 9 and 10, the screws 61 and 62 of the light shielding plate 22 are attached to the upper case 40 when the DMD 14 a is to be supported (when the circuit board 33 is set in the normal orientation). The light shielding plate 22 is screwed in the screw holes 43 and 44 to attach the light shielding plate 22 to the upper case 40 (first attachment state of the light shielding plate 22). On the other hand, when adapting to the DMD 14b (when the circuit board 33 is turned in the reverse direction), the screws 61 and 62 of the light shielding plate 22 are screwed in the screw holes 45 and 46 of the upper case 40 to raise the light shielding plate 22 upward. It attaches to case 40 (2nd attachment state of light-shielding plate 22).

  Therefore, in the first attachment state of the light shielding plate 22, as shown in FIG. 5, the off-light 17a is set to pass through the opening hole 22x of the light shielding plate 22, and in the second attachment state of the light shielding plate 22. As shown in FIG. 12, the OFF light 17b is set to pass through the opening hole 22x.

  As a result, the upper case 40 itself can be formed in one form regardless of the forward and reverse states of the circuit board 33 and the first and second attachment states of the light shielding plate 22. The cost of the dedicated mold required for the production can be suppressed, and it is particularly effective when applied to a projection type projector that has a long service life and is used for business use in a variety of small-lot production.

  The circuit board 33 in the video display apparatus according to the present embodiment can selectively set the photodetecting element 15 to either the first or second arrangement (forward direction state or reverse direction state). In addition, the light detection unit 39 includes the light detection element 15.

  The first arrangement includes an arrangement capable of receiving off-light 17a when using the DMD 14a having a driving angle of ± 12 degrees (first driving angle), and the second arrangement has a driving angle of ± It includes an arrangement capable of receiving off-light 17b when the DMD 14b of 14 degrees (second drive angle) is in the forest.

  Therefore, by setting the photodetecting elements 15 on the circuit board 33 to the first and second arrangements so as to be compatible with the DMD 14a and DMD 14b (first and second reflective display devices) used as the DMD 14. The light detecting element 15 can accurately detect the off-light 17a and off-light 17b (first and second negative reflected light) from the DMD 14a and DMD 14b.

  As a result, regardless of which of the DMD 14a and DMD 14b having different driving angles is used, the light detection unit 39 positions the light detection element 15 in the first or second arrangement, so that the light detection element 15 turns off the light 17a. In addition, since the off-light 17b can be accurately detected, an image display device with high versatility of the light detection unit 39 can be obtained.

  In addition, the circuit board 33 sets the photodetecting element 15 in the first and second arrangements, and the position of the photodetecting element 15 in the forward orientation (first state) and the reverse orientation (first The position of the photodetecting element 15 in the state (2) has a point-symmetric relationship with respect to the reference point SP (predetermined reference point).

  The reference point SP on the mounting plane of the circuit board 33 on which the photodetecting element 15 is mounted is between the optical axis center line of the off-light 17a from the DMD 14a and the optical axis center line of the off-light 17b from the DMD 14b. The line ML is set to pass.

  Therefore, with respect to the circuit board 33 on which the photodetecting element 15 is mounted, either the forward state or the reverse state of the relation rotated by 180 degrees around the reference point SP is set so as to conform to the DMD 14a and DMD 14b. Thus, the off-light 17a and the off-light 17b from the DMD 14a and the DMD 14b can be appropriately accurately detected by the light detection element 15.

  As a result, it is possible to set either a forward state or a reverse state rotated 180 degrees around the reference point SP by a relatively simple change in which the circuit board 33 is arranged upside down. Therefore, it is possible to obtain a video display device with high versatility of the light detection unit 39 without complicating the assembly work.

  In the video display device according to the embodiment, the light shielding plate 22 (outside unit light shielding plate) subjected to the black surface treatment is provided between the DMD 14 (prism 13) and the light detection unit 39, so that the opening hole 22x. Only the optical path to the opening hole 23x of the light shielding plate 23 (the light shielding plate in the unit) of the off light 17a and the off light 17b (first and second negative direction reflected light) is selectively made effective, and other than the opening hole 22x. Other light paths are blocked by the light blocking area.

  As a result, since the reflected light in the light detection unit 39 with respect to the off-light 17 can be made substantially zero, it is possible to project a display image with high accuracy without causing deterioration of the contrast of the display image even when used for a long time. it can.

  Further, the light detection unit 39 (light detection element 15) is disposed at a position relatively close to the DMD 14 (prism 13) (for example, the diffuse transmission plate 16 is located approximately 26 mm away from the upper surface 13S of the prism 13 by a linear distance). As a result, the light detection element 15 can detect the light amount with high accuracy at a distance where the in-plane luminance distribution of the off-light 17 is relatively uniform. At this time, as described above, the presence of the light shielding plate 22 subjected to the black surface treatment does not adversely affect the display image by the ON light 18.

  Furthermore, by disposing the light detection unit 39 at a position close to the DMD 14 (prism 13), it is possible to reduce the size of the transmission diffusion plate 16 and the circuit board 33 (L can be reduced). Miniaturization of the unit 39 can be realized.

  In addition, by providing the light shielding plates 22 and 23, deterioration due to fading of the black paint on the mirror interior surface 21 can be avoided, so that the lifetime of the video display device according to the embodiment is improved by increasing the durability. Can be planned.

  In this embodiment, DMD is taken as an example of the reflective semiconductor device, but LCOS (Liquid crystal on silicon, registered trademark) of reflective liquid crystal may be used. For example, LCOS (registered trademark) generally does not have a plurality of reflection directions, but the present invention can be applied when there are a plurality of reflection angles of the change prisms used in combination.

  1B, 1G, 1R Semiconductor light emitting module, 13, 13a, 13b Prism, 14, 14a, 14b DMD, 15 Photodetector, 16 Diffuse transmission plate, 17, 17a, 17b Off light, 18 On light, 20, 20a, 20b Fine mirror, 22, 23 light shielding plate, 39 light detection unit.

Claims (3)

A reflective type that generates reflected light in the positive and negative directions by changing the reflection direction by driving a plurality of fine mirror sections at predetermined driving angles in the positive and negative directions respectively for illumination light emitted from the light source A display device;
A photodetection unit having a photodetection element capable of detecting the reflected light in the negative direction and detecting the amount of the reflected light. Is configurable,
The first arrangement includes an arrangement capable of detecting the first negative direction reflected light that is the reflected light in the negative direction when the predetermined driving angle of the reflective display device is the first driving angle, In the second arrangement, the second negative direction reflected light that is the reflected light in the negative direction when the predetermined driving angle of the reflective display device is a second driving angle larger than the first driving angle. Including a detectable arrangement,
Video display device. The video display device according to claim 1,
The light detection unit includes a circuit board in which the light detection element is fixedly disposed on a predetermined mounting plane.
The circuit board can be installed in different first and second states with respect to the reflective display device,
In the circuit board, the position of the light detection element in the first state and the position of the light detection element in the second state are points with respect to a predetermined reference point on the predetermined mounting plane. Have a symmetrical relationship,
The center line of the optical axis center line of the first negative direction reflected light and the optical axis center line of the second negative direction reflected light is the above-mentioned circuit board set in the first and second states. Having a positional relationship passing through a predetermined reference point,
Video display device. The video display device according to claim 2,
The light detection unit includes:
A diffusion transmission plate provided on the reflective display device side with respect to the circuit board and capable of diffusing and transmitting the first and second negative direction reflected light;
An in-unit light shielding plate that is provided on the reflective display device side with respect to the diffuse transmission plate and guides the first and second negative direction reflected light from the reflective display device to the diffuse transmission plate through an opening hole When,
A holding member for connecting and holding the diffusion transmission plate and the unit light shielding plate and the circuit board;
The relative positional relationship between the diffuse transmission plate and the light shielding element in the unit is not changed in the first and second states,
Provided only between the light detection unit and the reflection side display device, and selectively enabling only the optical path of the first and second negative direction reflected light to the opening hole of the light shielding plate in the unit; A light shielding plate outside the unit that blocks the light path other than, the light shielding plate outside the unit is subjected to a black surface treatment,
Video display device.