JP2013257374A - Projection type image display device - Google Patents

Abstract

An object of the present invention is to increase the amount of shift in the vertical direction when performing vertical projection by rotating a projection image display device 90 degrees.
Light from a discharge lamp 101 passes through a rod integrator 103 and enters a total reflection prism 117 having a gap between two triangular prism portions. The light incident on the total reflection prism 117 is modulated by the DMD 108 and is incident on the projection lens 126 disposed in the vicinity of the total reflection prism via the total reflection prism 117. The projection lens 126 is provided with a lens shift mechanism 127 that can move in parallel with the optical axis orthogonal to the image display surface of the DMD 108, and the shift amount is a value that is asymmetric in the horizontal direction of the image display unit of the DMD 108. Yes.
[Selection] Figure 1

Description

 The present invention uses a DMD (Digital Micromirror Device: registered trademark) as an image display element, is provided with a total reflection prism for separating the incident / exit light, and moves the projection lens parallel to the image display surface of the image display element. The present invention relates to a projection-type image display device having a shift function that makes the screen movable. In particular, the present invention relates to a projection-type image display device that can realize a vertically long projected image by changing the installation direction of the 90-degree device so that the image display surface of the image display element (DMD) that is a horizontally long rectangle is in the vertical direction. is there.

 In a configuration using a DMD (digital micromirror device) as a conventional image display element, light illuminating the DMD is condensed so as to form a pupil in the vicinity of the rear lens (incident side lens) of the projection lens. The rear diaphragm configuration and the light that illuminates the DMD include a telecentric optical configuration in which the optical principal ray is parallel to the optical axis.

 The former enables a relatively small optical system, but has a problem in the uniformity of the projected image. The latter increases the overall system size, but is excellent in the uniformity of the projected image. Therefore, the former is used in a small and simple projection type image display device, and the latter is used in a system projection type image display device that requires high image quality. Yes.

 In the latter configuration using a telecentric optical system, a total reflection prism (also referred to as TIR or internal total reflection prism) as described in Patent Document 1 is used to separate the optical path between incident light and outgoing light to the DMD. Use. In this total reflection prism, two triangular prisms are joined with a parallel gap. Incident light from the light source is incident on the incident side prism, is totally reflected by the incident side surface of the gap, and then exits from the surface parallel to the DMD image display surface of the incident side prism and enters the DMD.

 The light reflected by the micro mirror in the ON state arranged in the image display area of the DMD is incident substantially perpendicularly to the incident side prism of the total reflection prism, and the surface constituting the gap of the incident side prism, the gap, and the emission The surface of the side prism, the exit side prism, and the exit side prism projection side face are transmitted through the projection lens to illuminate the screen.

 In an actual product, when the DMD is viewed from the projection lens side, the incident light to the DMD is designed to enter from the lower right oblique 45 ° direction. This is because the rotation axis of the DMD micromirror is inclined by 45 degrees. Therefore, the total reflection prism for guiding the incident light to the DMD is also tilted in the lower right diagonal direction.

 On the other hand, if the projection lens is designed with a short back focus, it is possible to reduce the size and cost of the projection lens. Therefore, the projection lens and the exit-side prism projection side surface of the total reflection prism are configured as close as possible without causing interference. ing.

 As a system projection type image display apparatus using the DMD having the above-described configuration, there is a system provided with a projection lens shift mechanism that allows the projection image to be moved by moving the projection lens in parallel. The amount of movement is an area in which the DMD image display unit is within an image circle that means an image plane (DMD image display plane) range in which the performance of the projection lens can guarantee performance. For this purpose, it is assumed that there is no interference with the surroundings even if the projection lens moves and the mechanism structure that enables operation.

 In an actual product, the movable range of the projection lens is restricted in the lower right direction when viewing the DMD from the projection lens side in order to avoid interference with the incident side prism of the total reflection prism. In other words, the operating range becomes narrower in the horizontal axis rightward and downward directions.

 In the actual product, regarding the downward shift, if the entire device is turned upside down and can be used, it can be shifted in both the upward and downward directions, so that only the upward shift is made or very small compared to the downward direction. The amount of shift is the amount. On the other hand, in the horizontal direction, the amount of shift in the right direction is restricted, so that the horizontal direction is used in a range with a margin in the image circle. At this time, there is no interference with the total reflection prism in the left direction, but if the operating range is mechanically widened, it is necessary for the peripheral members to escape and the device becomes large. Generally, the amount is the same as the amount of rightward movement because of difficulty.

JP 2012-2873 A

 In recent years, the use of projection-type image display devices has been diversified. In particular, there is a need for portrait projection in which the conventional projection direction is twisted 90 degrees, particularly in bulletin board applications. In order to cope with this, a countermeasure is taken such as twisting the image using a plurality of mirrors or rotating the projection type image display device 90 degrees and projecting it. However, in the former, the entire apparatus becomes large, and in the latter, since the projection type image display apparatus light source generally uses a discharge lamp, the discharge electrode axis is parallel to the direction of gravity, which impedes the life of the light source.

 On the other hand, in recent years, products using a solid-state light source that is not affected by the attitude difference of the light source are being offered to the market, and the wall for portrait projection is being removed.

 On the other hand, the above-described system projection type image display device for permanent use requires lens shift. However, in the conventional configuration, the shift movement amount is suppressed even if the image circle of the projection lens has a margin for the shift movement amount. It was forced.

 In view of this point, an object of the present disclosure is to provide a projection type image display apparatus capable of increasing a variable shift amount during portrait projection.

 A projection-type image display apparatus according to the present disclosure includes a light source, an image display element that modulates incident light by operating a plurality of reflective elements in which incident light is two-dimensionally arranged by an input signal from the outside, A relay optical system for guiding light from the light source and a gap between the first and second triangular prism portions, and the first triangular prism portion totally reflects incident light from the relay optical system and displays the image. A total reflection prism that transmits the reflected light from the image display element, which is guided to the element and is controlled by the first and second triangular prisms, and a projection lens capable of enlarging and projecting an image on the image display element; The projection lens includes shift projection with variable projection position while maintaining imaging performance by making the projection lens movable while maintaining the optical axis of the projection lens in parallel, and the amount of shift is displayed on the image display element. In the horizontal direction Characterized in that it is bilaterally asymmetrical values are.

  According to the present disclosure, in particular, it is possible to increase the variable shift amount with a minimum investment in a projection-type image display device that uses a DMD and uses a total reflection prism and has a high image quality and is capable of long projection. To do. This makes it possible to greatly improve user convenience.

The side view of the structure of the optical mechanism and light source part in Embodiment 1 of this invention Partial side view showing the configuration between the total reflection prism and the projection lens Enlarged view of total reflection prism Front view of the first embodiment Viewed from the direction of arrow A in FIG. Configuration diagram of a device equipped with a projection lens shift mechanism The figure which shows the structural example of Embodiment 2. The figure which shows the structural example of Embodiment 3. FIG. Illustration when projecting vertically from the ceiling

Hereinafter, embodiments will be described in detail with reference to the drawings.
(Embodiment 1)
1 is a side view of a configuration of an optical mechanism and a light source unit of a projection type image display apparatus 100 according to Embodiment 1 of the present invention, and FIG. 2 is a partial side view showing a configuration between a total reflection prism and a projection lens. 3 is an enlarged view of a total reflection prism, FIG. 4 is a front view of FIG. 1, FIG. 5 is a view seen from the direction of arrow A in FIG. 4, and FIG.

  The light source 101 is a discharge lamp, for example, and is driven by a driving device (not shown) to emit white light. The white light from the light source has a first focal point in the vicinity of the light source 101 and a second focal point in the vicinity of the incident surface 102 of the rod integrator 103 arranged so that the incident surface 102 is positioned on the electrode axis extension of the light source 101. The light is reflected by the reflector 104 having a reflective layer deposited on the ellipsoidal surface and condensed on the incident surface of the rod integrator 103.

 The light repeatedly reflected in the rod integrator 103 passes through the color selection filter 107 of the color wheel unit 106 disposed in the vicinity of the emission surface 105.

 The color selection filter 107 is composed of a plurality of different dichroic filters that select an arbitrary fan-like color for a motor that rotates at high speed and reflects other colors. The type of color light that passes through the color filter and the switching timing are not shown. Thus, it is driven so as to interlock with control of the DMD 108 which is an image display element.

 The color light transmitted through the color selection filter 107 enters the relay optical system 109. The relay optical system 109 includes a plurality of lenses and two folding mirrors. The light incident on the condenser lens 110 passes through the condenser lenses 111 and 112, is reflected by the folding mirror 113, passes through the condenser lens 114, is reflected by the folding mirror 115, and is guided by the condenser lens 116. The light enters the total reflection prism 117.

 As shown in FIG. 3, the total reflection prism 117 is provided with beaded adhesives 120a, 120b, 120c, and 120d between the first prism 118 having a triangular prism shape and the triangular prism portion of the second prism 119 having a trapezoidal cross section. Are combined to form a slight air gap. Although the light incident on the surface 121 of the first prism 118 reaches the surface 122, the incident angle is set so as to exceed the critical angle. Therefore, the light totally reflected by the surface 122 transmits the surface 123 and passes through the DMD 108. Is incident on.

 The DMD 108 has a number of micromirrors (reflective elements) arranged in a two-dimensional manner, and modulates incident light by changing its inclination at two inclination angles by an input signal from a control circuit (not shown). be able to. The light incident at the first tilt angle (= when tilted in the incident light direction) is configured to be emitted in the front direction with respect to the DMD 108. At this time, the light from the DMD incident on the surface 123 of the first prism 118 passes through the surface 122, enters the surface 124 of the second prism 119 through the air layer, and then enters the projection lens 126 through the surface 125. By entering, an image on a mirror surface (image display surface) that is an image display unit of the DMD 108 can be enlarged and projected onto a screen (not shown). When the projection lens 126 is increased in size, the price dramatically increases. Therefore, the distance from the total reflection prism 117 is made as close as possible within a range in which interference does not occur (not in contact with each other) even when variation is taken into account.

 Light incident at the second tilt angle of the micromirror of the DMD 108 (= when tilted to the opposite side of the incident light direction) causes the DMD 108 to emit light with a large angle. At this time, the light is similarly transmitted through the total reflection prism 117 and emitted. Since the light at this time is set so as not to be incident on the incident side lens of the projection lens 126, the mirror portion in the second tilt angle state has an arbitrary color in the image formed on the screen by the projection lens 126. Is displayed in black.

  Incidentally, in the optical system using the total reflection prism 117 as described above, since the total reflection is used, the principal ray is a parallel telecentric optical system so that the angle of incidence on the surface does not vary depending on the portion of the light beam.

  The image circle indicating the range in which the performance of the projection lens can guarantee the performance on the image plane (equivalent to the micromirror surface of the DMD 108) is larger than the range of the micromirror surface of the DMD 108. This means that the projection lens 126 can be projected even if it is disposed at a position shifted from the center of the image display area, which is the minute mirror surface range of the DMD 108. The projected image position on the screen can be changed by moving the projection lens 126 using this. This can be configured as a lens shift function.

 FIG. 6 shows a configuration including a shift mechanism 127 that can move the projection lens 126 in parallel without changing the distance in the optical axis direction from the micromirror surface of the DMD 108. The shift mechanism 127 is fixed to a set housing of a projection type image display apparatus (not shown), and the projection lens 126 on the shift mechanism 127 can be moved by moving the operation lever 128.

The following three factors determine the amount of movement.
1. A DMD image display section is included in the image circle of the projection lens 126.
2. The operating range of the shift mechanism 127 is sufficient.
3. When the projection lens 126 moves, it does not interfere with surrounding members.

 The third factor is often the constraint. Specifically, since the distance between the projection lens 126 and the total reflection prism 117 becomes narrow, the shift movement amount is restricted in order to avoid interference here.

 Incidentally, in this embodiment, the interval is shown by 2.5 mm in FIG. 5, and about 1.5 mm in consideration of the back focus variation of the projection lens 126 and the variation of the position of the portion that restricts the lens movement. become. Since the total reflection prism 117 is disposed obliquely as can be seen from the front view, it indicates that the operating range in the obliquely downward direction is limited. The products currently on the market have a large upward shift amount in the front view, the left and right directions are within a range to avoid interference with the total reflection prism 117, and the shift amount to the opposite side of the total reflection prism 117 is also the same amount. . The reason for limiting the amount of movement to the side opposite to the total reflection prism 117 is that it is difficult to explain to the user why this is the case, and that the shift mechanism can be reduced in size by the amount of shift. .

 Note that the shift amount has a larger value in the direction away from the total reflection prism.

  On the other hand, in the case of a discharge lamp, when the light source electrode axis is in the direction of gravity, the electrode temperature and the temperature in the tube are biased and there is a problem in reliability. I could not do it.

 In the present embodiment, since the light source electrode axis is parallel to the optical axis of the projection lens 126, even if the entire apparatus is rotated by 90 degrees, the electrode axis does not become the direction of gravity, so that it is possible to perform portrait projection. . FIG. 9 shows a state in which the projection type image display device 100 is mounted using the ceiling mount 150 so that the horizontal display method of the image display unit of the DMD can be projected in the vertical direction in the vertical direction of the projected image during image projection. Is shown.

 In this vertical projection, the horizontal shift during horizontal projection is the vertical shift, so according to the conventional design, the amount of movement from the installed position toward the center of the screen is small, which inconveniences the user. It was.

  In the present embodiment, the direction in which the shift amount is large in vertical projection is from the apparatus installation position to the center of the screen, which is the projection surface, so that the convenience for the user can be greatly improved.

  In this embodiment, the amount of movement to the side opposite to the total reflection prism 117 is expanded to the range in which the image display area is inscribed in the image circle of the projection lens 126 or in the vicinity thereof. By not arranging surrounding constituent members (not shown) so as not to interfere even if they are increased, the operation range is expanded in the left direction during landscape projection in the front view of FIG.

 In particular, when the device is arranged by rotating 90 times, it means that the amount of movement in the vertical direction is increased. The direction in which the amount of movement sometimes increases can be improved by rotating the device so that it is set upward when the device is placed on the floor and downward when the device is suspended from the ceiling. . At this time, it is necessary to release the peripheral member in order to avoid interference with the surroundings in the direction in which the shift mechanism becomes slightly larger and the operating range is increased, but this can be realized without any change that affects the cost and the merchantability.

 As described above, in this embodiment, a DMD that is an image display element that modulates incident light by operating a discharge lamp and a number of reflective elements in which incident light is two-dimensionally arranged by an input signal from the outside. And a relay optical system for guiding light from the discharge lamp. In the embodiment, there is a total reflection prism, which is configured with a gap between the first and second triangular prism portions, and the first triangular prism portion totally reflects the incident light from the relay optical system. Then, the first and second triangular prism portions transmit the reflected light from the image display element, which is guided to the DMD and controlled in a desired manner. Further, the embodiment includes a projection lens capable of enlarging and projecting an image on the DMD. The projection lens is provided with shift projection with variable projection position while maintaining the imaging performance by making the projection lens movable while maintaining the optical axis of the projection lens in parallel, and the shift amount of the image display unit of the image display element In the horizontal direction, the value is asymmetrical about the reference position.

By doing so, the vertical shift amount in the case of projecting vertically long can be increased.
(Embodiment 2)
In this embodiment, since the projection lamp electrode axis is parallel to the optical axis of the projection lens to obtain a vertically long projection, there is no problem in reliability even if the apparatus is rotated. However, in the second embodiment, it is not affected by the attitude difference. An LED which is a solid light source is used.

 FIG. 7 shows an embodiment of a projection-type image display device 129 using LEDs as light sources. The light source sections are LED condensing lenses 131, 133, 135, and 138, red LEDs 130, green LEDs 134, blue LEDs 137, and red transmission dichroic. A mirror 132 and a green reflecting dichroic mirror 136 are included.

 The blue light from the blue LED passes through the LED condensing lens 138, then passes through the green reflecting dichroic mirror 136, is reflected by the red transmitting dichroic mirror 132, and enters the LED condensing lens 133. Green light from the green LED 134 passes through the LED condensing lens 135, is reflected by the green reflecting dichroic mirror 136, is reflected by the red transmitting dichroic mirror 132, and enters the LED condensing lens 133. The color light from the red LED 130 passes through the LED condensing lens 131, then passes through the red transmitting dichroic mirror 132, and enters the LED condensing lens 133. In this way, the blue light, the green light, and the red light are collected so as to enter the incident surface 102 of the rod integrator 103 after entering the LED condensing lens 133.

 Since the configuration of the projection type image display device 129 other than the light source using the LED is the same as that of the first embodiment, the description thereof is omitted.

As described above, when the LED is used as a light source, the arrangement such as the vertical placement can be freely performed without considering the arrangement direction, which is effective in the case where the shift amount can be increased during the vertical placement.
(Embodiment 3)
FIG. 8 shows an embodiment of a projection-type image display device 139 using a laser as a light source. The light source unit includes a blue laser 140, a collimating lens 141, red reflecting dichroic mirrors 142 and 147, condenser lenses 143 and 145, and a mirror 146. 149, red reflection fluorescence, green transmission fluorescence, and blue transmission phosphor wheel 144.

  Blue light from the blue laser 140 is collected through the path of the collimating lens 141, the red reflecting dichroic mirror 142, the red reflecting fluorescence, the green transmitting fluorescence, the blue transmitting phosphor wheel 144, the condenser lens 145, the mirror 146, and the red reflecting dichroic mirror 147. The light enters the lens 148.

 The light from the blue laser 140 also excites the red phosphor on the phosphor wheel 144, and the red light emitted from the phosphor is reflected by a reflective film applied to the opposite surface of the phosphor layer of the phosphor wheel 144. The light enters the condenser lens 148 through the path of the condenser lens 143, the red reflecting dichroic mirror 142, the mirror 149, and the red reflecting dichroic mirror 147.

 The light from the blue laser 140 also excites the red fluorescent light, the green transmitted fluorescent light, and the green fluorescent material applied on the opposite side of the light transmitting side of the blue transmitted fluorescent wheel 144, and the green light emitted from the fluorescent material is The light enters the condenser lens 148 through the path of the condenser lens 145, the mirror 146, and the red reflecting dichroic mirror 147.

 The blue light, red light, and green light incident on the condensing lens 148 are condensed and incident on the incident surface 102 of the rod integrator 103.

 Since the configuration of the projection type image display device 129 other than the light source using the laser is the same as that of the first embodiment, the description thereof is omitted.

 When the laser is used as the light source in this way, the arrangement such as the vertical placement can be freely performed without considering the arrangement direction, which is effective in the case where the shift amount can be increased during the vertical placement.

 In the third embodiment, only the blue laser is used, but it goes without saying that the same configuration can be obtained by combining other colors of LEDs.

  Further, in each of the above embodiments, it is obvious that the same can be said for a three-chip system having DMD for each color light of red, green, and blue, using a total reflection prism and having a short back focus.

  The present disclosure can be used for a projection image display apparatus including a total reflection prism and a lens shift mechanism using a DMD as a modulation element.

100 Projection Image Display Device 101 Light Source (Discharge Lamp)
DESCRIPTION OF SYMBOLS 102 Incident surface 103 Rod integrator 104 Reflector 105 Output surface 106 Color wheel unit 107 Color selection filter 108 DMD (digital mirror device)
109 Relay optical system 110, 111, 112, 114, 116, 148 Condensing lens 113, 115 Folding mirror 117 Total reflection prism 118 First prism 119 Second prism 120a, 120b, 120c, 120d Beaded adhesive 121, 122, 123 First prism surface 124, 125 Second prism surface 126 Projection lens 127 Shift mechanism 128 Operation lever 129 Projection-type image display device 130 Red LED
131, 133, 135, 138 LED condensing lens 132 Red transmissive dichroic mirror 134 Green LED
136 Green reflective dichroic mirror 137 Blue LED
139 Projection-type image display device 140 Blue laser 141 Collimate lens 142, 147 Red reflection dichroic mirror 143, 145 Condenser lens 146, 149 Mirror 144 Red reflection fluorescence, green transmission fluorescence, blue transmission phosphor wheel 150

Claims (9)

A light source;
An image display element that modulates incident light by operating a number of reflective elements in which incident light is two-dimensionally arranged according to an external input signal;
A relay optical system for guiding light from the light source;
The first and second triangular prism portions are provided with a gap, and the first triangular prism portion totally reflects incident light from the relay optical system and guides it to the image display element, and the desired control is performed. A total reflection prism that transmits reflected light from the image display element through the first and second triangular prism portions;
A projection lens capable of enlarging and projecting an image on the image display element;
The projection lens can be moved while maintaining the optical axis of the projection lens in parallel to provide shift projection with a variable projection position while maintaining imaging performance, and the shift amount is a horizontally long image display portion of the image display element. A projection-type image display device characterized in that the value is asymmetrical in the direction.   The projection type image display apparatus according to claim 1, wherein the shift amount has a large value in a direction away from the total reflection prism.   2. The projection type image display apparatus according to claim 1, wherein when projecting an image, it is possible to perform a longitudinal projection in which the lateral direction of the image display unit of the image display element is the vertical direction of the projected image.   4. The projection type image display apparatus according to claim 3, wherein the direction in which the shift amount is large in the longitudinal projection is from the apparatus installation position to the center side of the screen, which is the projection surface.   The projection image display apparatus according to claim 1, wherein a solid light source is used as the light source.   6. The projection image display apparatus according to claim 5, wherein the solid-state light source is an LED light source.   6. The projection image display apparatus according to claim 5, wherein the solid-state light source is a laser light source.   4. The projection type image display apparatus according to claim 3, wherein the light source is a discharge lamp arranged so that an electrode axis is in a direction perpendicular to a gravitational direction during the longitudinal projection.   2. The projection type image according to claim 1, wherein when the incident light to the image display element is incident from an obliquely lower right direction when viewed from the front, the direction in which the movement amount of the projection lens is large is the left direction. Display device.

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