JP5609687B2 - Projection display - Google Patents

Description

  The present invention relates to a projection-type display device that enlarges and displays a color image on a screen by synthesizing image light projected by a projection lens with human eyes.

  As this type of projection display device, for example, the one disclosed in Patent Document 1 has been proposed. For example, in order to realize a small and inexpensive projection display device, it is necessary to use only one reflective spatial light modulator and to make the light source as small as possible. In order to obtain sufficient brightness with a small light source, the illumination effective range (illumination likelihood) of illumination light is limited to the display range of the reflective spatial light modulation element, and it is necessary to increase the light utilization efficiency.

Japanese Patent Application Laid-Open No. 11-352452

  However, if the illumination likelihood is reduced with respect to the display range of the reflective spatial light modulator, the illumination can be performed depending on the component accuracy and the assembly accuracy (the illumination range of the illumination light is shifted from the display range of the reflective spatial light modulator). There is a possibility that a shadow is formed in a part of the display area). If the component accuracy and the assembly accuracy are increased in order to prevent the lighting from being lost, an inexpensive projection display device cannot be realized.

  Therefore, an object of the present invention is to provide a projection display device that can easily adjust the position of the illumination range by illumination light with respect to the display range of the reflective spatial light modulator without increasing the component accuracy and assembly accuracy.

The first invention is a light emitting device (1) that switches each color light of R, G, and B at regular intervals, and a reflective spatial light modulator that modulates light with a signal for each color light in synchronization with the switching of each color light. (2) and the first polarized component light of each incident color light is reflected and incident on the reflective spatial light modulator (2), and each color light modulated by the reflective spatial light modulator (2) is reflected. A PBS prism (3) that transmits the second polarized component light, a projection lens (4) that projects the second polarized component light emitted from the PBS prism (3) as image light, and the PBS prism (3), A rotation adjustment mechanism that rotates and adjusts an optical axis from a light source that is a component of the light emitting device (1) to a PBS prism (3) as a rotation axis (11); and the reflective spatial light modulation element (2), A plane parallel to the rotation axis direction of the PBS prism (3) In comprising a position adjusting means for position adjustment in one direction, and the rotation adjusting mechanism, the PBS prism (3) mounted collimator lens (6) to a base hole formed in (9) (10) The PBS prism (3) is inserted and rotatably mounted with the optical axis from the light source to the PBS prism (3) as a rotation axis (11), and the screw (12) provided on the base (9) is turned to A projection-type display device configured to rotate and adjust the PBS prism (3) by pressing the PBS prism (3) .

In a second aspect based on the first aspect, the position adjusting means includes a guide pin (18) provided on a holding member (14) for holding the reflective spatial light modulator (2), and the reflective pin. The attachment position of the reflective spatial light modulation element (2) with respect to the holding member (14) is made parallel to the rotation axis direction by being inserted into and engaged with a long hole (19) formed in the spatial light modulation element (2). A projection-type display device configured to slide .

  According to the present invention, the PBS prism can be rotated and adjusted with the optical axis from the light source to the PBS prism as the rotation axis, and the reflective spatial light modulator is arranged in one direction within a plane parallel to the rotation axis direction of the PBS prism. Since the position can be adjusted, the projection display device can easily adjust the position of the illumination range by the illumination light with respect to the display range of the reflective spatial light modulator without increasing the component accuracy and assembly accuracy.

FIG. 1 is a perspective view showing the overall configuration of the projection display device of this embodiment. FIG. 2 is a perspective view showing the PBS prism of the projection display device of FIG. 1, and shows a state where a collimator lens is bonded to the lower surface. FIG. 3 is a perspective view showing an assembled state of the PBS prism assay and the base in the projection display device of FIG. FIG. 4 is a perspective view showing a state in which rotational pressure is applied to the PBS prism assay in the projection display device of FIG. FIG. 5 is a perspective view showing a state in which the PBS prism assay is rotationally adjusted with the rotational adjustment screw in the projection display device of FIG. FIG. 6 is a perspective view for explaining a method of adjusting the vertical direction of the reflective spatial light modulation element assembly. FIG. 7 is a diagram showing the margin (illumination likelihood) of the effective illumination range with respect to the display range of the reflective spatial light modulator. FIG. 8 is a diagram showing a deviation of the effective illumination range with respect to the display range of the reflective spatial light modulator that can occur after assembly. FIG. 9 is a diagram showing the relationship between the rotation angle θ of the PBS prism and the illumination range movement amount of the illumination light.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. FIG. 1 shows the overall configuration of a projection display device to which the present invention is applied. The projection display device includes a light emitting device 1, a reflective spatial light modulator assembly 2 having a reflective spatial light modulator, a PBS prism 3, a projection lens 4, and a rotation adjustment that rotates and adjusts the PBS prism 3. It has a mechanism part and a position adjusting means for adjusting the position of the reflective spatial light modulator in one direction.

  The light emitting device 1 has RGB (color light) LEDs (light sources), and switches each color light at regular intervals. The RGB light emitted from the LED and switched at regular intervals enters the light tunnel 5 provided in front of the light source, and is repeatedly reflected several times in the light tunnel 5 to average the in-plane light intensity. The averaged light passes through a collimator lens group composed of several collimator lenses 6 arranged in front of the light tunnel 5.

  Of the light that has passed through the collimator lens group, S-polarized light (first polarized component light) is reflected by the polarizing mirror surface 7 of the PBS prism 3 to change the optical path, passes through the field lens 8, and then is reflected into the reflective spatial light The light enters the reflective spatial light modulation element of the modulation element assembly 2. The reflective spatial light modulation element assembly 2 includes a reflective spatial light modulation element for modulating incident light with a signal for each color light in synchronization with switching of each color light.

  The P-polarized light (second polarized component light) that has been light-modulated and reflected by the reflective spatial light modulator is transmitted through the polarization mirror surface 7 of the PBS prism 3 and enters the projection lens 4.

  The projection lens 4 projects P-polarized light (second polarized component light) from the PBS prism 3 onto a screen (not shown) as image light. The projection lens 4 is disposed on the same optical axis with respect to the reflective spatial light modulation element assembly 2 and the field lens 8 with the PBS prism 3 interposed therebetween.

  As shown in FIGS. 2 to 5, the rotation adjusting mechanism unit inserts the collimator lens 6 attached to the PBS prism 3 into the hole 10 formed in the base 9, and moves the PBS prism 3 from the light source (LED) to the PBS. The optical axis reaching the prism 3 is rotatably mounted as a rotation axis 11, and the PBS prism 3 is rotationally adjusted by rotating the rotation adjusting screw 12 provided on the base 9 and pushing the PBS prism 3. .

  As shown in FIG. 2, a circular collimator lens 6 is bonded to the center position of the lower surface 3a of the PBS prism 3. As shown in FIGS. 3 and 4, the base 9 includes a prism mounting portion 13 for mounting the PBS prism 3, an assembly mounting portion 14 for mounting the reflective spatial light modulation element assembly 2, and a projection lens 4. A lens mounting portion 15 to be mounted is provided.

  The prism mounting portion 13 is formed with a bottom portion 13 a that receives the bottom surface 3 a of the PBS prism 3 and side wall portions 13 b and 13 c that receive two opposite side surfaces 3 b and 3 c of the PBS prism 3. A circular hole 10 for inserting the collimator lens 6 attached to the PBS prism 3 is formed in the bottom portion 13a. A slight gap is formed between the side wall portions 13 b and 13 c and the side surfaces 3 b and 3 c of the PBS prism 3 for rotating the PBS prism 3 around the rotation shaft 11. In this gap, an elastically deformable cushion 16 is arranged. The cushions 16 are respectively disposed on the diagonal lines of the PBS prism 3 and apply a preload that rotates in a fixed direction to the PBS prism 3.

  Also, a screw hole 17 for rotating the PBS prism 3 by pressing a part of the side wall 3b of the PBS prism 3 with the rotation adjusting screw 12 is formed in one side wall portion 13b. The screw hole 17 is provided at a position facing the cushion 16 disposed on the other side wall portion 13c. By screwing the rotation adjusting screw 12 into the screw hole 17, the PBS prism 3 can be pushed and rotated at the screw tip protruding inside the side wall portion 13b. As a result, the PBS prism 3 can rotate about the optical axis of the incident illumination light, and the rotation angle thereof is adjusted by adjusting the screw of the rotation adjusting screw 12. When the rotation adjusting screw 12 is loosened, the PBS prism 3 is reversely rotated in the direction opposite to the screw pushing direction by being pushed by the cushion 16 to which the preload is applied.

  When the rotation angle of the PBS prism 3 is adjusted in this way, the tilt angle of the polarization mirror 7 in the prism is adjusted, so that the horizontal irradiation range of the illumination light incident on the reflective spatial light modulator can be adjusted. become.

  As shown in FIG. 5, the assembly mounting portion 14 has holding walls 14 a and 14 b that hold the corner portions on both side edges of the reflective spatial light modulation element assembly 2 to be positioned and held. The reflective spatial light modulation element assembly 2 is attached to the assembly mounting portion 14 by position adjusting means so as to slide along the axial direction (one direction) in a plane parallel to the rotational axis direction. Yes.

  As shown in FIG. 6, the position adjusting means includes a guide pin 18 provided on the assembly mounting portion 14, which is a holding member for holding the reflective spatial light modulation element assembly 2, with the reflective spatial light modulation element assembly. By inserting and engaging with the long hole 19 formed in the three-dimensional body 2, the attachment position of the reflective spatial light modulation element assembly 2 with respect to the assembly mounting portion 14 is along one direction within a plane parallel to the rotation axis direction. The position can be adjusted by sliding it.

  The guide pins 18 are respectively provided on both holding walls 14a and 14b of the assembly mounting portion 14, and are inserted into and engaged with the respective long holes 19, thereby slidably guiding the reflective spatial light modulation element assembly 2. ing. The sliding position of the reflective spatial light modulation element assembly 2 with respect to the assembly mounting portion 14 is fixed by screwing the reflective spatial light modulation element assembly 2 to the assembly mounting portion 14 with a fixing screw 20.

  According to the position adjusting means configured in this way, the reflective spatial light modulation element assembly 2 is moved by moving the reflective spatial light modulation element assembly 2 along the guide pins 18 provided in the assembly mounting portion 14. 2 can be translated along the direction of the rotation axis of the PBS prism 3. This makes it possible to adjust the position of the illumination range in the vertical direction of the illumination light incident on the reflective spatial light modulator.

  The lens mounting portion 15 is provided with lens guide walls 15a, 15b, and 15c for positioning the projection lens 4 by guiding the bottom portion and both side portions, respectively.

  The effects of the projection display device of this embodiment will be specifically described based on the following examples. In the embodiment, as shown in FIG. 7, the effective illumination range S2 (the range surrounded by the dashed rectangle) is 0 for the entire circumference with respect to the display range S1 (the range indicated by the oblique lines) of the reflective spatial light modulator. A margin (illumination likelihood) W of 2 mm is provided. In other words, in a state where the position adjustment of the illumination range is properly adjusted, the illumination region by S2 extends to the outside of the display range S1 on the entire outer periphery of the display range S1 of the reflective spatial light modulator.

  However, due to the effects of component accuracy and assembly accuracy, the effective illumination range S2 may shift M from the display range S1 of the reflective spatial light modulator after assembly, as shown in FIG. In the projection display device of the present embodiment, the PBS prism 3 can be rotated within a range of about ± 3 degrees from the design reference position.

  FIG. 9 shows the relationship between the rotation angle θ of the PBS prism 3 and the illumination range movement amount X of the illumination light. When the PBS prism 3 is rotated once, it can be seen from FIG. 9 that the effective illumination range S2 of the illumination light incident on the reflective spatial light modulator is moved by about 0.35 mm in the horizontal direction. Further, when the PBS prism 3 is rotated ± 3 degrees which is the maximum value of the adjustment range, the effective illumination range S2 in the horizontal direction moves ±± 1 mm. As can be seen, by rotating the PBS prism 3, the deviation of the illumination effective range S2 can be adjusted in the horizontal direction in the range of M ≦ about 1 mm.

  Here, if the rotation range of the PBS prism 3 is further increased, the illumination range movement amount X is increased, so that the position adjustment range of the illumination range can be expanded. However, if the rotation range of the PBS prism 3 is excessively large, it is necessary to provide a large gap between the PBS prism 3 and the side wall portions 13b and 13c of the base 9 and the volume of the entire engine increases. Also, it is not preferable to make the tilt angle of the PBS prism 3 too large, because the illumination light incident on the reflective spatial light modulator has an unintended incident angle. Therefore, it is important to balance the illumination adjustment range that can be adjusted in the horizontal direction by the rotation of the PBS prism 3 and the positional accuracy of the reflective spatial light modulation element assembly 2 that is regulated by component accuracy and assembly accuracy.

  Further, according to the projection display device of the present embodiment, the PBS prism 3 can be inserted into the hole 10 formed in the base 9 and the PBS prism 3 can be rotated with the optical axis from the light source to the PBS prism 3 as the rotation axis 11. Since the rotation adjustment mechanism is configured so that the rotation adjustment screw 12 provided on the base 9 can be turned and the PBS prism 3 can be pushed to adjust the rotation, the rotation adjustment screw 12 can be simply turned to enter the reflective spatial light modulator. The position of the illumination light to be adjusted can be adjusted in the horizontal direction.

  Further, according to the projection type display device of the present embodiment, the guide pin 18 provided on the assembly mounting portion 14 that holds the reflective spatial light modulation element assembly 2 is formed on the reflective spatial light modulation element assembly 2. Since the position adjusting means is configured to be inserted and engaged with the elongated hole 19 so that the attachment position of the reflective spatial light modulation element assembly 2 to the assembly mounting portion 14 is slid in parallel with the rotation axis direction. The illumination light incident on the reflective spatial light modulator can be easily adjusted in the vertical direction by simply sliding the reflective spatial light modulator assembly 2 using the pin 18 as a guide.

  As described above, according to the projection display device of the present embodiment, the effective illumination range S2 incident on the reflective spatial light modulation element is changed by operating the rotation adjusting mechanism and the position adjusting unit. With respect to the display range S1, it is possible to increase the light use efficiency as far as the display range without increasing the component accuracy and the assembly accuracy more than necessary. Therefore, in this projection display device, sufficient brightness can be obtained with a small light source.

  Although specific embodiments to which the present invention is applied have been described above, various modifications can be made in the present invention without being limited to the above-described embodiments. For example, in the above-described embodiment, the PBS prism 3 is rotated with the circular collimator lens 6 bonded to the center of the lower surface of the PBS prism 3 as the rotation axis. However, the collimator lens 6 may not be used as the rotation axis. For example, a sheet metal may be combined on the upper surface of the PBS prism 3 and a pin may be provided at the center of the sheet metal, and this pin may be used as the rotation axis.

  The present invention can be used in a projection display device that synthesizes image light projected by a projection lens with a human eye and enlarges and displays it on a screen as a color image.

1 Light-emitting device (light source)
2 Reflective spatial light modulator assembly (reflective spatial light modulator)
DESCRIPTION OF SYMBOLS 3 PBS prism 4 Projection lens 5 Light tunnel 6 Collimator lens 7 Polarization mirror surface 8 Field lens 9 Base 10 Hole formed in the base 11 Rotating shaft 12 Rotation adjustment screw 13 Prism mounting part 14 Assembly mounting part 15 Lens mounting part 16 Cushion 17 Screw hole 18 Guide pin 19 Long hole 20 Fixing screw S1 Display range of reflective spatial light modulator S2 Effective illumination range

Claims (2)

A light-emitting device that switches each color light of R, G, and B at regular intervals;
A reflective spatial light modulator that modulates light with a signal for each color light in synchronization with switching of each color light;
A PBS prism that reflects the first polarized component light of each color light incident thereon, enters the reflective spatial light modulator, and transmits the second polarized component light of each color light modulated by the reflective spatial light modulator; ,
A projection lens that projects the second polarized component light emitted from the PBS prism as image light;
A rotation adjustment mechanism that adjusts the rotation of the PBS prism about the optical axis from the light source that is a component of the light-emitting device to the PBS prism;
Position adjusting means for adjusting the position of the reflective spatial light modulator in one direction within a plane parallel to the rotation axis direction of the PBS prism;
Equipped with a,
The rotation adjustment mechanism unit is inserted into a hole formed in a base of a collimator lens attached to the PBS prism, and the PBS prism is attached to be rotatable about an optical axis from the light source to the PBS prism as a rotation axis. The PBS prism is configured to rotate and adjust by rotating the screw provided on the plate and pushing the PBS prism .
A projection type display device characterized by that. The projection display device according to claim 1,
The position adjusting means inserts and engages a guide pin provided in a holding member that holds the reflective spatial light modulation element into a long hole formed in the reflective spatial light modulation element, thereby the reflective spatial light. A projection-type display device configured to slide a mounting position of a modulation element with respect to the holding member in parallel with the rotation axis direction .

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