JP7086149B2 - Projection type display device - Google Patents

Description

The present invention relates to a projection type display device provided with two light modulation elements and capable of projecting an image for two screens.

In recent years, large screens have been used in various fields such as monitors for video conferencing systems in which multiple people can participate via the Internet, monitors for surveillance systems equipped with multiple surveillance cameras, medical monitors, and educational monitors. Moreover, a multi-pixel display device is required.

Conventionally, a projection type display device having a light modulation element such as a DMD element or a liquid crystal element and a projection optical system and displaying an image by magnifying and projecting it on a screen or the like has been known. In the light modulation element used in the projection type display device, the pixels are miniaturized and the number of pixels is increasing, and XGA (1024 x 768 pixels), WXGA (1280 x 800 pixels) to WUXGA (1920 x 1200 pixels), and so on. It has evolved to 4K.

However, if the number of pixels of the light modulation element is increased, the unit price of the light modulation element tends to increase significantly due to reasons such as a decrease in manufacturing yield. Further, when the pixel pitch of the light modulation element is miniaturized, the ratio of the area occupied by the opening to the pixel wiring and the drive transistor tends to decrease, and the utilization efficiency of the illumination light may decrease. Further, when the number of pixels is increased, the temperature of the light modulation element substrate tends to rise easily during driving.
Therefore, in the projection type display device using the light modulation element of a single plate, there is a limit in increasing the number of pixels and reducing the pixel size.

Therefore, as a method for enabling a large screen display relatively easily, a method is known in which a plurality of projection type display devices are provided side by side and projected images are displayed side by side.
For example, Patent Document 1 proposes an adjustment method for projecting an image from a plurality of projection-type display devices provided therein so that differences in brightness and chromaticity of each projection-type display device become inconspicuous. ..

Japanese Unexamined Patent Publication No. 2009-159372

It is also conceivable that a large screen display can be easily realized by displaying the projected images side by side by installing a plurality of projection type display devices side by side. However, in reality, in order to prevent the observer from feeling uncomfortable when viewing multiple projected images displayed side by side, it is necessary for the operator to have a high level of skill when installing and adjusting the projection type display device. A large load was required.

This is because each of the projection display devices has an independent projection optical system and a light modulation element. In order to match the position, size, tilt, focus state, etc. of adjacent images projected from each device to a level that does not make the observer feel uncomfortable, the position when installing each image projection device, etc. This is because it is necessary to precisely adjust the setting of the projection optical system of each projection type display device.

In this regard, the method disclosed in Patent Document 1 is a drive adjustment method for making the difference in brightness and chromaticity inconspicuous at the screen boundary of a projected image, and is a drive adjustment method, in which the position, size, inclination, and focusing of adjacent images are inconspicuous. It does not adjust the state.

Therefore, images modulated by two light modulation elements are projected side by side to display a large screen, but projection that does not require a large load for adjusting the position, size, tilt, focusing, etc. of adjacent images. There was a demand for a type display device.

One aspect of the present invention includes a first optical modulation element that modulates the first illumination light according to the image signal, a second optical modulation element that modulates the second illumination light according to the image signal, and the like. A first relay lens that forms a first intermediate image by forming an image of the first illumination light modulated by the first optical modulation element, and the second light modulated by the second optical modulation element. From the second relay lens that forms a second intermediate image by forming an image of the illumination light of the above, the first reflecting surface that totally reflects the light incident from the first relay lens, and the second relay lens. A roof-shaped reflective optical element having a second reflecting surface that totally reflects incident light, a roof-shaped reflecting optical element having an apex angle formed by the first reflecting surface and the second reflecting surface, and a projection lens are provided. The illumination light modulated by the light modulation element 1 is reflected by the first reflecting surface and then forms the first intermediate image, and the illumination light modulated by the second light modulation element is the second. After being reflected by the reflecting surface, the second intermediate image is formed, the optical axis of the projection lens passes through the apex angle of the reflecting optical element, and the projection lens is formed between the first intermediate image and the second intermediate image. It is a projection type display device characterized by arranging and magnifying images side by side.

According to the present invention, images modulated by two light modulation elements are projected side by side and displayed on a large screen, but a large load is applied to the adjustment of the position, size, tilt, focusing, etc. of the adjacent images. It is possible to provide a projection type display device that does not require it. In addition, it is possible to realize miniaturization and cost reduction of the device as compared with the conventional method in which a plurality of projection type display devices are provided side by side.

The schematic diagram which shows the optical structure of the projection type display device which concerns on Embodiment 1. FIG. (A) The figure which shows an example of the display image projected on the screen SC. (B) The figure which shows another example of the display image projected on the screen SC. (A) The figure which shows an example of the positional relationship of a relay lens 300A, a roof prism 401, and an intermediate image 500A in Embodiment 1. FIG. (B) The figure which shows another example of the positional relationship of a relay lens 300A, a roof prism 401, and an intermediate image 500A in Embodiment 1. FIG. (C) The figure which shows the example which configured the reflection optical element which has the roof of the apex angle α by combining the plate-shaped mirror. (A) Schematic diagram showing an optical configuration of a projection type display device as Comparative Example 1. (B) The figure which shows the spectral characteristic of the polarization beam splitter 800 used in the comparative example 1. FIG. (A) Schematic diagram showing an optical configuration of a projection type display device as Comparative Example 2. (B) The schematic diagram which shows the optical structure of the projection type display device as a comparative example 3. The schematic diagram for demonstrating the horizontal position adjustment method of an image in Embodiment 2. The schematic diagram for demonstrating the vertical position adjustment method of an image in Embodiment 2. The schematic diagram which shows the optical structure of the projection type display device which concerns on Embodiment 3 provided with the reflection type light modulation element. FIG. 6 is a schematic diagram showing an optical configuration of a projection type display device according to a fourth embodiment including a roof prism 402 having an apex angle α of 60 degrees. FIG. 6 is a schematic diagram showing an optical configuration of a projection type display device according to the fifth embodiment in which an intermediate image is formed in a convex lens. (A) Schematic diagram showing the optical configuration of the projection type display device according to the sixth embodiment in which the image plane of the intermediate image is curved. (B) Schematic diagram showing the optical configuration of the projection type display device according to the sixth embodiment in which the image plane of the intermediate image is tilted. (A) The figure of the embodiment which projected the display image 700A and the display image 700B horizontally side by side. (B) The figure of the embodiment which projected the display image 700A and the display image 700B vertically side by side.

[Embodiment 1]
FIG. 1 is a schematic diagram showing an optical configuration of a projection type display device according to the first embodiment. The projection type display device 1 includes a transmission type light modulation element 201A (first light modulation element) and a transmission type light modulation element 201B (second light modulation element). The transmission type light modulation element 201A modulates the illumination light ILA (first illumination light) emitted from the illumination light source 100A based on the image signal, and the transmission type light modulation element 201B is irradiated from the illumination light source 100B. Illumination light ILB (second illumination light) is modulated based on an image signal. As the transmissive light modulation element 201A and the transmissive light modulation element 201B, for example, a transmissive liquid crystal panel is used, and as the illumination light source 100A and the illumination light source 100B, for example, a light emitting element such as a laser diode or an LED is used. Will be. The illumination light source 100A and the illumination light source 100B may be configured by individually arranging light emitting elements, or it is effective to divide the light emitted from the same light source and guide it to each optical modulation element by a separate optical path. There may be a configuration in which two lighting light sources exist.

The display light emitted from the transmissive light modulation element 201A is focused by the relay lens 300A (first relay lens) whose optical axis is parallel to the Y direction, and the intermediate image 500A (first intermediate) is placed at a predetermined position. Statue) is tied. However, the display light emitted from the transmissive light modulation element 201A is totally reflected by the slope (first reflection surface) of the roof prism 401, and the image formation position of the intermediate image 500A is set from the apex of the roof prism 401. Is also set to the position advanced in the X direction. Similarly, the display light emitted from the transmissive optical modulation element 201B is collected by the relay lens 300B (second relay lens) whose optical axis is parallel to the Y direction, but another slope of the roof prism 401. The image of the intermediate image 500B (second intermediate image) is set to a position advanced in the X direction from the apex of the roof prism 401 so as to be totally reflected by the (second reflecting surface). The setting of these positional relationships will be described later with reference to FIGS. 3 (a) and 3 (b).

The projection type display device 1 of the present embodiment includes a projection lens 600 for collectively magnifying and projecting an intermediate image 500A formed by the relay lens 300A and an intermediate image 500B formed by the relay lens 300B. ing. The optical axis LX of the projection lens 600 is parallel to the X direction, and the optical axis LX is positioned so as to pass through the apex angle of the roof prism 401. Note that FIG. 1 shows only a small part of the display light emitted from the transmissive light modulation element 201A among the light flux projected by the projection lens 600.

FIG. 2A shows an example of a display image projected on the screen SC, the display image 700A is a magnified projection of the intermediate image 500A, and the display image 700B is a magnified projection of the intermediate image 500B. Is.

Further, FIG. 3A is a diagram showing the positional relationship between the relay lens 300A, the roof prism 401, and the intermediate image 500A. Although the relay lens 300B and the intermediate image 500B are omitted for convenience of illustration, the relay lens 300B is arranged symmetrically with the relay lens 300A with respect to the optical axis LX of the projection lens 600, and the intermediate image 500B is. It is formed at a position symmetrical to the intermediate image 500A with respect to the optical axis LX of the projection lens 600.

The apex angle α of the roof prism 401 is, for example, 90 degrees. In that case, the orientation of the roof prism is set so that the angles formed by the left and right reflecting surfaces of the roof prism with respect to the optical axis LX of the projection lens are both symmetrical at 45 degrees. The angle formed by the optical axis LA of the relay lens 300A with respect to the optical axis LX of the projection lens is 90 degrees. That is, the incident angle at which the main ray of the display light passing through the relay lens 300A is incident on the slope of the roof prism 401 is set to 45 degrees. It is also possible to configure the optical system with the apex angle α of the roof prism set to an angle other than 90 degrees as in the embodiment described later. However, considering the layout of each optical element, it is preferable to set the apex angle α within the range of 60 degrees or more and 90 degrees or less in order to prevent the projection type display device from becoming large.

As the roof prism 401, for example, a prism in which the surface of the base material made of optical glass is mirror-processed can be used, but the present invention is not limited to this, and the display light incident from both sides of the apex angle is reflected with high efficiency. Any reflection optical element that can deflect toward the projection lens may be used. For example, as shown in FIG. 3 (c), a roof-shaped reflective optical element in which a plate-shaped mirror 403A and a plate-shaped mirror 403B are combined to form an apex angle α may be used.

The F number of the projection lens 600 is set to F2.3 to F2.8 by the etendue of the illumination system, and the luminous flux angle is ± 12 degrees in, for example, F2.5. (That is, the magnitude of θ shown in FIG. 3A is 12 degrees.)
In order to utilize the display light connected by the relay lens 300A without loss, all the luminous flux of ± 12 degrees is reflected by the roof prism 401. At this time, as shown in FIG. 3A, the distance between the apex of the roof prism 401 and the intermediate image 500A in the X direction is L, and the distance between the apex of the roof prism 401 and the intermediate image 500A in the Y direction (that is, the projection lens). (Distance from the optical axis LX) is h, then tan θ = h / L holds.

Therefore, as shown in FIG. 3B, the distance in the Y direction separating the relay lens 300A and the roof prism 401 is slightly larger than that in FIG. 3A, and the apex of the roof prism 401 and the intermediate image 500A are X. By reducing L, which is the distance in the direction, h, which is the distance between the apex of the roof prism 401 and the intermediate image 500A in the Y direction, can also be reduced. Therefore, as shown in FIG. 2B, the distance in the Y direction separating the display image 700A and the display image 700B on the screen SC can be made smaller than that in FIG. 2A.

Theoretically, the closer L, which is the distance between the apex of the roof prism 401 and the intermediate image 500A, in the X direction, the closer the distance in the Y direction that separates the display image 700A and the display image 700B on the screen SC from zero. Can be approached to.

In reality, it may not be necessary to completely eliminate the distance between the apex of the roof prism 401 and the intermediate image 500A in the X direction, for the following reasons. Generally, in a light modulation element, the openings of the pixels are not adjacent to each other without a gap. For example, in the case of a liquid crystal element, the openings of the pixels are separated from each other by a pixel wiring or a drive transistor, and the portion separating the openings is optically masked. Further, for example, in the case of a DLP element, a gap is provided between the reflective surface and the reflective surface in order to enable the reflective surface of each pixel to operate independently. The illumination light applied to this gap portion is not projected as a part of the display image. As described above, microscopically, a black band or a grid exists between the pixels of the display image magnified and projected on the screen SC.

Therefore, in FIG. 2A, even if the distance of 2 × h separating the intermediate image 500A and the intermediate image 500B is not set to zero, the width of the black band or the grid existing between the pixels of the intermediate image and the 2 × h If the position of the relay lens is adjusted to a level where the difference is not remarkable, the boundary between the displayed image 700A and the displayed image 700B becomes inconspicuous to the observer.

As described above, in the projection type display device 1 of the present embodiment, the transmission type light modulation element 201A and the transmission type light modulation element 201B are arranged with the roof prism 401 interposed therebetween, and the respective transmission type light modulation elements and the roof prism are arranged. A relay lens for forming an intermediate image is provided between them. Relative to the transmissive light modulation element, roof prism, and relay lens so that the intermediate image formed by each relay lens is arranged symmetrically with respect to the optical axis LX of the projection lens 600 near the apex of the roof prism. The positional relationship is adjusted, and each optical element is fixed to the frame or housing of the projection type display device 1. Although not shown, when the transmissive light modulation element 201A and the relay lens 300A are viewed as a unit, an adjustment mechanism for adjusting the relative position and orientation (vertical direction, horizontal direction, rotation direction) of the unit with respect to the roof prism is provided. It is desirable to provide it. Similarly, when the transmissive light modulation element 201B and the relay lens 300B are viewed as a unit, a positioning mechanism for adjusting the relative position and orientation (vertical direction, horizontal direction, rotational direction) of the unit with respect to the roof prism is provided. Is desirable.

Then, the display light emitted from the transmission type light modulation element 201A and the display light emitted from the transmission type light modulation element 201B are totally reflected by the roof prism 401 and deflected in the direction of the projection lens 600 without loss.

The projection type display device of the present embodiment having such a configuration displays the display images from the two light modulation elements side by side on the screen, but the position, size, inclination, and in-focus state of the two intermediate images are determined in advance. It is consistent. Therefore, the operator only needs to adjust the projection lens 600 when it is necessary to adjust the zoom magnification or the focusing of the entire image, for example, and the projection optical system of each of the two light modulation elements is individually adjusted as in the conventional case. There is no need to adjust to. Further, since only one projection lens is required, it is possible to reduce the size and cost of the projection type display device.

The screen SC may always be used as a set with the projection type display device 1 as a component of the projection type display system, but the embodiment of the present invention is not limited thereto. As described above, the projection type display device 1 according to the embodiment is suitable for portable use because the operation for optically adjusting the display image is easy. For example, the wall of a building without a screen is installed. The display image can be easily projected on any surface in any place.

Next, an advantage over the comparative example of the first embodiment will be described with reference to a comparative example. Among the constituent elements of the comparative example, those having the same function as the constituent elements of the first embodiment are illustrated with the same reference numbers as those of the first embodiment, and the description thereof will be omitted.

[Comparative Example 1]
FIG. 4A is a schematic diagram showing an optical configuration of a projection type display device as Comparative Example 1. In Comparative Example 1, the illumination light is modulated by using the transmission type light modulation element 201A and the transmission type light modulation element 201B, and the display light modulated by both light modulation elements is transferred to the screen SC by using one projection lens 600. It is common with the first embodiment in that it projects.

However, the first embodiment includes a roof prism 401, and the display light emitted from the two light modulation elements is totally reflected by the two surfaces of the roof prism 401 and deflected in the direction of the projection lens 600, whereas the comparative example. Reference numeral 1 guides the display light emitted from the two light modulation elements in the direction of the projection lens 600 by using the polarized beam splitter 800 instead of the roof prism 401.

In Comparative Example 1, first, a polarizing beam splitter 803 is used to split the illumination light into a P-polarized component and an S-polarized component. That is, the polarization beam splitter 803 is an optical element that selectively reflects S polarization and selectively transmits P polarization on the diagonal surface on which the dielectric multilayer film is formed. Of the illumination light, the reflected S-polarized component is guided to the transmitted light modulation element 201B via the mirror 802, and the transmitted P-polarized component is guided to the transmitted light modulation element 201A via the mirror 802.

The P-polarized display light modulated by the transmissive light modulation element 201A and the S-polarized display light modulated by the transmissive light modulation element 201B are incident on the polarizing beam splitter 800 from different directions. The polarization beam splitter 800 is an optical element that selectively transmits P-polarization and selectively reflects S-polarization on a diagonal surface on which a dielectric multilayer film is formed. Therefore, the display light from the transmission type light modulation element 201A passes through the polarization beam splitter 800 and travels toward the projection lens 600, and the display light from the transmission type light modulation element 201B is reflected on the diagonal surface of the polarization beam splitter 800. And is deflected towards the projection lens 600. If the relative positions of the transmissive light modulation element 201A, the transmissive light modulation element 201B, and the polarization beam splitter 800 are appropriately adjusted, the display images from the two light modulation elements can be displayed side by side.

When the color images of Comparative Example 1 and the first embodiment were displayed under the condition that the screen size displayed on the screen SC was the same and the image quality was compared, the color unevenness of the comparative example 1 was larger than that of the first embodiment. , The image quality was inferior. The reason is as follows.

Comparative Example 1 and the first embodiment use the same projection lens 600, but as described above, for example, if the F number of the projection lens 600 is F2.5, the luminous flux angle is ± 12 degrees.
When the angle between the diagonal surface of the polarizing beam splitter 800 and the main light of the display light is set to 45 degrees, the incident angle of the luminous flux incident on the diagonal surface of the polarizing beam splitter 800 is 33 degrees to 57 degrees. It becomes a range.

By the way, it is well known that the S / P splitting ability of a polarizing beam splitter changes depending on the incident angle and wavelength. FIG. 4B shows the spectral characteristics of the polarization beam splitter 800 used in Comparative Example 1. From the graph, the separability of S-polarization and P-polarization changes depending on the incident angle and wavelength. Recognize. Regarding the incident angle of 45 degrees corresponding to the optical axis, it can be seen that the transmittance of P-polarized light is high and the transmittance of S-polarized light is low (that is, the reflectance is high) in almost the entire visible wavelength region.

However, at an incident angle of 33 degrees, the transmittance of P polarization decreases on the long wavelength side in the visible wavelength range, and that of S polarization increases on the short wavelength side in the visible wavelength range (that is, the reflectance is low). You can see that there is. This is because the long wavelength component of the display light incident on the polarization beam splitter 800 from the transmissive light modulation element 201A at an incident angle of 33 degrees is lost, and the display light incident on the transmissive optical modulation element 201B at an incident angle of 33 degrees is short. It means that the wavelength side loses a lot.

Further, even when the incident angle is 57 degrees, since the spectral characteristics of P-polarization and S-polarization in the visible wavelength range are unbalanced, the display light on the transmission type light modulation element 201A side and the display light on the transmission type light modulation element 201B side. The wavelength range in which the loss occurs in the polarized beam splitter 800 is different.

From the above, in the projection type display device of Comparative Example 1, since the above-mentioned unbalanced loss occurs in the polarizing beam splitter 800, not only the utilization efficiency of the illumination light is lowered as compared with the first embodiment, but also the lighting is adjacent to each other. The color balance between the two screens displayed on the screen was poor. That is, the projection type display device of the first embodiment was superior in the image quality of the displayed image.

[Comparative Example 2]
FIG. 5A is a schematic diagram showing an optical configuration of a projection type display device as Comparative Example 2. In Comparative Example 2, the illumination light is modulated by using the transmission type light modulation element 201A and the transmission type light modulation element 201B, and the display light modulated by both light modulation elements is transferred to the screen SC by using one projection lens 600. In terms of projection, it is common with the first embodiment and the first comparative example.

In Comparative Example 1, the polarizing beam splitter 800 was used to guide the display light emitted from the two optical modulation elements in the direction of the projection lens 600, whereas in Comparative Example 2, a half mirror was used instead of the polarizing beam splitter 800. Using the 804, the display light emitted from the two light modulation elements is directed in the direction of the projection lens 600. That is, half of the display light from the transmission type light modulation element 201A passes through the half mirror 804 and travels toward the projection lens 600, and half of the display light from the transmission type light modulation element 201B is reflected by the half mirror 804. It is deflected toward the projection lens 600. If the relative positions of the transmissive light modulation element 201A, the transmissive light modulation element 201B, and the half mirror 804 are appropriately adjusted, the display image 701A from the transmissive light modulation element 201A and the display image from the transmissive light modulation element 201B are displayed. The 701Bs can be displayed side by side.

Since the half mirror 804 is used in Comparative Example 2, unlike the polarization beam splitter 800 used in Comparative Example 1, the spectral characteristics are unbalanced between the display light on the transmission type light modulation element 201A side and the display light on the transmission type light modulation element 201B side. Can be suppressed.

However, half of the display light from the transmission type light modulation element 201A is reflected in the Y direction by the half mirror 804, and half of the display light from the transmission type light modulation element 201B is transmitted in the Y direction by the half mirror 804. None of these are suitable for the projection lens 600, so that they are lost light that is not utilized for display.

Therefore, when the color image is displayed under the condition that the screen size displayed on the screen SC is the same for Comparative Example 2 and the first embodiment, the first embodiment is under the condition that the intensity of the illumination light is the same. In comparison, in Comparative Example 2, the brightness of the displayed image was significantly reduced. Further, under the condition that the brightness of the displayed image is the same, it is necessary to significantly increase the intensity of the illumination light in Comparative Example 2, and the power consumption of Comparative Example 2 is significantly increased as compared with the first embodiment.

From the above, in the projection type display device of Comparative Example 2, since the above-mentioned loss occurs in the half mirror 804, the utilization efficiency of the illumination light is extremely low as compared with the first embodiment. That is, the projection type display device of the first embodiment was superior in power efficiency.

[Comparative Example 3]
FIG. 5B is a schematic diagram showing an optical configuration of a projection type display device as Comparative Example 3. In Comparative Example 3, the illumination light is modulated by using the transmission type light modulation element 201A and the transmission type light modulation element 201B, and the display light modulated by both light modulation elements is transferred to the screen SC by using one projection lens 600. In terms of projection, it is common to the first embodiment and other comparative examples.

In Comparative Example 3, the total reflection mirror 805 for deflecting the display light from the transmission type light modulation element 201B toward the projection lens 600 is provided, but the display light from the transmission type light modulation element 201A is passed through the optical element. Instead, it is incident on the projection lens 600. If the relative positions of the transmissive light modulation element 201A, the transmissive light modulation element 201B, and the total reflection mirror 805 are appropriately adjusted, the display image 702A from the transmissive light modulation element 201A and the display from the transmissive light modulation element 201B are displayed. Images 702B can be displayed side by side.

In Comparative Example 3, the generation of color unevenness caused by the polarizing beam splitter 800 as in Comparative Example 1 and the generation of light amount loss caused by the half mirror 804 as in Comparative Example 2 can be suppressed. However, in Comparative Example 3, there arises a problem that the boundary of the screen is conspicuous because the brightness near the boundary between the display image 702A from the transmission type light modulation element 201A and the display image 702B from the transmission type light modulation element 201B is lowered. rice field.

This is because when the display image 702A and the display image 702B are to be adjacent to each other on the screen, the optical axis of the display light from the display image 702A is aligned with the end of the total reflection mirror 805, and the display light from the display image 702B is aligned. It is necessary to align the optical axis of the image with the end of the total reflection mirror 805. As described above, for example, if the F number of the projection lens 600 is F2.5, the luminous flux is incident from an angle range of ± 12 degrees, and the total reflection mirror 805 has a thickness. Therefore, in the vicinity of the end of the total reflection mirror 805, a part of the display light from the transmission type light modulation element 201B is not reflected by the total reflection mirror 805, or one of the display lights from the transmission type light modulation element 201A. The portion is shielded by the total reflection mirror 805, and a loss occurs.

From the above, in the projection type display device of Comparative Example 3, the above-mentioned loss occurs near the end of the total reflection mirror 805, so that the boundary of the screen is conspicuous as compared with the first embodiment. That is, the projection type display device of the first embodiment was superior in the image quality of the displayed image.

[Embodiment 2]
In the first embodiment, the relative positional relationship between the transmissive light modulation element, the roof prism, and the relay lens is mechanically adjusted in advance to make the boundary between the screens of the adjacent display images 700A and the display images 700B inconspicuous. That is, the relative positional relationship of each optical element is mechanically adjusted so that the end portion of the display image emitted from each transmissive light modulation element is as close as possible to the apex of the roof prism.

In the second embodiment, in order to relax the adjustment accuracy required mechanically, the modulation area size of the light modulation element is made larger than the display image area size to provide redundancy in terms of size. Then, the relative positional relationship between the transmissive light modulation element, the roof prism, and the relay lens is mechanically adjusted so that the apex of the roof prism is included in the region covered by the modulation area. The mechanical adjustment accuracy required at this time may be looser than that of the first embodiment. Then, the drive of the light modulation element is electrically corrected based on the mechanical adjustment result. That is, the position of the displayed image in the modulation area is corrected based on the mechanical adjustment result.

First, a method of adjusting the horizontal position for adjoining the display image 700A and the display image 700B on the screen SC shown in FIG. 2B without a gap along the Y direction will be described.
FIG. 6 is a schematic diagram for explaining the adjustment method according to the second embodiment, and the positional relationship between the transmissive light modulation element 201A, the relay lens 300A, the roof prism 401, and the intermediate image 500A is shown in the center of the drawing. ing. Further, the area 4A on the right side of the figure shows a plan view of the transmissive light modulation element 201A seen from the relay lens 300A side, and the intermediate image 500A is seen from the roof prism 401 side in the area 4B on the upper side of the figure. A plan view is shown. Although the illustration and description of the transmissive light modulation element 201B, the relay lens 300B, and the intermediate image 500B are omitted, it is said that they are arranged symmetrically with respect to the optical axis of the projection lens in consideration of the following description. If you think about it, it will be easy to understand.

As shown in area 4A, the transmissive light modulation element 201A includes a modulation area MX larger than the horizontal size DX of the image to be displayed. Then, the transmission type light modulation element 201A, the relay lens 300A, and the roof prism 401 are provided so that the apex of the roof prism 401 is included in the range of the luminous flux emitted from the transmission type light modulation element 201A through the relay lens 300A. Adjust the positional relationship. Then, of the light flux passing through the relay lens 300A, the light beam passing in the X direction from the apex of the roof prism 401 is not reflected by the roof prism 401. Therefore, the image display position in the modulation area MX of the transmission type light modulation element 201A is corrected so that the horizontal end of the display image is located exactly at the apex of the roof prism 401. Specifically, in the image signal for driving the transmissive light modulation element 201A, the length of the horizontal blanking period in which the display is not performed is adjusted with reference to the horizontal synchronization signal, and appropriately within the modulation area MX. Set the width non-display area BLH. As a result, the horizontal end of the displayed image is located at the position where the apex of the roof prism 401 is irradiated, and the displayed image does not separate in the horizontal direction as shown in FIG. 2 (a). The images on the two screens can be adjacent to each other in the horizontal direction. The light emitted from the non-display region BLH of the transmissive light modulation element 201A is not reflected by the roof prism 401 as shown in FIG. 6, but in order to prevent stray light in the projection type display device. In addition, it is desirable that the non-display region BLH modulates the illumination light so that the brightness level is the same as that of black in the displayed image, and controls so that the light is not emitted from the light modulation element.

In the present embodiment, the light modulation element has a redundancy corresponding to the difference between the modulation area MX and the horizontal size DX of the display image, and the image display position in the horizontal direction can be adjusted, so that the position can be adjusted mechanically. The required accuracy is relaxed.

Next, a method of adjusting the vertical position of the display image 700A and the display image 700B shown in FIG. 2B so as not to be displaced in the Z direction on the screen SC will be described.
FIG. 7 is a diagram for explaining the adjustment method according to the second embodiment, and the positional relationship between the roof prism 401 and the intermediate image 500A and the intermediate image 500B is shown at the lower part of the figure. Further, in the area 5A on the upper side of the drawing, a plan view of the intermediate image 500A and the intermediate image 500B as viewed from the roof prism 401 side is shown.

As can be seen from the intermediate image shown in the area 5A, the transmissive light modulation element 201A and the transmissive light modulation element 201B have a modulation area MZ larger than the vertical size DZ of the image to be displayed. That is, the light modulation element has redundancy corresponding to the difference between the modulation area MZ and the vertical size DZ of the display image. When the position adjustments of the transmissive light modulation element 201A and the transmissive light modulation element 201B are deviated in the Z direction, the image display position in each modulation area is corrected. Specifically, in the image signal for driving the transmissive light modulation element 201A, a vertical blanking period in which display is not performed is set with reference to the vertical synchronization signal, and a non-display area BLVA is set in the modulation area MZ. Set. Similarly, in the image signal for driving the transmissive light modulation element 201B, the vertical blanking period in which the display is not performed is set with reference to the vertical synchronization signal, and the non-display area BLVB is set in the modulation area MZ. .. By adjusting the positions and sizes of the non-display area BLVA and the non-display area BLVB according to the positional deviation of the light modulation element in the Z direction, the positions of the intermediate image 500A and the intermediate image 500B in the Z direction can be aligned. .. Regarding the non-display area BLVA and the non-display area BLVB, the illumination light is modulated so as to have the same luminance level as black in the displayed image, and the light is controlled so as not to be emitted from the light modulation element.

In the present embodiment, the light modulation element has a redundancy corresponding to the difference between the modulation area MZ and the vertical size DZ of the display image, and the image display position in the vertical direction can be adjusted, so that the position can be adjusted mechanically. The required accuracy is relaxed.

It should be noted that the light modulation element may be provided with redundancy in both the horizontal direction and the vertical direction of the displayed image, or only one of them may be provided with redundancy. It is possible to relax the required accuracy of mechanical position adjustment of the light modulation element in the direction of providing redundancy.

[Embodiment 3]
Although the first to second embodiments show an example in which the projection type display device is configured by using the transmission type light modulation element, the present invention can also be carried out by using the reflection type light modulation element. That is, it is also possible to configure a projection type display device corresponding to the first to second embodiments by using a reflective light modulation element such as a DMD in which micromirror devices are provided in an array or a reflective liquid crystal device. be.

FIG. 8 is a schematic diagram showing an optical configuration of the projection type display device according to the third embodiment. The projection type display device includes a reflection type light modulation element 200A and a reflection type light modulation element 200B. For example, the illumination light emitted by the light source device 100 provided with a light emitting element such as a laser diode or an LED is half reflected by the half mirror 190 and incident on the reflection type light modulation element 200A. The illumination light modulated according to the image signal is reflected as display light toward the relay lens 300A. On the other hand, half of the illumination light transmitted through the half mirror 190 passes through the total reflection mirror 191 and is incident on the reflection type light modulation element 200B. The illumination light modulated according to the image signal is reflected as display light toward the relay lens 300B. The relay lens, roof prism, and projection lens can exhibit the same effects as those of the first and second embodiments using the transmissive light modulation element, but the overlapping description is omitted here.

The projection type display device of the present embodiment, which is configured by using the reflection type light modulation element, also displays the display images from the two light modulation elements side by side on the screen, but the position, size, and the position and size of the intermediate images are set in advance. The tilt and focus states are aligned. Therefore, for example, when it is necessary to adjust the zoom magnification or the focusing of the entire image, the operator only needs to adjust the projection lens, and adjusts the projection optical system of each of the two light modulation elements as in the conventional case. There is no need.

[Embodiment 4]
As described in the first embodiment, the apex angle α of the roof prism can be, for example, 90 degrees, but even if it is other than 90 degrees, it is preferable as long as it is within the range of 60 degrees or more and 90 degrees or less. It is possible to construct an optical system.
FIG. 9 shows the optical of the projection type display device according to the fourth embodiment, which includes a reflection type light modulation element as in the third embodiment, but has a roof prism 402 having an apex angle α of 60 degrees instead of 90 degrees. It is a schematic diagram which shows the structure.

In the third embodiment in which the apex angle α of the roof prism is 90 degrees, the incident angle at which the main light ray passing through the relay lens is incident on the reflection surface of the roof prism is set to 45 degrees. On the other hand, in the present embodiment, the apex angle α of the roof prism 402 is set to 60 degrees, and the main light beam passing through the optical axis LA (and the optical axis LB) of the relay lens 300A (and the relay lens 300B) is the roof prism 402. The angle of incidence incident on the reflective surface of the above was set to 60 degrees. Further, in the present embodiment, unlike the third embodiment, the illumination light is guided only by the half mirror 190 without using the total reflection mirror 191 to guide the illumination light to the reflection type light modulation element.

In this way, by appropriately setting the apex angle α of the roof prism within the range of 60 degrees or more and 90 degrees or less, the optical axis LA and the optical axis LB of the relay lens and the optical axis LX of the projection lens 600 can be set. The angle of intersection can be appropriately shifted from 90 degrees. Since the layout of the optical element in the projection type display device can be changed, the outer dimension of the projection type display device in the Y direction can be miniaturized, and the cooling structure in the projection type display device can be optimized.

[Embodiment 5]
FIG. 10 is a schematic diagram showing an optical configuration of the projection type display device according to the fifth embodiment.
In the present embodiment, a field lens type projection lens provided with a lens 601 and a field lens 602 is used as the projection lens. In this case, the roof prism, the relay lens, and the light modulation element can be arranged so that the positions of the intermediate image 500A and the intermediate image 500B of the relay lens are inside the field lens 602 which is a convex lens. The light modulation element may be a transmission type light modulation element or a reflection type light modulation element.
By arranging the intermediate image inside the convex lens, the amount of aberration correction in the projection lens can be reduced, so the number of lenses that make up the projection lens can be reduced, and the size and cost of the device can be reduced. Can be planned.

[Embodiment 6]
In the above-mentioned first to fifth embodiments, an example in which an intermediate image by the relay lens is formed on a plane orthogonal to the optical axis of the projection lens has been described. However, the embodiment of the present invention is not limited to this, and the image plane of the intermediate image may be curved or tilted so that the image plane of the intermediate image is not orthogonal to the optical axis of the projection lens. can.

For example, FIG. 11A is a schematic diagram showing an optical configuration of the projection type display device according to the fifth embodiment. The reflective surface 401RA and the reflective surface 401RB of the roof prism 401 are not flat surfaces but curved surfaces, and the image plane of the intermediate image 500A and the image plane of the intermediate image 500B are curved, respectively. Then, the optical axis LA of the relay lens 300A and the optical axis LB of the relay lens 300B are respectively Y so that the intermediate image 500A and the intermediate image 500B are smoothly adjacent to each other along the spherical surface R near the optical axis LX of the projection lens 600. It is tilted with respect to the direction. In FIG. 11A, the curved surface shapes of the reflecting surface 401RA and the reflecting surface 401RB, and the inclination of the optical axis LA and the optical axis LB are simply shown and not exactly shown. In order to bend the field of field of the intermediate image, the design of the relay lens may be changed and the field of field may be curved by intentionally controlling the aberration.

In this way, in the projection type display device of the present embodiment, in which the image plane of the intermediate image 500A and the image plane of the intermediate image 500B are curved so as to be connected so as to be close to a spherical surface, the image of the projection lens 600 is formed. Since the influence of the curvature of field aberration can be reduced, the image quality of the projected display image can be improved as compared with the first to fifth embodiments. Alternatively, if the curvature of field aberration of the projected display image is the same as that of the first to fifth embodiments, the curvature of field correction in the projection lens 600 is light in the present embodiment, so that the projection lens 600 is used. It is possible to reduce the number of constituent lenses, which leads to a reduction in size and weight and cost of the device.

Further, FIG. 11B is a schematic diagram showing an optical configuration of the projection type display device according to another example of the fifth embodiment. In the example of FIG. 11A, the shape of the reflective surface 401RA and the reflective surface 401RB of the roof prism 401 is curved, but in FIG. 11B, the reflective surface remains a flat surface and the intermediate image of the relay lens is formed. The image plane is not orthogonal to the optical axis of the projection lens. In this example, the image planes of the intermediate image 500A and the intermediate image 500B are flat, but the image plane is tilted so as to be closer to the projection lens 600 as the position is farther from the optical axis LX of the projection lens 600. That is, in FIG. 11B, the image planes of the intermediate image 500A and the intermediate image 500B are arranged so as to be V-shaped with the optical axis LX of the projection lens as the axis of symmetry. In order to arrange the intermediate image in this way, the optical axis LA of the relay lens 300A and the optical axis LB of the relay lens 300B are respectively tilted with respect to the Y direction, or the apex angle α of the roof prism 401 is made larger. Or do both.

In the example of FIG. 11B, since the reflective surface of the roof prism 401 does not need to be curved, the roof prism can be manufactured more easily than the example of FIG. 11A. In this example as well, the image planes of the intermediate image 500A and the intermediate image 500B are closer to the projection lens 600 as the image planes are farther from the optical axis LX of the projection lens 600, so that the curvature of field of the projection lens 600 is increased. The influence can be reduced, and the image quality of the projected display image can be improved as compared with the first to fourth embodiments. Alternatively, if the curvature of field aberration of the projected display image is the same as that of the first to fifth embodiments, the curvature of field correction in the projection lens 600 is light in the present embodiment, so that the projection lens is configured. It is possible to reduce the number of lenses to be used, which leads to a reduction in size and weight and cost of the device.

[Other embodiments]
The implementation of the present invention is not limited to the above-described embodiments and specific examples, and many modifications can be made within the technical idea of the present invention. Each of the above-described embodiments may be implemented alone or in combination of a plurality of embodiments in one projection type display device.

The image signal input to the two light modulation elements may be a divided image obtained by dividing a single image, or may be a completely different image. The source of the image signal may be a single computer or another computer.

For example, as shown in FIG. 12A, image signals input from different computers are input to different light modulation elements in a projection type display device, and the display image 700A and the display image 700B are projected horizontally side by side. You may.

Alternatively, as shown in FIG. 12B, image signals input from different computers are input to different light modulation elements in the projection type display device, and the display image 700A and the display image 700B are vertically arranged and projected. You may.

1 ... Projection type display device / 100A, 100B ... Illumination light source / 200A, 200B ... Reflection type light modulation element / 201A, 201B ... Transmission type light modulation element / 300A, 300B ... Relay Lens / 401 ... Roof prism / 401RA, 401RB ... Reflective surface / 402 ... Roof prism / 403A, 403B ... Plate mirror / 500A, 500B ... Intermediate image / 600 ... Projection lens / 602 ... Field lens / 700A, 700B, 701A, 701B, 702A, 702B ... Display image / 800 ... Polarized beam splitter / 802 ... Mirror / 803 ... Polarized beam splitter / 804 ...・ Half mirror / 805 ・ ・ ・ Full reflection mirror / BLVA, BLVB ・ ・ ・ Hidden area / BLH ・ ・ ・ Hidden area / DX ・ ・ ・ Horizontal size of displayed image / DZ ・ ・ ・ Vertical of displayed image Size / ILA, ILB ... Illumination light / LX ... Projection lens optical axis / MX ... Modulation area / MZ ... Modulation area / SC ... Screen

Claims (9)

A first light modulation element that modulates the first illumination light according to an image signal,
A second light modulation element that modulates the second illumination light according to the image signal,
A first relay lens that forms a first intermediate image by forming an image of the first illumination light modulated by the first light modulation element.
A second relay lens that forms a second intermediate image by forming an image of the second illumination light modulated by the second light modulation element.
A first reflecting surface that completely reflects the light incident from the first relay lens and a second reflecting surface that completely reflects the light incident from the second relay lens are provided, and the first reflecting surface and the first reflecting surface are provided. 2 A roof-shaped reflective optical element whose apex angle is formed by a reflective surface, and
With a projection lens,
The illumination light modulated by the first light modulation element is reflected by the first reflecting surface and then forms the first intermediate image.
The illumination light modulated by the second light modulation element is reflected by the second reflecting surface and then forms the second intermediate image.
The optical axis of the projection lens passes through the apex angle of the reflection optical element, and the projection lens projects the first intermediate image and the second intermediate image side by side in an enlarged manner.
A projection type display device characterized by this. The catoptric element is either a roof prism or a roof-shaped catoptric element in which a plate-shaped mirror is combined.
The projection type display device according to claim 1. The size of the apex angle is 60 degrees or more and 90 degrees or less.
The projection type display device according to claim 1 or 2. The light emitted by the same light source is divided to form the first illumination light and the second illumination light.
The projection type display device according to any one of claims 1 to 3. The projection lens includes a field lens and
The first intermediate image and the second intermediate image are formed inside the field lens.
The projection type display device according to any one of claims 1 to 4. The image planes of the first intermediate image and the second intermediate image are inclined or curved with respect to a plane orthogonal to the optical axis of the projection lens.
The projection type display device according to any one of claims 1 to 5. An adjustment mechanism for adjusting the relative position and orientation of the first light modulation element and the first relay lens with respect to the reflection optical element, and / or.
The second optical modulation element and the second relay lens are provided with an adjustment mechanism for adjusting the relative position and orientation of the second relay lens with respect to the reflection optical element.
The projection type display device according to any one of claims 1 to 6, wherein the projection type display device is characterized. The first light modulation element and the second light modulation element include a modulation area larger than the display image area in the horizontal direction of the display image.
The horizontal position of the display image area in the modulation area of the first light modulation element is adjusted according to the relative position of the first light modulation element and the reflection optical element.
The horizontal position of the display image area in the modulation area of the second light modulation element is adjusted according to the relative position of the second light modulation element and the reflection optical element.
The projection type display device according to any one of claims 1 to 7. The first light modulation element and the second light modulation element have a modulation area larger than the display image area in the vertical direction of the display image.
The vertical position of the display image area in the modulation area of the first light modulation element is adjusted according to the relative position of the first light modulation element and the reflection optical element.
The vertical position of the display image area in the modulation area of the second light modulation element is adjusted according to the relative position of the second light modulation element and the reflection optical element.
The projection type display device according to any one of claims 1 to 8.

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