JP4984005B2 - Projector device - Google Patents

Description

  The present invention relates to a projector device.

  Conventionally, a small projector device mounted on a digital camera or the like is known (for example, see Patent Document 1). In the projector device, illumination light from the light source unit is incident on a rectangular reflective liquid crystal display element via a polarization beam splitter (PBS).

JP 2002-287084 A

  However, since the illumination light irradiated through the PBS is irradiated not only on the display area of the display element but also on the outer area, there is a problem that the use efficiency of the illumination light is lowered.

The projector device according to claim 1 is a rectangular parallelepiped PBS block having two end faces orthogonal to the polarization separation plane and four side faces perpendicular to the end faces, and on any one side of the PBS block A light source disposed oppositely and a rectangular display region disposed opposite to the illumination light exit surface of the PBS block from which illumination light polarized and separated by the polarization separation surface is emitted, and polarized light is separated by the polarization separation surface. A reflective liquid crystal display element that modulates the illuminated light into modulated light and emits it to the PBS block; and is disposed between the light source and the PBS block, and the illumination light emitted from the light source is converted into divergent light. An illumination optical system that is incident on the PBS block with a luminous flux, and the illumination light that is disposed between the reflective liquid crystal display element and the PBS block and is incident on the PBS block. Of the luminous flux having divergent light converted by the system, light incident on the rectangular display area is incident on the surface on which the reflective liquid crystal display element of the PBS block is totally reflected by the side surface or the end surface. And a projection optical system for forming a projection image by forming an image of light obtained by polarization-separating the modulated light with the polarization separation surface.
A projector device according to a second aspect is the projector device according to the first aspect, further comprising a retardation plate disposed between the PBS block and the reflective liquid crystal display element.
According to a third aspect of the present invention, in the projector device according to the first or second aspect, the illumination optical system is configured by a single lens whose one surface is a cylindrical surface.
According to a fourth aspect of the present invention, in the projector device according to the first or second aspect, the illumination optical system is configured by a single lens having an aspherical surface.
The projector device according to claim 5 is a rectangular parallelepiped-shaped PBS block having two end faces perpendicular to the polarization separation plane and four side faces perpendicular to the end faces, and on any one side of the PBS block A light source disposed oppositely and a rectangular display region disposed opposite to the illumination light exit surface of the PBS block from which illumination light polarized and separated by the polarization separation surface is emitted, and polarized light is separated by the polarization separation surface. A reflective liquid crystal display element that modulates the illuminated light into modulated light and emits it to the PBS block; and is disposed between the light source and the PBS block, and the illumination light emitted from the light source is converted into divergent light. And a diverging light converted by the illumination optical system that is incident on the PBS block. Among the luminous fluxes having, the reflective liquid crystal is so arranged that light rays that are totally reflected by the side surface or the end surface and enter the surface on which the reflective liquid crystal display element of the PBS block is disposed do not enter the rectangular display region. A display element is arranged.

  According to the present invention, it is possible to improve the utilization efficiency of illumination light.

It is a figure which shows the digital camera carrying the projector apparatus of this Embodiment, (a) shows the time of non-use, (b) shows the time of projection. FIG. 2 is a diagram showing a configuration of a projector unit 22. It is a figure which shows schematic structure of the liquid crystal display element 224, (a) is a top view, (b) is a side view. It is a figure which shows the positional relationship of the liquid crystal surface element 224, and a projection image, (a) shows the case where P polarization is used as illumination light, (b) shows the case where S polarization is used as illumination light. It is a figure explaining the light ray radiate | emitted from the condensing lens 222, (a) shows the case where P polarization is used as illumination light, (b) shows the case where S polarization is used as illumination light. It is a figure which shows the light ray at the time of using a surface light source as a light source, (a) shows the case where P polarization is used as illumination light, (b) shows the case where S polarization is used as illumination light. It is a figure explaining the relationship between the angle (alpha) of light rays, and polarization separation performance. It is a perspective view which shows PBS223 and the liquid crystal display device 224. FIG. It is a figure explaining generation | occurrence | production of a ghost. It is a figure explaining a total reflection light emission area | region. 4 is a diagram for explaining a display area 240 of a liquid crystal display element 224. FIG. It is a figure explaining the total reflection light emission area | region in case PBS223 is a cube. It is a figure which shows the mask 228 in detail, (a) is a perspective view, (b) is B1-B1 sectional drawing. It is a figure which shows the other example of the mask 228, (a) is a perspective view, (b) is B2-B2 sectional drawing. It is a figure explaining arrangement | positioning of the phase difference plate with respect to PBS223, (a) is a side view, (b) is an enlarged view. It is a figure which shows the other example of arrangement | positioning of the quarter wavelength plate. It is a figure explaining arrangement | positioning of the liquid crystal display element 224 with respect to PBS223, (a) is a top view, (b) is a side view. It is a figure which shows the illumination area | region of the illumination light with respect to the display area | region 240, (a) shows the case where it is circular, (b) shows the case where it is oval. It is a figure explaining an illumination optical system provided with the cylindrical lens 222B. It is a figure which shows arrangement | positioning of the liquid crystal display element 224 in the case of using the single lens 222 which has the cylindrical surface CS for an illumination optical system, and utilizing S polarized light. It is a figure which shows the structure at the time of making the extending direction of the polarization splitting film 223a correspond to the short side direction (y direction) of the display area 240. FIG. It is a front view of the digital camera 1 in a modification. It is a figure which shows the structure of the projector unit 22 in the case of using P polarized light as illumination light, (a) is the side view seen from the camera side, (b) is the figure seen from the camera back. It is a figure which shows the structure of the projector unit 22 in the case of using S polarized light as illumination light, (a) is the side view seen from the camera side, (b) is the figure seen from the camera back.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. The projector device according to the present invention relates to an ultra-small projector device mounted on a camera, a portable device, or the like. FIG. 1 is a diagram showing a digital camera equipped with the projector device of the present embodiment. The digital camera 1 has a main body portion 10 and a lens barrel portion 20, and the lens barrel portion 30 is provided so as to be rotatable with respect to the main body portion 10 by a coupling mechanism (not shown).

FIG. 1A shows a non-use state in which the lens barrel 20 is not rotated with respect to the main body 10. On the upper surface of the main body 10, a power switch 106, a release button 107 that is operated when performing a photographing operation, and a PJ button 108 that performs an on / off operation of a projector device (hereinafter referred to as a projector unit) 22 are disposed.

  FIG. 1B shows a projection state in which the lens barrel 20 is rotated 90 degrees with respect to the main body 10. The lens barrel unit 20 is provided with a photographing unit 21 including an image sensor and a projector unit 22. The photographing lens 210 of the photographing unit 21 is provided on the upper end side of the lens barrel 20 in the state of FIG. On the other hand, the projection window 22 a of the projector unit 22 is provided on the bottom surface side of the lens barrel 20. When the lens barrel 20 is rotated to face the front of the projection window 22a and the PJ button is turned on, a projected image is projected to the front of the camera.

  Note that the image projected by the projector unit 22 is based on image data stored in a recording medium provided in the main body unit 10, image data photographed by the photographing unit 21, or the like.

  FIG. 2 is a diagram showing a schematic configuration of the projector unit 22. The projector unit 22 includes a light source 221 such as a high-intensity white LED, a condenser lens 222, a polarizing beam splitter (PBS) 223, a liquid crystal display element 224, a projection lens 225, a mask 228, and a case for housing these. 226. The liquid crystal display element 224 is provided in close contact with the side surface (illumination light emission surface) of the PBS 223. As the liquid crystal display element 224, a reflective liquid crystal panel such as LCOS is used. The liquid crystal display element 224 of the present embodiment is a color type reflective liquid crystal panel, and light receiving elements including color filters are two-dimensionally arranged.

  In the present embodiment, a surface perpendicular to the paper surface of PBS 223 shown in FIG. 2 is referred to as a side surface, and a surface perpendicular to the four side surfaces is referred to as an end surface. Such a PBS 223 can be formed by bonding a pair of triangular prisms so as to sandwich the polarization separation film. The polarization separation film 223 a is formed perpendicular to both end surfaces of the PBS 223, and the liquid crystal display element 224 is provided on the side surface of the PBS 223.

  The condensing lens 222 makes the light from the light source 221 substantially parallel and enters the PBS 223. The PBS 223 is formed with a polarization separation film 223a inclined by 45 degrees with respect to the incident optical axis of the illumination light, and the P-polarized light incident on the PBS 223 is transmitted through the polarization separation film 223a to illuminate the liquid crystal display element 224. .

  The light incident on the liquid crystal display element 224 travels through the liquid crystal layer, is reflected by the reflective electrode of the liquid crystal display element 224, and travels back through the liquid crystal layer and is emitted from the liquid crystal display element 224. Since the liquid crystal layer to which the voltage is applied functions as a phase plate, the P-polarized light incident on the pixel area to which the voltage is applied is S-polarized when exiting the liquid crystal display element 224, and the voltage is applied. P-polarized light is emitted from the non-pixel region. For example, when a black and white image is displayed on the liquid crystal display element 224, P polarized light is modulated into S polarized light in the white region, and P polarized light is emitted from the black region.

  Since optical glass generally has a reflection loss of about 4 to 8%, an antireflection film is formed on the surface indicated by symbol AR in FIG. 2 in order to prevent the light amount from being lost at the entrance / exit surface of PBS 223. Coat. As a result, it is possible to prevent a light amount loss on each surface of the PBS 223 and obtain a high transmittance. For example, a dielectric multilayer film is used as the antireflection film, and the amount of transmitted light is improved by about 5% on each surface. On the end face of the PBS 223, a marking 223b for confirming the arrangement of the PBS 223 at the time of assembly is formed.

As described above, the P-polarized light incident on the liquid crystal display element 224 is modulated according to the displayed image. The modulated light emitted from the liquid crystal display element 224 enters the PBS 223 again, and is polarized and separated by the polarization separation film 223a. That is, P-polarized light in the modulated light is transmitted through the polarization separation film 223a, and S-polarized light is reflected by the polarization separation film 223a toward the projection lens 225. The S-polarized light reflected by the polarization separation film 223a is imaged on the projection plane by the projection lens 225.

  3A and 3B are diagrams showing a schematic configuration of the liquid crystal display element 224. FIG. 3A is a plan view and FIG. 3B is a side view. The LCOS display element has a structure in which a liquid crystal layer is sandwiched between a silicon substrate 231 on which a reflective electrode is formed and a glass substrate 230 on which a transparent electrode is formed. Light from the light source 221 enters from the glass substrate side. Reference numeral 232 denotes a flexible printed circuit board (FPC), and the joint portion 234 is molded with resin or the like.

  Here, the long side of the display area 240 is denoted by reference numeral 240a, and the short side is denoted by reference numeral 240b. As shown in FIG. 3, in the liquid crystal display element 224, the side with the long side 240a is called the long side, and the side with the short side 240b is called the short side. A rectangular area indicated by a broken line is a display area 240, and an image corresponding to the projection image is displayed in the display area 240. In this embodiment, the joint portion 234 of the FPC 232 is provided on the long side of the liquid crystal display element 224 and is formed so as to protrude outward from the edges of the glass substrate 230 and the silicon substrate 231.

  FIG. 4A is a diagram illustrating a relationship between an image displayed on the liquid crystal display element 224 and a projected image. The liquid crystal display element 224 is arranged so that the long side 240a of the display region 240 and the long side of the projection image are parallel so that an erect rectangular projection image is projected onto the projection surface. With this arrangement, the number of parts of the projector unit 22 can be reduced and the size can be reduced. For example, in FIG. 4A, when the liquid crystal display element 224 is arranged so that the short side 240b of the display region 240 is orthogonal to the long side of the projection image, the normal surface as shown in FIG. In order to project a standing image, an optical system that rotates the image by 90 degrees must be provided, which increases the number of components and increases the size of the projector unit.

  The arrangement of the liquid crystal display element 224 shown in FIGS. 2 and 4A is a configuration in the case where the P-polarized light separated by the polarization separation film 223a is used as illumination light. On the other hand, when using S-polarized light as illumination light, as shown in FIG. 4B, a liquid crystal display element 224 is disposed at a position facing the projection lens 225 with the PBS 223 interposed therebetween. Also in this case, by arranging the liquid crystal display element 224 so that the long side 240a of the display region 240 and the long side of the projection image are parallel, the same operational effects as those shown in FIG. Can do.

  By the way, the condenser lens 222 is an optical element that converts the light emitted from the light source 221 into parallel light. However, in the case of the ultra-compact projector unit 22 as in the present embodiment, the distance between the light source 221 and the PBS 223 is extremely large. Becomes smaller. Therefore, it becomes difficult to make illumination light into ideal parallel light, and as shown in FIG. 5, it becomes a conical light beam having light emitted obliquely. 5A shows a case where the liquid crystal display element 224 and the light source 221 are arranged so as to face each other with PBS interposed therebetween, and P-polarized light is used as illumination light. FIG. 5B shows S-polarized light as illumination light. The case where it is used is shown.

  Moreover, when the light source 221 is a surface light source as shown in FIG. 6, it cannot become parallel light. FIG. 6 shows a case where the light source 221 is a surface light source. Light incident from one of the left and right ends of the surface light source and incident on one point of the display element is incident on the polarization separation film of the PBS. Are different from each other. Also in FIG. 6, as in FIG. 5, (a) shows a case where P-polarized light is used as illumination light, and (b) shows a case where S-polarized light is used.

<Reduction of shading>
In FIG. 5A, a liquid crystal display element 224A indicated by a solid line indicates a case where the extending direction of the short side 240b of the display region 240 is arranged in the horizontal direction of the drawing. On the other hand, the liquid crystal display element 224 </ b> B indicated by a two-dot chain line indicates a case where the long side 240 a of the display region 24 is arranged so that the extending direction is the left-right direction. Light rays L11 and L12 indicate illumination light incident on the left and right boundary portions (long side 240a portions) of the display region 240 of the liquid crystal display element 224A. On the other hand, light rays L21 and L22 indicate illumination light incident on the left and right boundary portions (short side 240b portions) of the display region 240 of the liquid crystal display element 224B.

  As shown in FIG. 3, since the display area 240 of the liquid crystal display element 224 is rectangular, their opening angles (inclinations with respect to the optical axis J) when the light beams L11, L12, L21, and L22 enter the polarization separation film 223a. The angle) of the light rays L21 and L22 incident on the short side 240b portion is larger than the light rays L11, L12 and L21 incident on the long side 240a portion.

  By the way, the polarization separation performance of the PBS 223 varies depending on the angle of the light beam when entering the polarization separation film 223a. FIG. 7 is a diagram for explaining the relationship between the angle α of the light beam and the polarization separation performance. FIG. 7B schematically shows an example of the P-polarized light transmittance when the angle α between the incident light and the polarization separation film 223a is 35 degrees and 55 degrees.

  When α = 55 degrees, the transmittance is almost constant in the wavelength range of 450 nm to 700 nm. However, when α = 35 degrees, the transmittance decreases as the wavelength decreases from 700 nm to 600 nm. The value is almost constant between 450 nm and 600 nm. Therefore, even in the same color region on the liquid crystal display element 224, the color of the region projected with the incident light of α = 35 degrees is the color of the region projected with the incident light of α = 55 degrees. The image becomes more reddish. Such a coloring phenomenon is generally called shading.

  The relationship shown in FIG. 7B shows the angle in the yz plane indicated by the thick line arrow L100 in FIG. 8, that is, the opening angle in the extending direction of the short side 240b of the display region 240. On the other hand, with respect to the angle in the xz plane indicated by the thin line arrow L200 in FIG. The degree of influence is small.

  Therefore, in the present embodiment, the liquid crystal display element 224 is arranged so that the long side extending direction in which the width of the display region 240 is wide coincides with the extending direction (x direction) of the polarization separation film 223a. That is, the long side 240a of the display area 240 extends in the x direction, and the short side 240b extends in the y direction. By arranging in this way, the opening angle in the y direction, which is greatly influenced by shading, can be suppressed to be small, and shading can be effectively suppressed.

《Ghost prevention》
FIG. 9 is a diagram for explaining the occurrence of a ghost, which becomes a problem when the PBS 223 is made smaller by downsizing. Assuming that the light source 221 is a point light source, a part of the light emitted from the light source 221 in an oblique direction (L300) is totally reflected on the side surface of the PBS 223 after entering the PBS 223, and the code A It is emitted from the range indicated by (total reflection light emission region). When the light L300 totally reflected in the PBS block enters the display area 240 of the liquid crystal display element 224, the light L300 is reflected by the liquid crystal display element 224 and then reflected by the polarization separation film 223a toward the projection lens 225. Cause.

Therefore, in order to avoid such a ghost, it is necessary to set the size of the PBS 223 so that the display area 240 enters the area inside the range A where the totally reflected light is emitted. In FIG. 9, when the distance between the light source 211 and the liquid crystal display element 224 is constant, the PBS 22
As the width dimension in the horizontal direction in FIG. 3 decreases, the dimension of the range in which the total reflected light is incident is increased. Conversely, when the width dimension is increased, the dimension of the range in which the total reflected light is incident is decreased.

  FIG. 10 is an enlarged view of the total reflection portion of FIG. However, the position of the broken line indicating the boundary of the display area was changed to match the position of the side surface of the PBS 223. In this case, as shown by the two-dot chain line in FIG. 10, when the side surface of the PBS 223 is moved by a distance A / 2 in the left direction in the drawing, that is, when the left-right width dimension of the PBS 223 is set to be large by A, total reflection is performed on the side surface. Light can be prevented from entering the display area 240 of the liquid crystal display element 224. The size of the portion indicated by the symbol A can be estimated based on the size of the display region and the distance from the divergence point of the illumination light diverging in a conical shape in FIG. 9 to the display region.

FIG. 11 is a view of the PBS 223 and the liquid crystal display element 224 shown in FIG. 8 as viewed from the minus direction of the z-axis. The dimensions of the BPS 223 in the long side direction (the horizontal direction in the figure) and the short side direction (the vertical direction in the figure) are x0 and y0. That is, consider the case where the PBS 223 is a rectangular parallelepiped. Then, let Ax be the dimension of the range A in which the totally reflected light is incident, assuming that the dimension x0 is equal to the dimension x1 of the long side 240a of the display region 240. Therefore, if the dimension x0 is set as in the following equation (1), total reflected light does not enter the display region 240, and ghosting in the long side direction can be prevented. That is, x2 in FIG. 11 is set such that x2> Ax / 2.
x0> x1 + Ax / 2 (1)

Similarly, when it is assumed that the dimension y0 in the short side direction is equal to the dimension y1 of the short side 240b of the display area 240, the dimension of the range A in which the total reflected light is incident is Ay. If the dimension y0 is set as in the following equation (2), total reflected light does not enter the display region 240, and ghosting in the short side direction can be prevented. That is, y2 in FIG. 11 is set such that y2> Ay / 2. As can be seen from FIG. 10, since the range A is larger in the short side direction, Ay> Ax.
y0> y1 + Ay / 2 (2)

  In addition, when PBS 223 is set to a cube as shown in FIG. 12, that is, when x0 = y0 is set, the length x0 of one side is set as shown in Expression (1) from the above-mentioned ghost prevention condition. The The hatched area indicates the total reflection light emission area where the total reflection light is emitted. Since the display area 240 is narrower in the y direction than in the x direction, the dimension of the PBS 223 in the y direction has a margin with respect to the display area with respect to ghost prevention.

《Mask effect》
13A and 13B are diagrams showing the details of the mask 228, wherein FIG. 13A is a perspective view and FIG. 13B is a cross-sectional view along B1-B1. Note that the liquid crystal display element 224 is also displayed in the B1-B1 cross-sectional view. As shown in FIGS. 11 and 12, even when the PBS 223 is downsized to reduce the size of the projector unit 22, the size of the illumination light exit surface of the PBS 223 is at least the display areas Ax and Ay. It must be larger than 240. For this reason, in the present embodiment, light incident on the outer area (non-display area) of the display area 240 of the liquid crystal display element 224 is reflected by the liquid crystal display element 224, and the reflected light is prevented from being scattered in the PBS 223. Therefore, a mask 228 is provided between the liquid crystal display element 224 and the PBS 223.

The mask 228 is formed of a metal plate or a resin material, and the surface of the mask 228 is subjected to processing for preventing light reflection (for example, black matte treatment). By providing the mask 228, the non-display area of the liquid crystal display element 224 can be prevented from being projected. Further, a guide for attaching the mask 228 to the PBS 223 in a portion of the mask 228 that masks the short side 240b side of the display region 240, that is, the upper and lower portions in FIG. 13A or the left and right portions in FIG. Since 228a is formed, the opening 228b of the mask 228 is P
It is accurately positioned at a predetermined position on the illumination light exit surface of BS 223.

  In the case of the mask 228 shown in FIG. 13A, the left and right positions of the mask 228 are positioned by the case wall surface of the case 226 in which the PBS 223 is stored. Of course, as indicated by the two-dot chain line in FIG. 13A, guides 228a are also provided at the left and right positions of the mask 228 (on the display area long side 240a side), and the mask 228 is positioned vertically and horizontally by the guides 228a. Also good. The mask 228 may be attached to the PBS 223 by adhesion, or may be assembled by attaching the mask 228 to the case 226 side and dropping the PBS 223 between the guides 228a of the mask 228.

  14A and 14B are diagrams showing another example of the mask 228, in which FIG. 14A is a perspective view and FIG. 14B is a B2-B2 sectional view. The mask 228 is composed of a pair of mask members provided on the long side 240a side of the display region 240. If the PBS 223 is made as small as possible to reduce the size of the projector unit 22, the width of the upper and lower portions of the mask 228 shown in FIG. 13A becomes equal to Ax shown in FIG. For this reason, this portion is easily deformed during assembling work or the like, and if the deformation occurs, the assembling work is troublesome.

  Therefore, in the example shown in FIG. 14, only the wide part corresponding to the long side part 240a of the display area 240 is masked. Each mask 228 is formed with a guide 228a, and the mask 228 is positioned at a predetermined position of the PBS 223 by the guide 228a.

  By the way, when the linearly polarized light is modulated by the liquid crystal display element 224, it is ideal that the linearly polarized light incident on the liquid crystal display element 224 is emitted as linearly polarized light rotated by 90 °. However, due to the influence of the pretilt angle at which the liquid crystal molecules are not perfectly horizontal, the linearly polarized light is often emitted in an elliptically polarized state without being completely rotated by 90 °, which tends to cause a decrease in contrast. Therefore, as shown in FIG. 15A, a quarter-wave plate 251 that is a retardation plate is provided between the liquid crystal display element 224 and the PBS 223, and the elliptically polarized light emitted from the liquid crystal display element 224 is converted into linearly polarized light. By aligning, it is possible to improve contrast.

  Note that 250a and 250b are linear polarizers. The linear polarizer 250 a extracts P-polarized light (linearly polarized light) that passes through the polarization separation film 223 a from the light of the light source 221. On the other hand, the linear polarizer 250 b functions to remove P-polarized light from the light emitted from the PBS 223.

  In the case of the sheet-like linear polarizers 250 a and 250 b and the quarter wavelength plate 251, the sheet-like linear polarizers 250 a and 250 b are often used by being attached to the surface of the PBS 223. Therefore, as shown in FIG. 15B, a quarter-wave plate 251 is disposed in the opening of the mask 228. The quarter-wave plate 251 is obtained by forming an adhesive layer 251b on both surfaces of an optical film 251a that functions as a quarter-wave plate, and the adhesive layer 251b attaches the quarter-wave plate 251 to the PBS 223. Then, the liquid crystal display element 224 is fixed to the quarter wavelength plate 251.

  In the case of the configuration shown in FIG. 13, since an air layer is interposed between the liquid crystal display element 224 and the PBS 223, the difference in refractive index is large, so that light rays are reflected on the respective surfaces, resulting in loss of light quantity. However, in the configuration shown in FIG. 15B, generation of an air layer is prevented by setting the thickness of the quarter-wave plate 251 to be equal to or greater than the thickness of the mask 228, and the glass substrate 230 ( By adopting the adhesive layer 251b having the same refractive index as that of the optical member of the PBS 223 or the optical member of the PBS 223, the light amount loss due to the reflection described above can be reduced.

The quarter-wave plate 251 is set to have the same shape as the display area 240 of the liquid crystal display element 224 or a rectangular shape that is larger than the display area 240 and slightly smaller than the opening of the mask 228. Thereby, it is possible to prevent an adverse effect on the projected image due to the mask 228 riding on the quarter wavelength plate 251 or conversely, the quarter wavelength plate 251 riding on the mask 228.

  FIG. 16 is a diagram illustrating another example of the arrangement of the quarter-wave plate 251. In the example shown in FIG. 16, the quarter wavelength plate 251 is sized so as to be disposed not only between the mask opening but also between the mask 288 and the PBS 223. By adopting such a shape, the mask 288 is fixed to the PBS 223 by the adhesive layer 251b of the quarter-wave plate 251. In this case, since a gap is formed between the quarter-wave plate 251 and the liquid crystal display element 224, a transparent member (for example, an adhesive) having a refractive index comparable to that of the adhesive layer 251b is filled in the gap. I made it.

  In this way, by filling a transparent member such as an adhesive between the quarter-wave plate 251 and the liquid crystal display element 224, it is possible to prevent loss of light amount. Further, by attaching the mask 288 using the quarter-wave plate 251, it is possible to simplify the mask attachment to the PBS 223.

<< About miniaturization of FPC accommodation space >>
As shown in FIG. 3, in this embodiment, the flexible printed circuit board (FPC) 232 of the liquid crystal display element 224 is provided on the long side of the liquid crystal display element 224. When the cubic PBS 223 is used, a wider margin space can be obtained on the long side of the liquid crystal display element 224 than on the short side as described above. Then, as shown in FIG. 3, by providing the FPC 232 on the long side of the liquid crystal display element 224, the connecting portion 234 of the FPC 232 is disposed in this extra space, and the connecting portion 234 protrudes outward from the right side surface of the PBS 223 in the drawing. The amount to be reduced can be reduced.

  Further, as shown in FIG. 17, the liquid crystal display element 224 is disposed on the PBS 223 so as to be biased toward the projection side by using a margin space on the side opposite to the connection portion 234, so that the connection portion 234 protrudes from the PBS surface. It is also possible to prevent this. In the example shown in FIG. 17, since the width dimension x3 of the liquid crystal display element 224 and the connection portion 234 is smaller than the length x0 of one side of the PBS 223, the long side 240a of the display area 240 is the boundary of the total reflected light emitting area. By bringing it close to the vicinity, the connecting portion 234 is prevented from protruding to the right side from the right side surface of the PBS 223 in the figure.

  As described above, by providing the connection portion 234 on the long side of the liquid crystal display element 224 and disposing it at the projection side of the liquid crystal display element 224, the FPC 232 can be bent more acutely at the corner portion of the PBS 223. The space required for housing the FPC 232 can be further reduced. As shown in FIG. 5B, in the case of a projector unit configured to cause the P-polarized light of the illumination light to enter the liquid crystal display element 224, the liquid crystal display element 224 may be arranged so as to be biased toward the light source. The connecting portion of the FPC 232 is located at the upper right corner of the PBS 223, and the FPC 232 is bent along the upper surface of the PBS 223.

  Further, by chamfering the corners of the PBS 223 indicated by the symbol E in FIG. 17B, the bending radius of the FPC 232 can be increased, the FPC 232 can be easily bent, and the projector unit can be made smaller. Can be achieved. Even if the chamfered portion is formed at the portion indicated by the symbol E, the liquid crystal display element 224 is shifted to the opposite side (projection side), so there is almost no influence on the projected image.

On the other hand, when the connection part 234 is arranged on the short side of the liquid crystal display element 224, the width dimension x3 of the liquid crystal display element 224 and the connection part 234 is likely to be larger than the dimension x0 of one side of the PBS 223. In that case, the accommodation space of the FPC 232 becomes large, which becomes an obstacle to downsizing.

《Improved use efficiency of illumination light》
By the way, in the embodiment described above, the shape of the illumination region 300 by illumination light is circular as shown in FIG. 18A with respect to the liquid crystal display element 224. This is because the light source light is emitted isotropically in the x direction and the y direction, and the refractive power of the condenser lens 222 is isotropic in the x direction and the y direction. However, since the display area 240 is a rectangle that is long in the x direction, the illumination light in the hatched area 302 is not used and is wasted.

  Accordingly, an illumination optical system as shown in FIG. 19 is adopted, and the shape of the illumination region 300 in FIG. 18A is deformed into a horizontally long shape as shown in FIG. 18B. The illumination optical system shown in FIG. 19 is provided with a cylindrical lens 222B in addition to the condenser lens 222 described above. A cylindrical surface CS is formed on the cylindrical lens 222B, and has a refractive power in the y direction, that is, the direction in which the short side 240b of the display region 240 extends. Therefore, the illumination optical system including the condenser lens 222 and the cylindrical lens 222B has a large refractive power in the short side direction (y direction) of the display region 240 and a small refractive power in the long side direction (x direction). ing.

  As a result, as shown in FIG. 18 (b), the illumination area 304 has a narrower range in the short side direction, the illumination area outside the display area 240 becomes narrower, and the use efficiency of illumination light is improved. If an illumination optical system having a large refractive power in the short side direction is used as described above, the deviation from the ideal parallel light in the short side direction is larger than that in the long side direction, which is a reverse effect to the reduction of shading. is doing. However, since the illumination range in the short side direction is narrowed around the optical axis as shown in FIG. 18B, shading due to deviation from ideal parallel light can be suppressed.

  Although FIG. 19 illustrates the configuration in the case of using the P-polarized light of the illumination light, the configuration shown in FIG. 20 is used in the case of using the S-polarized light. In the example shown in FIG. 19, the illumination optical system is configured by a plurality of lenses 222 and 222B so that the refractive power in the y direction is larger than the refractive power in the x direction. However, in the example shown in FIG. One surface (incident surface) of the condenser lens 222 is a cylindrical surface CS. By using a single lens in this way, the projector unit can be reduced in size. Further, instead of the cylindrical surface, an aspherical surface configured to increase the refractive power in the y direction may be formed.

  In the example described above, the long side direction of the display region 240 and the direction in which the polarization separation film 223a of the PBS 223 extends (the x direction in FIG. 19) are matched from the viewpoint of suppressing shading. However, if only the use efficiency of illumination light is considered, the extending direction of the polarization separation film 223a may be made to coincide with the short side direction (y direction) of the display region 240 as shown in FIG.

[Modification]
22-24 is a figure which shows the modification of this Embodiment. FIG. 22 is a diagram showing the appearance of the camera. In the camera 1 shown in FIG. 22, a photographing unit 21 and a projector unit 22 are provided in the camera body 10. The photographing unit 21 includes an image sensor 211 and captures a subject image via a photographing window 212 provided on the front surface of the camera. On the other hand, the projector unit 22 also has a projection window 22a in front of the camera, and projects a projection image in front of the camera.

FIG. 23 is a diagram showing a configuration of the projector unit 22 and shows a case where P-polarized light is used as illumination light. In FIG. 23, (a) is a side view seen from the side of the camera, and (b) is a view seen from the rear of the camera. 2 differs from the projector unit 22 shown in FIG. 2 in that a triangular prism 227 is provided after the projection lens 225, and the light source 211, the condenser lens 22, and the PBS 223 are arranged from the front side to the back side of the camera. ing. Projection light from the projection lens 225 is reflected forward by the triangular prism 227 and projected from the opening 226a of the case 226 to the front of the camera. The liquid crystal display element 224 is arranged so that the long side 240a of the display region 240 is horizontal so that the long side of the projected image is projected horizontally (in the horizontal direction in the drawing).

  FIG. 24 shows an arrangement of the liquid crystal display device 224 when S-polarized light is used as illumination light. Also in the case of FIG. 24, (a) is a side view of the camera module 22 and (b) is a view as seen from the rear of the camera, as in FIG. In this case, the liquid crystal display element 224 is disposed at a position facing the side surface from which S-polarized illumination light is emitted.

  In the above-described embodiment, the projector device mounted on the digital camera has been described as an example. However, the present invention is not limited to the digital camera and can be applied to a small projector device mounted on a portable device such as a mobile phone. . In addition, the present invention is not limited to the above embodiment as long as the characteristics of the present invention are not impaired.

  1: digital camera, 21: photographing unit, 22: projector unit, 221: light source, 222: condenser lens, 222B: cylindrical lens, 223: polarization beam splitter (PBS), 223a: polarization separation film, 224, 224A, 224B : Liquid crystal display element, 225: projection lens, 226: case, 227: triangular prism, 228: mask, 228a: guide, 251: quarter wave plate, 250a, 250b: linear polarizer, 232: FPC, 234: connection Part, 240: display area, 240a: long side, 240b: short side, 300: illumination area, CS: cylindrical surface

Claims (5)

A rectangular parallelepiped PBS block having two end faces perpendicular to the polarization separation plane and four side faces perpendicular to the end faces;
A light source disposed opposite to any one side of the PBS block;
It has a rectangular display area disposed opposite to the illumination light exit surface of the PBS block from which the illumination light polarized and separated by the polarization separation surface is emitted, and the illumination light polarized and separated by the polarization separation surface is used as modulated light. A reflective liquid crystal display element that modulates and emits to the PBS block;
An illumination optical system that is disposed between the light source and the PBS block and causes the illumination light emitted from the light source to enter the PBS block with a light beam having diverging light;
Of the luminous flux having divergent light, which is disposed between the reflective liquid crystal display element and the PBS block and is incident on the PBS block and converted by the illumination optical system, is totally reflected on the side surface or the end surface. A mask for preventing light incident on the surface of the PBS block on which the reflective liquid crystal display element is disposed, from entering the rectangular display area;
A projection optical system comprising: a projection optical system that forms an image by forming an image of light obtained by polarization-separating the modulated light on the polarization separation surface. The projector device according to claim 1,
A projector device, further comprising a retardation plate disposed between the PBS block and the reflective liquid crystal display element. In the projector apparatus of Claim 1 or 2,
The illumination optical system includes a single lens whose one surface is a cylindrical surface. In the projector apparatus of Claim 1 or 2,
The projector apparatus, wherein the illumination optical system includes a single lens having an aspherical surface. A rectangular parallelepiped PBS block having two end faces perpendicular to the polarization separation plane and four side faces perpendicular to the end faces;
A light source disposed opposite to any one side of the PBS block;
It has a rectangular display area disposed opposite to the illumination light exit surface of the PBS block from which the illumination light polarized and separated by the polarization separation surface is emitted, and the illumination light polarized and separated by the polarization separation surface is used as modulated light. A reflective liquid crystal display element that modulates and emits to the PBS block;
In a projector apparatus comprising: an illumination optical system that is disposed between the light source and the PBS block and causes the illumination light emitted from the light source to enter the PBS block with a light beam having diverging light,
Of the luminous flux having divergent light converted by the illumination optical system that is incident on the PBS block, it is totally reflected on the side surface or the end surface and incident on the surface on which the reflective liquid crystal display element of the PBS block is disposed. The projector is characterized in that the reflective liquid crystal display element is arranged so that the light beam to be incident does not enter the rectangular display area.

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