TWI401524B - Projection apparatus - Google Patents

Description

Projection device

The present invention relates to a display device, and more particularly to a projection device.

Today's projection devices, such as single beam projectors and liquid crystal projectors, have been able to project images of high image quality and high brightness. In addition, with the advancement of manufacturing technology, the projection device is becoming lighter, thinner, shorter, more portable, and suitable for various occasions. Therefore, optical projection devices are gradually being used by the general public.

In conventional projection devices, an illumination system is used to form an illumination beam that illuminates a light valve, which in turn converts the illumination beam into an image beam. The projection lens is disposed on the transmission path of the image beam to project the image beam onto the projected screen to form an image frame.

In general, the size of the projection screen and the distance of the projection screen relative to the optical projection device can be limited by the space in the environment of use. Therefore, on the projection lens of the projection device, an adjustment ring for focusing or zooming is often provided to allow the user to adjust the projection of the projection lens by adjusting the ring. The size of the picture or the clarity of the picture. Since the imaging plane of the image frame projected by the conventional projection device is a plane, when the projection screen is a curved surface, the imaging surface of the image frame cannot overlap with the projection screen. At this time, even if the position of the image plane is adjusted by adjusting the loop, the entire image screen cannot be made clear.

It is an object of the present invention to provide a projection apparatus that can reduce aberrations of an image projected on a curved projection surface.

The invention provides a projection device comprising a projection unit and a movable curved projection surface. The projection unit has an optical axis and includes a light valve and a projection lens. The light valve is adapted to provide an image beam. The projection lens is disposed on the transmission path of the image beam and is adapted to project the image beam. The movable curved projection surface is adapted to cut in or cut away from the transmission path of the image beam projected by the projection lens. When the movable curved projection surface cuts into the transmission path of the image beam projected by the projection lens, the optical axis of the projection unit is not perpendicular to the tangent plane where the movable curved projection surface intersects the optical axis of the projection unit, and the depth of field of the projection lens covers A projecting area in which the movable curved projection surface is illuminated by the image beam. The offset of the projected area from the projection lens is greater than zero.

In one embodiment of the invention, the offset of the projection area relative to the projection lens is greater than 100%.

In an embodiment of the invention, the obtuse angle of the optical axis of the projection unit and the tangent plane is closer to the center of the projection area than the acute angle.

In an embodiment of the invention, the projection device further includes an actuator coupled to the movable curved projection surface to drive the movable curved projection surface to cut into or away from the transmission path of the image beam projected by the projection lens. The projection lens is adapted to project an image beam onto a projection plane when the actuator drives the movable curved projection surface to cut away from the transmission path of the image beam projected by the projection lens. The distance from the projection lens to the projection plane may be greater than the distance from the projection lens to the movable curved projection surface.

In an embodiment of the invention, the projection unit further includes at least one mirror disposed on the transmission path of the image beam projected by the projection lens, and located between the projection lens and the movable curved projection surface.

In an embodiment of the invention, the light valve is a digital micro-mirror device (DMD), a liquid-crystal-on-silicon panel (LCOS panel) or a transmissive liquid crystal panel.

In an embodiment of the invention, the center of curvature of the movable curved projection surface is located on the same side of the movable curved projection surface as the projection unit.

In an embodiment of the invention, the movable curved projection surface is a spherical surface.

In an embodiment of the invention, the movable curved projection surface is an aspherical surface.

Based on the above, in the projection apparatus of the embodiment of the present invention, since the optical axis of the projection unit is not perpendicular to the tangent plane where the movable curved projection surface intersects the optical axis of the projection unit, when the projection unit projects the image onto the movable bending When projecting a surface, the depth of field of the projection lens can cover the illuminated area on the curved projection surface. In this way, the aberration of the projected image can be reduced, and the image projected on the movable curved projection surface can maintain the image quality close to the image projected on the plane projection surface.

The above described features and advantages of the present invention will be more apparent from the following description.

1 is a schematic view of a projection apparatus according to an embodiment of the present invention, and FIG. 2 is an enlarged schematic view of the projection unit of FIG. 1. Referring to FIG. 1 and FIG. 2, the projection device 100 includes a projection unit 110 and a movable curved projection surface 120. The projection unit 110 includes a light valve 114 and a projection lens 112. The light valve 114 is adapted to provide an image light beam L1. The projection lens 112 is disposed on the transmission path of the image light beam L1 and is located between the light valve 114 and the movable curved projection surface 120. The projection lens 112 is adapted to project the image light beam L1 onto the movable curved projection surface 120 to form an image.

In the present embodiment, the projection unit 110 can include an illumination system 116 and includes an internal total reflection stop 150. Illumination system 116 emits an illumination beam L2 that is reflected by internal total reflection 稜鏡 150 to light valve 114, such as a digital micromirror element. The light valve 114 converts the incident illumination light beam L2 into the image light beam L1, and emits the image light beam L1 to the internal total reflection 稜鏡150. The image light beam L1 passes through the internal total reflection 稜鏡150 and is projected onto the movable curved projection surface 120. on. In addition, in other embodiments, the light valve 114 may also be a liquid-based liquid crystal panel or a transmissive liquid crystal panel, and the position of the illumination system 116 is not limited to that shown in FIG. 2, and may be disposed at other positions in conjunction with the light valve 114.

In this specification, the offset can be illustrated by Figure 3. Figure 3 is a schematic diagram of the offset of the projected area. Referring to FIG. 3, the offset of the projection area S is defined by the following formula:

Wherein, A is the distance from one edge of the projection lens optical axis P (shown in FIG. 1 ) of the projection area S (or the image image) closer to the projection lens 112 to the optical axis P of the projection lens. If the projection lens optical axis P passes through a point in the image frame, the value of A is a negative value. Conversely, if the projection lens optical axis P does not intersect the image frame, the value of A is a positive value. H is the width of the image frame in the offset direction, and the values of H are all positive values. For example, the value of A in Figure 3 is a positive value, and the value of A and H is substituted into the formula of the offset and the offset can be calculated.

When the movable curved projection surface 120 cuts into the transmission path of the image light beam L1 projected by the projection lens 112, that is, when the projection unit 110 projects the image onto the movable curved projection surface 120, the optical axis P of the projection unit 110 is not perpendicular to the movable type. A tangent plane 122 where the curved projection surface 120 intersects the optical axis P of the projection unit 110. In the present embodiment, the obtuse angle T1 of the optical axis P of the projection unit 110 and the tangent plane 122 is closer to the center of the projection area S than the acute angle T2, and the depth of field D of the projection lens 112 covers the movable curved projection surface 120 by the image beam. A projection area S illuminated by L1 causes the image projected on the movable curved projection surface 120 to be deformed without causing excessive aberration. In other words, in the present embodiment, by making the optical axis P of the projection unit 110 tilt relative to the movable curved projection surface 120, the depth of field D is more easily covered by the projection area S, so that the projection lens 112 can be made larger in the depth of field D. In this case, the projection area S can be covered. In this way, it is possible to simultaneously form a clear image while improving the design flexibility of the projection lens 112.

In contrast, referring to FIG. 4, when the optical axis P" of the projection unit 110' is not tilted relative to the movable curved projection surface 120', but is vertically disposed (ie, the optical axis P" is perpendicular to the movable curved projection surface. When the 120' is at the tangent plane 122' where the optical axis P" of the projection unit 110' intersects, the depth of field D' of the projection lens 112' must be significantly larger than the depth of field of the projection lens 112' of the present embodiment to cover the projection area S. However, such a large depth of field D' is generally not easy to achieve, so that the projection device of the optical axis P" vertical movable curved projection surface 120' is liable to cause an excessive aberration of the image projected on the movable curved projection surface 120'.

In the present embodiment, the movable curved projection surface 120 may be a spherical surface, and the center of curvature and the projection unit 110 are located on the same side of the movable curved projection surface 120. However, in other embodiments of the invention, the movable curved projection surface 120 may be aspherical.

In addition, in the present embodiment, the distance from a projection plane 130 to the projection lens 112 is greater than the distance from the movable curved projection surface 120 to the projection lens 112. In other words, the projection plane 130 is located behind the movable curved projection surface 120. When the movable curved projection surface 120 is cut away from the path of the image beam L1, the image beam L1 is projected onto the projection plane 130 and is located at a remote location. An image is formed on the projection plane 130.

In the present embodiment, the optical axis P' of the projection unit 110 is the optical axis P of the projection lens 112. The offset of the projection area S relative to the projection lens 112 is greater than zero, the light valve 114 is offset from the optical axis P by an X% offset in a first direction D1, and the offset of the projection area S relative to the projection lens 112 is More than 100%.

In more detail, the projection lens 112 is composed of a plurality of lenses, and the following table will list the preferred parameter values in the projection lens 112 in conjunction with FIG. However, the data set forth in the following table is not intended to limit the invention, and any person skilled in the art, after referring to the present invention, may make appropriate changes to its parameters or settings, but still fall within the scope of the present invention. Inside.

In FIG. 2, the first lens 112a is a convex-concave lens having a surface S1 and a surface S2. The second lens 112b is a convex-concave lens having a surface S3 and a surface S4. The third lens 112c is a lenticular lens having a surface S5 and a surface S6. The fourth lens 112d is a convex-concave lens having a surface S8 and a surface S9. The fifth lens 112e is a biconcave lens having a surface S10 and a surface S11, and the sixth lens 112f is a lenticular lens having a surface S11 and a surface S12, wherein the fifth lens 112e and the sixth lens 112f constitute a double cemented lens, and the surface S11 is The surface of the fifth lens 112e that is connected to the sixth lens 112f. The seventh lens 112g is a lenticular lens having a surface S13 and a surface S14. The eighth lens 112h is a convex-concave lens having a surface S15 and a surface S16. Further, the surface S7 is the surface of the aperture stop 160.

In the above table, the distance refers to the linear distance between two adjacent surfaces on the optical axis P. For example, the distance in the table corresponding to the surface S1, that is, the line between the surface S1 and the surface S2 on the optical axis P The distance d1 corresponds to the distance from the surface S2 in the table, that is, the linear distance d2 between the surface S2 and the surface S3 on the optical axis P. The radius of the surface is the length of each surface (projection surface OBJ and surfaces S1 to S16) on the Y-axis. For the refractive index and Abbe number corresponding to each lens in the remark column, refer to the values corresponding to the refractive indices and Abbe numbers in the same column.

Figure 5A and Figure 5B are imaging optical simulation data of the fixed-focus lens of Figure 1. Please refer to FIG. 5A to FIG. 5B, wherein FIG. 5A is an optical transfer function (MTF) whose horizontal axis is the field in the Y direction (shown in FIG. 2), and the vertical axis is optical. The modulus of the optical transfer function. In Fig. 5A, a simulation data diagram of light having a wavelength from 486 nm to 656 nm is used, in which a solid line refers to data of a radial (sagittal) ray, and a broken line refers to data of a tangential ray. In addition, in FIG. 5B, the left-to-right order is a pattern of field curvature and distortion, and is an analog data diagram of light having wavelengths of 486 nm, 588 nm, and 656 nm. Since the patterns shown in FIGS. 5A to 5B are all within the standard range, the projection apparatus 100 of the present embodiment can maintain good image quality under the above-described arrangement.

Figure 6A is a schematic illustration of a projection apparatus in accordance with another embodiment of the present invention. Referring to FIG. 6A, in the present embodiment, the projection unit 110 further includes a plurality of mirrors 118 (shown as two) disposed on the transmission path of the image beam L1 projected by the projection lens 112. These mirrors 118 form a folded optical path to reduce the volume occupied by the projection unit 110. By folding the optical path to shorten the stroke distance of the projection beam, the length of the projection unit 110 in the direction parallel to the optical axis of the projection lens 112 can be less than 20 cm, so that the entire group of projection units 110 can be disposed in a chassis 140, Increase the convenience of carrying. In particular, the chassis 140 is, for example, the body of the robot or other suitable location such that the projection unit 110 located within the chassis 140 can move with the robot and perform a projection function.

Figure 6B is a schematic view of the movable curved projection surface of Figure 6A away from the initial position. Referring to FIG. 6A and FIG. 6B, in the embodiment, the movable curved projection surface 120 may be a part of the chassis 140. The projection device 100 further includes an actuator 142 coupled to the movable curved projection surface 120 and disposed in the chassis 140 for driving the movable curved projection surface 120 to cut into or away from the image beam L1 projected by the projection lens 112. On the delivery path. When the movable curved projection surface 120 is at the initial position, the projection unit 110 projects the image on the movable curved projection surface 120 in a back projection manner, and the user can view the projected image outside the chassis 140. When the user needs to project the image on the other projection plane 130, the operable actuator 142 cuts the movable curved projection surface 120 away from the transmission path of the image beam L1, so that the projection unit 110 can be projected in the past. The image is projected onto the projection plane 130.

In summary, in the projection apparatus of the embodiment of the present invention, since the optical axis of the projection unit is not perpendicular to the tangent plane where the movable curved projection surface intersects the optical axis of the projection unit, when the projection unit projects the image When the projection surface is movably curved, the depth of field of the projection lens can cover the illumination area on the curved projection surface. In this way, the aberration of the projected image can be reduced, and the image projected on the curved projection surface and the image projected on the plane projection surface have similar imaging quality. In addition to the curved projection surface, the projection device of the embodiment of the present invention can move the movable curved projection surface out of the transmission path of the image beam, so that the projection device projects the image onto another projection plane. In addition, the projection unit may further include a plurality of mirrors for reducing the transmission path of the image beam, so that the projection unit can be assembled into a casing, which makes the projection device easier to carry and install.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

100. . . Projection device

110. . . Projection unit

112. . . Projection lens

114. . . Light valve

116. . . Lighting system

118. . . Reflector

120. . . Movable curved projection surface

122. . . Cutting plane

130. . . Projection plane

140. . . Chassis

150. . . Internal total reflection稜鏡

160. . . Aperture stop

A, H. . . distance

D, D’. . . Depth of field

L1. . . Image beam

L2. . . Illumination beam

P. . . Projection lens optical axis

P', P"... projection unit optical axis

T1, T2. . . Angle

S. . . Projection area

1 is a schematic diagram of a projection apparatus in accordance with an embodiment of the present invention.

Figure 2 is an enlarged schematic view of the projection unit of Figure 1.

Figure 3 is a schematic diagram of the offset of the projected area.

Figure 4 is a schematic illustration of a projection apparatus that directs the optical axis perpendicular to the movable curved projection surface.

Figure 5A and Figure 5B are imaging optical simulation data of the fixed-focus lens of Figure 1.

Figure 6A is a schematic illustration of a projection apparatus in accordance with another embodiment of the present invention.

Figure 6B is a schematic view of the movable curved projection surface of Figure 6A away from the initial position.

100. . . Projection device

110. . . Projection unit

112. . . Projection lens

114. . . Light valve

116. . . Lighting system

120. . . Movable curved projection surface

122. . . Cutting plane

D. . . Depth of field

L1. . . Image beam

P. . . Projection lens optical axis

T1, T2. . . Angle

S. . . Projection area

Claims (10)

A projection device comprising: a projection unit having an optical axis, the projection unit comprising: a light valve adapted to provide an image beam; and a projection lens disposed on the transmission path of the image beam and adapted to be projected The image beam; and a movable curved projection surface adapted to cut into or cut off a transmission path of the image beam projected by the projection lens, wherein the movable curved projection surface cuts into the image beam projected by the projection lens When the path is transmitted, the optical axis of the projection unit is not perpendicular to a tangent plane where the movable curved projection surface intersects the optical axis of the projection unit, and the depth of field of the projection lens covers the movable curved projection surface by the image a projection area illuminated by the beam, wherein the projection area has an offset from the projection lens that is greater than zero. The projection device of claim 1, wherein the projection area is offset from the projection lens by more than 100%. The projection apparatus of claim 1, wherein an obtuse angle of the optical axis of the projection unit and the tangent plane is closer to a center of the projection area than an acute angle. The projection device of claim 1, further comprising an actuator coupled to the movable curved projection surface to drive the movable curved projection surface to cut into or cut off the image beam projected by the projection lens a transfer path adapted to project the image beam onto a projection plane when the actuator drives the movable curved projection surface to cut away a transmission path of the image beam projected by the projection lens. The projection device of claim 4, wherein a distance from the projection lens to the projection plane is greater than a distance from the projection lens to the movable curved projection surface. The projection device of claim 1, wherein the projection unit further comprises at least one mirror disposed on a transmission path of the image beam projected by the projection lens, and located at the projection lens and the movable curved projection Between the faces. The projection device of claim 1, wherein the light valve is a digital micromirror device, a germanium-based liquid crystal panel, or a transmissive liquid crystal panel. The projection device of claim 1, wherein a center of curvature of the movable curved projection surface is located on a same side of the movable curved projection surface as the projection unit. The projection device of claim 1, wherein the movable curved projection surface is a spherical surface. The projection device of claim 1, wherein the movable curved projection surface is an aspherical surface.