CN115407598A

CN115407598A - Automatic focusing lens for projector and projector

Info

Publication number: CN115407598A
Application number: CN202211197307.6A
Authority: CN
Inventors: 邓飞跃; 余强; 李玖华; 王健; 曾先远
Original assignee: Shenzhen Yingguan Technology Co ltd
Current assignee: Shenzhen Yingguan Technology Co ltd
Priority date: 2022-09-29
Filing date: 2022-09-29
Publication date: 2022-11-29
Anticipated expiration: 2042-09-29
Also published as: CN115407598B

Abstract

The invention discloses an automatic focusing lens for a projector and the projector, and relates to the technical field of projectors. The invention comprises an outer barrel, wherein an inner barrel is arranged in the outer barrel in a sliding manner, a concave mirror is arranged in the inner barrel, one end of the outer barrel is provided with a connecting sleeve, the peripheral side of the connecting sleeve is rotatably provided with a rotating rod, one end of the rotating rod is positioned outside and connected with a motor, the motor is arranged on the connecting sleeve, a plurality of conducting rods are arranged in a circular array on the peripheral side of the inner barrel, and the other end of the rotating rod is positioned in the connecting sleeve and provided with a transmission assembly acting on the plurality of conducting rods. Compared with the prior art, the rotating rod is driven to rotate by the rotation of the motor, and the plurality of conducting rods are stressed uniformly by matching with the transmission assembly, so that the inner cylinder cannot rotate and is stressed uniformly when moving, and the possibility of deviation or inclination of a projection shaft is reduced, thereby being more creative.

Description

Automatic focusing lens for projector and projector

Technical Field

The invention relates to the technical field of projectors, in particular to an automatic focusing lens for a projector and the projector.

Background

The projector is a device for projecting images or videos onto a curtain or a wall, and is widely applied to families, offices, schools, entertainment places and the like, and the focal length of the projector needs to be adjusted according to different projection distances and curtain sizes in the using process so as to present clear pictures. The existing projector focusing mode is generally to adjust the inner cylinder and the outer cylinder to slide telescopically for focusing, a concave mirror is arranged in the inner cylinder, the existing projector is generally directly connected with the inner cylinder through a focusing ring in a threaded manner, and the focusing ring drives the inner cylinder to move spirally when rotating, so that focusing is realized. However, the inner cylinder can be integrally rotated by the adjusting mode, the concave mirror installed in the inner cylinder can also rotate, imaging is easily influenced by the concave mirror in the rotating process, and due to errors of processing and assembling, deviation or inclination of a projection optical axis is easily caused in the rotating process of the lens, especially when the focusing range is required to be large, the imaging effect of the projector is particularly seriously influenced, the existing lens is inconvenient to disassemble the projector when damaged, a shell cover plate of the projector needs to be disassembled by screws, and deviation is easily caused when the inner cylinder and the outer cylinder are installed in the later period of reinstallation, so that the imaging effect is easily influenced.

Disclosure of Invention

The invention aims to: in order to solve the above-mentioned problems in the background, the present invention provides an automatic focusing lens for a projector and a projector.

The invention specifically adopts the following technical scheme for realizing the purpose:

the utility model provides an automatic focusing lens for projecting apparatus, includes the urceolus, slidable mounting has the inner tube in the urceolus, inner tube internally mounted has the concave mirror, the adapter sleeve is installed to the one end of urceolus, adapter sleeve periphery side rotates and installs the dwang, the one end of dwang is located the outside and is connected with the motor, the motor is installed on the adapter sleeve, a plurality of conduction poles are installed to inner tube periphery side circular array, the other end of dwang is located the adapter sleeve and installs and act on a plurality of the transmission assembly of conduction pole works as when the conduction pole rotates, through transmission assembly is with to a plurality of the conduction pole provides the drive power that is on a parallel with inner tube axis direction, in order to form the inner tube is followed urceolus axis direction removes.

Further, the transmission assembly is installed including rotating the rolling disc of connecting cover week side, circular array slidable mounting has a plurality of drive plates in the connecting cover, the quantity of drive plate with the quantity of conduction pole is unanimous, just drive plate slip direction orientation inner tube axis direction, and is a plurality of the drive plate with it has the hinge rod to articulate between the conduction pole, the dwang with install the interlock subassembly between the rolling disc, when the dwang rotates, through the interlock subassembly so that the rolling disc is followed inner tube axis direction rotates, it is a plurality of to install on the rolling disc and act on the conduction piece of drive plate, works as when the rolling disc rotates, through the conduction piece is so that a plurality of the drive plate is close to or keeps away from simultaneously the inner tube axis.

Further, the conduction piece is including seting up the plane thread groove of rolling disc one side, the equidistance is constructed the card and is established on the drive plate joint piece on the plane thread groove.

Furthermore, the linkage assembly comprises a bevel pinion arranged at one end of the rotating rod, and a bevel gear disc meshed with the bevel pinion is arranged at one end, far away from the plane thread groove, of the rotating disc.

Furthermore, a plurality of connecting rods are installed in a circular array at one end of the connecting sleeve, a guide rod is installed between each connecting rod and one end of the outer cylinder, and a plurality of guide sleeves are respectively sleeved on the connecting rods and are constructed on the outer peripheral side of the inner cylinder.

The invention also provides a projector, which comprises the automatic focusing lens for the projector, and further comprises a shell, wherein a plurality of limiting insertion strips are constructed on the periphery of the connecting sleeve along the length direction of the connecting sleeve, one side of the shell is provided with an insertion hole for the connecting sleeve to be inserted, a plurality of limiting insertion slots for the limiting insertion strips to be inserted are formed on the periphery of the insertion hole, a positioning piece acting on the connecting sleeve is installed on the shell, and when the connecting sleeve is inserted into the insertion hole, the connecting sleeve is fixedly released or fixed in the insertion hole through the positioning piece.

Furthermore, the setting element includes that circular array rotates to be installed the locating plate of casing, spacing cutting one end is located the outside and is constructed the flange, set up the confession on the flange the joint groove of establishing is inserted to the locating plate, it is a plurality of to install the drive on the casing locating plate pivoted drive assembly is in order to form a plurality of the locating plate is blocked respectively and is established a plurality of the joint inslot.

Further, drive assembly installs including rotating swivel on the casing, the internal gear is installed to swivel intra-annular week side, the locating plate rotates through the pivot and installs on the casing, install in the pivot with gear engagement's drive gear, install the locating part that is used for spacing its turned angle on the swivel.

Furthermore, the periphery of the rotating ring is provided with threads, the limiting piece is a limiting ring sleeved on the periphery of the rotating ring through threads, and one end of the limiting ring abuts against one side of the shell.

Furthermore, an inclined plane is formed on one side of the positioning plate, and one side face of the clamping groove is attached to the inclined plane.

The invention has the following beneficial effects:

1. compared with the prior art, the rotating rod is driven to rotate by the rotation of the motor, and the plurality of conducting rods are stressed uniformly by matching with the transmission assembly, so that the inner cylinder cannot rotate and is stressed uniformly when moving, and the possibility of deviation or inclination of a projection shaft is reduced, thereby being more creative.

2. The connecting sleeve is fixed in the inserting hole through the positioning piece, so that the connecting sleeve can be prevented from shaking in the inserting hole, the mounting precision between the lens and the shell is conveniently ensured, and the lens is dismounted and mounted only through the positioning piece during later-stage dismounting, so that the later-stage maintenance is more convenient.

3. In order to prevent the positioning plate from being separated from the clamping groove due to the accidental rotation of the rotating ring, the rotating angle of the rotating ring is limited by the limiting piece, and the possibility that the positioning plate is separated from the clamping groove by accident is reduced.

Drawings

FIG. 1 is a general structural display diagram of the present invention;

FIG. 2 is a diagram showing a lens structure according to the present invention;

FIG. 3 is an exploded view of a portion of the structure of FIG. 2 in accordance with the present invention;

FIG. 4 is a view showing the structure of the casing of the present invention;

FIG. 5 is yet another perspective view of the present invention shown in FIG. 2;

FIG. 6 is a perspective semi-sectional view of FIG. 2 of the present invention;

FIG. 7 is a perspective partial cross-sectional view of the invention of FIG. 2;

reference numerals: 1. an outer cylinder; 2. an inner barrel; 3. a concave mirror; 4. a bevel; 5. connecting sleeves; 6. rotating the rod; 7. a motor; 8. a conductive rod; 9. a transmission assembly; 901. rotating the disc; 902. a drive plate; 903. a hinged lever; 10. a linkage assembly; 1001. a bevel pinion gear; 1002. a bevel gear disc; 11. a conductive member; 1101. a planar thread groove; 1102. a clamping block; 12. a connecting rod; 13. a guide bar; 14. a guide sleeve; 15. a housing; 16. limiting the cutting; 17. inserting holes; 18. limiting slots; 19. a limiting ring; 20. a positioning member; 2001. positioning a plate; 2002. a convex plate; 2003. a clamping groove; 21. a drive assembly; 2101. a rotating ring; 2102. an internal gear; 2103. a transmission gear; 22. and a limiting member.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention.

As shown in fig. 1 to 7, an automatic focusing lens for a projector and a projector comprise an outer barrel 1, an inner barrel 2 is slidably installed in the outer barrel 1, a concave mirror 3 is installed inside the inner barrel 2, a connecting sleeve 5 is installed at one end of the outer barrel 1, a rotating rod 6 is rotatably installed at the outer peripheral side of the connecting sleeve 5, one end of the rotating rod 6 is located outside and is connected with a motor 7, the motor 7 is installed on the connecting sleeve 5, a plurality of conducting rods 8 are installed at the outer peripheral side of the inner barrel 2 in a circular array, the other end of the rotating rod 6 is located in the connecting sleeve 5 and is installed with a transmission assembly 9 acting on the plurality of conducting rods 8, when the conducting rods 8 rotate, a driving force parallel to the axial direction of the inner barrel 2 is provided for the plurality of conducting rods 8 through the transmission assembly 9 to form that the inner barrel 2 moves along the axial direction of the outer barrel 1, and when an output shaft of the motor 7 rotates, the rotating rod 6 can rotate, dwang 6 provides the drive power of the same dynamics to every conduction pole 8 through drive assembly 9 at the pivoted in-process, and the drive power direction that provides is unanimous and be on a parallel with the axis of inner tube 2, thereby make the removal of a plurality of conduction poles 8 level to, because conduction pole 8 is connected with inner tube 2, so can make inner tube 2 remove along 1 axis direction of urceolus, inner tube 2 ground connection drives the concave mirror 3 and the distance between the reflection source changes in gliding process, thereby realize the adjustment roll adjustment, compared with the existing, rotate drive dwang 6 through motor 7 and rotate, it makes a plurality of conduction poles 8 atress unanimous to cooperate drive assembly 9 again, thereby can not take place the rotation and the atress is even when making inner tube 2 remove, projection shaft skew or the inclined possibility has been reduced, therefore, have more creativity.

As shown in fig. 2-6, in some embodiments, the transmission assembly 9 includes a rotating disc 901 rotatably mounted on the inner peripheral side of the connecting sleeve 5, a plurality of driving plates 902 are slidably mounted on the inner peripheral side of the connecting sleeve 5, the number of the driving plates 902 is equal to the number of the conductive rods 8, preferably, the number of the conductive rods 8 is four, which is sufficient to ensure that the inner cylinder 2 slides accurately, and the driving plates 902 slide in the direction toward the axis of the inner cylinder 2, hinge rods 903 are hinged between the plurality of driving plates 902 and the conductive rods 8, and an interlocking assembly 10 is mounted between the rotating disc 6 and the rotating disc 901, when the rotating disc 6 rotates, the rotating disc 901 rotates in the direction of the axis of the inner cylinder 2 through the interlocking assembly 10, a conductive member 11 acting on the plurality of driving plates 902 is mounted on the rotating disc 901, when the rotating disc 901 rotates, the plurality of driving plates 902 are simultaneously hinged close to or far from the axis of the inner cylinder 2 through the conductive member 11, that when the output shaft of the motor rotating disc 7 rotates, the rotating disc 6 rotates, the rotating disc 901 rotates in the direction around the axis of the inner cylinder 2 through the conductive rods 903, so that the driving plates 902 are simultaneously close to or far from the axis of the driving plates 902, and the driving plates 902 are moved by the driving rods 903, and the driving rods 902, thereby providing the same driving force to the driving rods 903, and the driving rods 902, and the driving rods 8, and the driving rods 903 providing the same driving force during the driving rods 903, and the driving rods 903 can be hinged force.

As shown in fig. 2-7, in some embodiments, the conductive element 11 includes a planar thread groove 1101 formed on one side of the rotary disc 901, and a clamping block 1102 clamped on the planar thread groove 1101 is equidistantly configured on the drive plate 902, when the rotary disc 901 rotates, because the clamping block 1102 on the drive plate 902 is located in the planar thread groove 1101, and one end of a hinge rod 903 hinged to the drive plate 902 is hinged to the conductive rod 8, the conductive rod 8 can only slide but cannot rotate, the rotary disc 901 can rotate the planar thread groove 1101 during rotation, so that the clamping block 1102 moves in the planar thread groove 1101, and thus a plurality of drive plates 902 simultaneously approach or leave the axis of the inner cylinder 2, because the planar thread groove 1101 and the drive plate 902 are in threaded fit, have a certain self-locking property, and therefore, when the position of the inner cylinder 2 is adjusted, it is not easy to move by itself due to external factors.

As shown in fig. 2 to 7, in some embodiments, the linkage assembly 10 includes a bevel pinion 1001 installed at one end of the rotation rod 6, and a bevel pinion 1002 engaged with the bevel pinion 1001 is installed at one end of the rotation disk 901 away from the planar thread groove 1101, it should be noted that the number of teeth of the bevel pinion 1001 is much smaller than the number of teeth of the bevel pinion 1002, the larger the difference between the number of teeth of the bevel pinion 1002 and the number of teeth of the bevel pinion 1001 is, the higher the adjustment precision is, when the output shaft of the motor 7 rotates to drive the rotation rod 6 to rotate, the rotation rod 6 rotates to drive the bevel pinion 1001 to rotate, because the bevel pinion 1001 is engaged with the bevel pinion 1002, the rotation of the bevel pinion 1001 can rotate the bevel pinion 1002, thereby realizing the rotation of the rotation disk 901.

As shown in fig. 5 and 7, in some embodiments, a plurality of connecting rods 12 are installed in a circular array at one end of the connecting sleeve 5, a guide rod 13 is installed between the connecting rod 12 and one end of the outer cylinder 1, a plurality of guide sleeves 14 respectively sleeved on the connecting rods 12 are configured on the outer peripheral side of the inner cylinder 2, the guide rod 13 and the guide sleeve 14 play a role in guiding and limiting, preferably, the number of the guide rods 13 and the number of the guide sleeves 14 are four, which is enough to ensure the precision of the inner cylinder 2 during sliding, so that the inner cylinder 2 is smoother during moving, and errors are reduced.

As shown in fig. 1, 4 and 5, the present invention further provides a projector, including the above-mentioned automatic focus adjusting lens for a projector, further including a housing 15, a plurality of limiting insertion strips 16 are configured on an outer circumference side of the connection sleeve 5 along a length direction thereof, one side of the housing 15 is provided with an insertion hole 17 for the connection sleeve 5 to be inserted, a plurality of limiting insertion slots 18 for the limiting insertion strips 16 to be inserted are formed on an inner circumference side of the insertion hole 17, a positioning member 20 acting on the connection sleeve 5 is installed on the housing 15, when the connection sleeve 5 is inserted in the insertion hole 17, the connection sleeve 5 is released or fixed in the insertion hole 17 by the positioning member 20, the limiting insertion strips 16 and the limiting insertion slots 18 play a role of positioning, when the connection sleeve 5 is inserted in the insertion hole 17, the limiting insertion strips 16 are located in the limiting insertion slots 18, then the connection sleeve 5 is fixed in the insertion hole 17 by the positioning member 20, so that the connection sleeve 5 can be prevented from shaking in the insertion hole 17, which not only facilitates the installation of the lens and the housing 15, and the positioning member 20 is needed to achieve the later disassembly of the connection sleeve and the positioning member, thereby facilitating the installation of the lens (the lens 2 and the maintenance of the outer barrel 2).

As shown in fig. 1, 4 and 5, in some embodiments, the positioning member 20 includes a positioning plate 2001 rotatably installed in a circular array in the housing 15, one end of the limiting insert 16 is located outside and is configured with a convex plate 2002, the convex plate 2002 is provided with a clamping groove 2003 into which the positioning plate 2001 is inserted, the housing 15 is provided with a driving assembly 21 for driving the plurality of positioning plates 2001 to rotate, so as to form that the plurality of positioning plates 2001 are respectively clamped in the plurality of clamping grooves 2003, that is, the plurality of positioning plates 2001 are arrayed around the axial direction of the insertion hole 17, and when the connecting sleeve 5 is inserted in the insertion hole 17, the plurality of positioning plates 2001 are simultaneously rotated by the driving assembly 21, so that the plurality of positioning plates 2001 are respectively inserted in the plurality of clamping grooves 2003.

As shown in fig. 1, 4 and 5, in some embodiments, the driving assembly 21 includes a rotating ring 2101 rotatably mounted on the housing 15, an inner gear 2102 is mounted on an inner circumference side of the rotating ring 2101, the positioning plate 2001 is rotatably mounted on the housing 15 through a rotating shaft, a transmission gear 2103 engaged with the inner gear 2102 is mounted on the rotating shaft, a limiting member 22 for limiting a rotation angle of the rotating ring 2101 is mounted on the rotating ring 2101, that is, when the connecting sleeve 5 is fully inserted into the inserting hole 17, the rotating ring 2101 is rotated at this time to rotate the inner gear 2102 mounted in the rotating ring 2101, the inner gear 2102 rotates the transmission gear 2103 engaged with the inner gear 2102 during the rotation, because the transmission gear 2103 is connected with the rotating shaft of the positioning plate 2001, the transmission gear 2103 rotates the positioning plate 2001, so that the plurality of positioning plates 2001 are rotated synchronously and in the same direction, thereby achieving that the plurality of positioning plates 2001 are simultaneously inserted into the plurality of catching grooves 2003, and in order to prevent the positioning plate 2001 from being accidentally rotated to disengage the positioning plate 2001 from the catching groove 2003, so that the rotation angle of the positioning plate 2101 is rotated by the limiting member 22, the possibility of the positioning plate 2001 being accidentally disengaged from the limiting member 2003 is reduced.

As shown in fig. 1 to 7, in some embodiments, a thread is formed on an outer peripheral side of the rotating ring 2101, the limiting member 22 is a limiting ring 19 that is threaded on an outer peripheral side of the rotating ring 2101, and one end of the limiting ring 19 abuts against one side of the housing 15, preferably, as shown in fig. 4, when the positioning plate 2001 is required to be inserted into the fastening groove 2003, the rotating ring 2101 needs to rotate clockwise, so that when the rotating ring 2101 continues to rotate clockwise, and when the positioning plate 2001 is positioned in the fastening groove 2003 to achieve fastening, the rotating ring 2101 continues to rotate, at this time, clockwise rotation of the limiting ring 19 causes the limiting ring 19 to perform spiral motion in a direction toward the housing 15 until the limiting ring 19 abuts against one side of the housing 15, and limiting of the rotating ring 2101 is achieved by means of abutting and increasing friction.

As shown in fig. 2 and fig. 4, in some embodiments, a slope 4 is configured on one side of the positioning plate 2001, one side of the clamping groove 2003 is attached to the slope 4, the slope 4 is designed such that the positioning plate 2001 not only plays a role of guiding during the process of being inserted into the clamping groove 2003, but also when the connecting sleeve 5 is not completely inserted into the plug hole 17, when the positioning plate 2001 rotates the clamping plate to be arranged in the clamping groove 2003, the connecting sleeve 5 is moved towards the plug hole 17 by the slope 4 until the clamping groove 2003 is completely inserted into the plug hole 17, and the positioning plate 2001 is also completely located in the clamping groove 2003 at this time, thereby further improving the precision in connection.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. The utility model provides an automatic focusing lens for projecting apparatus, a serial communication port, including urceolus (1), slidable mounting has inner tube (2) in urceolus (1), inner tube (2) internally mounted has concave mirror (3), adapter sleeve (5) are installed to the one end of urceolus (1), adapter sleeve (5) periphery side is rotated and is installed dwang (6), the one end of dwang (6) is located the outside and is connected with motor (7), motor (7) are installed on adapter sleeve (5), a plurality of conduction poles (8) are installed to inner tube (2) periphery side circular array, the other end of dwang (6) is located adapter sleeve (5) and installs and be acted on a plurality ofly transmission assembly (9) of conduction pole (8), works as when conduction pole (8) rotate, through transmission assembly (9) are with to a plurality of conduction pole (8) provide the drive power that is on a parallel with inner tube (2) axis direction, in order to form inner tube (2) are followed urceolus (1) axis direction removes.

2. The auto-focus lens for projectors according to claim 1, wherein said transmission assembly (9) comprises a rotating disc (901) rotatably mounted on an inner peripheral side of said connecting sleeve (5), said connecting sleeve (5) has a plurality of driving plates (902) slidably mounted therein, said driving plates (902) have a number corresponding to the number of said conductive rods (8), and said driving plates (902) slide in a direction toward an axis of said inner cylinder (2), a plurality of hinge rods (903) are hinged between said driving plates (902) and said conductive rods (8), a linking assembly (10) is mounted between said rotating disc (6) and said rotating disc (901), when said rotating disc (6) rotates, said rotating disc (901) rotates in an axis direction of said inner cylinder (2) through said linking assembly (10), said rotating disc (901) has a conductive member (11) mounted thereon for acting on said plurality of said driving plates (902), and when said rotating disc (901) rotates, said plurality of said driving plates (902) simultaneously approach or depart from said inner cylinder (2) through said conductive member (11).

3. The auto-focus lens for a projector according to claim 2, wherein the conductor (11) includes a flat screw groove (1101) opened at one side of the rotary plate (901), and the driving plate (902) is equidistantly configured with a catching block (1102) caught on the flat screw groove (1101).

4. The auto-focus lens for a projector according to claim 3, wherein the linkage assembly (10) comprises a bevel pinion (1001) mounted at one end of the rotating lever (6), and a bevel gear plate (1002) engaged with the bevel pinion (1001) is mounted at one end of the rotating plate (901) away from the planar thread groove (1101).

5. The automatic focus lens for a projector according to claim 4, wherein a plurality of connecting rods (12) are installed at one end of the connecting sleeve (5) in a circular array, a guide rod (13) is installed between the connecting rod (12) and one end of the outer cylinder (1), and a plurality of guide sleeves (14) are configured at the outer peripheral side of the inner cylinder (2) and are respectively sleeved on the connecting rods (12).

6. A projector is characterized by comprising the automatic focusing lens for the projector according to any one of claims 1 to 5, and further comprising a housing (15), wherein a plurality of limiting insertion strips (16) are formed on the outer periphery of the connecting sleeve (5) along the length direction of the connecting sleeve, an insertion hole (17) for the connecting sleeve (5) to be inserted is formed in one side of the housing (15), a plurality of limiting insertion slots (18) for the limiting insertion strips (16) to be inserted are formed in the inner periphery of the insertion hole (17), a positioning piece (20) acting on the connecting sleeve (5) is installed on the housing (15), and when the connecting sleeve (5) is inserted into the insertion hole (17), the connecting sleeve (5) is released or fixed in the insertion hole (17) through the positioning piece (20).

7. The projector as claimed in claim 6, wherein the positioning member (20) comprises a circular array of positioning plates (2001) rotatably mounted in the housing (15), one end of the position-limiting strip (16) is located outside and is configured with a convex plate (2002), the convex plate (2002) is provided with a clamping groove (2003) for the positioning plates (2001) to be inserted, and the housing (15) is mounted with a driving assembly (21) for driving a plurality of the positioning plates (2001) to rotate, so as to form a plurality of the positioning plates (2001) to be respectively clamped in the plurality of clamping grooves (2003).

8. A projector as claimed in claim 7, wherein said driving unit (21) comprises a rotating ring (2101) rotatably mounted on said housing (15), an internal gear (2102) is mounted on an inner peripheral side of said rotating ring (2101), said positioning plate (2001) is rotatably mounted on said housing (15) by a rotating shaft, a transmission gear (2103) engaged with said internal gear (2102) is mounted on said rotating shaft, and a limiting member (22) for limiting a rotation angle of said rotating ring (2101) is mounted on said rotating ring (2101).

9. A projector as claimed in claim 8, wherein the outer periphery of the rotating ring (2101) is threaded, the position-limiting member (22) is a position-limiting ring (19) threaded on the outer periphery of the rotating ring (2101), and one end of the position-limiting ring (19) abuts against one side of the housing (15).

10. A projector according to claim 9, wherein said positioning plate (2001) is formed with a slope (4) on one side, and said engagement groove (2003) is formed with a side surface abutting on said slope (4).