JP2568173B2 - Optical device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical device having a lens used in an optical system of an LBP that can be molded by a mold, and a container that houses the lens.

(2) Related Art Conventionally, various optical elements such as lenses and prisms have been used in various optical devices and have played a role as a key component constituting the device. In recent years, this type of optical element has been increasingly formed by a mold such as a so-called glass mold or plastic mold in order to improve mass productivity and reduce cost. FIG. 4 shows a schematic configuration diagram of a laser beam printer (hereinafter, referred to as LBP) as an example in which an optical element such as a lens formed by this molding is incorporated in the apparatus. In the figure, 8 is a container for fixing the optical system of LBP,
9 is a laser light source, 10 is a photosensitive drum, 11 is a laser light source 9
A polygon mirror for scanning the laser light emitted from the photosensitive drum 10 in the axial direction is rotated by a motor (not shown). Reference numeral 12 denotes a cylindrical lens for converging the laser light emitted from the laser light source 9 and collimated by a collimator lens (not shown) on the surface of the polygon mirror 11, 13, 1.
4 is the photosensitive drum 10 that collects the light flux on the surface of the polygon mirror 11.
A spherical lens and a Toric lens, which are convergently convergently and have f-θ characteristics, are shown for convenience of the LBP optical system. The optical system 15 of the LBP is composed of the optical elements described above, and various lenses are supported and fixed. Here, as an example, FIG. 5 shows a state in which the toric lens 14 is supported and fixed. In the figure, the same members as those in FIG. 4 are designated by the same reference numerals. Incidentally, 8a is an arm for positioning the torque lens 14 in the optical axis direction,
Reference numeral 8b denotes a pedestal that positions the toric lens 14 in a direction orthogonal to the optical axis, 16 denotes a leaf spring that presses the toric lens 14 toward the arm 8a side, and 17 denotes a leaf spring that presses the toric lens 14 toward the pedestal 8b side. When supported and fixed by such respective members, the leaf spring 16 on the light flux emission side of the toric lens 14 is
The curved surface of the toric lens 14 is pushed, so that the toric lens 14 causes a slip at the contact surface with the leaf spring 16 to exert a force to escape upward. Therefore, the Torre Cleanse 14
If the force of pressing the toric lens 14 against the pedestal 8b by the leaf spring 17 is weak when the lens is assembled and fixed in the optical system 15, the toric lens 14 floats above the pedestal 8b and the optical axis is deviated. On the other hand, if the force of the leaf spring 17 is too strong, the torque lens 14 will be deformed. Also, the Torre Cleanse 14
The contact portion of the plate spring 16 with the leaf spring 16 may be cracked.

As described above, in order to accurately support and fix the torque lens 14, it is necessary to pay close attention to the adjustment of the force of each supporting member. It was very difficult to manage. In addition, the conventional lens supporting and fixing method is not limited to the above method, and the outer periphery of the lens is used to fit the lens into the fitting portion and screw it with a pressing metal fitting, or the lens is abutted to a butting surface for positioning. Etc., or by providing a flat surface on a part of the lens in order to improve the mounting accuracy, there are multiple directions to stop the leaf spring etc. for fixing the lens,
It is not possible to assemble from only one direction when automating the assembly,
The assemblability was poor and the productivity was reduced.

(3) Summary of the Invention An object of the present invention is to provide an optical device capable of performing accurate and easy fixed support when a lens is assembled in view of the above-mentioned conventional problems.

In order to achieve the above object, the optical device according to the present invention,
In the optical device having a lens used in an optical system of LBP that can be molded by a mold, and a container that houses the lens, a flat surface on the bottom surface that serves as a mounting reference surface of the lens is integrally molded by a mold, and A plurality of pins for positioning the lens in a direction orthogonal to the optical axis, an elongated hole for fitting the pin in the container is provided, and when the lens is assembled in the container, the elongated hole is fitted in the pin. By so doing, the mounting position accuracy of the lens with respect to the container is ensured, and an elastic member that presses the lens against the container is provided to prevent the lens from rising.

Further objects and features of the present invention will be clarified by the following embodiments.

(4) Example FIG. 1 and FIG. 2 show an example of the optical element according to the present invention. FIG. 1 is a perspective view and FIG. 2 shows the state in which the optical element is supported and fixed on the optical axis. FIG. 6 is a cross-sectional view represented in a plane perpendicular to. In the figure, 1 is a toric lens molded by glass or resin, and 2a and 2b are pins provided on a flat surface on the bottom side which is a mounting reference surface of the toric lens 1. The pins are integrally molded by the mold and the toric lens 1 is formed.
Are positioned in a direction orthogonal to the optical axis. Also, 3 is a container for accommodating optical elements such as various lenses including the toric lens 1, a light source, a mirror, 4a and 4b are elongated holes for fitting pins 2a and 2b of the toric lens 1, 5a and 5b, respectively. Is a leaf spring for pressing the torque lens 1 so that it does not float up, and one end of each is fixed to the container 3.

Therefore, as shown in FIG. 1, when the pins 2a and 2b whose optical dimensional position accuracy is guaranteed are integrally formed on the mounting reference surface (bottom surface) side of the torque lens 1 by molding, and are assembled in the container 3, This pin 2 is placed in the long holes 4a and 4b that were previously made in the container 3.
By fitting and supporting and fixing a and 2b, the accuracy of the mounting position of the torque lens 1 with respect to the container 3 is guaranteed.
Therefore, it is possible to provide a lens suitable for mass production, which has a small number of constituent parts, can be easily supported and fixed with high accuracy.

FIG. 3 shows a modified example of the optical element according to the present invention, 6 is a resin-molded toric lens, and 7 is a pin having slits. Slotted pins 7 having a diameter slightly larger than the diameters of the long holes 4a, 4b shown in FIG. 2 are formed integrally with the lens, or they are formed after the lens is formed and the long holes 4a, 4b are formed.
By fitting into b, the pin 7 and the long holes 4a and 4b have almost no rattling, and positioning can be performed with higher accuracy. Furthermore, it is clear that the same effect can be obtained by slotting the cross shape.

Also, for ordinary pins 2a, 2b as shown in FIG. 1, elongated holes 4a,
A small leaf spring is formed on the inner side surface of 4b, or the fitting portion is formed of an elastic body, and when the pins 2a and 2b are inserted, the pins 2a and 2b are fixed by the pressure or elastic force of the leaf spring. Such a method is also effective. Further, although the pin shape shown in this embodiment is a cylinder, it may of course be a cone, a quadrangular prism or the like, and any shape may be used as long as a sufficient fitting can be achieved by combining with the elongated hole.

As described above, the present invention has been described by taking a torque lens used in an optical system such as LBP as an example, but the present invention is not limited to this torque lens and can be applied to any shape and an optical element for a purpose, and highly accurate positioning is possible. It is possible to provide an optical element that can be supported and fixed. It should be noted that if molding is possible, a lens that is extremely effective in terms of productivity is preferable. For example, it is very convenient if molding can be performed when forming not only two pins but three or more pins as described above.

Further, in the above embodiment, the pins or the like are formed on the predetermined surface of the torque lens, but the non-lens member integrally formed with the outer peripheral portion of the lens by molding may be provided with the positioning means such as the pins. Further, it goes without saying that the present invention can be applied not only to lenses but also to other optical elements such as prisms.

Further, structurally, the most preferable optical element for the present invention is an element having a predetermined flat surface like the Toric lens of the above-mentioned embodiment, and providing a positioning means such as a pin on the flat surface also relates to molding. In fact, it is most effective in terms of easiness and accuracy when assembled in an optical device. Further, the positioning means is preferably a small and simple structure such as a pin, but may be any size and shape as long as it does not affect the optical performance and the mounting accuracy.

Furthermore, if an elastic body such as rubber is attached to a predetermined portion that comes into contact with the optical element or when the optical element is assembled, or if a fixing member or a supporting member is formed by the elastic body, it is possible to prevent the optical element from being damaged. Not only that, the adhesion can be improved and stable support and fixation can be achieved.

(5) Effects of the Invention As described above, in the optical device according to the present invention, the flat surface on the bottom surface side that is the mounting reference surface of the lens used in the optical system of the LBP that can be molded by molding is integrally molded by the mold, and A plurality of pins for positioning the lens in a direction orthogonal to the optical axis, a container for housing the lens is provided with an elongated hole for fitting the pin, and when the lens is assembled into the container, the elongated hole is fitted for the pin. This ensures the accuracy of the mounting position of the lens with respect to the container, and by providing an elastic member that presses the lens against the container to prevent the lens from rising, it is possible to improve the mounting position accuracy of the lens with respect to the container. It is very effective for automatic assembly because it can be easily installed.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an optical element according to the present invention. FIG. 2 is a sectional view showing a state in which the optical element of FIG. 1 is fixed to a container. FIG. 3 is a diagram showing a modification of the optical element according to the present invention. FIG. 4 is a schematic configuration diagram of a laser beam printer. FIG. 5 is a view showing a torque lens mounted in a laser beam printer by a conventional method. 1,6 …… Toric lens 2a, 2b …… Positioning pin 3 …… Container for optical system 4a, 4b …… Slot 5a, 5b …… Leaf spring 7 …… Slotted positioning pin

Continuation of the front page (56) Reference JP 60-64316 (JP, A) JP 61-22284 (JP, A) JP 54-116945 (JP, A) JP 53-118141 (JP , A) JP 59-140406 (JP, A) JP 58-153907 (JP, A) Actual development 60-143418 (JP, U) Actual development 59-164014 (JP, U) Actual development 60-74111 (JP, U)

Claims (1)

(57) [Claims] 1. An optical device having a lens used in an optical system of an LBP that can be molded by a mold and a container for accommodating the lens, wherein a flat surface on a bottom surface serving as a mounting reference surface of the lens is integrally molded by a mold. A plurality of pins that are molded and that position the lens in a direction orthogonal to the optical axis, an elongated hole that is fitted to the pin is provided in the container, and when the lens is assembled in the container, By fitting the elongated hole, the mounting position accuracy of the lens with respect to the container is ensured, and an elastic member that presses the lens against the container is provided to prevent the lens from rising. Optical device.