JP2006145924A - Optical module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To downsize a module as a whole by devising a structure for holding a lens in a module case. <P>SOLUTION: The optical module includes: the case 10 which houses a light source or photodetection portion and; a circularly sectioned lens unit 20 which is held in the case 10 and emits light from the light source to the outside or guides external light to the photodetection portion. A lens-holding-side surface 11a of the case 10 is rectangular, lens holding columns 12a to 12d are projected on the surface 11a where they do not overlap the lens unit 10 when viewed along a lens optical axis, and the lens unit 20 is held inside those lens holding columns 12a to 12d. A projection lens 20 and lens holding columns 12a to 12c are thread-cut and the projection lens 20 is screwed and held inside the lens holding columns. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical module mounted on a portable electronic device or the like, which is designed to reduce the size by devising a lens holding structure.

  Patent Document 1 discloses a small projector module incorporated in a mobile phone. The projector module irradiates light from a light source toward an image generation unit such as a liquid crystal panel, and projects the transmitted light to the outside by a projection lens. When the projector unit is assembled in advance, the light source and the image generation unit are accommodated in the casing, and the projection lens is held in the casing.

Patent Document 2 discloses a camera module mounted on a mobile phone. The camera module causes the image sensor to receive the light beam transmitted through the photographic lens, and processes the photoelectric conversion output to generate and record image data. In the case of grouping, the image sensor is housed in a housing, and the photographing lens is held in the housing.
Patent Document 3 discloses a lens holding structure.

Japanese Patent Laid-Open No. 2001-21992 JP 2004-179736 A JP 63-45562 A

  The projector module and the camera module described above are required to be miniaturized due to the nature of being incorporated into a portable device. Since the light source, the image generation unit, the image sensor, and the like are relatively easy to downsize, the housing that accommodates them can be downsized to a minimum. Since the image generation unit and the image sensor are rectangular, the surface on the lens holding side of the housing is necessarily rectangular. On the other hand, since the lens has a circular cross section, the holding portion for holding the lens has a cylindrical shape, and the cylindrical lens holding portion is integrally molded or attached to the rectangular casing surface. FIG. 9 shows an example thereof, in which 101 is a housing, 102 is a lens, and 103 is a lens holding portion. The surface of the housing 101 on the lens holding side is an A × A rectangle (square), and the lens 102 having a diameter A is held here. The outer diameter B of the lens holding portion 103 is necessarily the thickness thereof. Therefore, the lens holding portion 103 protrudes from the housing 101 by the thickness, which hinders downsizing of the entire module.

An optical module according to the present invention includes a housing that houses a light source or a light receiving unit, and a lens unit that is held in the housing and that irradiates light from the light source to the outside or guides external light to the light receiving unit. Prepare. The lens holding side surface of the housing is rectangular, and lens holding columns protrude from the surface at least two locations that do not overlap the lens unit when viewed in the lens optical axis direction. The unit is held.
In the invention of claim 2, the lens holding side surface of the housing is a square whose side is substantially the same size as the diameter of the lens, and the lens holding column protrudes from at least two diagonal portions of this surface. Yes.
In the invention of claim 3, the lens holding column protrudes from the four corners of the surface on the lens holding side.
In the invention of claim 4, a male screw is engraved on the peripheral surface of the lens unit, and a female screw for engraving the male screw to hold the lens unit is engraved on the lens holding column.
According to the invention of claim 5, the lens unit is composed of a single transparent lens, and the male screw is directly engraved on the peripheral surface of the lens.
According to a sixth aspect of the present invention, at least one lens holding column is formed with a stopper that abuts against the abutting portion of the lens unit and restricts movement of the lens unit in the optical axis direction.
According to the seventh aspect of the present invention, the lens unit can advance and retreat in the optical axis direction with respect to the casing within a range where the stopper and the contact portion do not contact.
In the invention of claim 8, the lens holding column on which the stopper is formed is shaped to be more easily elastically deformed than the other lens holding columns.
The invention of claim 9 is applied to a projector module.
The invention of claim 10 is applied to a camera module.
Here, the “lens unit” referred to in the claims is a concept including a unit formed by supporting a single lens or a plurality of lenses on a lens barrel or a frame in addition to a single lens.

  According to the present invention, the lens holding columns protrude from at least two locations on the lens holding side surface (rectangle) of the housing that do not overlap the lens unit, and the lens units are held by these lens holding columns. Therefore, the lens holding column can hold the lens without protruding outward from the surface on the lens holding side, so that the entire module can be reduced in size.

A first embodiment when the present invention is applied to a liquid crystal projector module will be described with reference to FIGS.
As shown in FIGS. 1 to 3, the liquid crystal projector module includes a high-intensity white LED 31 as a light source, a color filter type QVGA (Quarter Video Graphics Array) size (320 × 240 dots) liquid crystal panel 32, and these LEDs 31. , A housing 10 that houses the liquid crystal panel 32 and a projection lens 20 that is held by the housing 10.

  This projector module is incorporated in a portable device such as a mobile phone, and the liquid crystal panel 32 can display, for example, an image captured by a camera module (not shown) or an image captured from outside. The liquid crystal drive signal is input to the panel 32 from the control circuit of the portable device body via the flexible printed board 33. When the LED 31 is turned on in synchronization with the image display, the LED light is transmitted through the liquid crystal panel 32 and then enlarged and projected onto a screen or the like prepared outside via the projection lens 20. Therefore, for example, it is very convenient when a plurality of people want to view an image.

Next, the case 10, the projection lens 20, and the holding structure thereof will be described in detail.
The projection lens 20 is made of a single cylindrical transparent member (for example, made of glass) and has an outer diameter of 10 mm. A male screw is directly engraved on the outer peripheral surface of the projection lens 20, and a groove 22 is formed on the entire tip of the threaded portion 21. On the other hand, the housing 10 is made of, for example, resin, and is formed by integrally molding a substantially rectangular parallelepiped housing portion 11 that houses the LED 31, the liquid crystal panel 32, and the like, and the four lens holding columns 12a to 12d. An end surface (hereinafter referred to as a lens holding surface) 11a on the lens holding side of the accommodating portion 11 is a square having a side of 10 mm, which is the same as the lens diameter, and guides the transmitted light of the liquid crystal panel 32 to the projection lens 20 at the center thereof. The circular opening 11b is formed.

  As shown in the front view of FIG. 1, the projection lens 20 is held such that its optical axis coincides with the center of the housing 10, whereby the LED 31, the liquid crystal panel 32, the opening 11 b and the projection lens 20 are arranged coaxially. . According to this arrangement, when the housing 10 is viewed from the front of the lens, the portions of the lens holding surface 11a that do not overlap with the projection lens 20 are four corners, and these corners are extended forward as they are. Thus, the lens holding columns 12a to 12d are formed. The inner surfaces (surfaces facing the optical axis) of the lens holding columns 12a to 12d are all arc surfaces having the same curvature as the peripheral surface of the projection lens 20, and are positioned so that the four arc surfaces constitute the circumference of the same circle. is doing. Internal threads are formed on the arc surfaces of the three lens holding columns 12a to 12c, and the threaded portion 21 of the projection lens 20 can be screwed into these internal threads. Unlike the others, only the lens holding column 12d is thinned by dropping a corner, and a projection 13 (FIG. 3) that functions as a stopper is formed on the arc surface instead of a screw. The reason for thinning the lens holding column 12d is to facilitate elastic deformation.

  The projection lens 20 is held by screwing the screw portion 21 into the three lens holding columns 12a to 12c from the front. At the beginning of screwing, the projection 13 is floated by elastically deforming the lens holding column 12d outward, and the deformation is released when the groove 22 comes to the position of the projection 13. Thereby, the protrusion 13 enters the groove 22 (see FIG. 4), and the lens holding is completed. According to this holding structure, when viewed from the front of the optical axis, none of the four lens holding columns 12a to 12d protrudes outside the lens holding surface 11a, and the projection lens itself is within the lens holding surface 11a. Since it fits in the limit, even if the conditions are the same as those in the example of FIG.

  By the way, the engagement of the projection 13 and the groove 22 prevents the projection lens 20 from coming off. However, as can be seen from FIG. 4, the width of the groove 22 is longer than the lens stopper 13 by L. It is possible to move in the optical axis direction within the range of. That is, by rotating the projection lens 20 while holding the front end side, the lens 20 advances and retracts in the direction of the optical axis due to the screw action, and thus focusing can be performed. In the present embodiment, the projection lens 20 is not held over the entire circumference, but the lens peripheral surface is exposed at the portion between the lens holding columns, so that this portion is exposed to the outside. If it is built into a portable device, it can be rotated by touching the lens surface.

  Other embodiments will be described below. The shape and size of the storage portion 11 of the housing 10 and the members to be stored are the same in each embodiment (same as in the first embodiment).

  FIG. 5 shows a second embodiment. In this embodiment, neither the projection lens 20A nor the lens holding columns 14a to 14d are threaded, and the projection lens 20A is placed between the lens holding columns 14a to 14d. Hold by fitting. If there is no need for focusing, there is no problem even with such a fitting method, but there is an advantage that assembly is facilitated. The positions of the lens holding columns 14a to 14d and the inner surfaces thereof are arc surfaces having the same curvature as the projection lens 20A, as in the previous embodiment. Further, any one of the lens holding columns 14a to 14d may have a shape that is easily elastically deformed, and the protrusion for the stopper may be formed here. However, in this example, since it is not necessary to allow the projection lens 20A to move in the optical axis direction, the width of the groove on the lens side may be the same as the protrusion.

  FIG. 6 shows a third embodiment, which is an example in which the projection lens 20 is held by two lens holding columns 15a and 15b. The lens holding columns 15a and 15b are provided at two opposite corners of the lens holding surface 11a, and a screw is formed on each inner surface. Therefore, similarly to the first embodiment, the projection lens 20 can be held by a screwing type. If the projection lens 20 is not subjected to a large force, the projection lens 20 can be held by two lens holding columns. In this case, since the exposed area of the lens peripheral surface is larger than that of the first embodiment, it is easy to perform a focusing operation by touching the peripheral surface.

  FIG. 7 shows a fourth embodiment. In the present embodiment, a projection lens unit UN is used in which the projection lens is not a single transparent lens, but a plurality of lenses 51 a to 51 d are held in a lens barrel 52. The lens barrel 52 has a cylindrical shape with an outer diameter of 10 mm, and an external thread 52a and a groove 52b are formed on the outer peripheral surface in the same manner as the projection lens 20. Therefore, the holding method exactly the same as that of the first embodiment is possible.

  Also in the second to fourth embodiments described above, since the projection lens 20 and its holding columns 12a to 12d do not protrude from the lens holding surface of the housing 10 as in the first embodiment, The size can be minimized.

  Although the projector module has been described above, the present invention can also be applied to a small digital camera module mounted on a portable device or the like. In the case of a digital camera module, as shown in FIG. 8, an image pickup device 51 such as a CCD is housed in the housing portion 11 of the housing 10, and a photographing lens 52 is held in the housing 10. The transmitted light flux of the photographing lens 52 is received by the image sensor 51, and image data is generated from the photoelectric conversion output. In holding the photographic lens 52 in the housing 10, the same holding structure as described above can be used.

  The length of one side of the lens holding surface 11a and the lens diameter are not limited to 10 mm. Further, the side length of the lens holding surface and the lens diameter are not necessarily equal. Even if the lens diameter is somewhat larger, a lens holding column can be provided at the corner of the lens holding surface, and a lens holding structure similar to the above can be realized. In this case, a part of the lens slightly protrudes from the holding surface, but the lens holding part does not protrude, so that the size of the entire module can be minimized.

  Further, as described in the projector module and the camera module, the light source or the light receiving unit is housed in the housing, and the lens unit that irradiates light from the light source to the outside or guides external light to the light receiving unit is held in the housing. The present invention can also be applied to other optical modules having a structure. In addition, there are no particular restrictions on the equipment and the method of incorporating the optical module. For example, it may be incorporated so that only the front surface of the lens is exposed, or may be incorporated such that the housing part is exposed to some extent. In either case, the advantage of miniaturizing the module is great.

FIG. 2 is a front view, a side view, and a rear view of the liquid crystal projector module according to the first embodiment of the present invention. II-II sectional view taken on the line of Fig.1 (a). The disassembled perspective view of a liquid crystal projector module. IV-IV sectional view taken on the line of Fig.1 (a). The disassembled perspective view of the liquid-crystal projector module in 2nd Embodiment. The disassembled perspective view of the liquid-crystal projector module in 3rd Embodiment. The front view and bb sectional view taken on the line of the liquid crystal projector module in 4th Embodiment. Sectional drawing at the time of applying this invention to a digital camera module. The figure explaining the problem at the time of providing a cylindrical lens holding part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Case 11 Accommodating part 11a Lens holding surface 12a-12d, 14a-14d, 15a-15d Lens holding pillar 13 Protrusion 20, 20A Projection lens 21 Screw part 22 Groove 31 LED
32 Liquid crystal panel 33 Flexible printed circuit board 51 Image sensor 52 Shooting lens

Claims (10)

A housing that houses a light source or a light receiving unit;
A lens unit having a circular cross section that is held by the casing and irradiates light from the light source to the outside or guides external light to the light receiving unit;
The surface of the housing on the lens holding side is rectangular, and on this surface, lens holding columns protrude from at least two locations that do not overlap the lens unit when viewed in the lens optical axis direction. The lens unit is held in the optical module.   The surface on the lens holding side of the casing is a square having one side substantially the same size as the diameter of the lens, and the lens holding column protrudes from at least two diagonal portions of the surface. The optical module according to claim 1.   The optical module according to claim 2, wherein the lens holding columns protrude from four corners of the lens holding side surface.   An external thread is engraved on the peripheral surface of the lens unit, and an internal thread for engraving the external thread to hold the lens unit is engraved on the lens holding column. The optical module according to claim 1.   The optical module according to claim 4, wherein the lens unit is formed of a single transparent lens, and the male screw is directly engraved on a peripheral surface of the lens.   6. The stopper according to claim 1, wherein at least one lens holding column is formed with a stopper that abuts against a contact portion of the lens unit and restricts movement of the lens unit in the optical axis direction. The optical module according to any one of the above.   The optical module according to claim 6, wherein the lens unit is configured to be movable back and forth in the optical axis direction with respect to the housing within a range in which the stopper and the contact portion do not contact each other.   The optical module according to claim 6 or 7, wherein the lens holding column on which the stopper is formed has a shape that is more easily elastically deformed than other lens holding columns.   The transmissive image generation unit is provided in the housing, and light from the light source is sequentially transmitted through the image generation unit and the lens unit and projected to the outside. The optical module in any one of -8.   The imaging device as the light receiving device is provided in the housing, and a subject light beam that has passed through the lens unit is configured to be received by the imaging device. Optical module.

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