JP3885552B2 - Ranging device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a distance measuring device mounted on an autofocus camera or the like, and particularly relates to a housing structure of the module.
[0002]
[Prior art]
First, the principle of an external light triangular distance measuring device mounted and used in an autofocus camera or the like will be described with reference to FIG. That is, as shown in the figure, the distance measuring device includes an imaging optical system including a pair of left and right distance measuring lenses 1L and 1R disposed on the front surface of the camera, and a pair of left and right photosensor arrays 5L that convert the subject image into an electrical signal. , 5R, the quantizing circuits 51L, 51R for converting the output signals of the photosensor arrays 5L, 5R into digital signals, and the logic unit 52 for calculating the distance signal based on the digital signals from the quantizing circuits 51L, 51R on one chip. It consists of a combination with an integrated semiconductor optical sensor chip 5. The subject T is incident on the distance measuring lenses 1L and 1R that are arranged on the left and right sides with a base line length B therebetween, and is imaged on the photosensor arrays 5L and 5R of the semiconductor optical sensor chip 5. Here, the distance d from the lens to the subject T is given by the following equation based on the principle of triangulation.
[0003]
[Formula 1]
d = B · fe / (x1 + x2) = B · fe / x
Here, fe is the distance between the distance measuring lenses 1L and 1R and the photosensor arrays 5L and 5R (equal to the focal length of the distance measuring lenses 1L and 1R), and x1 and x2 are the image point positions on the photosensor arrays 5L and 5R. The distance from the image point position when the subject T is at infinity, x (= x1 + x2) is the relative shift amount (phase amount) of the subject images on the photosensor arrays 5L and 5R.
[0004]
Next, an assembly structure of the distance measuring device modularized for mounting a camera or the like is shown in FIGS. In each figure, 1 is an optical lens unit provided with a pair of left and right distance measuring lenses 1L and 1R, and 2 is a light beam incident on the distance measuring lenses 1L and 1R to the photosensor arrays 5L and 5R of the semiconductor optical sensor chip 5. The diaphragm part (lens barrel) 3 is a sensor stage in which the semiconductor optical sensor chip 5 is incorporated, and these three parts are made of plastic, and are superposed vertically and bonded together to bond together. It is assembled to.
[0005]
Here, distance measuring lenses 1 </ b> L and 1 </ b> R are integrally formed on the optical lens unit 1 side by side. The diaphragm 2 has a pair of left and right light guide gaps 2a for guiding incident light to the photosensor arrays 5L and 5R of the semiconductor optical sensor chip 5 corresponding to the distance measuring lenses 1L and 1R, respectively. In addition, aperture holes 2L and 2R for determining the amount of light to the semiconductor optical sensor chip 5 are formed in each light guide gap 2a. On the other hand, a lead frame 4 is insert-molded on the sensor stage 3, and the semiconductor optical sensor chip 5 mounted and fixed at a fixed position in the stage and the lead are connected by a bonding wire.
[0006]
Further, in the housing internal space of the distance measuring module described above, in order to prevent the pad portion and the bonding wire of the semiconductor optical sensor chip 5 from deteriorating due to temperature / humidity, thermal stress, foreign matter, etc., for example, a transparent silicone gel is used. A transparent filler 6 is filled to seal the semiconductor optical sensor chip 5 and its periphery.
Next, the filling method of the transparent filler 6 will be described with reference to FIG. That is, the above-described assembly is turned upside down as shown in the figure, and in this posture, the open side of the back side of the sensor stage 3 (the thermal expansion of the transparent filler on the back side of the sensor stage also serves as the transparent filler inlet, A syringe filled with a fluid-filled transparent filler is set in the open space so as to absorb heat shrinkage, and the transparent filler 6 is injected through the space between the semiconductor optical sensor chip 5. As a result, the transparent filler 6 flows into the space surrounded by the lens unit 1, the diaphragm unit 2, and the sensor stage 3 to fill this region, and further covers the semiconductor optical sensor chip 5. Thereafter, a heat treatment is performed to cure the transparent filler 6. The filling amount of the transparent filler 6 is managed so as to completely fill the open surface of the sensor stage 3 when the injection is completed.
[0007]
[Problems to be solved by the invention]
By the way, in the device assembly having the conventional structure described above, the following problems occur when the inside of the casing is filled with the transparent filler.
That is, if there is a variation in the injection speed and the injection amount in the filling process, the transparent filler may not be able to be completely filled into the left and right light guide gaps 2a formed in the body of the throttle unit 2. If the heat treatment is performed as it is, the unfilled portion becomes a bubble and remains in the field of view between the lens / photosensor, and as a result, a normal subject image is not formed on the left and right photosensors. Arise.
[0008]
Therefore, the inventors investigated the cause of the unfilled occurrence, and found that the cause is as follows. That is, in the injection process of the transparent filler 6 shown in FIG. 9, there is only one injection hole for the transparent filler, but the filling area in the housing branches into two light guide gaps on the left and right sides in the throttle portion 2. ing. Here, since the lens unit 1 is in contact with the front end of the diaphragm 2, and the light guide gaps 2a are separated by the partition walls 2b (see FIG. 8), the left and right light guide gaps are pocket-shaped. A gap is formed, and an intermediate portion of the gap is narrowed by the throttle holes 2R and 2L.
[0009]
Accordingly, in the filling process of the transparent filler shown in FIG. 9, as long as the transparent filler flows into the area between the lens portion 1 little by little through the aperture holes 2L and 2R, the inside of the gap replaced with the transparent filler The air can escape upward through the throttle hole, but the transparent filler that flows into the upper surface side of the throttle hole closes the narrow throttle holes 2R and 2L even though an unfilled portion remains in this gap region. In such a state, the air in the unfilled portion loses the escape field and is trapped in the region below the throttle hole, and the transparent filler cannot be filled any more, and bubbles are generated in the layer of the transparent filler.
[0010]
In addition, as described above, the amount of the transparent filler that flows in from the injection port of the sensor stage 3 and splits into the left and right light guide gaps 2a of the narrowed portion 2 varies and does not balance right and left. When the liquid level of the transparent filler that has flowed into the light guide gap reaches the height level of the throttle hole earlier than the other light guide gap, the transparent filler is filled on the other side, including the overflow. The concentrated flow into the light guide gap causes the narrow throttle hole to be closed and unfilled to occur.
[0011]
Further, when an unfilled region is generated inside the housing, an amount of transparent filler corresponding to the volume overflows from the injection port of the sensor stage 3 and adheres to the outer wall surface of the plastic housing and the terminal portion of the lead frame 4. The problem of deteriorating the appearance is also derived.
The present invention has been made in view of the above points, and its object is to solve the above-mentioned problems, and without filling the left and right light guide gaps of the diaphragm portion with a transparent filler without degrading the performance as a distance measuring device. An object of the present invention is to provide a distance measuring device having an improved casing structure so that it can be filled evenly into every corner without leaving any part.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, an optical lens unit having a pair of distance measuring lenses arranged on the left and right sides, a pair of left and right light guide gaps corresponding to the lenses individually in the body, and incident light A diaphragm portion in which a diaphragm hole is formed and a sensor stage containing a semiconductor optical sensor chip for measuring the distance from a subject image formed through a distance measuring lens to a subject are overlapped and joined together to form a housing. In the distance measuring device sealing the semiconductor optical sensor chip configured by filling the void inside the body with a transparent filler,
The diaphragm portion communicates between the left and right light guide gaps to form a conductive flow path of the transparent filler in the partition wall (Claim 1). As a specific aspect of the diaphragm portion, Concave grooves are formed in the partition walls that partition the light guide gaps on the opening end side.
[0013]
With the above configuration, when the transparent measuring agent assembly is turned upside down and transparent filler is injected into the gap inside the housing from the injection port of the sensor stage, the following process is followed without generating an unfilled region: The entire interior space of the housing is completely filled. That is, in the process of injecting the transparent filler, the liquid level of the transparent filler is increased between the two gaps due to variations in the amount of the transparent filler that is split into two from the injection port and flows into the right and left light guide gaps of the throttle portion. When a difference occurs, the transparent filler moves from the high level side to the low level side through the conduction channel that communicates between the left and right light guide gaps due to the action of gravity corresponding to the liquid level difference. The liquid level on the left and right is balanced.
[0014]
Accordingly, the transparent filler that has flowed into the light guide gap of the aperture portion rises while maintaining the same liquid level on the left and right. As a result, the filling proceeds smoothly without being closed by the transparent filler flowing in from above, and the light guide gap is filled to every corner without leaving any unfilled transparent filler. . Further, since the liquid level of the transparent filler rises even in the vicinity of the semiconductor optical sensor chip, it is possible to inject all of the specified amount of the transparent filler without overflowing from the injection port of the sensor stage. Furthermore, since the inflow of the transparent filler proceeds smoothly in this way, the injection process time can be shortened.
[0015]
Further, in the present invention, the light incident on the light guide gap through the lens in the conductive channel of the transparent filler described above is prevented from passing through the conductive channel of the transparent filler and entering the other light guide gap. A light-shielding wall is provided (Claim 3), and as a specific aspect thereof, the light-shielding wall is composed of at least two walls protruding alternately from the side toward the conductive flow path of the transparent filler (Claim). 4) Further, an air gap is formed between the light shielding wall and the optical lens portion.
[0016]
With this configuration, some of the light rays that have entered through the lens, particularly those having a large incident angle, refracted through the lens portion and then travel straight through the light guide gap in the aperture portion or are reflected off the wall and reflected first. Although it goes to the conduction | electrical_connection channel mentioned, it is blocked | interrupted by the light-shielding wall provided in the conduction | electrical_connection flow path, and a light beam cannot enter into an adjacent light guide space | gap space | gap area | region, but is reflected or absorbed by the light-shielding wall and disappears. In this respect, if there is no light shielding wall in the conduction channel, a part of the light beam that has entered the light guide gap through the lens passes through the conduction channel and enters the adjacent light guide gap. The distance measurement accuracy may decrease because the subject is prevented from correctly forming an image on the photosensor array of the semiconductor optical sensor chip, but such a stray light phenomenon is not caused by providing a light shielding wall. .
[0017]
Further, in this case, by providing staggered light shielding walls in the conduction flow path, a labyrinth-shaped light guide flow passage is secured between the left and right light guide gaps by sewing between the light shielding walls, Smooth filling of the transparent filler into the housing can be ensured.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the illustrated examples. In addition, the same code | symbol is attached | subjected to the same member corresponding to FIGS. 6-8 in each Example figure, and the detailed description is abbreviate | omitted.
[Example 1]
First, the structure of the Example corresponding to Claim 1, 2 of this invention is shown in FIG. 1, FIG. That is, in this embodiment, the basic assembly structure is the same as the conventional structure described with reference to FIGS. 6 to 8, but between the left and right light guide gaps 2 a formed in the body of the diaphragm 2. A conduction channel 2c is formed so as to communicate. The conduction channel 2 c is a concave groove formed in a partition wall separating the left and right light guide gaps 2 a on the end surface side facing the optical lens unit 1, and the groove depth is guided from the end surface of the diaphragm unit 2. A diaphragm hole 2L. It is determined to reach the same level as the opening position of 2R.
[0019]
With such a configuration, when the optical lens unit 1, the diaphragm unit 2, and the sensor stage 3 are stacked and assembled in an up-and-down manner and assembled, The assembly of the apparatus is turned upside down in the same manner as described above, and a syringe containing the gel-like transparent filler 6 is set in the injection port opened on the back side of the sensor stage 3 in this inverted position, Inject clear filler at the specified rate.
[0020]
In this filling step, the transparent filler that has flowed into the diaphragm 2 and divided into two from here and flowed into the left and right diaphragm holes 2L, 2R flows down the light guide gap 2a and reaches the surface of the lens section 1. Here, the above-described conduction channel 2c is formed in the end surface portion of the diaphragm unit facing the lens unit 1, and the left and right light guide gaps 2a communicate with each other through the conduction channel 2c. . Accordingly, the transparent fillers separately flowing through the left and right restricting holes 2L and 2R and accumulated on the lens unit 1 are electrically connected to each other through the conduction flow path 2c, whereby the progress of injection of the transparent filler is progressed. Accordingly, the liquid level of the transparent filler filled in the left and right light guide gaps rises while maintaining an equilibrium state on the left and right sides, and almost reaches the opening levels of the throttle holes 2L and 2R almost simultaneously.
[0021]
As a result, the unfilled area of the transparent filler does not remain in the light guide gap of the aperture portion 2, and the generation of gaps in the layer due to the unfilled transparent filler, which has been a problem in the past, is prevented. Transparent filler can be reliably filled to every corner of the body. In addition, after the space | gap in the trunk | drum of the aperture | diaphragm | squeezing part 2 is filled up, a transparent filler fills the inside of the sensor stage part 3, covers a bonding wire and the semiconductor optical sensor chip 5, and a predetermined amount of transparent fillers inject | pour. In the finished state, the injection port opened on the back surface of the sensor stage 3 is fully filled.
[0022]
[Example 2]
Next, an embodiment corresponding to claims 3 and 4 of the present invention, which is a further improvement of the first embodiment, will be described with reference to FIGS. In this embodiment, a light shielding wall 2d is additionally provided in the flow path as shown in FIG. The light shielding wall 2d is composed of two walls that are formed so as to protrude alternately from the concave groove side wall of the conduction flow path 2c into the flow path, and is sewn between the light shielding walls 2d to guide the left and right light guides. A labyrinth-like conduction channel 2c is formed between the gaps 2a. The height of the light shielding wall 2d is set to be slightly lower than the depth of the conduction channel 2c, and is set so that the light shielding wall 2d does not contact the lens surface in the assembled state in which the diaphragm portion 2 and the lens portion 1 are combined. ing. Thereby, it does not affect the welding of the lens part 1 and the free part 2.
[0023]
With this configuration, as described in the first embodiment, in the filling process of the transparent filler 6, the unfilled portion is left in the left and right light guide gaps 2 a formed in the body of the throttle portion 2 through the conduction channel 2 c. The light shielding wall 2d plays the role as described below.
That is, in FIGS. 4 (a) and 4 (b), FIG. 4 (a) adopts the conduction channel 2c described in the first embodiment as it is, and FIG. 4 (b) shows the light shielding wall 2d of FIG. Assuming the provided configuration, this represents a traveling optical path of a light beam incident at a large incident angle from the lens unit 1, and a part of the light beam having a large incident angle is refracted through the lens unit 1 and the diaphragm unit 2. The light enters the light guide gap 2a and proceeds straight as it is, or is reflected by the bottom wall in the gap and reaches the conduction flow path 2c.
[0024]
In this case, if the light-shielding wall 2d is not provided in the conduction channel 2c as shown in (a), the light beam passes through the channel 2c and enters the adjacent light guide gap, and this light beam becomes stray light. As described above, the distance measurement accuracy is reduced. On the other hand, if the light shielding wall 2d is provided in the flow path 2c as shown in (b), the light beam that has reached the flow path 2c is blocked by the light shielding wall 10 and cannot enter the adjacent light guide gap. Since the light is reflected or absorbed by the light shielding wall 2d and disappears, no stray light phenomenon is caused.
[0025]
3 (c) and 3 (d) show another embodiment relating to the light shielding wall 2d described above. In FIG. 3 (c), three light shielding walls 2d are provided along the conduction channel 2c. d) In the figure, four light shielding walls 2d are provided alternately.
[0026]
【The invention's effect】
As described above, according to the present invention, an optical lens unit including a pair of distance measuring lenses arranged on the left and right sides, a pair of left and right light guide gaps corresponding to the lenses individually in the body, and an aperture hole for incident light And a sensor stage containing a semiconductor optical sensor chip that measures the distance from the subject image formed through the distance measuring lens to the subject, are joined together in an integrated manner. In a distance measuring device in which a semiconductor optical sensor chip is sealed by filling a transparent filler in the gap, a conductive channel for transparent filler is formed in the partition by communicating between the left and right light guide gaps. In addition, since the light shielding wall is provided in the conduction channel, the following effects can be obtained.
[0027]
(1) When filling the housing of the distance measuring device with the transparent filler, the transparent filler is applied to every corner of the gap without leaving unfilled portions in the left and right light guide gaps formed in the cylinder of the diaphragm. It is possible to completely fill, thereby suppressing the generation of bubbles due to the unfilling of the transparent filler and improving the product yield.
(2) Also, by eliminating the unfilled part of the transparent filler, the specified amount of transparent filler specified in the filling process can be filled into the housing without excess or deficiency, and the transparent filler overflows from the injection port. It is possible to prevent appearance defects such as coming out and adhering to the outer wall of the sensor stage or the lead terminal.
[0028]
(3) Furthermore, since the transparent filler is smoothly filled, the filling speed can be increased and the working time of the transparent filler filling process can be shortened, thereby improving productivity. To do.
(4) In addition, by providing a light shielding wall in the conduction channel, the effect of the conduction channel is ensured in the filling process of the transparent filler, and the lens is transmitted to the diaphragm portion during actual use of the distance measuring device. It is possible to prevent the incident light beam from passing through the conduction channel and entering the adjacent light guide gap, thereby avoiding the stray light phenomenon and the decrease in ranging accuracy due to the stray light phenomenon.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing an assembly structure of a distance measuring apparatus according to Embodiment 1 of the present invention. FIG. 2 is a longitudinal sectional view of an assembled state of the apparatus shown in FIG. (A) is a longitudinal cross-sectional view, (b) is an external perspective view of the diaphragm in FIG. (A), and (c) and (d) are different from FIG. (B), respectively. FIG. 4 is a diagram for explaining the function of the light shielding wall in FIG. 3, wherein (a) and (b) are the cases without the light shielding wall and with the light shielding wall, respectively. FIG. 5 is a diagram showing the principle of an external light triangle type distance measuring device. FIG. 6 is an assembly configuration diagram of a conventional distance measuring device. FIG. (b) is a front view, (c) is a side view [FIG. 7] FIG. 8 is an exploded perspective view of a lens unit, a diaphragm portion, and a sensor stage in FIG. 6. [FIG. 8] A longitudinal sectional view of the distance measuring device shown in FIG. 9 Inside the distance measuring device of FIG. Illustration of a method of filling the bright filler EXPLANATION OF REFERENCE NUMERALS
DESCRIPTION OF SYMBOLS 1 Optical lens part 1L, 1R Distance measuring lens 2 Aperture part 2L, 2R Aperture hole 2a Light guide space | gap 2b Partition 2c Conduction flow path 2d Light-shielding wall 3 Sensor stage 5 Semiconductor optical sensor chip 5L, 5R Photosensor array 6 Transparent filler

Claims (5)

An optical lens unit provided with a pair of distance measuring lenses, a pair of light guide gaps corresponding to the lenses individually in the body, a diaphragm unit formed with a diaphragm hole for incident light, and a subject imaged through the distance measuring lens The sensor stage containing the semiconductor optical sensor chip that measures the distance from the image to the subject is overlapped and bonded together, and the semiconductor optical sensor chip is sealed by filling the gap inside the housing with a transparent filler. In the distance measuring device, a distance between the pair of light guide gaps is formed in the diaphragm portion so that a conductive channel for transparent filler is formed in the partition wall. 2. The distance measuring device according to claim 1, wherein a concave groove is formed in a partition wall separating the light guide gaps on the opening end side of the diaphragm portion facing the lens as the conductive flow path of the transparent filler. Ranging device. 3. The distance measuring device according to claim 1, wherein light that has entered the light guide gap through the lens enters the conduction channel of the transparent filler and enters the other light guide gap after passing through the conduction channel. A distance measuring device provided with a light-shielding wall that prevents the light from moving. 4. The distance measuring device according to claim 3, wherein the light shielding wall includes at least two walls that protrude alternately from the side toward the conductive flow path of the transparent filler. 5. The distance measuring device according to claim 3, wherein a gap is provided between the light shielding wall and the optical lens unit.

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