JPH0711624B2 - Ranging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a distance measuring device for a camera using a triangulation method.

(Prior art) As a range finder used in an autofocus camera, it emits a range-finding beam toward a subject, receives reflected light from the subject with a photoelectric conversion element, and measures up to the subject by a triangulation method. A distancer is used. The conventional distance measuring device based on such a system generally has a narrow distance measuring range on the screen. For example, when two persons are lined up, if the center portion of the finder is placed between the two persons, the distance measuring beam will be two persons. It is illuminated during the period, and the background of the person is in focus, resulting in incorrect distance measurement.

In order to solve such a problem, it is conceivable to measure the distances at a plurality of points on the screen as shown in FIG. 4, for example.
As one example of this, a method of arranging a plurality of light emitting elements in one row along a base length direction connecting a light projecting lens and a light receiving lens and horizontally arranging the light emitting element row and the light receiving element is disclosed in US Pat. No. 4,470,681. It is described in the specification and JP-A-60-140306.

In all of these, a plurality of light emitting elements are sequentially turned on, a subject is scanned in the horizontal direction by a distance measuring beam generated from the light emitting elements, and the position where reflected light from the subject is incident on the light receiving element is calculated to calculate the distance. Thus, it is possible to obtain a distance measuring device wider than the above-mentioned conventional example.

However, in the above-mentioned US Pat. No. 4,470,681, the baseline length varies depending on the light emitting element that is turned on, and therefore the distance cannot be calculated instantaneously. This tendency becomes remarkable as the number of light emitting elements increases. However, when the number of light emitting elements is small, the distance measurement error increases, so that the number of light emitting elements must be increased and it takes time to calculate the distance.

Further, in the above-mentioned Japanese Patent Laid-Open No. 60-140306, since the direction of the distance measuring beam deviates from the optical axis direction of the finder, the distance measuring range cannot be displayed in the finder. That is, the distance measuring range cannot be matched between the distance measuring device and the taking lens.

In order to solve the above-mentioned problems, a plurality of light emitting elements are juxtaposed in a row in a direction orthogonal to the base line length direction, the base line length is unchanged, and the distance measuring beam and the optical axis direction of the finder are made to coincide with each other. A distance measuring device is described in Japanese Patent Application No. 61-67459.

Further, a structure in which a plurality of distance measuring light emitting sources (LEDs) are provided on a single semiconductor substrate to form a PN junction is disclosed, for example, in Japanese Patent Laid-Open No. 61-134085.

However, when a plurality of distance measuring light emitting sources (LEDs) are widely spaced, it is very costly to form a plurality of LEDs on a single semiconductor substrate.

(Problems to be Solved by the Invention) In the above-described distance measuring device, positioning of a plurality of light emitting sources is important as one condition for reducing the distance measuring error and performing accurate distance measuring. That is, it is important to accurately align the positions of a plurality of light emitting elements with respect to the positions of the light receiving elements according to the baseline length of the design value, but this increases cost and causes a problem in productivity. There is.

On the contrary, for example, if LED chips as light emitting sources are individually mounted on a flat lead frame by a bonding machine, mass production efficiency of the light emitting sources is improved, but the positioning accuracy for positioning the LED chips by the bonding machine is
It has a problem that directly affects the accuracy of distance measurement.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a distance measuring device that can obtain high distance measuring accuracy with a simple configuration.

[Structure of Invention]

(Means for Solving the Problem) A distance measuring device of the present invention electrically outputs a plurality of light emitting sources and a light emitting source according to a change in a light receiving position along the base line length direction with a base line length separated from the light emitting sources. A light receiving element is provided to irradiate a plurality of points from each of the light emitting sources, and when a subject is present at the illuminated position, light is reflected by the subject and is received by the light receiving element to measure a plurality of points. In the distance measuring device for distance measurement, the light emitting source is formed by attaching a segment as a semiconductor to each of a plurality of step portions formed on one lead frame.

(Operation) According to the present invention, a plurality of step portions are formed on the lead frame, and semiconductor pieces are attached to the step portions to form a plurality of light emitting sources. Then, when the semiconductor element emits light, it is reflected by the entire step portion, and when viewed from the outside, it looks like the entire step portion emits light, and each step element serves as a light emission source. Even if occurs, the light emitting position as each light emitting source does not change. On the other hand, when distance measurement is performed at a plurality of points using a plurality of light emitting sources, the positioning accuracy of mounting the light emitting sources has a great influence on the distance measurement result as it is. Get the accuracy of ranging.

Embodiment An embodiment of the distance measuring device according to the present invention will be described below with reference to the drawings.

First, referring to FIG. 2, the basic configuration of the distance measuring device using the triangulation means will be described. In Fig. 2, the width (x-axis) is 36m.
m, vertical (z axis) has a shooting surface of 24mm, so-called 35mm
The camera is shown in the vertical (z
A light projecting lens 12 and a light receiving lens 13 are arranged while maintaining a baseline length 1 in the (axis) direction. Reference numerals 14, 15 and 16 denote light emitting sources, and these light emitting sources 14, 15 and 16 are arranged in parallel along the x-axis direction facing the light projecting lens 12 and orthogonal to the direction of the base line length l. Has been done.

On the other hand, 18 is a light receiving device, and this light receiving device 18 uses a one-dimensional semiconductor position detecting element as a light receiving element.
It is arranged to face 13 and the longitudinal direction thereof is the longitudinal (z-axis) direction along the base line length l. In addition, this light receiving device 18
Are illuminated by multiple light sources 14, 15, 16
The reflected light reflected by 19 is received in the lateral direction in the figure. The light receiving position on the light receiving device 18 is displaced in the vertical (z-axis) direction according to the distance to the subject 19.

Further, FIG. 3 shows a plurality of light emitting sources 14, 15 and 16 and a light projecting lens 12.
The relationship between the light emitting sources 14, 15 and 16 is shown in an enlarged manner, and each of the light emitting sources 14, 15 and 16 has a constant width W and is arranged in a line at the center interval X. In this case, each light source 14,15,16 uses an LED that emits infrared light from the PN junction as a semiconductor element,
The width dimension of the LED chip is the width W of the light emitting sources 14, 15 and 16. As shown in FIG. 1, when the lead frame 21 is formed with a step portion 21a below the surface of the lead frame 21 by pressing or punching, and LED chips are bonded inside the step portion 21a, the light emitting sources 14, 15 The width W of 16 is the opening width of the stepped portion 21a larger than the width w of the LED chip.

With the above configuration, the light emitting sources 14, 15, 16 positioned at the step portion 21a of the lead frame 21 can be obtained.

Further, it is particularly effective if the depth of the step portion 21a is equal to or larger than the thickness of one semiconductor portion (for example, a P-type semiconductor portion). That is, since the LED chips which are the light sources 14, 15, 16 are immersed in the step portion 21a, the emitted light rays are effectively reflected by the side walls of the step portion 21a, etc., and almost all of the light source 14, 15, 16 are subject. This is because it can project in 19 directions.

Although the above embodiment has been described with respect to the 35 mm camera, the invention can be applied to a video camera and others.

〔The invention's effect〕

According to the distance measuring device of the present invention, since the lead frame is formed in the stepped portion and the semiconductor element is attached to the stepped portion, the positioning can be accurately performed, so that a high distance measuring accuracy can be obtained with a simple structure. Therefore, it is possible to improve the distance measurement system in the case of performing distance measurement at a plurality of points using a plurality of light emission sources.

[Brief description of drawings]

FIG. 1 is a sectional view showing a structural example of a light emitting source in an embodiment of a distance measuring device for a camera according to the present invention, FIG. 2 is a perspective view showing a structural example of a distance measuring device to which the present invention is applied, and FIG. FIG. 4 is an enlarged view showing the relationship between the light emitting source and the light projecting lens, and FIG. 4 is a view for explaining the state of irradiation of the distance measuring beam onto the subject. 14,15,16 ... Emitting light source, 18 ... Light receiving device having light receiving element, 19 ... Subject, 21 ... Lead frame, 21a ... Step portion.

Claims (1)

[Claims] 1. A plurality of light emitting sources, and a light receiving element for electrically outputting in response to a change in a light receiving position along the base line length direction with respect to the light emitting sources, with a plurality of light emitting elements provided from the light emitting sources. In a range finder that irradiates a point and a subject is present at this irradiated position, in the distance measuring device that reflects light at the subject and receives the light by the light receiving element to measure a plurality of points, A distance measuring device characterized in that a plurality of step portions formed on one lead frame are each formed by attaching an element as a semiconductor.