Optical distance measuring device and manufacturing method therefor

Abstract

The present invention provides an optical distance measuring device and manufacturing method therefor. In the optical distance measuring device of the invention, a second optical path is formed by a transparent resin formed in a region where a light emitting element and a second light receiving part are connected directly to each other. As the temperature increases, the length of the optical path increases while its refractive index decreases, so that the optical path length itself becomes generally constant. Therefore, the length of the second optical path can be kept generally constant independently of temperature. Further, a first light receiving part for a first optical path and a second light receiving part for the second optical path 18 are formed in one identical light receiving element. Therefore, characteristic variations of the first light receiving part and the second light receiving part due to temperature can be reduced. This optical distance measuring device can achieve high distance measuring accuracy even under environments of intense temperature changes.

Description

technical field [0001] The present invention relates to an optical distance measuring device and its manufacturing method. The distance to the distance-measuring object is measured by the two optical paths of the second optical path reaching the light receiving element. Background technique [0002] Conventionally, the so-called TOF (Time Of Flight) method is widely known as a distance measuring method in which the round-trip time of light is measured to calculate the distance to the measurement object. The ranging method is performed as follows: Since it is well known that the speed of light c is 3.0×10 8 m / s, so by measuring the round-trip time t1, the distance L to the object is calculated using the following formula (1). [0003] L=(c·t1) / 2...(1) [0004] The specific signal processing method in the above-mentioned TOF method has the following various proposals: For example, the distance measuring device disclosed in (Japanese) Patent Application Publication No. 6-186...

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Problems solved by technology

However, in the conventional distance measuring devices disclosed in the aforementioned Documents 3 to 5, there is no mention of the thermal expansion of the second optical path.

In addition, since the above-mentioned second optical path is composed of separate optical elements, the distance measuring device becomes large, and it becomes an inappropriate structure when used in electronic equipment.

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