Introducing Rain Sensor
rain sensor

What is Rain Sensor?

This sensor replaces the ETACS (Electronic Time Alarm Control System) that controls the wiper motor drive and is installed inside the top of WINDSHIELD. The sensor is a crucial part that automatically controls wiper operating time and low/high operation speed according to rainfall detection. As a means to increase the efficiency of raindrop detection on the surface of windshields, we installed a light source and a light receiving element on the surface of the windshield. The system is designed to prevent direction penetration of some light of the light source besides the light that discharge outside the windshield, thereby providing a solution to the problem that deteriorate raindrop detection due to interfering light of the light source (sensing noise). We developed a rain sensor that maximizes the rain sensing function with an optical interference structure of light source.


rain sensor

Design Concept

rain sensor

Based on Motor company's spec

  • Consider common use for all the world

    -Safety regulation(EMC, Car maker's request etc.)
    -LIN communication/ use common LIN map

  • Reduce the possible size

    -Convergence development considered
    -Minimize WIRING HARNESS & CONNECTOR showing
    -Not to interfere during MIRROR moving for adjusting.
    -Consider cost savings

  • Function

    -NO malfunction by vibration
    -Matte Black Color Case/ silicon Gel applied.

Core Technology

Core Technology

Arranged the light emitting element and light receiving element in a line at an angle to reduce ambient light influence 
- When the raindrop falls on the windshield, it receives the intensity of radiation reflected from the raindrop in the direction of the light source and detects the volume of raindrops
- In addition to the gloss reflected on the raindrop, the gloss reflected on the windshield prevents the light from being received structurally.

It outputs hundreds of milliseconds of instantaneous current at the modulated (pulse-modulating) frequency of the light emitting element 
- Instantaneous source of light emits light higher than ambient light (sunlight, other IR light) to prevent error by ambient light source.

Detects the point of raindrop by dividing into several areas by installing a multiple number of light source and a light receiving element

Differentiation of core technologies

Detection of raindrop without ambient reflected light effect of windshield 
- Precise decomposition detection of the volume of raindrops
- Prevents unnecessary movement of wiper motor

Minimizes device size by aligning light emitting element and light receiving element in a row

Simple implementation of functions based on simple pulse modulation (price reduction)

rain sensor


Morning Dew
Morning Dew


Morning Dew



Open Imagination


빗방울 감지센서
Open Imagination


빗방울 감지영역을 넓힌 격자배열 방식 빗방울 감지 센서
Open Imagination

US8,471,513 B22013.06.25

Open Imagination


Open Imagination



기존 기술 및 제품

Demand for special sensors for cars is growing rapidly with high-end automobile specifications
Prior to 2006, the rain sensor was applied only to vehicles of 2,000CC or higher. Since then, the application has expanded to 1,500CC mid-range vehicles. If the price decreases, the sensor can be applied to more models and the market will be expanded.
The rain sensor uses infrared technology as it is affected by external light, e.g. weather and sunlight.
Due to patent issues of TRW and BOSCH, market entry is challenging except existing five companies (Other companies use different detection technologies, e.g. IMAGE PROCESSING TYPE)
BOSCH has been withdrawn from the Korean market and HELLA has entered the market due to intensified price competition among global companies.


rain sensor