Kaga Street lighting Photo Controls

Since its establishment in 1946, the KAGA group has aggressively developed products in the fields of telecommunications, precision electronic parts, photoelectric controls, lighting and network systems with unique ideas and our own technologies to meet rapidly changing social demands. With society rapidly expanding, becoming more complex and increasingly globalised, we are constantly gathering and organising information from all over the world and have been contributing through creating world-class innovative and advanced products utilising improving technology with the motto "The Customer Comes First".

Kaga regards this contribution as its most important corporate mission and continues making efforts to be a trusted company and an innovative leader of the industry.

Kaga currently employs 160 employees and has offices and factories in Japan (5), China and the USA.

Kaga has the following certifications ISO9001, ISO1400, ISO9001, ISO14001

History of Kaga Photo Controls

With its long history, Kaga Photo Controls has earnt the trust of our customers and are now used in local governments and electric power companies all over Japan. Kaga Photo Controls are used regularly in various countries in the world, including Southeast Asia, Middle East and Oceania and are known as a world-leading brand.

1953 - The birth of Kaga Photo Controls

In 1953 the Japanese Ministry of Communications issued a request for the development of photo controls so that phone box lights could be turned on automatically when it became dark at night and similarly be turned off in the morning. In response to the request, our technicians devised a trial product using ether. The liquid ether caught the sunlight and its vaporization by the resultant heat was changed into kinetic energy to open and close the contact.?With to this principle, it was necessary to level the installation position and all our photo controls were equipped with levels. There was a lot of effort in developing this early product and examples of it are still retained today in the Kaga factory museum.

Kaga Street Lighting Photo ControlsKaga Street Lighting Photo Controls

1960 Development of photo controls utilising an optical sensor known as the photoconductive cell (CdS ) and a bimetallic switch

CdS is a sensor whose resistance value changes linearly according to brightness. When it is dark, resistance value becomes higher and the resistance level lowers when it is bright. Since the resistance value of CdS is low in the bright daytime, an electric current flows in the heater connected to it, the bimetal curves because of the heat from the heater, and the contact opens by pushing the spring with the contact. When it becomes dark, the resistance value of CdS becomes higher and the electric current of the heater does not flow. Then the curve of the bimetal is restored when the heater stops emitting heat and accordingly the spring with the contact comes back and the contact closes.

In order to operate it with the required brightness, it was necessary to delicately control the characteristic of CdS and the mechanical characteristics of opening/shutting the mechanical section using the bimetal. This basic principle has been used for current photo controls. The photo controls began to spread with the advent of this principle. The street lights at that time had a switch with a string and it is said that people living nearby pulled a string to turn on a street light when it grew dark in the evening. With the spread of photo controls such manual efforts disappeared.

Kaga Street Lighting Photo ControlsKaga Street Lighting Photo Controls

1970 JIS (Japanese Industrial Standards) approved the Kaga factory for photoelectric control production


1978 - Development for electronic photo controls utilising semiconductors

By utilising semiconductors, mechanical motion disappeared and greater life extension was realised. In addition, small Bimetal photo controls that were built in and used for street lights were developed and they were incorporated in our street lights. With this implementation, the installation work and wiring is simplified and now it is one of main features of our street lights.

Kaga Street Lighting Photo ControlsKaga Street Lighting Photo Controls

1986 Development for JIS type 2 (Inverse ratio of Illuminance) electronic photo controls

The issue with photo controls at that time was that turn-off illuminance was higher than turn-on illuminance (e.g., turn-on illuminance 30 luxes, turn-off 120 luxes). Therefore, there was a problem that lights were turned on in the evening but they weren't turned off even if it became bright in the morning.?To fix this, the JIS type 2 has turn-off illuminance lower than turn-on illuminance (e.g., turn-on illuminance 100 luxes, turn-off illuminance 50 luxes) and lights can be turned on early in the evening and turned off early in the morning. This leads to prevention of traffic accidents by lighting up early in the evening when there is relatively greater traffic. It also enables energy saving development of the product by turning off early in the morning when there is relatively little traffic. This helps significantly with the assimilation of time difference of 'dark adaption' (blackness is seen right after when going from well-lit area to a dark place and gradually the shape of things became clear) and 'light adaption' (you are dazzled for a moment when going out from dark place to well-lit area but adapt quickly) that human eyes have.


1987 Development for photo controls embedded in vending machines

As the installation environment for vending machines and the demand for brightness of light also varies, a function that changed the operating illuminance (turn on/turn off) within a certain range was incorporated. Many ideas were implemented in experiments/studies for the structure which changed operating illuminance, while there was restriction of the budget.

Kaga Street Lighting Photo ControlsKaga Street Lighting Photo Controls

1994 Development for photo controls with automatic seasonal correcting timer for energy saving

Kaga Street Lighting Photo Controls

The photo control with a timer at that time was the one that automatically turned off the light after lighting for a specific period of time. Therefore, since the sunset time varied widely according to the season (the time difference is more than two hours between winter and summer), the lights-out time differed accordingly. Because we act based on time, an automatic seasonal correcting timer was developed for the purpose of solving this inconvenience. The characteristic of this product does not use any general clock functions. Considering a constant relationship between the daytime length (hours) and night time length (hours) every season, the time of day was calculated by utilising the illuminance sensor of the photo control. In this way, the function to automatically correct the length of time for turning off the light after lighting up was included. This doesn’t mean that the function is completely accurate but it enables the light to be turned off with the time deviation within approx. 20 minutes all year round. It was not necessary to set the time at the installation site and back-up batteries

(for power failure) were not required either. There was an added benefit that the installation could be done the same way as general photo controls.

1995 - Development for photo controls with light checker to detect malfunctions in daytime

The maintenance of street lights was mostly carried out by patrolling at night and it would be a cost saving if it can be done in the daytime.?Our innovation to allow this display of the light operation of the previous night is displayed with the super luminosity LED in the daytime, by focusing phase shifting between electric current and voltage in the photo control.

2004 - Products using non-cadmium sensors as an environmental measure

Products using the non-cadmium sensors were developed as an environmental measure, in response to concerns regarding global warming.

Kaga Street Lighting Photo ControlsKaga Street Lighting Photo Controls

Kaga Street Lighting LogoLearn about the Kaga history of street lighting development

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