An electronic shelf label (ESL) system is used by retailers for displaying, typically on the front edge of retail shelving, product pricing on shelves that can automatically be updated or changed under the control of a central server.
ESL tag modules use electronic paper (E-paper) or liquid-crystal display (LCD) to show the current product price to the customer. E-paper is widely used on ESLs as it provides crisp display and supports full graphic imaging while needing only power during updates, but no power to retain an image. A communication network from the central server allows the price display to be automatically updated whenever a product price is changed, in contrast to static placards. Wireless communication must support application range, speed, battery life, and reliability. The means of wireless communication can be based on radio, infrared or even visible light communication. Currently, the ESL market leans heavily towards radio frequency communication.
History
Early product
An early System first offered for sale by NCR in 1997 used Modulated Backscatter of radio waves to provide two way wireless communications between the labels and the store’s radio network. By using modulated backscatter, the labels confirmed receipt of price changes (along with battery and display status) without the need for an active radio transmitter, thus saving cost and increasing battery life to over 5 years.
First generation: LCD and infrared communication
7-segment LCD ESL tags use a display similar to how a calculator displays the numerical values. The numerical value to display on the tags itself are then shown based on activating different combinations of these seven bars and segments. A disadvantage of using a liquid crystal displayated tag is the difficulties in displaying certain letters. The communication technology used for the transmitter to connect to the label is through diffused infrared communication. The values on the LCD tags are established by infrared bouncing off of surfaces. However, the speed of transmission is heavily compromised due to the data compression of each data packets from the transmitter. Another disadvantage is that LCDs need power to retain an image.
Second generation: e-paper and infrared or radio communication
Electronic paper (E-paper, electronic ink, or e-ink) describes a technology that mimics the appearance of ordinary ink on paper. An e-paper display is made up of multiple capsules in a thin film with Electrodes placed above and below the capsule film and when a charge is applied to an individual electrode, the color particle moves to either the top or bottom of the capsule, allowing the ESL to display a certain intensities of color within the capsule. E-paper generally uses an infrared or radio communication network to communicate from the central server transmitter to the tags. Typically, low frequency radio solutions are used for tags, but with the draw backs of low data rate that makes it difficult to show complex segmented images.Building information modeling
Third generation: geo-location and product finder
The current generation of ESL units utilize e-paper display technology along with wireless radio communications, are integrated with existing retail technologies such as electronic article surveillance, digital signage, and people counters. Therefore, retailers are able to upload a floor plan of the sales area into the label-management software. Once this has been done and all the hardware and other software pieces are in place, consumers can be automatically tracked (in real time) through the network of people-counting devices, or via their personal Bluetooth devices, in order to determine their positioning within the store at all times; allowing the individual customer to be subjected to targeted, customized marketing initiatives: discounts, individual pricing, etc.
General principles
A typical ESL utilizes ultra-low-power CPU and wireless communication solutions to meet low power of low cost constraints in order to displace the high number of static shelf labels required in an average retail store.
ESL consists of three components: