# US 12,601,946 B1 · Apparatus, system and method for controlling temperature of backlight unit of display system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,601,946 B1 - Document ID: US12601946B1 - Status: Granted - Kind: B1 - Application number: 19/097,939 - Filed: 2025-04-02 - Granted: 2026-04-14 - Earliest claimed: 2025-04-02 - Assignees: Distance Technologies Oy - Applicants: Distance Technologies Oy - Inventors: Ville Vehkaperä; Petri Savolainen; Mikko Juhola - Web page: https://patentgrep.com/patent/US12601946B1 ## CPC - G02F 1/133628: {with cooling means} - G02B 27/0149: {characterised by mechanical features (G02B27/0176 takes precedence)} - H05K 7/20263: {Heat dissipaters releasing heat from coolant} - G02F 1/133603: {with LEDs} - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS ## Abstract An apparatus for controlling temperature of backlight unit of display system includes: hollow heat transfer element arranged between optical element(s) of backlight unit and printed circuit board of backlight unit when apparatus is in use, wherein a first heat transfer fluid circulates within hollow space of hollow heat transfer element when apparatus is in use, to thermally couple hollow heat transfer element with at least one of: light-emitting elements arranged on printed circuit board, printed circuit board; and heat exchanger thermally coupled to hollow heat transfer element when apparatus is in use, wherein heat exchanger controls temperature of backlight unit to lie within a predefined operating temperature range, by exchange of thermal energy between heat exchanger and hollow heat transfer element via first heat transfer fluid. ## Claims ### Claim 1 An apparatus for controlling temperature of a backlight unit of a display system, wherein the apparatus comprises: a hollow heat transfer element arranged between one or more optical elements of the backlight unit and a printed circuit board of the backlight unit when the apparatus is in use, wherein a first heat transfer fluid circulates within a hollow space of the hollow heat transfer element when the apparatus is in use, to thermally couple the hollow heat transfer element with at least one of: light-emitting elements arranged on the printed circuit board, the printed circuit board; and a heat exchanger thermally coupled to the hollow heat transfer element when the apparatus is in use, wherein the heat exchanger controls the temperature of the backlight unit to lie within a predefined operating temperature range, by exchange of thermal energy between the heat exchanger and the hollow heat transfer element via the first heat transfer fluid; wherein the first heat transfer fluid manipulates the light emitted by the light-emitting elements by performing at least one of: reflection, refraction, diffraction, re-distribution, of said light. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the hollow heat transfer element is designed as a grid of interconnected hollow sub-sections, each hollow sub-section being arranged around at least one respective light-emitting element on the printed circuit board, and wherein each hollow sub-section has one or more reflective surfaces facing a light-emitting region of the at least one respective light-emitting element, such that the reflective surfaces direct the light emitted by the at least one respective light-emitting element towards the one or more optical elements. ### Claim 3 (depends on 2) The apparatus of claim 2, wherein the one or more reflective surfaces are implemented as one or more of: a surface made of a reflective material, a surface coated with a reflective coating. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the hollow heat transfer element is made from at least one of: a transparent material, a translucent material. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the first heat transfer fluid is at least one of: a liquid, a gas. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the heat exchanger is arranged on at least one side of the hollow heat transfer element. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the heat exchanger is arranged physically separate from the hollow heat transfer element when the apparatus is in use, the apparatus further comprising a fluidic channel between the heat exchanger and the hollow heat transfer element, and wherein a second heat transfer fluid circulates within the fluidic channel when the apparatus is in use, to thermally couple the hollow heat transfer element with the heat exchanger. ### Claim 8 A system for controlling temperature of a backlight unit of a display system, wherein the system comprises: an apparatus for enabling temperature control, wherein the apparatus is arranged in the backlight unit and comprises: a hollow heat transfer element arranged between one or more optical elements of the backlight unit and a printed circuit board of the backlight unit when the apparatus is in use, wherein a first heat transfer fluid circulates within a hollow space of the hollow heat transfer element when the apparatus is in use, to thermally couple the hollow heat transfer element with at least one of: light-emitting elements arranged on the printed circuit board, the printed circuit board; and a heat exchanger thermally coupled to the hollow heat transfer element when the apparatus is in use, wherein the heat exchanger controls the temperature of the backlight unit to lie within a predefined operating temperature range, by exchange of thermal energy between the heat exchanger and the hollow heat transfer element via the first heat transfer fluid; wherein the first heat transfer fluid manipulates the light emitted by the light-emitting elements by performing at least one of: reflection, refraction, diffraction, re-distribution, of said light; a first temperature sensor operable to measure a first temperature of the backlight unit; and a processor configured to: receive the first temperature from the first temperature sensor; detect when the first temperature lies outside a predefined operating temperature range of the display system; and control the heat exchanger of the apparatus to bring the first temperature within the predefined operating temperature range, by exchange of thermal energy between the heat exchanger and the hollow heat transfer element of the apparatus via the first heat transfer fluid circulating within the hollow space of the hollow heat transfer element when the system is in use, upon said detection. ### Claim 9 (depends on 8) The system according to claim 8, wherein the hollow heat transfer element and the first temperature sensor are arranged within a housing of the backlight unit, said housing also having arranged therein the one or more optical elements of the backlight unit and the printed circuit board of the backlight unit on which light-emitting elements are arranged. ### Claim 10 (depends on 8) The system according to claim 8, wherein the display system is implemented in a device, and wherein the system further comprises a second temperature sensor that is configured to measure a second temperature of an external environment of the device, and wherein the processor is further configured to: receive the second temperature from the second temperature sensor; detect when the second temperature lies outside the predefined operating temperature range of the display system; and control the heat exchanger to bring the first temperature within the predefined operating temperature range, by exchange of thermal energy between the heat exchanger and the hollow heat transfer element via the first heat transfer fluid, upon said detection. ### Claim 11 (depends on 10) The system according to claim 10, wherein the device is a vehicle, and wherein the display system is a head-up display system. ### Claim 12 A method for controlling temperature of a backlight unit of a display system, wherein the method comprises: receiving a first temperature of a backlight unit from a first temperature sensor; detecting when the first temperature lies outside a predefined operating temperature range of the display system; and controlling a heat exchanger of an apparatus to bring the first temperature within the predefined operating temperature range, by exchange of thermal energy between the heat exchanger and a hollow heat transfer element of the apparatus via a first heat transfer fluid circulating within a hollow space of the hollow heat transfer element when the system is in use, upon said detection, wherein the hollow heat transfer element is arranged between one or more optical elements of the backlight unit and a printed circuit board of the backlight unit when the apparatus is in use, the first heat transfer fluid circulating within a hollow space of the hollow heat transfer element when the apparatus is in use thermally coupling the hollow heat transfer element with at least one of: light-emitting elements arranged on the printed circuit board, the printed circuit board; and the heat exchanger is thermally coupled to the hollow heat transfer element when the apparatus is in use, wherein the first heat transfer fluid manipulates the light emitted by the light-emitting elements by performing at least one of: reflection, refraction, diffraction, re-distribution, of said light. ### Claim 13 (depends on 12) The method according to claim 12, wherein the hollow heat transfer element and the first temperature sensor are arranged within a housing of the backlight unit, said housing also having arranged therein one or more optical elements of the backlight unit and a printed circuit board of the backlight unit on which light-emitting elements are arranged. ### Claim 14 (depends on 12) The method according to claim 12, wherein the display system is implemented in a device, the method further comprising: receiving a second temperature of an external environment of the device, from a second temperature sensor that is operable to measure the second temperature; detecting when the second temperature lies outside the predefined operating temperature range of the display system; and controlling the heat exchanger to bring the first temperature of the display system within the predefined operating temperature range, by exchange of thermal energy between the heat exchanger and the hollow heat transfer element via the first heat transfer fluid, upon said detection.